A recent paper in JAMA and a Seinfeld episode shed some light on the change in diet and fat consumption in Americans initiated by national nutritional recommendations beginning in the 1970s.
Based on weak to nonexistent scientific evidence Americans were told to consume less total fat and cut saturated fat consumption to less than 10% of calories.
The paper shows that women in the St. Paul-Minneapolis area followed this advice and cut fat consumption as a % of total calories from 38.4% in 1980-1982 to 30.6% in 1995-1997. Saturated fatty acids dropped from 13.5 to 10.5%. (Since then, total fat % and SFA % has drifted slightly upward and calories downward )(for the full table see fat consumption table (PDF))
Media summaries and reports on this paper have emphasized that Americans have failed to cut their saturated fat consumption to meet recommendations of the USDA (<10%) and the American Heart Association (<6%) with a call for more promotion of these (mis)guidelines.
The skeptical cardiologist has a different take.
Interestingly total calories during these time intervals went up from 1645 to 1851. Thus, in replacement of the fat calories, the women were consuming the carbohydrates and sugars the food industry had obligingly added to food to make it more palatable, “heart healthy” and comply with guidelines.
The authors discuss the fact that during these time intervals, despite slashing fat consumption, overall rates of obesity substantially rose. Their explanation was that the women were “underreporting” fat consumption.
A simpler and more compelling explanation is that replacement of fat with carbohydrates along with overall increase in calorie consumption was the culprit.
The Non-Fat Yogurt Scam and Seinfeld
One ongoing contributor to the phenemon of replacing healthy real food fats with engineered, highly processed and highly sugared foods is the yogurt industry.
I wrote about the non fat yogurt scam about a year ago in this post.
I happened to see the fantastic Seinfeld episode “The Non-Fat Yogurt” last night . In this episode Jerry, Elaine and George eat at a non-fat frozen yogurt shop. Everyone concurs that the yogurt is surprisingly delicious given that it is “non-fat” and begin eating it regularly. Jerry and Elaine gain weight and begin suspecting that the yogurt is not truly “non-fat”.
This episode aired in 1993 during the height of the shift toward unhealthy low fat, processed substitutes. An analysis of the yogurt revealed that it was not non-fat and this is why they were gaining weight. In reality, people get fat on truly non-fat yogurt (even Greek Yogurt) and non-fat cookies and non-fat smoothies and anything with added sugar.
Fat consumption doesn’t make you fat.
Enjoy this snippet from the episode (and please excuse the bad language)
Every time I see a patient in my office I review in detail the medications the patient is taking. My office staff and I obsessively work on making sure the list I have in my electronic medical record matches exactly what the patient is taking.
As I review the medications I am asking myself the following questions:
Does the patient need this medication?
Is he/she having side effects from the medications?
Is this the right dosage?
Are there any interactions between the medications that are important?
Is there a cheaper or safer alternative?
For many patients, I will reduce or stop what I consider to be unnecessary medications. Often this results in the patient feeling better, sometimes this is live-saving.
Dr. John Mandrola (electrophysiologist and former colleague of mine in my former cardiology practice in Louisville, KY) writes an excellent blog at DrJohnM.org and has recently encouraged us all to ponder deprescribing, a verb that describes the process of stopping potentially inappropriate medications.
I encourage you to read his post (here) on deprescribing and his other informative posts on topics related to reducing inflammation in our lives, atrial fibrillation and cycling .
Since putting this post together, I saw a patient in my office whose mother would greatly benefit from deprescribing. My patient and I had in previous visits mutually decided that he did not need to be on a statin drug as he had had myalgia side effects from Lipitor and when we looked at his carotid artery it was not abnormally thickened and had no plaque. He asked me if his 95 year old mother (who is not my patient) should be taking Welchol and Zetia.
Zetia is a very expensive, brand name cholesterol lowering drug that has never been shown to improve cardiovascular outcomes despite effectively lowering the LDL or bad cholesterol. I never prescribe it.
Welchol is an expensive, brand name cholesterol lowering drug which has I only use in patients who have markedly elevated LDL cholesterol levels and evidence of marked atherosclerosis. It commonly causes constipation. I rarely prescribe it.
The data for treating cholesterol in patients over age 75 is lacking and by the time patients reach age 95 the risks of these drugs likely outweigh any benefits.
I think my patient’s 95 year old mother would greatly benefit from a healthy dose of deprescribing!
.The other day I received a letter from the “International Association of Cardiologists”. They informed me that I had been named one of “The Leading Physicians of the World”. My initial reaction to this was “Great! Somebody has finally recognized my mad doctoring skills.”
However, being the skeptical cardiologist I am naturally suspicious of any organization with which I am totally unfamiliar, bestowing honors upon me. I decided to look further into this organization since it is likely that patients may be making decisions on what doctors to see based on these types of “honors.”
How Do You Pick a Cardiologist?
It is extremely hard for the average patient to decide which cardiologist they should see. Reputation does not always correlate with competence. A good bedside manner doesn’t mean a doctor knows what is he doing. There is no way to view doctors’ quality of care statistics. Cardiologists who order lots of tests might seem to be on top of things but are the tests really indicated? Bad doctors can come from really good training programs and great doctors can come from weak training programs.
A useful starting point is to look for a cardiologist board-certified in cardiology and with FACC after their name. The American College of Cardiology (ACC) is our main organization and becoming a fellow in the college (FACC) means you have successfully completed a credentialed cardiology training program.
What does an honor like “Leading Physician of the World” mean?
I called the telephone number in the letter and began a fascinating conversation. After a few superficial questions about what kind of practice I was in, how long I had been in practice, and what my specialties were, the woman congratulated me on being a “very successful physician” and told me I had been honored as one of “The Leading Physicians of The World” and would accrue all the benefits of this status.
Benefits including publication in the “Leading Health Care Workers of the world” book and a listing in the “find a top doc” registry.
What followed was a classic high pressure marketing spiel. The best level, it seemed, for me was the “Diamond Level.” For only $969 up front, another $199 when my biography was published, and a monthly fee of $34.95, I would be featured in the prestigious diamond section of the book. The other benefits of the diamond section were a free gift and a companion airline ticket voucher worth up to $550. Cardiologists, she told me, usually went with this level because the airline ticket voucher was “cost-effective “.
When I said “I am not interested in paying any money” she told me that the Platinum level at $769 up front would then be a better fit. This continued through multiple precious metal levels and declining fees with associated smaller page listings until it became apparent that there was no level that did not require the monthly $34.95 fee and I ended the conversation.
After this experience it has become clear to me that this organization exists entirely to make money and the honors it bestows and its publications are meaningless. Doctors recognized by this organization are not necessarily special, leading, or at the top of their profession, they just elected to pay for a meaningless honor (or they mistakenly considered it an honor) perhaps in the hopes that it would generate more business.
Personally, I would be embarrassed to have such a listing and as a patient I would shy away from doctors who are paying for it.
The website for The Leading Physicians of the World is very slick and professional looking and states that the purpose of the organization is
“The Leading Physicians of the World was founded on the idea that personal achievement is deserving of recognition and reward. Through a variety of benefits offered LPW honors our selected physicians through massive multi media exposure in an effort to place consumers in the hands of the right doctor.”
and that physicians are
“Selected for their experience, forward thinking, and highest quality of care, The Leading Physicians of the World, are the most distinguished and desired medical professionals from every specialty.aaa (sic)”
In reality, this organization is a sham, there is no attempt to assess the “forward thinking” or “quality of care” of the physicians listed, the only thing that matters is the dollars the doctors paid.
The other benefit that I was offered if I paid up was a listing in “findatopdoc.com”. This website performs a search for doctors by specialty and by location and claims that you can make an instant appointment with the top docs identified in the search. Three cardiologists in the St. Louis area came up. When I clicked to make an appointment, the button was inactive.
Finding a good cardiologist is a very difficult process. I’ll write more on this in future posts. It is unfortunate that companies like “The International Association of Cardiologists”, “The International Association of Health Care Professionals” (and all of its International Associations of ____) and “findatopdoc.com” are preying on patients who are looking for guidance in the process.
The other night I had the best cioppino I have ever had. I’ve had variations of this wonderful tomato-based seafood stew all over the world (including the legendary bouillabaisse in Marseilles) but I left my heart with the Dungeness crab cioppino served at Sotto Mare Oysteria and Seafood restaurant in North Beach, San Francisco. It makes sense, since cioppino was invented by Genoan fishermen from the SF Bay Area in the 19th century who threw together the freshest catch from their day at sea.
The recipe for Sotto Mare’s cioppino is actually available online as follows:
¼ cup olive oil
1 tsp. crushed red chile flakes
8 cloves garlic, finely chopped
3 cups fish stock
1 ½ cups whole peeled tomatoes in juice, crushed
10 leaves basil
1 lb. cod, cut into 2″ chunks
1 lb. cleaned calamari, bodies cut into ½″-wide rings
12 oz. medium shrimp, deveined
12 oz. bay scallops
16 clams, cleaned
16 mussels, cleaned
2 2-lb. Dungeness crabs or snow crab legs, halved
Kosher salt and freshly ground black pepper, to taste
It involves a lot of shellfish: calamari, shrimp, scallop, clams, mussels, crabs and I think a large part of what made it so good was the freshness of the shellfish obtained from the nearby Pacific Ocean.
Shellfish, Dietary Cholesterol and Cardiovascular Risk
Shellfish contain a lot of cholesterol and many of my patients have been told to minimize or avoid shellfish, especially shrimp, due to concerns they will exceed the (completely arbitrary) 300 mg daily limit suggested by the American Heart Association and the USDA nutritional guidelines.
There is no scientific basis for being concerned about the amount of cholesterol one consumes when eating shellfish (or for any food for that matter, as I previously wrote about with regard to eggs here)
But there are definitely warnings out there on the internet and traditional new media from seemingly responsible authorities.
“Since our bodies make plenty of cholesterol for our needs,we do not need to add any in our diet. Cholesterol is found in all foods that come from animals: red meat, poultry, fish, eggs, milk, cheese, yogurt, and every other meat and dairy product. Choosing lean cuts of meat is not enough; the cholesterol is mainly in the lean portion. Many people are surprised to learn that chicken contains as much cholesterol as beef. Every four-ounce serving of beef or chicken contains 100 milligrams of cholesterol. Also, most shellfish are very high in cholesterol. All animal products should be avoided for this reason. “
The Physician Committee for Responsible Medicine appears to be a front for vegan-promotion. They go on to state that every 100 mg of cholesterol you consume raises your cholesterol by 5 mg/dl and that
“Every time you reduce your cholesterol level by 1 percent, you reduce your risk of heart disease by 2 percent. For example, a reduction from 300 mg/dl to 200 mg/dl (i.e., a one-third reduction) will yield a two-thirds reduction in the risk of a heart attack”
A Fox News publication simultaneously extolls the virtues of shrimp consumption (noting that “three ounces of shrimp (or about seven medium-sized shrimp) has a mere 84 calories, 1g of fat, and an impressive 18g of lean protein” and that they are a great source of selenium, “an antioxidant that fights cancer-causing free radicals in your body”) and warns you against eating it (“If you are watching your cholesterol, it’s best to go easy on shrimp because four large shrimp have 42.5mg of cholesterol”)
Other publications advise those with high cholesterol or higher risk of heart disease to choose low-cholesterol varieties of shellfish over shrimp.
The Science Supporting Shrimp
Let’s look at what is actually known about consuming shrimp and shellfish.
A study of over 13,000 subjects (the ARIC study) found no increased risk of cardiovascular disease in the high shellfish consumers versus the low shellfish consumers.
A study in 1996 compared consuming a diet with 300 grams (about 10 oz.) of steamed shrimp/day (providing 590 mg of cholesterol daily) versus a baseline diet of 107 mg/ cholesterol in 18 individuals without cholesterol problems. The shrimp consumers compared to baseline had a 7% higher LDL or bad cholesterol but a 12% higher HDL or good cholesterol. Thus, the ratio of total to good cholesterol went down. We now know that this ratio is a much more important risk marker for cardiovascular disease than the total cholesterol. Triglycerides dropped significantly when subjects were consuming shrimp versus the baseline, low cholesterol diet.
A 1990 study looked at multiple different types of shellfish substituted for meat, cheese and eggs, and found that oyster, clam, crab and mussel diets (with lower cholesterol and higher omega-3 fatty acid profiles) lowered VLDL triglycerides and VLDL cholesterol. These shellfish diets, except for the mussel diet, also lowered LDL and total cholesterol. Shrimp and squid had no effect on the lipid profiles.
Benefits of Shrimp and Shellfish Consumption
I’ve focused on shrimp in this post because it has the highest cholesterol content of all shellfish and therefore is the most likely to be considered bad for heart patients or patients with high cholesterol. I’m presuming if I can convince you that shrimp are heart healthy, then you will believe that all shellfish are.
Take a look at this chart of the nutrient composition of shrimp and you can understand that, once you eliminate unsubstantiated fears of the cholesterol content, this a great food.
I am not a big advocate of examining the macronutrient composition of foods in order to predict their health benefits. This approach to nutritional science resulted in the development of highly processed low-fat monstrosities that currently sit in boxes and bags and line the most prominent parts of supermarket shelves. The overall effect of foods on the cardiovascular system depends on an incredibly complicated interaction of food components, bacteria in the gut and genetic predispositions: areas we are only beginning to understand. However, for those readers who are concerned about such things there is reassurance.
Start with the fact that there are no carbohydrates in shellfish: since carbs and added sugar are likely the biggest culprits in our obesity epidemic, shrimp and shellfish are great tools in helping to manage weight. Shrimp have a very high percentage and quality of protein content for muscle building.
Some avid shrimp promoters insist that shrimp should be consumed regularly to reduce the risk of both cancer and heart disease. The fat in shrimp is mostly polyunsaturated fat with a high ratio of omega-3 to omega-6 which is considered optimal . Eating 100 ounces of shrimp daily gives you 180 mg of EPA and DHA (considered the most important of the omega-3 fish oils for heart health) daily, close to the 250 mg daily the USDA recommends for most adults.
Astaxanthin has been found to be a potent natural antioxidant, exceeding ten times the antioxidant activity of β-carotene and 500 times that of α-tocopherol. The astaxanthin level of wild shrimps has been reported to vary between 740 and 1400 μg/100 g in edible meat portions.
If I were a vegan or vegetarian I would consider slipping shrimp into my dishes instead of tofu.
The cioppino recipe above doesn’t add a lot to the shellfish and fish: a little olive oil and tomatoes, basil and garlic-these things are not going to jack up the calories, sugar or fat content.
Depending on how you cook shrimp, the resulting dish will have markedly different nutrient composition compared to the raw nutrients listed above.
Breading and deep frying the shrimp takes 3 oz from 60 calories to 206 and the fat grams from 1 to 10. I suspect that you or your body will figure this out and eat less later. Given the fairly low fat and carbohydrate content of the Sotto Mare cioppino, I am ashamed to admit, I ate that whole bowl pictured above (which the menu said could be shared between two).
The SOSC doesn’t share my love of cioppino; she ordered the linguine with clam sauce. Three ounces of clams have only 26 mg of cholesterol but it seems to me the majority of calories in this dish are coming from the carbs in the pasta and whatever the composition of the sauce is. In any event, the SOSC pronounced it the best she has ever had.
Mercury in Shellfish
The level of mercury is a concern in all the fish that we consume. Fortunately a recent study from Maine University found that shrimp is very low in mercury. This included varieties from Thai shrimp farms, Maine shrimp farms and the Gulf of Mexico. In comparison to other types of fish, shellfish are universally on the low end of the mercury level graph as shown below.
Fear neither the cholesterol nor the mercury in shrimp and consume your cioppino with gusto and without guilt!
The skeptical cardiologist dislikes running. When I start running my whole body seems to be telling me I am making a serious mistake. After running, my knees hurt (worse than the normal level of pain) and if I do enough of it, my hips hurt too.
Despite this, I have incorporated running into my exercise routine over the last few years since I stopped playing tennis. I primarily get my aerobic exercise now by using elliptical type devices and I try to get at least 150 minutes of vigorous elliptical work per week. About once a week, I run a mile on a treadmill at 6 MPH.
My current patient exercise recommendation is for 150 minutes of moderate intensity aerobic exercise. I have advised patients in the past, that walking at a moderate pace was adequate exercise, and I’ve felt, based on prior studies, that running was not necessary to achieve the cardiovascular benefits of exercise.
Any Running Associated With Lower Risk of Dying
A new study published recently in JACC has made me reconsider this advice.
As part of a prospective longitudinal cohort study at the Cooper Clinic in Dallas, Texas, Lee, et al. looked at data from a group of 55,137 adults on whom they had information on running or jogging activity during the previous 3 months.
To reduce confounding bias in the association between running and mortality, the total amount of other physical activities except running was adjusted in all multivariable regression models.
They obtained information on death from The National Death Index and over 15 years found 3,413 all-cause death and 1,217 deaths from cardiovascular disease.
Those individuals who described themselves as having done any running in the last 3 months had a 30% lower risk of all-cause mortality and a 45% lower cardiovascular mortality.
As you might expect, the non-runners were older, smoked more and were fatter. The investigators ran analyses that controlled for the differences in these factors. The protective effect of running, even a small amount, persisted, regardless of age, gender, body mass index, smoking or alcohol consumption.
Amazingly, it didn’t matter how much you ran.
This finding is quite remarkable.
Those who ran <51 minutes per week did just as well as those who ran >176 minutes per week.
Of the 20,67 that had two examinations, those who were runners at both examinations had the best outcomes with a 50% lower risk of CVD mortality.
These findings are not definitive. We need more studies in this area but they are food for thought.
Why Would Running Be A Better Form of Exercise For Your Heart
Perhaps the person who doesn’t want to run has a fundamentally different mindset about his/her health than the person who is willing to run just a little bit. Does this inclination to run mirror the person’s overall approach to their health? We can assess factors like cigarette smoking, obesity, diabetes and cholesterol but there are likely (so far) intangible factors that contribute to our health that tend to cluster with a pro-active health attitude.
Why do I run? After all, I don’t like it, it hurts my knees and I didn’t think it was contributing to my overall health. I did the mile run for a few reasons:
Running a mile in 10 minutes served as a milestone, a fixed goal if you will, for my cardiovascular fitness. I can get a very good idea of where I’m at by measuring my heart rate. I’m 60 years old and my predicted maximal heart rate (220 minus age) is 160. When I’m out of shape, my heart rate will get as high as 155 BPM during the mile, when in shape it is 10 BPM lower. 145 BPM is 91% of my predicted maximal HR.
My sense is that a good goal for cardiovascular fitness is to get the heart rate up to 90% or so of your predicted maximal. It may be that running more reliably gets you to that threshold than other activities.
Also, as the significant other of the skeptical cardiologist points out, “you can’t cheat at running.” There’s a certain amount of effort you have to put into it and there’s no way to escape it as there is on a bicycle or an elliptical. With walking you could choose a speed ranging from the snail-like up to 4 MPH or so.
Those who don’t run may also have orthopedic limitations (plantar fasciitis, osteoarthritis, rheumatoid arthritis) or pulmonary problems (COPD, asthma) or undiagnosed heart problems (heart failure, valve defects, rhythm problems) that are not captured by the examinations the investigators performed.
These findings, the authors of the paper suggest, may make people more likely to run:
“Because time is one of the strongest barriers to participate in physical activity, this study may motivate more people to start running and continue to run as an attainable health goal for mortality benefits. Compared with moderate-intensity activity, vigorous-intensity activity, such as running, may be a better option for time efficiency, producing similar, if not greater, mortality benefits in 5 to 10 min/day in many healthy but sedentary individuals who may find 15 to 20 min/day of moderate-intensity activity too time consuming.”
Some Possible Mechanisms For The Benefits of Running
As I was putting the finishing touches on this post I notice that the Sept 23 issue of the Journal of the American College of Cardiology sitting in front of me has two articles that are directly relevant to this issue. I haven’t had time to analyze these in detail but the conclusions of the first study are that
“low doses of casual, lifelong exercise do not prevent the decreased compliance and distensibility observed with healthy, sedentary aging. In contrast, 4 to 5 exercise sessions/week throughout adulthood prevent most of these age-related changes”
Thus, the mechanism through which running or more “committed” exercising improves survival could be mediated through improving the diastolic properties of the heart.
I spent most of my academic cardiology career studying diastolic function and it is an incredibly complicated and poorly understood area. Simply put, the heart has to contract to pump out blood (we call this systole) then it has to fill back up with blood (we call this diastole). With aging, the heart’s ability to contract doesn’t change but its ability to fill changes dramatically. Thus, diastolic properties become impaired with aging and this study suggests that dedicated regular exercise prevents that.
The other study showed that regular exercise helps to slow age-related increase in blood pressure. Lower blood pressure with aging could be a mechanism for preventing the age-related decline in diastolic performance of the heart.
Changing Exercise Prescription
From now on when I talk to my patients about exercise, I will inquire about running specifically and I’ll mention these studies which suggest a little running may go along way toward forestalling the aging process of the heart and lowering their risk of dying.
The Skeptical Cardiologist is not just researching low carb diets in The Big Easy. He has also been investigating the effects of marriage on cardiovascular risk.
I and the significant other of the skeptical cardiologist stayed at the wonderful Terrell House, a bed and breakfast nestled among the magnolias on Magazine Street in the Garden District of New Orleans. There, we participated in the marriage of our close friends, Dave and Barb.
Was marrying a heart healthy choice for Dave? for Barb?
Science seems to tell us yes. Marriage has been associated with a lower risk of cardiovascular disease compared to being single or divorced in multiple studies and for both sexes.
A study of the rate at which individuals in Finland developed what are termed acute coronary syndromes or ACS (think of these as heart attacks or heart attacks about to happen) showed that ACS events were approximately 58–66% higher among unmarried men and 60–65% higher in unmarried women, than among married men and women in all age groups.
The chance of dying within 28 days of an ACS were even worse for the unmarried. These mortality rates were found to be 60–168% higher in unmarried men and 71–175% higher in unmarried women, than among married men and women.
This meant a rate of death of 26% in the 35-64-year-old married men, 42% in men who had previously been married, and 51% in never-been-married men. Among women, the corresponding figures were 20%, 32%, and 43%.
As with all such observational studies, association does not prove causation.
How on earth does being married confer a lower risk of developing cardiac problems and halving of the death rate once one has an ACS?
Some speculation from the authors:
1. Perhaps a poor health status leads to not getting married or getting divorced more frequently.
2. Perhaps married people have better health habits and enjoy higher levels of social support than the unmarried which promotes lower risk
3. Perhaps prospects in the pre-hospital phase are better because of earlier intervention (wife bugging husband to get that indigestion checked out)
Do I believe that Dave and Barb have suddenly halved their risk of dying from cardiovascular disease because they tied the knot last night? Not at all!
Nothing has fundamentally changed in their lives that I can see that will have any significant impact on either one’s risk of a heart attack.
If Dave were a true bachelor and not in a committed monogamous relationship I can see certain factors that marriage would modify: perhaps unmarried Dave would be more inclined to engage in risky behaviors such as binge drinking, cigarette smoking, unhealthy food consumption or staying out late partying and listening to wild music. Perhaps married Dave’s wife will be watching over him carefully for any signs or symptoms of heart disease and encouraging an early visit to the doctor to get checked out.
Perhaps the presence of kids limits the married parents engagement in risky or unhealthy behaviors either because the parents are spending more time parenting than partying or because they are trying to serve as role models.
Perhaps, and this is likely unmeasurable, it is the “love” in the relationship (and the associated change in neurohormonal milieu) that lowers stress and inflammation and is crucial in stopping atherosclerosis.
Two individuals living together in a committed and loving relationship would seem to have these same factors on their side and I can’t fathom how the legal or religious sanctioning of their union modifies those factors favorably.
Unfortunately, the myriad studies that have been published on this topic totally fail to capture the important distinction between single and unattached and single but living in a committed and loving relationship.
In any event, in the immortal words from my toast to them last night:
“May your fights be short and your apologies many
May your desire to be in each other’s company grow stronger every year
And may all your bartenders look like Alan Alda”
Here’s to Barb and Dave and marriage and less death!
The Skeptical Cardiologist is in New Orleans this weekend on a dedicated quest to research low carb diets.
The low fat diets recommended by government guidelines and national organizations like the American Heart Association don’t help most individuals lose weight and they don’t lower the risk of heart disease. It’s very hard to understand why these are still promulgated by these organizations.
Some diets, such as the Atkins, South Beach and Paleo diets, advocate very low carbohydrate consumption and have helped many successfully lose weight. However, due to the high fat in such diets, there has been concern about their overall effect on cholesterol levels and heart disease.
A new study published in the Annals of Internal Medicine addressed the question of which of these dietary approaches is best. Researchers at Tulane University (located inNew Orleans!) randomly divided 148 obese (BMI>30) men and women (88% were women and 51% were black) into two groups: a low-carbohydrate group that was encouraged to consume no more than 40 grams of carbohydrates per day (the amount of two slices of bread), and a low-fat group, which was encouraged to consume less than 30 percent of their calories from fat and 55 percent from carbohydrates (based on the National Education Cholesterol Program guidelines).
Interestingly neither group was instructed to lower their overall calorie consumption and both groups were instructed NOT to change their overall physical activity level (the researchers were trying to minimize factors effecting their results other than the percentage of fat/carbs).
The funding source for the study was the National Institutes of Health so we can consider the study unbiased by industry.
After 12 months, the low-fat group had lost 1.8 kg (2.2lbs=1kg) and the low-carb group had lost 5.3 kg.
The low-carb group had lost 8 pounds more, a difference that was highly statistically significant (p<.001).
In addition, in the low-carb group fat mass had declined by 1.2% whereas it had risen by 0.3% in the low-fat group.
In other words, the low-carb group was losing body fat but the low-fat group was just losing lean body mass.
My patients, like most Americans, have had the lie that fat consumption causes obesity and contributes to fatty plaques in their arteries drummed into their heads for decades and fear low-carb diets because of concerns that they will cause their cholesterol levels to rise and increase their risk of heart disease.
This new study, however, showed that the low-carb diet (with almost double the amount of saturated fat consumed compared to low-fat diet) actually improved the subjects’ heart risk profile.
Low Carb Diet Improves Cardiac Risk Profile
At 12 months, there was no difference in the total or LDL (bad cholesterol) levels between the two groups. However, the good (HDL) cholesterol had significantly increased in the low-carb group causing a decrease in the ration of total to HDL cholesterol. The low-fat group had no increase in HDL. Triglycerides dropped in both groups but significantly more in the low-carb group.
Atherosclerosis is not just related to the cholesterol profile as I have discussed here, but it is a complex process involving multiple factors, including inflammation. A simple blood test, the C-reactive protein or CRP tracks inflammation. The CRP dropped by 6.7 nmol/L in the low-carb group and rose by 8.6 nm/L in the low-fat group. Lower CRP levels have been associated with lower risk of cardiovascular events in multiple studies.
This was a small study (but actually one of the largest prospective dietary studies available) but really well done.
The major take home points are as follows:
Low-carb diets for many are a very effective weight loss approach
Low-carb diets, even with their higher saturated and overall do not adversely effect the cholesterol profile or increase risk of heart disease.
This study suggests that low-carb diets improve good cholesterol, lower inflammation and are likely, therefore, long term to reduce the risk of heart attacks and strokes.
Realistic Dietary Approaches
I have found the extremely low-carb diets such as Atkins to be very hard for my patients to follow long term. Some modification of the strict limits on carb consumption are necessary I think to make diets interesting and healthy.
Although the goal of this study was to have the low-carb group consume less than 40 grams, the average carb consumption was 93 grams at 6 months and 127 grams at 12 months, a much more sustainable level of carb intake.
The first and most important thing anyone can do if they want to lose weight and improve their cardiovascular risk profile is eliminate added sugar from their diet.
Sugar-sweetened beverages are an easy first step. But equally important is avoiding foods masquerading as healthy due to their low fat content. Low-fat yogurt and smoothies, for example, are loaded with empty sugar calories. You are much better off consuming the full fat varieties as I have pointed out here.
This is the Skeptical Cardiologist signing off from beautiful New Orleans where my next investigation will be on the cardiovascular consequences of crawfish étouffée plus dixieland jazz.
Hopefully by now everyone has gotten the message that atrial fibrillation is associated with stroke (and, most importantly, that we have ways to prevent those associated strokes).
Atrial fibrillation occurs when the normal, regular, synchronous action of the upper chambers of the heart becomes chaotic, rapid and inefficient. Take a look at this video to get a good understanding of what happens in atrial fibrillation:.
How do you know if you have atrial fibrillation?
Some who go into atrial fibrillation know it right away because they feel bad-they feel what we doctors term palpitations:their heart beating rapidly or irregularly (fluttering).They may have other symptoms associated with this such as dizziness, chest pain or shortness of breath. Many, however, go into atrial fibrillation and are not aware of it.
The first symptom they feel may be a stroke due to a clot developing in the upper chambers of the heart dislodging and going down an artery to the brain, a process beautifully (seriously, this is really wonderful and the narrator has a great British accent) animated in this video:
The diagnosis is often made when the patient’s pulse is felt, and an irregularity is noted, or if an ECG is done for some reason (not uncommonly prior to surgery).
Atrial Fibrillation Can Be Diagnosed By Taking Your Pulse
Taking the pulse is an easy, cheap, low-tech technique which is surprisingly good at detecting atrial fibrillation.
The European Society of Cardiology recommends this as a screening technique for all patients over age 65 visiting their family doctor. This is based on a study published in the British Medical Journal in 2007, which compared systematic screening with an electrocardiogram (ECG) to screening by taking the pulse. If the pulse was irregular and ECG was then performed. The measurement of pulse was just as good as the systematic ECG technique.
Take a look at this great video featuring Archie Manning (former Saints great QB and father of Peyton and Eli) here which gives an excellent description of how to take your pulse and what to look for. Please ignore the bad accompanying music and the shameless hospital plug at the end.
Take 15 seconds out of your day, every day, and take your pulse.
Take your friends’ and relatives’ pulse when the opportunity presents itself.
You may help prevent a stroke in you or your loved ones.
The first day I tried to measure my salt consumption was one of the hottest we have had this summer in St. Louis with the thermometer reaching the high 90s and the heat index well over 100. In the midst of this heat I rode my bike to my local gym, worked out on the elliptical for about 35 minutes then rode home. Although the distance i rode was not far (maybe 3 miles) I was sweating profusely.
This profuse sweating was not the norm for me but it clearly was changing my salt “balance” for the day. The optimal amount of salt to consume may be controversial but clearly the more you sweat the more salt you should consume to replace the lost sodium.
“The recommendation for less than 1500 mg/day does not apply to people who lose large amounts of sodium in sweat, such as competitive athletes and workers exposed to extreme heat stress (for example, foundry workers and fire fighters)”
I was back on my elliptical today (after a bike ride that resulted in no sweating) and watched the men playing the round of 16 in The US Open Tennis Tournament on the large TV screens conveniently placed to entertain me. Temperatures have been unusually high In NYC this week and the players have been suffering as a result. The men play best of 5 sets and matches routinely last longer than 3 hours played in the heat of the day with full sun exposure.
Scientists have studied professional tennis players and measured their sweat loss to be as high as 2.5 L/ hour while playing singles in hot circumstances. A liter of sweat contains around 920 mg of sodium.
That means these guys are losing 2.3 grams of sodium per hour of tennis played! This happens to be one teaspoon of salt and equal to the more moderate limit on sodium consumption (compared to the AHA) of the USDA. Clearly, consumption of salt on the order of 8 grams/ day would be needed in these circumstances to maintain salt balance and acceptable sodium levels in the blood.
How much are more normal individuals losing daily and how much does that vary depending on activity, ambient temperature and humidity?
The simple answer has to be that no authority knows the amount of salt each individual loses daily. Sweating and salt loss vary widely between individuals and over time in the same individuals.
It is common for my patients to note that during the summer months their blood pressure drops when they spend time gardening or if they have a job that requires heavy exertion in hot conditions. Often a downward adjustment in blood pressure medications is needed to account for this (especially if a diuretic is one of their BP drugs).
These variations in salt loss in the context of large variations in cardiovascular physiology and blood pressure regulation between individuals is further support for abandoning the ultra-low salt limits suggested by the AHA and the USDA.
Moderation may not be best for all things in diet (processed foods and added sugar come to mind) but for salt consumption moderation appears best.
The updated AHA/ACC Cardiovascular Prevention Guidelines (CPG) which include the excessively wordy “The Treatment of Blood Cholesterol to Reduce Atherosclerotic Cardiovascular Risk in Adults Risk” were published late last year and immediately were the center of controversy.
After working with them for 9 months and using the iPhone app to calculate my patients’ 10 year risk of atherosclerotic cardiovascular disease (ASCVD, primarily heart attacks and strokes) it has become clear to me that the new guidelines will recommend statin therapy to almost all males over the age of 60 and females over the age of 70.
As critics have pointed out, this immediately adds about 10 million individuals to the 40 million or so who are currently taking statins.
Should we be starting all elderly Americans on statin drugs?
My simple answer is no. It doesn’t make sense to do this, because clearly not all elderly individuals have atherosclerosis or will ever develop its consequences of heart attack and stroke. Many have inherited the genes that allowed their parents to live free of heart disease into their 90s and will not benefit at all from long term statin therapy; they may actually suffer the expense and side effects instead.
How can we better decide who among the elderly will benefit from statin therapy?
If you have read my previous posts on searching for subclinical atherosclerosis here and here you probably know the answer. Let’s look at a specific case and apply those principles.
Robert is 69 years old. I see him because, in 2010, the posterior leaflet of his mitral valve ruptured, resulting in the mitral valve becoming severely incompetent at its job of preventing back flow from the left ventricle into the left atrium. I sent him to a cardiac surgeon who repaired the ruptured leaflet. Although he has a form of “heart disease,” this is a form that has nothing to do with cholesterol, hypertension or diabetes and is not associated with ASCVD.
However, it is my job to assess in him, like all individuals, the risk of developing coronary heart disease or ASCVD.
He has no family history of ASCVD and he feels great since the surgery, exercising aerobically 4-5 times per week.
His BMI is 23.87 which is in the normal range. His BP runs 116/80.
His total cholesterol is 210 and LDL or bad cholesterol is 142. Good or HDL cholesterol is 56 and triglycerides 59. The total and LDL cholesterol levels are considered “high,” but they could be perfectly acceptable for this man.
When I ran his 10 year ASCVD risk (risk of developing a heart attack or stroke over the next 10 years), it came back as 14%. The new guidelines would suggest having a conversation with him about starting a statin if his risk is over 7.5%. His risk is double this and statins are definitely recommended in this intermediate risk range. Interestingly, I cannot enter a cholesterol level or blood pressure for a man of this age that yields a risk less than 7.5%.
When I had my discussion with him about his risk for ASCVD, I plugged his numbers into my iPhone and showed him the results and gave him the guideline recommendation.
Lifestyle Changes to Lower Cholesterol
The new Cardiovascular Prevention Guidelines have a section devoted to Lifestyle Management to Reduce Cardiovascular Risk. Unfortunately, none of the lifestyle changes they recommend have been shown to reduce ASCVD risk in an individual like Robert. He already exercises the recommended amount, is at his ideal body weight and eats a healthy diet. If we were to tighten up on his diet by, say reducing red meat, eggs and high fat dairy, all we would accomplish would be to lower his LDL and HDL cholesterol levels and make his life and meals less satisfying. The lower total cholesterol and LDL cholesterol would not lower his risk of ASCVD and the calculated 10 year ASCVD risk would still be in the range where statins are recommended.
Therefore, I am not going to tell Robert that he should reduce his saturated fat consumption (he already has incorporated that into his diet since he’s been bombarded with the low fat mantra for 30 years).
Searching for Subclinical Atherosclerosis
I’m going to tell Robert that we need to know if he has atherosclerosis, the disease that we are attempting to modify.
We started with an ultrasound to look at the lining of the large arteries in his neck that supply blood to the brain, the carotid arteries (a process I describe in more detail here). Although severe atherosclerotic blockages in these arteries put one at risk of a stroke, I was much more interested in the subtle changes in the arteries that precede symptoms and are an early harbinger of atherosclerosis.
Careful ultrasound recording and measurement of the main common carotid arteries from both the left and right side showed that the IMT or thickness was lower than average for his age, gender and ethnicity. His carotid IMT was at the average for a 60 year old, therefore, his so-called vascular age was 60 years, younger than his chronological age. If I plug that age into the ASCVD risk estimator, I get an 8.2% 10 year risk, just barely above the statin treatment cut-off.
Careful scrutiny with ultrasound of the entire visible carotid system in the neck on both sides did not reveal any early fatty plaques or calcium in the lining of the carotid arteries. He had no evidence for atherosclerosis, even very subtle early forms, in this large artery, a finding which is usually predictive of what is going on in the other large arteries in the body, including the coronary arteries, which supply blood to the heart.
At this point, I think, we could have stopped the search for subclinical atherosclerosis and agreed that no statin therapy was warranted. However, Robert wanted further reassurance that his coronary arteries were OK, therefore we set him up with a coronary calcium study (see my full description of this test here).
Searching for Subclinical Atherosclerosis: The Calcium Score
Robert’s coronary calcium score came back at 21 (all in the LAD coronary artery) , which put him at the 26th percentile compared to normal men of his age and gender. A score of 21 is average for a 59 year old man and 82% of men aged 69 have a score greater than zero. Robert had much less calcium in his coronaries than men his age, another factor putting him in a low risk category.
Given the low risk findings from both the vascular screening and the coronary calcium, I felt comfortable recommending no statin therapy and going against the guidelines.
Statins: Better Targets for The Two-edged Sword
This is not an unusual scenario; many of my older patients without heart attacks, strokes or diabetes fall into the risk category that would warrant statin therapy and if they have no clinical or subclinical evidence of atherosclerosis, I don’t advise statin therapy. My patients are free to follow the guidelines and take statin drugs after this advice, but most are very grateful that another pill (which they likely have heard bad things about on the internet or from friends with adverse experiences) can be avoided.
Statins are wonderful drugs when utilized in the right population, but they also carry a 9% increased risk of diabetes and about a 10% real world risk of developing muscle aches and weakness (myalgia).
I think it is essential to aim these two-edged swords at the right targets if we are to maximize the overall health benefits.