Tag Archives: soluble fiber

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

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.

 

Cheerios, Soluble Fiber and Your Heart

IMG_3239The 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 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)

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 GM 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.”

For those concerned about GMO  the package also states “not made with genetically modified ingredients”

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.

Should We Be Treating High Cholesterol or 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. The recently revised cholesterol guidelines endorse the concept of treating risk of atherosclerosis rather than cholesterol levels.

Eat Real Foods, Mostly Plants, Not Too Much

If you follow Michael Pollan’s simple 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 healthy food choice.

To quote David Katz

Wholesome foods in sensible combinations, as prevail in the world’s Blue Zones, seemingly take care of all nutrients, by focusing on none. Such dietary patterns can be low in fat, as vegan and traditional Asian diets tend to be; or high in fat, as Mediterranean diets tend to be. Variations on a common theme nicely accommodate personal preference, allowing us all to find a dietary pattern to love that loves our health back.

Addendum

As promised, for those with inquiring minds and oatmeal-induced fortitude, I present from a recent review of fiber some discussion of proposed mechanisms of cholesterol lowering

The mechanism by which fiber lowers blood cholesterol remains undefined. Evidence suggests that some soluble fibers bind bile acids or cholesterol during the intraluminal formation of micelles. The resulting reduction in the cholesterol content of liver cells leads to an up-regulation of the LDL receptors and thus increased clearance of LDL cholesterol. However, increased bile acid excretion may not be sufficient to account for the observed cholesterol reduction. Other suggested mechanisms include inhibition of hepatic fatty acid synthesis by products of fermentation (production of short-chain fatty acids such as acetate, butyrate, propionate) ; changes in intestinal motility; fibers with high viscosity causing slowed absorption of macronutrients, leading to increased insulin sensitivity; and increased satiety, leading to lower overall energy intake.

and their take on soluble fibers overall importance

The modest reductions in cholesterol expected from intakes of soluble fiber within practical ranges may exert only a small effect on the risk of heart disease. For example, daily intake of 3 g soluble fiber from either 3 apples or 3 bowls (28-g servings) of oatmeal can decrease total cholesterol by ≈0.129 mmol/L (5 mg/dL), a ≈2% reduction. On the basis of estimates from clinical studies of cholesterol treatment,, this could lower the incidence of coronary artery disease by ≈4%.

and a comment on publication bias: the finding that studies that do not show a positive effect of the intervention tend not to get published.

Publication bias toward studies that showed positive results is always a potential issue in meta-analyses and could be operating in this study. If this were true, then the small effect estimates associated with intake of dietary soluble fiber would be further attenuated, further highlighting the need for conservative public health claims. The major benefit from eating fiber-rich foods may be a change in dietary pattern, resulting in a diet that is lower in saturated and trans-unsaturated fats and cholesterol and higher in protective nutrients such as unsaturated fatty acids, minerals, folate, and antioxidant vitamins.