Do Multivitamins Reduce Heart Disease Risk?

Written by Dr. Steve Chaney on . Posted in Healthy Lifestyle, Vitamins and Health, Vitamins and Heart Disease

Will A Multivitamin A Day Keep The Doctor Away?

Author: Dr. Stephen Chaney

 

Junk foods and convenience foods have become the American way. We are perhaps the most overfed and undernourished country on the planet. Even worse, we are exporting our unhealthy lifestyle to the rest of the world.

Because of the foods we eat experts estimate that only somewhere between 3% and 10% of us get the nutrients we need on a daily basis. For the vast majority of Americans who are undernourished, multivitamin use helps us fill the nutritional gaps in our diet.

But could multivitamin use do more than just fill nutritional gaps? Could it also help us protect our health?  Could multivitamins reduce heart disease risk?  Here things get a bit murky. We are confused by conflicting headlines. One day the headlines blare that multivitamins are placebos. They are useless. They are a waste of money. The next day the headlines claim that multivitamins are panaceas that can help protect us from heart disease, cancer, diabetes, and whatever else ails us.

In this week’s Health Tips From the Professor, I will review the latest study claiming that multivitamin use reduces heart disease risk and help you put that study into perspective.

Do Multivitamins Reduce Heart Disease Risk?

 

reduce heart disease riskThe current study (Rautianinen et al, Journal of Nutrition, doi: 10.3945/jn.115.227884, 2016)  was a re-analysis of data collected in the first Physician’s Health Study between 1982 and 1995. That study was originally designed to test the effect of aspirin and/or beta-carotene on heart disease and cancer. It enrolled a total of 22,071 male physicians over the age of 40 and followed them for an average of 12.2 years. The conclusions of the initial study were that aspirin use decreased cardiovascular risk while beta-carotene had little effect on either heart disease or cancer.

However, the study also collected data on a wide range of lifestyle factors (including diet and supplement use) and clinical outcomes, so it has provided a valuable database for many subsequent studies, including this one.

This study analyzed a subset of the population (18,530 male physicians) that did not have any sign of heart disease or cancer at the beginning of the study and looked at the effect of multivitamin usage on several cardiovascular disease outcomes including:

  • Non-fatal heart attacks
  • Non-fatal strokes
  • Death due to cardiovascular disease
  • Total cardiovascular events (the sum total of the previous three events)

Here were the results of the study:

  • When the authors simply asked whether the participants were using multivitamins or not at the beginning of the study, multivitamin use had no effect on any of the cardiovascular disease outcomes listed above. These results are similar to several similar studies.
  • However, when the authors compared those who had been using multivitamins for 20 years or more at the beginning of the study to non-users, long term multivitamin use was associated with a statistically significant 44% decrease in total cardiovascular events.
  • When the authors looked at each of the individual cardiovascular disease outcomes (heart attack, stroke, and death due to cardiovascular disease) there was a similar percentage decrease when comparing 20+ year multivitamin users with non-users, but there were not enough people in each of these individual categories for the differences to be statistically significant.

The authors concluded that their study suggests that “multivitamin use over a long duration may be associated with a lower risk of major cardiovascular events” but that further studies are needed because of the low number of long-term multivitamin users in the study.

Putting This Study Into Perspective

There are several clinical studies looking at the effect of multivitamin use on cardiovascular outcomes that have come up empty handed. However, there are an equal number of clinical studies that have shown a positive effect of multivitamin use on cardiovascular outcomes, at least under certain conditions and with certain population groups. For example:

  • For those physicians who had a prior history of heart disease, multivitamin use was associated with a 44% reduction in the risk of heart attack.  So, in this case multivitamins were shown to reduce heart disease risk.
  • There was a significant effect of age, with physicians who were 70 or older showing a stronger effect of multivitamin use on the reduction of overall cardiovascular disease.
  • This study did not ask how long the participants had been using multivitamins prior to the study so it could not assess the effects of long term multivitamin use.
  • Other studies suggest that long-term multivitamin use could also reduce heart disease risk in women. For example:

In short, the available data suggest that the benefits of multivitamin use are most likely to be apparent with those who are at highest risk of having a heart attack because of age or pre-existing disease as well as those who have been using multivitamins for decades, not just a few years.

Multivitamins And Heart Disease Risk:  Placebo Or Panacea?

placeboIf you just read the headlines you have every right to be confused. Some headlines claim that multivitamins are just placebos. They are a waste of money. Other headlines seem to suggest that multivitamins are panaceas that will prevent everything from heart disease to cancer and diabetes.  As usual, the truth lies somewhere in between.

Let’s start with the obvious. If you are in great health, have a heart healthy diet and lifestyle, and do not have a genetic predisposition to heart disease, your chances of having a heart attack, stroke or other forms cardiovascular disease are very low. A multivitamin might benefit you in other ways, but it is unlikely to significantly reduce your already low risk of heart disease. Many of the subjects in previous studies fall into this category, which is why many of those studies come up empty handed.

The people who are most likely to benefit from multivitamin use are those who have a poor diet, or are at increased risk of heart disease because of genetic predisposition, pre-existing disease or age. None of the studies to date have looked at groups with poor diets or genetic predisposition to see whether multivitamin use did reduce heart disease risk. The one study that did look at groups who were older or had pre-existing disease found a beneficial effect of multivitamin use in those groups.

The recent study, along with several other studies, also suggests that it may require decades of multivitamin use to significantly impact heart disease risk. That makes sense. Heart disease doesn’t just happen overnight. It takes decades to develop, so it is only logical that it might also require many years of multivitamin use to significantly impact heart disease risk.

If so, this highlights a very serious flaw in those studies reporting no effect of multivitamin use on heart disease risk. Most of the negative studies only inquired about multivitamin use at the beginning of the study. They did not ask how long those people had been using multivitamins. If you ignore the long term multivitamin users, you are very likely to get a negative result.

The study featured in this article (Rautianinen et al, Journal of Nutrition, doi: 10.3945/jn.115.227884, 2016)  is a perfect example. The group who had been using multivitamins for 20+ years had a 44% decrease in heart disease risk. However, this group represented only 5% of the multivitamins users. The size of this group was not large enough to influence the overall results. Consequently, when the authors of the study looked at multivitamin users as a whole, there was no significant effect of multivitamin use on heart disease risk.

 

The Bottom Line

The question of whether multivitamin use could reduce heart disease risk has been contentious in recent years, with some studies claiming that multivitamin use has no effect, and other studies suggesting that multivitamin use significantly reduces heart disease risk. A recent study helps provide a better understanding of why previous studies have reported such conflicting results.

  • This study found that when you just asked whether people were using multivitamins or not at the beginning of the study, there was no significant effect of multivitamin use on heart disease risk – in agreement with all of the previous negative studies.  That is because those studies did not take into account the length of multivitamin use.
  • However, when the authors of the study looked at the subgroup who had used multivitamins for 20 years or more, they had a 44% decreased risk of heart disease compared to non-users. It turns out that most of the previous studies reporting a beneficial effect of multivitamin use on heart disease risk also focused on long term multivitamin users.
  • Previous studies have also suggested that multivitamin use may significantly decrease heart disease risk for people at increased risk of heart attack, either due to age or pre-existing heart disease.
  • Taken together these studies suggest that long term multivitamin use may reduce your risk of heart disease. Even short term multivitamin use may be beneficial if you are at increased risk of heart disease.
  • Of course, multivitamin use is just one piece of the heart health puzzle. For the NIH’s recommendation for a heart healthy lifestyle, click a heart healthy lifestyle.

 

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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Latest Article

A Low Carb Diet and Weight Loss

Posted January 15, 2019 by Dr. Steve Chaney

Do Low-Carb Diets Help Maintain Weight Loss?

Author: Dr. Stephen Chaney

 

low carb dietTraditional diets have been based on counting calories, but are all calories equal? Low-carb enthusiasts have long claimed that diets high in sugar and refined carbs cause obesity. Their hypothesis is based on the fact that high blood sugar levels cause a spike in insulin levels, and insulin promotes fat storage.

The problem is that there has been scant evidence to support that hypothesis. In fact, a recent meta-analysis of 32 published clinical studies (KD Hall and J Guo, Gastroenterology, 152: 1718-1727, 2017 ) concluded that low-fat diets resulted in a higher metabolic rate and greater fat loss than isocaloric low-carbohydrate diets.

However, low-carb enthusiasts persisted. They argued that the studies included in the meta-analysis were too short to adequately measure the metabolic effects of a low-carb diet. Recently, a study has been published in the British Medical Journal (CB Ebbeling et al, BMJ 2018, 363:k4583 ) that appears to vindicate their position.

Are low carb diets best for long term weight loss?

Low-carb enthusiasts claim the study conclusively shows that low-carb diets are best for losing weight and for keeping it off once you have lost it. They are saying that it is time to shift away from counting calories and from promoting low-fat diets and focus on low-carb diets instead if we wish to solve the obesity epidemic. In this article I will focus on three issues:

  • How good was the study?
  • What were its limitations?
  • Are the claims justified?

 

How Was The Study Designed?

low carb diet studyThe investigators started with 234 overweight adults (30% male, 78% white, average age 40, BMI 32) recruited from the campus of Framingham State University in Massachusetts. All participants were put on a diet that restricted calories to 60% of estimated needs for 10 weeks. The diet consisted of 45% of calories from carbohydrate, 30% from fat, and 25% from protein. [So much for the claim that the study showed low-carb diets were more effective for weight loss. The diet used for the weight loss portion of the diet was not low-carb.]

During the initial phase of the study 161 of the participants achieved 10% weight loss. These participants were randomly divided into 3 groups for the weight maintenance phase of the study.

  • The diet composition of the high-carb group was 60% carbohydrate, 20% fat, and 20% protein.
  • The diet composition of the moderate-carb group was 40% carbohydrate, 40% fat, and 20% protein.
  • The diet composition of the low-carb group was 20% carbohydrate, 60% fat, and 20% protein.

Other important characteristics of the study were:

  • The weight maintenance portion of the study lasted 5 months – much longer than any previous study.
  • All meals were designed by dietitians and prepared by a commercial food service. The meals were either served in a cafeteria or packaged to be taken home by the participants.
  • The caloric content of the meals was individually adjusted on a weekly basis so that weight was kept within a ± 4-pound range during the 5-month maintenance phase.
  • Sugar, saturated fat, and sodium were limited and kept relatively constant among the 3 diets.

120 participants made it through the 5-month maintenance phase.

 

Do Low-Carb Diets Help Maintain Weight Loss?

low carb diet maintain weight lossThe results were striking:

  • The low-carb group burned an additional 278 calories/day compared to the high-carb group and 131 calories/day more than the moderate-carbohydrate group.
  • These differences were even higher for those individuals with higher insulin secretion at the beginning of the maintenance phase of the study.
  • These differences lead the authors to hypothesize that low-carb diets might be more effective for weight maintenance than other diets.

 

What Are The Pros And Cons Of This Study?

low carb diet pros and consThis was a very well-done study. In fact, it is the most ambitious and well-controlled study of its kind. However, like any other clinical study, it has its limitations. It also needs to be repeated.

The pros of the study are obvious. It was a long study and the dietary intake of the participants was tightly controlled.

As for cons, here are the three limitations of the study listed by the authors:

#1: Potential Measurement Error: This section of the paper was a highly technical consideration of the method used to measure energy expenditure. Suffice it to say that the method they used to measure calories burned per day may overestimate calories burned in the low-carb group. That, of course, would invalidate the major findings of the study. It is unlikely, but it is why the study needs to be repeated using a different measure of energy expenditure.

#2: Compliance: Although the participants were provided with all their meals, there was no way of being sure they ate them. There was also no way of knowing whether they may have eaten other foods in addition to the food they were provided. Again, this is unlikely, but cannot be eliminated from consideration.

#3: Generalizability: This is simply an acknowledgement that the greatest strength of this study is also its greatest weakness. The authors acknowledged that their study was conducted in such a tightly controlled manner it is difficult to translate their findings to the real world. For example:

  • Sugar and saturated fat were restricted and were at very similar levels in all 3 diets. In the real world, people consuming a high-carb diet are likely to consume more sugar than people in the other diet groups. Similarly, people consuming the low-carb diet are likely to consume more saturated fat than people in the other diet groups.
  • Weight was kept constant in the weight maintenance phase by constantly adjusting caloric intake. Unfortunately, this seldom happens in the real world. Most people gain weight once they go off their diet – and this is just as true with low-carb diets as with other diets.
  • The participants had access to dietitian-designed prepared meals 3 times a day for 5 months. This almost never happens in the real world. The authors said “…these results [their data] must be reconciled with the long-term weight loss trials relying on nutrition education and behavioral counseling that find only a small advantage for low carbohydrate compared with low fat diets according to several recent meta-analyses.” [I would add that in the real world, people do not even have access to nutritional education and behavioral modification.]

 

low carb diet and youWhat Does This Study Mean For You?

  • This study shows that under very tightly controlled conditions (dietitian-prepared meals, sugar and saturated fat limited to healthy levels, calories continually adjusted so that weight remains constant) a low-carb diet burns more calories per day than a moderate-carb or high-carb diet. These findings show that it is theoretically possible to increase your metabolic weight and successfully maintain a healthy weight on a low-carb diet. These are the headlines you probably saw. However, a careful reading of the study provides a much more nuanced viewpoint. For example, the fact that the study conditions were so tightly controlled makes it difficult to translate these findings to the real world.
  • In fact, the authors of the study acknowledged that multiple clinical studies show this almost never happens in the real world. These studies show that most people regain the weight they have lost on low-carb diets. More importantly, the rate of weight regain is virtually identical on low-carb and low-fat diets. Consequently, the authors of the current study concluded “…translation [of their results to the real world] requires exploration in future mechanistic oriented research.” Simply put, the authors are saying that more research is needed to provide a mechanistic explanation for this discrepancy before one can make recommendations that are relevant to weight loss and weight maintenance in the real world.
  • The authors also discussed the results of their study in light of a recent, well-designed 12-month study (CD Gardener et al, JAMA, 319: 667-669, 2018 ) that showed no difference in weight change between a healthy low-fat versus a healthy low-carbohydrate diet. That study also reported that the results were unaffected by insulin secretion at baseline. The authors of the current study noted that “…[in the previous study] participants were instructed to minimize or eliminate refined grains and added sugars and maximize intake of vegetables. Probably for this reason, the reported glycemic load [effect of the diet on blood sugar levels] of the low-fat diet was very low…and similar to [the low-carb diet].” In short, the authors of the current study were acknowledging that diets which focus on healthy, plant-based carbohydrates and eliminate sugar, refined grains, and processed foods may be as effective as low-carb diets for helping maintain a healthy weight.
  • This would also be consistent with previous studies showing that primarily plant-based, low-carb diets are more effective at maintaining a healthy weight and better health outcomes long-term than the typical American version of the low-fat diet, which is high in sugar and refined grains. In contrast, meat-based, low-carb diets are no more effective than the American version of the low-fat diet at preventing weight gain and poor health outcomes. I have covered these studies in detail in my book “Slaying The Food Myths.”

Consequently, the lead author of the most recent study has said: “The findings [of this study] do not impugn whole fruits, beans and other unprocessed carbohydrates. Rather, the study suggests that reducing foods with added sugar, flour, and other refined carbohydrates could help people maintain weight loss….” This is something we all can agree on, but strangely this is not reflected in the headlines you may have seen in the media.

The Bottom Line

 

  • A recent study compared the calories burned per day on a low-carb, moderate-carb, and high-carb diet. The study concluded that the low-carb diet burned significantly more calories per day than the other two diets and might be suitable for long-term weight control. If confirmed by subsequent studies, this would be the first real evidence that low-carb diets are superior for maintaining a healthy weight.
  • However, the study has some major limitations. For example, it used a methodology that may overestimate the benefits of a low-carb diet, and it was performed under tightly controlled conditions that can never be duplicated in the real world. As acknowledged by the authors, this study is also contradicted by multiple previous studies. Further studies will be required to confirm the results of this study and show how it can be applied in the real world.
  • In addition, the kind of carbohydrate in the diet is every bit as important as the amount of carbohydrate. The authors acknowledge that the differences seen in their study apply mainly to carbohydrates from sugar, refined grains, and processed foods. They advocate diets with low glycemic load (small effects on blood sugar and insulin levels) and acknowledge this can also be achieved by incorporating low-glycemic load, plant-based carbohydrates into your diet. This is something we all can agree on, but strangely this is not reflected in the headlines you may have seen in the media.
  • Finally, clinical studies report averages, but none of us are average. When you examine the data from the current study, it is evident that some participants burned more calories per hour on the high-carb diet than other participants did on the low carb diet. That reinforces the observation that some people lose weight more effectively on low-carb diets while others lose weight more effectively on low-fat diets. If you are someone who does better on a low-carb diet, the best available evidence suggests you will have better long-term health outcomes on a primarily plant-based, low-carb diet such as the low-carb version of the Mediterranean diet.

For more details 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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