Category Archives: Diet and Heart Disease

Is A Canine Cardiomyopathy Being Created By Crazy Chow?

The eye of the  skeptical cardiologist was caught by an FDA alert issued recently:

FDA Investigating Potential Connection Between Diet and Cases of Canine Heart Disease

According to the alert:

reports of canine dilated cardiomyopathy (DCM) in dogs eating certain pet foods containing peas, lentils, other legume seeds, or potatoes as main ingredients. These reports are unusual because DCM is occurring in breeds not typically genetically prone to the disease.

What Is Dilated Cardiomyopathy?

Dilated cardiomyopathy refers to a disease of the heart muscle characterized by enlargement and global weakness of the main pumping chambers, the ventricles.

The image below is from the echocardiogram of a human with a severe dilated cardiomyopathy.

Humans with DCM experience weakness, shortness of breath and swelling in the legs due to heart failure. Severe cases of DCM are at risk for dying suddenly.

Cardiomyopathy Used To Be A Disease of Large Dogs

According to Lisa Freeman a veterinarian at the Cummings Veterinary Center at Tufts University

Heart disease is common in our companion animals, affecting 10-15% of all dogs and cats, with even higher rates in Cavalier King Charles Spaniels, Doberman Pinschers, and Boxer dogs.

Dilated Cardiomypathy in dogs

typically occurs in large- and giant-breeds, such as Doberman pinschers, Boxers, Irish Wolfhounds, and Great Danes, where it is thought to have a genetic component.

The FDA alert indicates that DCM

 is less common in small and medium breed dogs, except American and English Cocker Spaniels. However, the cases that have been reported to the FDA have included Golden and Labrador Retrievers, Whippets, a Shih Tzu, a Bulldog and Miniature Schnauzers, as well as mixed breeds

Is Doggy Dilated Disease Due To Demented Diets?

Writing last year, Dr. Freeman noted that

“In the last few years I’ve seen more cases of nutritional deficiencies due to people feeding unconventional diets, such as unbalanced home-prepared diets, raw diets, vegetarian diets, and boutique commercial pet foods.  The pet food industry is a competitive one, with more and more companies joining the market every year.  Marketing is a powerful tool for selling pet foods and has initiated and expanded fads, that are unsupported by nutritional science, including grain-free and exotic ingredient diets.  All this makes it difficult for pet owners to know what is truly the best food for their pet (as opposed to the one with the loudest or most attractive marketing).  Because of the thousands of diet choices, the creative and persuasive advertising, and the vocal opinions on the internet, pet owners aren’t able to know if the diets they’re feeding have nutritional deficiencies or toxicities – or could potentially even cause heart disease.

Purina has a whole line of grain-free wet and dry dog food under their Beyond label

Apparently, it has become trendy in the pet world (just like the human world) to vilify grains as in this article highlighting potential signs of doggy grain allergy at the dogbaker.com.

Freeman notes that grains are not felt to significantly contribute to pet diseases:

Many pet owners have, unfortunately, also bought into the grain-free myth.  The fact is that food allergies are very uncommon, so there’s no benefit of feeding pet foods containing exotic ingredients.  And while grains have been accused on the internet of causing nearly every disease known to dogs, grains do not contribute to any health problems and are used in pet food as a nutritious source of protein, vitamins, and minerals.

The FDA alert notes that in 4 cases of doggy DCM (3 of which were golden retrievers) taurine levels were low and with a change back to a normal diet and taurine supplementation the cardiomyopathy resolved. However, some reported cases had normal taurine levels.

Reconsider Your Dog’s Diet

To avoid doggy DCM, Dr. Freeman recommends

  • Reconsider your dog’s diet. If you’re feeding a boutique, grain-free, or exotic ingredient diets, I would reassess whether you could change to a diet with more typical ingredients made by a company with a long track record of producing good quality diets.  And do yourself a favor –  stop reading the ingredient list!  Although this is the most common way owners select their pets’ food, it is the least reliable way to do so.  And be careful about currently available pet food rating websites that rank pet foods either on opinion or on based on myths and subjective information. It’s important to use more objective criteria (e.g., research, nutritional expertise, quality control in judging a pet food). The best way to select what is really the best food for your pet is to ensure the manufacturer has excellent nutritional expertise and rigorous quality control standards (see our “Questions you should be asking about your pet’s food” post).
  • If you’re feeding your dog a boutique, grain-free, or exotic ingredient diet, watch for early signs of heart disease – weakness, slowing down, less able to exercise, short of breath, coughing, or fainting. Your veterinarian will listen for a heart murmur or abnormal heart rhythm and may do additional tests (or send you to see a veterinary cardiologist), such as x-rays, blood tests, electrocardiogram, or ultrasound of the heart (echocardiogram).

Anticardiomyopathically Yours,

-ACP

Three More Nails In The Omega-3 Supplement Coffin: Stop Taking Fish Oil Pills (The Complete Post)

If by now you are still taking fish oil supplements despite my last post on the topic I present three more reasons to stop wasting your money and destroying the ocean’s ecosystem.

The first nail: No Reason To Take Fish Oil Pills

A Cochrane review showing shows there is little or no effect of omega 3 supplements on our risk of experiencing heart disease, stroke or death.

This is the most extensive systematic assessment of effects of omega-3 fats on cardiovascular health to date. Moderate- and high-quality evidence suggests that increasing EPA and DHA has little or no effect on mortality or cardiovascular health (evidence mainly from supplement trials). Previous suggestions of benefits from EPA and DHA supplements appear to spring from trials with higher risk of bias. Low-quality evidence suggests ALA may slightly reduce CVD event risk, CHD mortality and arrhythmia.

Second Nail. Peruvian Anchoveta: Put Them On A Pizza Not in A Pill

Paul Greenberg’s recently published book, The Omega Principle, emphasizes the damage the fish oil supplement business is doing to the ocean environment,

During a recent interview on Fresh Air on NPR he summarized the concerns:

GREENBERG: So omega-3 supplements come from this critical layer of the ocean biosphere that are small – what are called pelagic fish. They’re the silvery, little fish like anchovies and herring and other fish called menhaden that most people haven’t heard of, but it’s actually the most caught fish in the lower 48 of the United States. These fish are really essential for ecosystem dynamics in the ocean.

So the way that oceans work is that all the energies coming from the sun – it goes – all that energy is processed by plankton, by phytoplankton. And it’s really these fish that are – these little fish that are used for omega-3 supplements that transfer the energy from plankton to larger fish. So in other words, you know, you have the solar energy going into the plankton. The little fish then eat the plankton. And then they are in turn eaten by larger fish. So if you harvest this middle layer – if you overharvest this middle layer of anchovies, of herring, of menhaden – if you take them out of the picture, there’s no way for the energy to be transferred from phytoplankton up to larger predators. So I guess that’s my main concern here.

So in particular, where are the omega-3 supplements coming from? Most of the omega-3 supplement oil is coming from a fish called a Peruvian anchoveta. And it is the most caught fish in the world. In some years, Peruvian anchoveta harvests have equaled as much as 10 million metric tons. Just to give you some perspective, that’s like one-eighth of all the fish caught in the world. And the crazy thing about it is that those fish are completely, totally edible. I’ve eaten them. They’re delicious. You can have them on a pizza. You could do anything with them. But 99 percent of those Peruvian anchoveta are ground up into animal feed, boiled down into oil and turned into supplements. So to me, to my mind, that is not necessarily the wisest use to be made of this really, really important source both for the ecology of the ocean but also for humans

Nail Three. Save the Krill!

The supplement industry is incredibly creative in their marketing. As the uselessness of fish oil supplementation has become clear, supplement manufacturers have begun touting krill oil as superior to fish oil.

Claims like the following are all over the internet:

Krill have an edge over your ordinary fish – when you take a krill oil supplement, you also get astaxanthin along with your DHA and EPA. It’s an antioxidant. In terms of antioxidant power of potency, it’s been found to be 500x to 6,000x stronger than regular vitamins like vitamin E and vitamin C.

This is just hogwash. There is no good clinical evidence to support any health claim for krill oil in general or astaxanthin in particular. Please read my post on the failure of anti-oxidant supplements and vitamins and recognize that claims of antioxidant power do not indicate any health benefit.

A technical paper from Greenpeace review the importance of krill to to the marine ecosystem in the Antarctic and this paper, entitled “License to Krill” details the problem.

Do you want to be responsible for starving penguins, whales and seals??!

Let me reiterate my original 2013 fish oil post pithy summary:

the bottom line on fish oil supplements is that  the most recent scientific evidence does not support any role for them  in preventing heart attack, stroke, or death. There are potential down sides to taking them, including contaminants and the impact on the marine ecosystem. I don’t take them and I advise my patients to avoid them (unless they have triglyceride levels over 500.)

Prokrilly Yours

-ACP

 

 

 

 

Heart Healthy Breakfast Choices?: Cheerios, Honey-Nut Cheerios and Soluble Fiber Revisited

A reader commenting on my Plant Paradox post questioned nutritional  recommendations to consume fiber. This has prompted me to revisit a post I wrote in 2014 on Cheerios and Soluble Fiber.

I mentioned at that time that Honey-Nut Cheerios was the #1 selling ready-to-eat breakfast cereal and Cheerios #4. This update Screen Shot 2018-07-15 at 7.22.55 AMindicates little has changed in the rankings or consumption of breakfast cereal since then despite a more widespread recognition that added sugar is the major toxin in our diet and that these food items are basically a vehicle for sugar.

Apparently, Americans believe honey is not sugar. But Honey Nut Cheerios contain 9 times as much sugar as cheerios. Here are the top ingredients:

Whole Grain Oats, Sugar, Oat Bran, Corn Starch, Honey, Brown Sugar Syrup, Salt, Tripotassium Phosphate, Rice Bran Oil and/or Canola Oil,

General Mills tries to emphasize the healthiness of Honey Nut Cheerios, focusing on their close relationship with bees and the natural goodness of honey in its advertising along with other factors that we now know are not important (low fat, 12 vitamins and minerals, source of iron).Screen Shot 2018-07-15 at 7.56.32 AM

Little has changed with respect to the science supporting fiber consumption to reduce cardiovascular disease since 2014.  It is still weak and based on observational studies and surrogate biomarkers.

Between the lines below is my original post with current annotations in red.


The skeptical cardiologist usually eschews the breakfast offerings in the Doctor’s lounge. I’m not really interested in consuming donuts, muffins, or bagels with their high carbohydrate load. As I’ve ranted out about previously, the only yogurt available is Yoplait low fat , highly sugared-up yogurt which is arguably worse than starting the day with a candy bar.

A selection of breakfast cereals is available including Cheerios, Raisin Bran, and Frosted Flakes. Occasionally, when I have neglected to bring in my own full-faty yogurt, granola and/or fruit I will open up one of the Cheerios containers and consume a bowl mixed with 2% milk (full-fat, organic milk which I passionately advocate here and here is not available) (2018 update, I have said “cheerio” to all breakfast cereals and no longer eat Cheerios in the doctor’s lounge). 

Pondering the Cheerios packaging and the cute little O’s made me wonder whether this highly processed and packaged food with a seemingly endless shelf life was truly a healthy choice.

The “Ready-To-Eat”  And Allegedly Heart-Healthy Cereal

Cheerios and Honey-nut cheerios were  the #4 and #1 breakfast cereals in the US in 2013, generating almost a billion dollars in sales. Both of these General Mills blockbusters undoubtedly have reached their popularity by heavily promoting the concept that they are heart healthy.

The Cheerios label is all about the heart. The little O’s sit in a heart-shaped bowl. A prominent red heart with a check inside it attests to the AHA having certified Cheerios as part of its checkmark.heart.org program. Additional text states “low  in Saturated fat and cholesterol” and “diets low in saturated fat and cholesterol may reduce the risk of heart disease.”

Is The Fiber In Cheerios “Heart-Healthy” ?

Beta-glucan is a soluble fiber primarily located in the endosperm cell wall of oats. Early studies showed that oats and beta-glucan soluble fiber could reduce total and LDL (bad cholesterol) levels. The mechanism isn’t really known. (see the end of post for possible mechanisms). The Quaker oats web site oversimplifies the mechanism thusly :

“In your digestive tract, it acts as a sponge, soaking up cholesterol and carrying it out of the body”

This narrative fits with the oversimplified and now discredited descriptions of atherosclerosis which attribute it directly to consumption of cholesterol and fatty acids. See here if you’d like to appreciate how complex the process truly is.

The FDA Sanctions Oats As Heart Healthy

In 1997, the FDA reviewed 33 studies (21 showing benefit and 12 not) and decided to allow a health claim for foods that contain oats and soluble fiber. A minimum dose of 3 grams/day of oat beta-glucan was suggested for a beneficial reduction in blood cholesterol and (presumably, although never documented) a subsequent decline in coronary heart disease.

In 1998 Johnson, et al, published the results of a study funded by a grant from General Mills that showed that  inclusion of whole grain oat ready to eat cereal providing 3 grams of beta-glucan as part of a low fat diet reduced  LDL cholesterol by 4% after 6 weeks. HDL was unchanged. Patients in this study consumed 45 grams (1.5 oz) of cheerios at breakfast and then again in the evening. There was a total of 3 grams of soluble fibre in this amount of Cheerios. A control group consumed corn flakes in a similar fashion without change in LDL.

General Mills took this weak data and ran with it and began posting on Cheerios the following statements

 “Did you know that in just 6 weeks Cheerios can reduce bad cholesterol by an average of 4 percent? Cheerios is … clinically proven to lower cholesterol. A clinical study showed that eating two 1 1/2 cup servings daily of Cheerios cereal reduced bad cholesterol when eaten as part of a diet low in saturated fat and cholesterol.”

Although the FDA had approved verbiage indicating oats may reduce heart disease “when eaten as part of a diet low in saturated fat and cholesterol” the agency objected to General Mills claiming that Cheerios lowers cholesterol “when eaten as part of a diet low in saturated fat and cholesterol”.

The FDA  issued a warning letter to General Mills in 2009 in which the agency alleged “serious violations” of the FDC Act in the label and labeling of Cheerios cereal.

Based on claims made on your product’s label, we have determined that your Cheerios® Toasted Whole Grain Oat Cereal is promoted for conditions that cause it to be a drug because the product is intended for use in the prevention, mitigation, and treatment of disease.

Lowering Cholesterol Is Not The Same As Preventing Heart Disease

The FDA was telling General Mills that it was OK to say that Cheerios may reduce heart disease but not that it can reduce cholesterol because that made it a drug. It makes no sense.

The only thing that had been demonstrated for oat soluble fiber and Cheerios in particular was a reduction in cholesterol. There has never been a study with oats showing a reduction in heart disease..

It’s the heart disease, the atherosclerosis clogging our arteries and causing heart attacks and strokes that we want to prevent. We could care less about lowering cholesterol if it doesn’t prevent atherosclerosis.

A recent review of studies since the FDA ruling shows that 70% of studies show some reduction in LDL with beta-glucan. Interstingly, the studies which added beta-glucan to liquids were generally positive whereas addition to solids such as muffins usually did not show benefit.

I’m going to accept as evidence-based the claim that whole oats can lower your LDL about 7% if you consume a very large amount of them on a daily basis.

However, the critical question for any drug or dietary intervention is does it prevent atherosclerosis, the root cause of heart attacks and strokes. There has been in the past an assumption that lowering cholesterol by any means would result in lowering of atherosclerosis.

This theory has been disproven by recent studies showing that ezetimibe and niacin which significantly lower LDL do not reduce surrogate markers of atherosclerosis or cardiovascular events any more than placebo when added on to statin drugs. (There is now weak evidence that ezetimibe does lower cardiovascular events ). The recently revised cholesterol guidelines endorse the concept of treating risk of atherosclerosis rather than cholesterol levels.


 

I do like the food writer Michael Pollan’s simple rules to “Eat Food. Mostly Plants. Not Too Much.” and this NY Times piece summarizes much of what is in his short, funny and helpful Food Rules book:

you’re much better off eating whole fresh foods than processed food products. That’s what I mean by the recommendation to eat “food.” Once, food was all you could eat, but today there are lots of other edible foodlike substances in the supermarket. These novel products of food science often come in packages festooned with health claims, which brings me to a related rule of thumb: if you’re concerned about your health, you should probably avoid food products that make health claims. Why? Because a health claim on a food product is a good indication that it’s not really food, and food is what you want to eat.

If you follow Pollan’s dictum you will get plenty of fiber, soluble or otherwise and you will avoid the necessity to obsess over the macronutrients in your diet, fiber or otherwise. Throw in some Cheerios and oatmeal every once in a while if you like them;  in their unadulterated state they are a heart-healthy food choice.

Cheerio,

-ACP

Why You Should Ignore “The Plant Paradox” by Steven Gundry

The skeptical cardiologist first encountered the blather of Dr. Steven Gundry while researching and writing a post entitled  The #1 Red Flag of Quackery.

Gundry came across my quack radar screen due to the popularity of his useless supplements and his pseudoscientific justifications. He is also widely described as a cardiologist but he is not, He is (or was) a cardiac surgeon (like, strangely enough, the celebrity prince of quackery, Dr. Oz)

Gundry is also a Goop doctor, which means Gwyneth Paltrow, the  celebrity queen of weird quackery endorses him.

I’ve been meaning to write specifically about his most popular useless supplement, Vital Reds.

In the meantime, Gundry has  come out with a best-selling.  book entitled  “The Plant Paradox: The Hidden Dangers in Healthy Foods That Cause Disease and Weight Gain”.

This book claims to reveal to its readers the great dietary “secret” that is causing almost all chronic diseases. Of course, Gundry is the only person with the brilliance and insight to have recognized this. Only those who are willing to plunk down the money to buy his book will learn this secret and the (mostly gobbledook) science behind it.

This  technique of convincing the naive that only you are aware of the “hidden” factor which is  the cause of their various maladies can probably be considered the #2 Red Flag of Quackery.

The Plant Paradox would have you believe that lectins are the major danger in our diet.

I’ve come across two well-researched pieces which destroy any validity to the concepts put forth by Gundry in The Plant Paradox.

Campbell: Is It Possible Gundry Is Out To Make A Quick Buck?

The first is from T. Colin Campbell of China Study fame. While I don’t agree with his overall dietary philosophy (see here) in his article he has taken the time to read Gundry’s book in detail and address in great detail the multiple bogus claims and the lack of scientific support. Campbell begins:

The claims come fast and furious in this book, stated with a degree of certainty, without nuance, that undoubtedly appeals to many readers. But the referencing is so lacking and sloppy that Dr. Gundry should be embarrassed. The references that are cited in this book do a poor job of trying to justify its claims. And the bulk of the author’s wild claims lack references at all, with several examples of easily verifiable falsehoods. Because his claims are quite profound and novel, referencing of the findings of others and his own results are especially important. This is especially troubling for an author who touts his own research experience.

After debunking Gundry’s lectin claims , Campbell suggests that Gundry’s major goal is selling more useless supplements, including one that will protect readers from the dreaded lectin:

In conclusion, there are many people who desire good health and deserve good information and we resent that they must suffer such poor quality and confusing information under the assumption that it is good science. Is it possible that Dr. Gundry is just out to make a quick buck? He admits that his patients give up to a dozen vials of blood for testing every couple of months at his clinic. Overtesting is common practice in supplement-driven clinics. This extensive testing, (which are another topic), is almost always used to demonstrate some type of nutritional pathology, which of course can only be corrected by taking the suggested supplements. And of course, Dr. Gundry sells supplements, including “Lectin Shield” for about $80 a month. According to his website, “This groundbreaking new formula was created to offset the discomforting effects of lectins (proteins commonly found in plants that make them harder to digest). Lectin Shield works to protect your body from a pile-up of lectins and to promote full-body comfort.”

Are Lectins The Next Gluten?

The second article I highly recommend was written for The Atlantic last year by one of my favorite medical writers, James Hamblin, MD.

Entitled, “Lectins Could Become the Next Gluten“, the article combines a tongue–in-cheek commentary with interviews with scientists who debunk Gundry’s claims. Hamblin also interviews Gundry which is particularly revelatory as to Gundry’s lack of credibility.

Although Gundry claims his writing is not motivated by money, Hambling notes:

Yes, he also sells supplements he recommends. The last 20 or so minutes of his infomercial is a string of claims about how supplies are running low, and it’s important that you act immediately, and that if you do manage to get through to a customer representative you should order as much as you have room to store—the shelf life is great, etc. And the necessity of supplements is the crucial argument of the book. He writes, “Getting all of the nutrients you need simply cannot be done without supplements.”

The GundryMD line of products includes something he invented called vitamin G6. Another is a “lectin shield” that’s “designed to neutralize the effects of lectins.” These are available on his website for $79.99. There you can also get six jars of Vital Reds for $254.70.

Fake Dietary Science Undermines Valid Dietary Recommendations

Hambling closes his piece by noting that book publishers have no accountability for publishing dietary/health misinformation as they are incentivized to publish and profit from the most outrageous claims.

This is a problem much bigger than any plant protein. Cycles of fad dieting and insidious misinformation undermine both public health and understanding of how science works, giving way to a sense of chaos. It seems that every doctor has their own opinion about how to protect your body from calamity, and all are equally valid, because nothing is ever truly known.

Lectiophilically

-ACP

N.B. Gwyneth Paltrow (GOOP) deserves a prominent place in the Quackery Hall of Shame.

Julia Belluz of Vox has a typically spot-on piece about GOOP which begins:

Gwyneth Paltrow has made a career out of selling pseudoscience on her lifestyle website, Goop. Over the years, the actress has proclaimed women should steam their vaginas, that water has feelings, and that your body holds secret organs. Mixed into these absurd assertions is her bogus detox diet and cleansing advice, all of it in service of promoting Goop’s beauty and wellness products

Dr. P’s Heart Nuts and The Flawed But Still Relevant PREDIMED Trial

The skeptical cardiologist was somewhat disheartened to read  the New York Times headline today that the  PREDIMED study was flawed. I frequently reference this landmark randomized trial of the mediterranean diet when I’m citing the cardiovascular benefits of nuts and EV olive oil.

Science mag summarizes the problem which prompted a re-analysis of the study:

A months-long inquiry by the Spanish researchers and NEJM staff uncovered that up to 1588 people in the trial hadn’t been properly randomized: Some were assigned to the same diet as someone else in their household (a common feature of diet studies, but not reported in the original paper). Others, who lived in a rural area, were assigned to different diets based on the clinic closest to them—for example, one group had to pick up a liter of olive oil each week. “The investigator realized he couldn’t get people to travel as far as they needed so he made his study ‘cluster randomized,’” by clinic rather than by individual, Drazen says.

The authors reanalyzed their data without those 1588 participants and found that despite the missteps, the conclusion held: Nuts, olive oil, and fatty fish remained a net positive on heart health, though the conclusions came with somewhat less statistical oomph than in the original paper.

Here’s what I wrote about nuts and the PREDIMED study when I first started distributing Dr. P’s Heart Nuts to my patients.

The skeptical cardiologist has finally prepared Dr. P’s Heart Nuts for distribution. IMG_8339The major stumbling block in preparing them was finding almonds which were raw (see here), but not gassed with proplyene oxide (see here), and which did not contain potentially toxic levels of cyanide (see here).

During this search I learned a lot about almonds and cyanide toxicity, and ended up using raw organic almonds from nuts.com, which come from Spain.

I’ll be giving out these packets (containing 15 grams of almonds, 15 grams of hazelnuts and 30 grams of walnuts) to my patients because there is really good scientific evidence that consuming 1/2 packet of these per day will reduce their risk of dying from heart attacks, strokes, and cancer.

IMG_7965The exact components are based on the landmark randomized trial of the Mediterranean diet, enhanced by either extra-virgin olive oil or nuts (PREDIMED, in which participants in the two Mediterranean-diet groups received either extra-virgin olive oil (approximately 1 liter per week) or 30g of mixed nuts per day (15g of walnuts, 7.5g of hazelnuts, and 7.5g of almonds) at no cost, and those in the control group received small nonfood gifts).

After 5 years, those on the Mediterranean diet had about a 30% lower rate of heart attack, stroke or cardiovascular death than the control group.

It’s fantastic to have a randomized trial (the strongest form of scientific evidence) supporting nuts, as it buttresses consistent (weaker, but easier to obtain), observational data.

Despite the statistical flaws PREDIMED is still an important study demonstrating the benefits of nuts.  PREDIMED was the best randomized trial data we had for nuts but there are tons of observational data which are very consistent and show a strong association between increased nut consumption and reduced mortality..

Consequently, I made up a new batch of Dr. P’s Heart Nuts in honor of the survival of PREDIMED and will be distributing them to patients today.

Meditativeterraneanly Yours,

-ACP

Flaxseed: Plant-Based Omega 3 Super Food or Faux Fish Oil?

Ground flaxseed plus Trader’s Point Creamery full fat plain yoghurt. It’s not pretty but tastes pretty good.

The skeptical cardiologist has a confession to make: he’s been adding ground flaxseed to his typical late morning full fat yoghurt plus berries and almonds.

Adding flaxseed seems dangerously close to dietary behaviour I have been advising against: supplementing instead of eating real food.

Also, I am philosophically opposed to going out of my way to eat any edible that is consistently promoted as a “super food” or a “functional food.” To me, these are meaningless terms and marketing blather

When I began writing this post in 2017 I was getting my flaxseed from Stober Farms (Est. 1901) who had been producing “for over 100 years  the finest flax in the world.”  Stober Farms provided me with “organic Golden Flax Seed which has been Cold-Milled Processed.”

Stober Farms (who have since mysteriously gone into bankruptcy) also informed me:

Flax is digested most effectively when ground. Some grinding methods generate heat when milled, spurring early omega-3 oxidation. Stober Farms uses a unique cold-milled process, which gently grinds the seed without significantly raising the temperature. This proprietary method preserves the nutrients, flavor and extends the shelf life to 22 months.

Honestly, I don’t recall exactly why I began “flaxing” but I suspect I felt it was a good way to boost the fat content in my full fat yoghurt (yes, I am now spelling yoghurt with an h) and berries and perhaps sufficiently satiate me that it would be the only food I would need to consume until dinner or late afternoon.

Two tablespoon (14 grams) is what I typically  imprecisely add. These tablespoons provide 75 kcal of energy which comes from 3 grams of protein, 6 grams of fat, and 4 grams of carbs.  Three of the four carb grams are soluble fibre.

About half of the fat in flaxseed is in the form of alpha-linolenic acid (ALA)(18:3) an omega-3 polyunsaturated (PUFA) fat.  Flaxseed oil contains five times more ALA than walnut oil or canola oil, which are the next highest sources of ALA.

Is Flaxseed A Super Functional Food?

Many seemingly authoritative sites on the internet proclaim that flaxseed is incredibly healthy. For example, Healthline.com’s “Authority Nutrition” (they must be authoritative as authority is in their name)  presents their 10 health benefits of eating flaxseed “backed by science”  and concludes:

They can be used to improve digestive health, lower blood pressure and bad cholesterol, reduce the risk of cancer and may benefit people with diabetes.

But typical of  Authority Nutrition’s overblown claims  these are not truly proven by science. The studies cited are weak; typically short-term tests of biomarkers or animal studies or human studies with very small numbers. Most importantly. these studies , which are often funded by flaxseed promoters are highly likely to be biased in favor of positive results.

Most websites tout the cardiovascular benefits of the omega-3 PUFA in flaxseed, the high percentage of soluble fibre and  the benefits of a chemical which cannot be named (due to a name which is too difficult to pronounce), SDG.

Omega-3 PUFAs and fibre I’ve touched on previously (and positively) but what about the mysterious and unpronounceable SDF. Per a 2010 review article

Flaxseed is the richest source of the lignan secoisolariciresinol diglucoside (SDG). After ingestion, SDG is converted to secoisolariciresinol, which is further metabolised to the mammalian lignans enterodiol and enterolactone. A growing body of evidence suggests that SDG metabolites may provide health benefits due to their weak oestrogenic or anti-oestrogenic effects, antioxidant activity, ability to induce phase 2 proteins and/or inhibit the activity of certain enzymes, or by mechanisms yet unidentified.

Like so many putative wonder phytochemicals, SDG has a “growing body of evidence” for lots of things but actual proof that it does anything worthwhile in humans is lacking and awaits  well done randomized clinical trials

Poorly researched articles on flaxseed are highly likely to tout its anti-inflammatory properties. These properties are seen in rats but unfortunately haven’t been proven in my favorite species, Homo Sapiens ,  Flaxseed doesn’t seem to decrease the inflammatory marker CRP in humans as reported in this systematic review and meta-analysis.

ALA and Cardiovascular Disease

As I’ve indicated in previous posts, evidence supports fatty fish consumption as beneficial in reducing cardiovascular disease presumably by increasing levels of marine omega-3 PUFAs in the body.

The value of fish oil supplementation, however, is not proven (see here).

How does ALA compare to the seafood omega 3s  in preventing cardiovascular disease (CVD)?

In 2012, researchers at the Harvard School of Public Health published a systematic review and meta-analysis of the existing data on ALA and the risk of CVD..

Their introductory paragraph nicely lays out why ALA could be very important to public health:

A large body of evidence supports a potential protective effect of seafood omega-3 (n−3) fatty acids, particularly EPA (20:5n−3) and DHA (22:6n−3), on coronary heart disease (CHD. However, fewer studies have evaluated how the plant-derived omega-3 fatty acid α-linolenic acid (ALA; 18:3n−3) relates to risk of CHD and other cardiovascular disease (CVD) outcomes, and the results have been inconsistent As an essential fatty acid that cannot be synthesized by humans, ALA is mainly consumed from plant sources, including soybeans, walnuts, and canola oil. Compared with seafood omega-3 fatty acids, ALA from plant sources is more affordable and widely available globally. Thus, whether ALA can reduce the risk of CVD is of considerable public health importance.

If plant-derived ALA can provide our omage-3 PUFA needs then perhaps we can stop stripping the ocean of all the menhaden.

In the Harvard analysis when all 27 studies were combined the authors found a significant risk reduction of 14% in CVD events with flaxseed.

There were lots of issues with the data which I won’t bore you with leading the authors to conclude that “ALA consumption may be beneficial “.  They emphasized the need for additional well-designed observational studies and randomized clinical trials in the area.

Since observational studies cannot prove causality, I await a good randomized clinical trial of ALA supplementation before I can recommend ALA supplementing to prevent heart disease.

After Performing This Review Is The Skeptical Cardiologist Still “Flaxing”?

I am. Because I’ve found that when I consume flaxseed I feel 20 years younger, full of vitality. and with a youthful golden sheen to my hair, nails and skin.

Actually, that last sentence is untrue.

I’m still adding ground flaxseed to my yoghurt but not with any expectation that it is reducing my risk of heart attack and definitely not because I perceive it as a super or functional food.

I like the taste, the convenience, and the extra (presumably healthy) calories it provides but I’m still an advocate of just eating real food rather than trying to identify specific nutrients, nutraceuticals or supplements and add them to your diet.

Flaxseedingly Yours,

-ACP

N.B. I did not touch on omega-6/omega-3 ratios in the diet. I’ve been examining that inflammatory (enjoy the pun) topic for years and once I come across a good study that adds to understanding in the area I will likely publish a post on it.

 

The Eggsoneration Continues: Why Does Anyone Eat Egg Whites?

The skeptical cardiologist pointed out in 2013 that there was no good evidence supporting limiting dietary cholesterol to 300 mg per day.  I exulted, therefore, in 2016 , when this long-standing dietary recommendation came out of the US dietary guidelines.

Recognizing that dietary cholesterol doesn’t need to be limited means that eggs and egg yolks are fine.

Egg Whites: A Product of Nutritional Misinformation?

Why, then do egg whites continue to be created and consumed?

On a regular basis, patients tell me that they are eating egg white omelettes because they believe egg yolks are not heart healthy.

Old bad nutritional dogma takes a long time to reverse apparently. To this day, for example, the National Lipid Association still recommends limiting daily cholesterol consumption to <200 mg/ day

Therefore I find it necessary to highlight additional new studies that further eggsonerate eggs.

To wit, I shall briefly discuss two articles that were published earlier this month and brought to my attention by friends and readers who are aware of my rabid support for the egg.

Article One: The Wonderfully Acronymed DIABEGG Study

Entitled  “Effect of a high-egg diet on cardiometabolic risk factors in people with type 2 diabetes: the Diabetes and Egg (DIABEGG) Study—randomized weight-loss and follow-up phase” our fist study was performed in Australia at the Sydney Medical School,

Investigators randomized 128 patients with prediabetes or type 2 diabetes (T2D) to a high egg or a low egg diet.

Throughout all study phases, including the 3-mo weight-loss phase, participants consuming the high-egg diet were instructed to eat 2 eggs/d at breakfast for 6 d/wk (12 eggs/wk). Those in the low-egg group were directed to consume <2 eggs/wk, and to match the protein intake that the high-egg group had consumed at breakfast with 10 g lean animal protein (meat, chicken, or sh) or other protein-rich alternatives, such as legumes and reduced-fat dairy products (also consumed at breakfast). Recommended egg-cooking methods were boiled or poached, but they could also be fried if a polyunsaturated cooking oil, such as olive oil, was used. The prescribed diets were energy and macronutrient matched, as reported previously

At the end of 12 months both groups had lost about 3 kg in weight.
The investigators measured everything they could to look at diabetic and cardiometabolic biomarkers which might suggest adverse effects of egg eating on the cardiovascular system but they could find no difference between the egg eaters and the non egg eaters.
High egg consumption had no adverse effects on the following factors that are felt to be important in the development of atherosclerosis:

-measures of systemic and vascular inflammation [high sensitivity C-reactive protein (hs-CRP), IL-6, soluble E-selectin (sE-selectin)],

-oxidative stress (F2-isoprostanes), the adipokine adiponectin (which also modulates insulin resistance), and

-glycemia [fasting plasma glucose, glycated hemoglobin (HbA1c), and a medium-term measure of glycemia, 1,5-anhydroglucitol (1,5AG)].

The authors suggested that nutritional guidelines stop worrying about limiting eggs.

Article Two: Half A Million Chinese Can’t Be Wrong

This observational study published in Heart found that egg consumption in a huge Chinese population was associated with less stroke, and major cardiac events (MCE):

Compared with non-consumers, daily egg consumption was associated with lower risk of CVD (HR 0.89, 95% CI 0.87 to 0.92). Corresponding multivariate-adjusted HRs (95% CI) for IHD, MCE, haemorrhagic stroke and ischaemic stroke were 0.88 (0.84 to 0.93), 0.86 (0.76 to 0.97), 0.74 (0.67 to 0.82) and 0.90 (0.85 to 0.95), respectively. There were significant dose-response relationships of egg consumption with morbidity of all CVD endpoints (P for linear trend <0.05). Daily consumers also had an 18% lower risk of CVD death and a 28% lower risk of haemorrhagic stroke death compared to non-consumers.

The lower risk for stroke and cardiovascular death in egg eaters persisted after accounting for known CVD risk factors.

(And yes, I agree this is an observational study which we should take with huge grains of salt and pepper).

Are EGG Whites The Skim Milk Scam of The Egg Industry?

I’ve written about the scam that is skim milk but it occurs to me that egg white consumption is equally nonsensical.

What happens to the wonderfully nutritious yolk of the egg when it is brutally separated from its white? It is put in a container and sold as  liquid egg yolk. Makers of mayonnaise are big consumers of liquid egg yolk.

Thus, like dairy farmers who double their sales by selling skim milk and its dairy fat separately, egg producers are probably delighted that Americans are consuming egg whites , allowing them to get two products from a single egg.

As I wrote previously: not everyone is an egg lover and I’m fine with that. There is no evidence that you have to eat them. You could feel towards them as did Alfred Hitchcock :

“I’m frightened of eggs, worse than frightened, they revolt me. That white round thing without any holes … have you ever seen anything more revolting than an egg yolk breaking and spilling its yellow liquid? Blood is jolly, red. But egg yolk is yellow, revolting. I’ve never tasted it.”

For those that don’t find yellow revolting, however, avoiding egg yolk makes no nutritional sense.

Eggsplicatively Yours,

-ACP

Dear Dr. Gottlieb, Full Fat Dairy is “Healthy”. Why Are You Pushing Low-Fat Dairy?

By all accounts, Scott Gottlieb, the Trump appointed director of the FDA is doing a good job.

Vox points out, he has announced substantial FDA moves to reduce cigarette consumption and is committed to improving competition in generic drugs.

However, he gave a recent speech at the National Food Policy Conference  on “Reducing the Burden of Chronic Disease” which indicates he is misinformed on crucial aspects of nutritional science.

Gottlieb indicated he wanted the FDA to play a bigger role in guiding Americans to eat a healthier diet to reduce the burden of chronic disease.

To facilitate this he is looking to define what foods are “healthy”:

We’re keeping all these considerations in mind as we pursue rulemaking to update the definition of “healthy” so it’s based on nutrition criteria and food considerations that are more up-to-date than those being used for the current definition….

Once updating the definition, Gottlieb wants to label food as “healthy” In a way that makes it easier for consumers to understand:

To address this, we’ve had discussions about whether there should be a standard icon or symbol for the word “healthy” that everyone could use on food packages.

Gottlieb goes on to bemoan a focus on nutrients rather than foods but in the very  next sentence recommends a food, dairy, in a form that has one important nutrient stripped from it-fat.

Traditionally, we’ve focused primarily on the nutrients contained in food in considering what is healthy. But people eat foods, not nutrients.

This is why we’re asking the important question of whether a modernized definition of “healthy” should go beyond nutrients to better reflect dietary patterns and food groups, like whole grains, low fat dairy, fruits and vegetables and healthy oils?

Obviously, the first step in getting Americans to eat healthier is to make sure you are doling out the correct advise and in his speech Dr. Gottlieb indicates he has bought into  long-standing fundamental errors. I wrote him the following letter hoping to correct these errors.


Dear Dr. Gottlieb,

Congratulations on your recent appointment as FDA director and kudos for your fine work to date. I read your recent comments on developing an updated definition of “healthy” and the importance of  conveying that information to American consumers  I applaud your efforts in this area as well as your ongoing efforts to limit cigarette smoking and improve generic competition.

I am fine with guiding consumers to healthy foods but I beg of you, let this determination of what is healthy be guided by the actual science, not prior dogma.

In your recent speech you indicate that Americans are not consuming enough dairy and you recommend low-fat dairy which implies that you and the FDA believe that scientific studies have demonstrated that dairy fat is unhealthy.

Five years ago I, too , thought dairy fat was unhealthy and recommended my patients avoid butter, full-fat yogurt and cheese. However, when challenged on this belief, I reviewed the scientific literature on dairy fat and cardiovascular disease.

It turns out when objectively analyzed (as I have written about here and here ) there is no scientific evidence that supports the concept that dairy processed to remove dairy fat is healthier than the original unadulterated product.

In fact, evidence suggests full fat dairy reduces central obesity, diabetes, cardiovascular disease and atherosclerosis in general.

As a result of misguided recommendations to avoid dairy fat, it is virtually impossible in most grocery stores to find full fat yogurt or milk. The vast majority of the dairy aisle is devoted to various low or non fat concoctions which have had loads of sugar and chemicals added and are arguably worse than a Snickers bar.

Dr. Gottlieb ,I am not cherry-picking the data here or relying on out of date studies. I’ve reviewed everything I can find on this issue and reviewed it without bias. Evidence continues to accumulate supporting the healthiness of full fat dairy.

For example, here’s a 2018 review from researchers totally unaffiliated with the dairy industry which asks the question “Dairy Fats and Cardiovascular Disease: Do We Really Need to Be Concerned?”

After a exhaustive review they conclude the answer is no.

recent research and meta-analyses have demonstrated the benefits of full-fat dairy consumption, based on higher bioavailability of high-value nutrients and anti-inflammatory properties. … In general, evidence suggests that milk has a neutral effect on cardiovascular outcomes but fermented dairy products, such as yoghurt, kefir and cheese may have a positive or neutral effect.

Flawed Reasons for Low Fat Dairy Recommendations

As I have written previously, I believe there are three reasons for the failure of major nutritional recommendations such as the 2015  Dietary Guidelines For Americans  to correct previously  flawed advice to choose  non or low-fat dairy over full fat:

1. In  few randomized dietary studies showing benefits of a particular diet over another, non fat or low fat dairy was recommended along with a portfolio of other healthy dietary changes.

The overall benefit of the superior diet had nothing to do with lowering the dairy fat but was due to multiple other changes.

2. The dairy industry has no motivation to promote full fat dairy. In fact, they do better financially when they can take the fat out of milk and sell it for other purposes such as butter, cheese, and cream. (Please read my interview with a plastic surgeon dairy farmer on the skim milk scam here.)

3. Saturated fat is still mistakenly being treated as a monolithic nutritional element.  Although dairy fat is mostly saturated, the individual saturated fats vary widely in their effects on atherogenic lipids and atherosclerosis. In addition, the nature of the saturated fat changes depending on the diet of the cow.

4. Since authorities have been making this low fat dairy recommendation for so long they are extremely reluctant to reverse their advice. It lowers their credibility.

There Is No Scientific Consensus On What Constitutes A Healthy Oil

Finallly, Dr. Gottlieb, I would like to briefly point out that there is considerable ongoing scientific debate about what constitutes a “healthy oil.”

I summarized this last year on a post on coconut oil (which I fear you will also pronounce “unhealthy”).

In many respects, the vilification of coconut oil by federal dietary guidelines and the AHA resembles the inappropriate attack on dairy fat and is emblematic of the whole misguided war on dietary fat. In fact, the new AHA advisory  after singling out coconut oil goes on to cherry-pick the data on dairy fat and cardiovascular disease in order to  support their faulty recommendations for choosing low or nonfat dairy.

Canola and corn oil, the products of extensive factory processing techniques, contain mostly mono or polyunsaturated fats which have been deemed “heart-healthy” on the flimsiest of evidence.

The most recent data we have on replacing saturated fat in the diet with polyunsaturated fat comes from the Minnesota Coronary Experiment performed from 1968 to 1973, but published in 2016 in the BMJ.

Data from this study, which substituted liquid corn oil in place of the usual hospital cooking fats, replaced corn oil margarine for butter and added corn oil to numerous food items, showed no overall benefit in reducing mortality. In fact, individuals over age 65 were more likely to die from cardiovascular disease if they got the corn oil diet.

So, Dr. Gottlieb, please continue your efforts to make Americans healthier but make sure the current scientific evidence actually supports your recommendations. Keep in mind, the disastrous public health experiments of previous decades.


Skeptically Yours,

-ACP

N.B. Some of my posts on dairy fat are below.

Dairy Fat Makes You Thinner

The Skim Milk Scam

More Evidence That Diary Fat is associated with a lower risk of heart disease

What happens to cholesterol levels when you switch to low or non fat dairy?

Dietary Guidelines 2015: Why Lift Fat and cholesterol limits but still promote low fat dairy?

In defense of real cheese.


h/t to the always excellent Conscien Health for bringing Gottlieb’s speech to my attention.


Credit for the featured image of dairy cows from the wonderful Trader’s Point Creamery

The Skeptical Cardiologist Answers Good Questions: Retesting For Symptomatic Benign PVCs?

One of the many things I enjoy about writing this blog is the interesting comments and questions that readers post. Many of them stimulate me to better answer and inform my patients.

Here’s one such question (about premature ventricular contractions):

Wondering your opinion on retesting. I’ve had PVCs since I was 15 (63 now) and they have come and gone over the years, attributed to hormones, low potassium, stress, and dehydration/bad diet. Recently they started again and are driving me insane and none of the usual fixes are working. Two ER visits with normal EKGs and my cardiologist all say no worries. I’m thinking maybe I should have another ultrasound, buy MD doesn’t think it’s necessary. I had a perfectly normal cath in 2015 but no tests since. Your thoughts? Thank you.

This was the response I typed off the top of my head:

Good question. I consider retesting for patients who have not had documentation of “structurally normal heart” for some time and who have a significant change in their symptoms. You would qualify since no testing in 3 years and worsened symptoms.
Typically I would order a stress echocardiogram which allows a reassessment of both LV structure and function and for any blockage in the coronary arteries and I would consider some kind of monitor-a 24 hour Holter would be fine if you are having daily symptoms.
You might also consider acquiring an AliveCor device to monitor your rhythm with symptoms. I’ve written a lot about this elsewhere on this site. Unfortunately AliveCor does not identify PVCs but if you connect via KardiaPro with your physician your recordings can be viewed and interpreted by him/her.

The answer reflects my clinical practice, which is based on 30 years of experience taking care of patients with PVCs, in conjunction with regularly reading papers, reviews and guidelines in this area.

Periodically, both for specific patient problems and for blog questions, I will search the medical/scientific literature and review guideline publications to see if there is any new information that I am unaware of to ensure that my recommendations are scientifically grounded.

In this case, a more prolonged search of the literature did not yield precise guidance on the frequency of retesting of patients with benign PVCs.

This 2014 guideline comments briefly on the evaluation and treatment of PVCs without structural heart disease (SHD):

In the absence of SHD, the most common indication for treating PVCs remains the presence of symptoms that are not improved by explanation of their benign nature and reassurance from the physician.

In addition, some patients may require treatment for frequent asymptomatic PVCs if longitudinal imaging surveillance reveals an interval decline in LV systolic function or an increase in chamber volume.

For patients with  >10,000 PVCs/24 h, follow-up with repeat echocardiography and Holter monitoring should be considered.

In patients with fewer PVCs, further investigation is only necessary should symptoms increase.

It should also be recognized that PVC burden often fluctuates over time.

This initial testing approach corresponds closely to what I wrote in my post on benign PVCs here.

Retesting with echocardiography and Holter monitoring is advised for those few patients who have lots of PVCs, but the frequency of this retesting is not specified and cardiologists have to use their best judgement, balancing the cost (to patient and to society) and patient safety.  Most cardiologists will err on the side of more frequent repeat testing for a variety of reasons.

Personally, I will advise an annual echocardiogram to such patients since they are at a higher risk of developing a cardiomyopathy.

In the absence of really frequent PVCs (>10,000 per 24 hours is a nice round number, but the precise cut-off is debatable), we should probably only repeat testing if the patient recognizes a significant change in their symptoms.

The reader clearly fits into that category, and retesting in her will provide reassurance that all is still good with her heart. This, in turn, should help with managing symptoms and preventing recurrent ER visits.

The final question (and the toughest) that we could pose related to retesting is “What is the time interval that one should wait before retesting in a patient with worsened symptoms?”

For example, if the reader had a normal echocardiogram 6 months ago should we repeat it when symptoms worsen? My reflex answer would be no, but at some time interval depending on the individual characteristics of the case-patient risks for heart disease, patient anxiety levels, patient symptom severity and frequency, the answer would become yes.

Cardiologists have to answer dozens of questions like this daily.  There is no science to inform a precise answer, consequently the answers will vary wildly from one cardiologist to another depending on a variety of factors specific to the cardiologist.

Those cardiologist-specific factors are complex and sometimes controversial. Part of this makes up the art of medicine and part reflects the business of medicine. They are definitely worthy of another post when time permits.

Questioningly Yours,

-ACP

N.B. The Eternal Fiancee’ (my layperson surrogate) expressed surprise that one could have 10 000 PVCs per day. I told her that if your heart beats roughly once per second (6o beats per minute) since there are  60 x 60 x 24 = 86400 seconds in a day, your heart beats almost 90 000 times in 24 hours.

Thus, roughly  1 in 9 beats is a PVC.

Low-Fat Versus Low-Carb Diet: DIETFITS Show Both Can Work If They Are “Healthy”

In the ongoing nutritional war between adherents of low-fat and low-carb diets, the skeptical cardiologist has generally weighed in on the side of lower carbs for weight loss and cardiovascular health.

I’ve questioned the vilification of saturated fat and emphasized the dangers of added sugar. I’ve even dabbled in nutritional ketosis.

The science in  nutrition is gradually advancing and the DIETFITS study recently published in JAMA is a welcome addition.

DIETFITS is a  really well done study which provides important insights into three huge questions about optimal diet:

  1. Should we choose a low-fat or a  low-carb diet for  weight loss and cardiovascular health?
  2. Do baseline insulin dynamics predict who will respond to low-fat versus low-carb diet?
  3. Can we predict who will respond to low-fat versus low-carb by genetic testing?

The Details Of DIETFITS

Stanford investigators recruited 609 San Francisco area individuals between the ages of 18 to 50 years with BMI of 28 to 40  and randomized them to a “healthy” low-fat diet or a “healthy” low-carb diet.

During the first 8 weeks of the study, low-fat participants were instructed to reduce fat consumption to <20 gm/ day while the low carb participants were instructed to reduce digestible carbohydrate to <20 gms/day.

Then individuals were allowed to add back fats or carbs back to their diets in increments of 5 to 15 g/d per week until “they reached the lowest level of intake they believed could be maintained indefinitely.”  Importantly no explicit instructions for energy restriction were given.

The “healthy” instructions for both groups were as follows

  1. maximize vegetable intake
  2. minimize intake of added sugar, refined flours and trans-fats
  3. focus on whole foods that are minimally processed, nutrient dense and prepared at home whenever possible

Dietfits Outcomes-Diet And Weight

Major findings

  1. Total energy intake was reduced by 500-600 kcal/d for both groups
  2. The low-fat vs the low-carb intake at 12 months was 48% versus 30% for carbs, 29 vs 43% for fat and 21 vs 23% for protein.
  3. Mean 12 months weight change was -5.3 kg for low-fat vs 6-6.0 kg for low-carb which was not significantly different
  4. There was no difference between groups in body fat percentage or waist circumference
  5. Both diets improved lipid profiles and lowered blood pressure, insulin and glucose levels
  6. LDL (bad cholesterol) declined more in the low-fat group whereas HDL (good cholesterol) increased more and triglycerides declined more in the low-carb group.

Thus both diets were successful for weight loss and both improved risk markers for cardiovascular disease after a year.

DIETFITS- Can Genes and Insulin resistance Predict Best Diet?

Surprisingly, the study found no significant diet-genotype interaction and no diet-insulin secretion interaction with weight loss.

This means that they could not predict (as many believed based on earlier studies) who will benefit from a low carb diet based on either currently available genetic testing or a generally accepted measure of insulin resistance.

As the authors point out, these findings “highlight the importance of conducting large, appropriately powered trials such as DIETFITS for validating early exploratory analyses.”

DIETFITS-Perspectives

As you can imagine this study has led to quite an uproar and backlash from dedicated combatants in the macronutrient wars.

A reasoned summary and response from Andreas Eenfeldt, a low carb proponent can be found on his excellent low carb/keto Diet Doctor site here.

Eenfeldt concludes

If I’m allowed to speculate, the reason that we did not see any major additional benefit from low carb in this study is that the groups ended up so similar when it came to bad carbs. The low-fat group ended up eating fewer carbs too (!) and significantly less sugar, while the low-carb group ended with a somewhat weak low-carb diet, reporting 130 grams of carbs per day.

Eenfeldt emphasizes that low-fat diets never “win” these macronutrient dietary skirmishes:

On the whole, this study adds to the 57 earlier studies (RCTs) comparing low carb and low fat for weight loss.

From a standing of 29 wins for low carb, zero for low fat and 28 draws, we now have 29 wins for low carb and 29 draws. The wins for low fat stay at zero.

Larry Husten at Cardiobrief.org in his analysis of the study quotes a number of experts including Gary Taubes, the low carb pioneering journalist

Taubes speculates “that the weight loss may have been similar not because any diet works if you stick with it and cut calories (one possible interpretation) but because of what these diets had in common — avoid sugar, refined grains, processed foods. Whether the low-carb arm would have done even better had Gardner kept their carbohydrates low is something this study can’t say. (And Ornish [low-fat diet proponent] would probably say the same thing about fat consumption.)”

The low-fat or vegan disciples seem to have had a muted response to this study. I can’t find anything from John McDougal , Dean Ornish, Caldwell Esselstyn or Joel Fuhrman.

Readers feel free to leave comments which  link to relevant analysis from the low-fat proponents.

Dietfits-Perspective Of The Participants

Julia Volluz at Vox wrote a fascinating piece recently which involved interviewing some of the participants in this study.

She points out that although the average DIETFITS participant lost over 10 pounds, “Some people lost more than 60 pounds, and others gained more than 20 during the year.”

LOW_FAT_LOW_CARBS_DIETS1__1_

She obtained permission from the lead author, Christopher Gardner  and interviewed  “Dawn, Denis, Elizabeth*, and Todd — two low-fat dieters and two low-carb dieters — about their experiences of succeeding or faltering in trying to slim down”

LOW_FAT_LOW_CARBS_DIETS1

I highly recommend reading the entire article for details but Volluz concludes

And that leads us to one of the burning mysteries of diets: how to explain why some people fail where others succeed — or the extreme variation in responses. Right now, science doesn’t have compelling answers, but the unifying theme from the four study participants should be instructive: The particulars of their diets — how many carbs or how much fat they were eating — were almost afterthoughts. Instead, it was their jobs, life circumstances, and where they lived that nudged them toward better health or crashing.

DIETFITS-Importance of “Healthy” Diet

Most likely the success of both of these diets is due to the instruction that both groups received on following a “healthy” diet. This guidance is remarkably similar to what I advocate and is something that combatants in the diet wars ranging from paleo to vegan can agree on.

The JAMA paper only provides the description I listed above but Volluz adds that participants were instructed to:

… focus on whole, real foods that were mostly prepared at home when possible, and specifically included as many vegetables as possible, every day … choose lean grass-fed and pasture-raised animal foods as well as sustainable fish ... eliminate, as much as possible, processed food products, including those with added sugars, refined white flour products, or trans-fats … prepare as much of their own food as possible. …

Indeed, if you want to see a very detailed description of the instructional process for participants check out the very detailed description of the methods here.

Yours in Health,

-ACP

N.B. I was searching for a reasoned response to this study from the low fat camp and to my surprise came across this fascinating video featuring the lead author of the study, Christopher Gardner, on (no fat/vegan) John McDougal’s YouTube site. Gardner is clearly on the side of sustainable, local , ethical food consumption but to his credit, his research , publications and comments on DIETFITS don’t reveal this.