Do B Vitamins Reduce Heart Disease Risk?

Written by Dr. Steve Chaney on . Posted in current health articles, Drugs and Health, Health Current Events, Healthy Lifestyle, Supplements and Health, Vitamins and Health

What Role Do B Vitamins Play in a Heart Healthy Lifestyle?

Author: Dr. Stephen Chaney

b vitamins reduce heart attack riskTwo weeks ago I shared some studies that challenge the claim that vitamin E doesn’t reduce heart attack risk. To close out “Heart Health” month, I want to share some information that may change how you think about B vitamins and heart disease risk. Once again, you’ve seen the headlines: “B Vitamins Do Not Reduce the Risk of Heart Disease”. In fact, these headlines have been repeated so many times that virtually every expert thinks that it has to be true. Once again, I’m going to share some information with you that I learned from a seminar by Dr. Jeffrey Blumberg who disagrees with this commonly held belief.

Dr. Blumberg is a Professor in the Friedman School ofNutrition Science and Policy at Tufts. Dr. Blumberg has over 200 publications in peer-reviewed scientific journals. He is considered one of the world’s top experts on supplementation, and his specialty is conducting and analyzing clinical studies. He believes that the media has seriously misinterpreted the studies on B vitamins and heart disease risk. You might call this “The Rest of the Story” because you (and your doctor) definitely did not hear this part of the story in the news.

Do B Vitamins Reduce Heart Disease Risk?

heart disease in menThe study in question is called the “Heart Outcomes Prevention Evaluation-2“. In that study a group of middle aged men and women received 2.5 mg of folate, 50 mg of vitamin B6 and 1 mg of vitamin B12 versus a placebo and were followed for an average of 5 years.

The headlines that you may have seen said “B vitamins do not reduce the risk of major cardiovascular events in patients with vascular disease”. But, the headlines did not tell the whole story.

In the first place, that was only true for heart attacks and cardiovascular death. Strokes were reduced by 25%. I don’t know about you, but I consider strokes to be fairly major.

However, even when we focus on heart attacks and cardiovascular deaths the headlines didn’t tell the whole story. You see, even the best intentioned studies sometimes contain fatal flaws that aren’t obvious until after the study has been completed.

The Flaws In The Study

flawsThere were two major flaws in this study.

Flaw #1 was that 70% of the study subjects were eating foods fortified with folate and had adequate levels of that nutrient in their bloodstream before the study started.

For those people who were already getting enough folate in their diet, B vitamin supplementation didn’t make much of a difference. However, for those people not getting adequate levels of folate in their diet, B vitamin supplementation decreased their risk of heart disease by ~15%.

Flaw #2 was that ~90% of the people in the study had a history of coronary artery disease and most of them were already on cholesterol lowering medications.

To understand why this is a problem you have to understand both the proposed mechanism by which B vitamin supplementation has been proposed to lower the risk of heart disease AND how the cholesterol lowering drugs work.

Deficiencies of folate, B6 and B12 are thought to increase the risk of heart disease because the B vitamin deficiency causes an increase in homocysteinelevels in the blood, and high homocysteine levels are thought to increase inflammation – which is a risk factor for heart disease.  So supplementation with folate, B6 and B12 has been proposed to decrease heart disease risk by decreasing inflammation.

The problem is that the most commonly used cholesterol lowering medications also decrease inflammation.So you might not be surprised to learn that those people who had a history of coronary artery disease(and were taking cholesterol lowering medication that reduces inflammation) did not receive much additional benefit from B vitamin supplementation.

For those people in the study who were not taking cholesterol lowering medication, B vitamin supplementation also reduced their risk of heart attacks by ~15% – but there were too few people in that group for the results to be statistically significant.

So the headlines from this study really should have said “B vitamins do not reduce the risk of heart attacks or cardiovascular deaths in people who are already getting adequate folate from their diet or in people who are taking drugs that reduce the bad effects of B vitamin deficiency”. But that kind of headline just wouldn’t sell any newspapers.

What Does This Study Mean For You?

There are two very important take-home lessons from this study.

Lesson #1:  Once again this study makes the point that supplementation makes the biggest difference when people have an increased need. The studies discussed in Vitamin E and Heart Disease  two weeks ago illustrated increased need because of age, pre-existing disease, and genetic predisposition. This study illustrated increased need because of inadequate diet.

Lesson #2:  This study also illustrates a problem that is becoming increasingly common in studies of supplementation. It is considered unethical to not provide participants in both groups with what is considered the standard of care for medical practice. In today’s world the standard of care includes multiple drugs with multiple side effects, and some of those drugs may have the same mechanism of action as the supplement.

I have discussed this problem in the context of omega-3 fatty acids and heart disease in a previous “Health Tips From the Professor,”  Is Fish Oil Really Snake Oil?   In many cases it is no longer possible to ask whether supplement X reduces the risk of a particular disease. It is now only possible to ask whether supplement X provides any additional benefit for patients who are taking multiple drugs, with multiple side effects. That’s not the question that many of my readers are interested in.

 

The Bottom Line

  • Headlines have proclaimed for years the “B Vitamins Do Not Reduce Heart Disease Risk”. Dr. Jeffrey Bloomberg of Tufts University has reviewed one of the major studies behind this claim and found the headlines to be misleading.
  • For example, the study showed that B vitamin supplementation reduced strokes by 25%, which is a pretty significant finding in itself.
  • When he analyzed the portion of the study looking at heart attacks, he found two major flaws:

#1:  70% of the people in the study were already getting adequate amounts of B vitamins from their diet and would not be expected to benefit from supplementation. For the 30% who weren’t getting adequate amounts of B vitamins from their diet, supplementation reduced their risk of heart attack by 15%.

#2:  90% of the people in the study were taking a drug that masks the beneficial effects of B vitamin supplementation. For the 10% who weren’t taking the drug, supplementation with B vitamins also reduced their risk of heart attack by 15%, but there were too few people in that group for the results to be statistically significant.

Obviously, there were only a handful of people in the study who weren’t getting enough B vitamins from their diet AND weren’t on medication, so we have no idea what the effect of B vitamin supplementation was in that group.

  • Once again this study makes the point that supplementation makes the biggest difference when people have an increased need. The studies discussed in “Health Tips From the Professor” two weeks ago illustrated increased need because of age, pre-existing disease, and genetic predisposition. This study illustrated increased need because of inadequate diet.
  • This study also illustrates a problem that is becoming increasingly common in studies of supplementation. It is considered unethical to not provide participants in both groups with what is considered the standard of care for medical practice. In today’s world the standard of care includes multiple drugs, some of which may have the same mechanism of action as the supplement.

In many cases it is no longer possible to ask whether supplement X reduces the risk of a particular disease. It is now only possible to ask whether supplement X provides any additional benefit for patients who are taking multiple drugs, with multiple side effects. That’s not the question that many of my readers are interested in.

 

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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Is Our Microbiome Affected By Exercise?

Posted November 6, 2018 by Dr. Steve Chaney

Microbiome Mysteries

Author: Dr. Stephen Chaney

is our microbiome affected by exerciseIn a recent post,  What is Your Microbiome and Why is it Important,  of “Health Tips From The Professor” I outlined how our microbiome, especially the bacteria that reside in our intestine, influences our health. That influence can be either good or bad depending on which species of bacteria populate our gut. I also discussed how the species of bacteria that populate our gut are influenced by what we eat and, in turn, influence how the foods we eat are metabolized.

I shared that there is an association between obesity and the species of bacteria that inhabit our gut. At present, this is a “chicken and egg” conundrum. We don’t know whether obesity influences the species of bacteria that inhabit our gut, or whether certain species of gut bacteria cause us to become obese.

Previous studies have shown that there is also an association between exercise and the species of bacteria that inhabit our gut. In particular, exercise is associated with an increase in bacteria that metabolize fiber in our diets to short chain fatty acids such as butyrate. That is potentially important because butyrate is a primary food source for intestinal mucosal cells (the cells that line the intestine). Butyrate helps those cells maintain the integrity of the gut barrier (which helps prevent things like leaky gut syndrome). It also has an anti-inflammatory effect on the immune cells that reside in the gut.

However, associations don’t prove cause and effect. We don’t know whether the differences in gut bacteria were caused by differences in diet or leanness in populations who exercised regularly and those who did not. This is what the present study (JM Allen et al, Medicine & Science In Sports & Exercise, 50: 747-757, 2018 ) was designed to clarify.  Is our microbiome affected by exercise?

 

How Was The Study Designed?

is our microbiome affected by exercise studyThis study was performed at the University of Illinois. Thirty-two previously sedentary subjects (average age = 28) were recruited for the study. Twenty of them were women and 12 were men. Prior to starting the study, the participants filled out a 7-day dietary record. They were asked to follow the same diet throughout the 12-week study. In addition, a dietitian designed a 3-day food menu based on their 7-day recall for the participants to follow prior to each fecal collection to determine species of gut bacteria.

The study included a two-week baseline when their baseline gut bacteria population was measured, and participants were tested for fitness. This was followed by a 6-week exercise intervention consisting of three supervised 30 to 60-minute moderate to vigorous exercise sessions per week. The exercise was adapted to the participant’s initial fitness level, and both the intensity and duration of exercise increased over the 6-week exercise intervention. Following the exercise intervention, all participants were instructed to maintain their diet and refrain from exercise for another 6 weeks. This was referred to as the “washout period.”

VO2max (a measure of fitness) was determined at baseline and at the end of the exercise intervention. Stool samples for determination of gut bacteria and concentrations of short-chain fatty acids were taken at baseline, at the end of the exercise intervention, and again after the washout period.

In short, this study divided participants into lean and obese categories and held diet constant. The only variable was the exercise component.

 

Is Our Microbiome Affected By Exercise?

is our microbiome affected by exercise fitnessThe results of the study were as follows:

  • Fitness, as assessed by VO2max, increased for all the participants, and the increase in fitness was comparable for both lean and obese subjects.
  • Exercise induced a change in the population of gut bacteria, and the change was comparable in lean and obese subjects.
  • Exercise increased fecal concentrations of butyrate and other short-chain fatty acids in the lean subjects, but not in obese subjects.
  • The exercise-induced changes in gut bacteria and short-chain fatty acid production were largely reversed once exercise training ceased.

The authors concluded: “These findings suggest that exercise training induces compositional and functional changes in the human gut microbiota that are dependent on obesity status, independent of diet, and contingent on the sustainment of exercise.” [Note: To be clear, the exercise-induced changes in both gut bacteria and short-chain fatty acid production were independent of diet and contingent on the sustainment of exercise. However, only the production of short-chain fatty acids was dependent on obesity status.]

 

What Does This Study Mean For You?

is our microbiome affected by exercise gut bacteriaThere are two important take home lessons from this study.

  • With respect to our gut bacteria, I have consistently told you that microbiome research is an emerging science. This is a small study, so you should regard it as the beginning of our understanding of the effect of exercise on our microbiome rather than conclusive by itself. It is consistent with previous studies showing an association between exercise and a potentially beneficial shift in the population of gut bacteria.

The strength of the study is that it shows that exercise-induced changes in beneficial gut bacteria are probably independent of diet. However, it is the first study to look at the interaction between obesity, exercise and gut bacteria, so I would interpret those results with caution until they have been replicated in subsequent studies.

  • With respect to exercise, this may be yet another reason to add regular physical activity to your healthy lifestyle program. We already know that exercise is important for cardiovascular health. We also know that exercise increases lean muscle mass which increases metabolic rate and helps prevent obesity. There is also excellent evidence that exercise improves mood and helps prevent cognitive decline as we age.

Exercise is also associated with decreased risk of colon cancer and irritable bowel disease. This effect of exercise has not received much attention because the mechanism of this effect is unclear. This study shows that exercise increases the fecal concentrations of butyrate and other short-chain fatty acids. Perhaps, this provides the mechanism for the interaction between exercise and intestinal health.

 

The Bottom Line

A recent study has reported that:

  • Exercise induces a change in the population of gut bacteria, and the change was comparable in lean and obese subjects.
  • Exercise causes an increase in the number of gut bacteria that produce butyrate and other short-chain fatty acids that are beneficial for gut health.
  • These effects are independent of diet, but do not appear to be independent of obesity because they were seen in lean subjects but not in obese subjects.
  • The exercise-induced changes in gut bacteria and short-chain fatty acid production are largely reversed once exercise training ceases.

The authors concluded: “These findings suggest that exercise training induces compositional and functional changes in the human gut microbiota that are dependent on obesity status, independent on diet, and contingent on the sustainment of exercise.”

For more details and my interpretation of the data, read the article above.

 

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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