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Are Diets and Supplements Useless for Your Heart?

An analysis of more than 200 trials concluded that diets and supplements won't protect you from heart attacks. But this conclusion might not apply to you.
Mixed leaf salad with smoked salmon, spinach, cucumber, red onion, herbs and black kumin. Healthy diet. Low carb meal. Copy space

Most people believe that a good diet is a cornerstone of vibrant health. Many also take supplements as dietary insurance to make sure that they get the nutrients they need. A massive new review of 277 clinical trials including close to a million participants has concluded that most diets and supplements are useless (Annals of Internal Medicine, July 9, 2019). Even those promoted to improve heart health do nothing to improve longevity or reduce complications.

What’s Wrong with Diets and Supplements?

The investigators examined the recommendations put forward in the US dietary guidelines. To find out how well the evidence supports these ideas, they looked for randomized controlled trials and meta-analyses of diets and supplements. They certainly found a great deal of data, but not all the studies were of the same quality. Most of the studies did not find that the intervention studied resulted in better survival or fewer heart attacks.

The investigators analyzed results for 16 different types of supplements and eight kinds of dietary interventions. These included approaches such as reducing saturated fat or increasing omega-3 alpha linolenic acid intake. In addition, they reviewed data on the Mediterranean diet.

They concluded that there is reasonable evidence that reducing salt intake lowers the likelihood of premature death. It appears to protect people with high blood pressure from heart problems. In addition, folic acid might reduce the risk of stroke according to these data. However, a large study in China had an outsize effect on this analysis. When it comes to stroke, they found a greater risk among people taking a combination of calcium and vitamin D. None of the other diets and supplements offered significant advantages or risks. 

What About the Mediterranean Diet?

This conclusion is especially surprising with regard to the Mediterranean diet. PubMed has more than 6,000 entries on this high-vegetable, high-olive oil, low-processed food approach to eating. Most of the published studies show benefits such as reducing the risk of diabetes (Endocrine, April 2017). Other studies suggest that a Mediterranean diet benefits brain health (Ageing Research Reviews, March 2015). Moreover, analyses indicate that people eating the Mediterranean way are less prone to cancer (Cancer Genomics & Proteomics, Nov-Dec. 2017). Consequently, we are surprised that the Mediterranean diet appeared useless in the current analysis.

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Dispense with Diets and Supplements? 

The editors of the Annals of Internal Medicine invited two prominent experts from the Scripps Clinic in La Jolla, CA, to write a commentary on this research. Drs. Amitabh Pandey and Eric Topol were skeptical of the value of supplements, but also of some of the conclusions of the analysis.

Among other objections, they pointed to the problems in the data linking sodium intake and heart problems:

“A longitudinal study of nearly 95 000 people from 18 countries lasting more than 8 years showed an inverse correlation between sodium intake and cardiovascular outcomes…

“With regard to salt intake, Messerli and colleagues have noted that “with an average lifespan of 87.3 years, women in Hong Kong top life expectancy worldwide despite consuming an average of 8-9 g of salt per day.” (10). This exemplifies the problem of amalgamating data from people and cultures with markedly different diet and supplement baselines.”  

They continue:

“Perhaps, however, the biggest difference that needs to be considered in the future is the individual. Only recently with machine learning of large data sets, which include multimodal data on physical activity, sleep, medications, demographic characteristics, intake and timing of all foods and beverages, and gut microbiome constituents, have we begun to learn that the use of any specific diet or supplement is likely to have markedly heterogeneous effects. Testing any diet or supplement in a broad population without acknowledging interindividual variability seems like a recipe for failure, especially because most trials are not randomized, are not of sufficient duration, or do not have enough hard outcome events.

“Unfortunately, the current study leaves us with the same foggy conditions that we started with. Until these conditions clear, it would be reasonable to hold off on any supplement or diet modification in all guidelines and recommendations.”

We agree that abandoning efforts to include more vegetables and fruits in our daily fare seems premature. Giving up on supplements doesn’t make sense for everybody either. You can learn more about the pros and cons of supplements for specific health conditions in Dr. Tieraona Low Dog’s excellent book, Fortify Your Life: Your Guide to Vitamins, Minerals, and More.

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About the Author
Terry Graedon, PhD, is a medical anthropologist and co-host of The People’s Pharmacy radio show, co-author of The People’s Pharmacy syndicated newspaper columns and numerous books, and co-founder of The People’s Pharmacy website. Terry taught in the Duke University School of Nursing and was an adjunct assistant professor in the Department of Anthropology. She is a Fellow of the Society of Applied Anthropology. Terry is one of the country's leading authorities on the science behind folk remedies. .
Fortify Your Life: Your Guide to Vitamins, Minerals, and More

Fortify Your Life gives you the evidence-based information you need to decide whether you need a supplement and which format and dose would be best.

Fortify Your Life: Your Guide to Vitamins, Minerals, and More
  • Khan SU et al, "Effects of nutritional supplements and dietary interventions on cardiovascular outcomes: An umbrella review and evidence map." Annals of Internal Medicine, July 9, 2019. DOI: 10.7326/M19-0341
  • Pandey AC & Topol EJ, "Dispense with supplements for improving heart outcomes." Annals of Internal Medicine, July 9, 2019. DOI: 10.7326/M19-1498
  • Esposito K et al, "Mediterranean diet for type 2 diabetes: Cardiometabolic benefits." Endocrine, April 2017. DOI: 10.1007/s12020-016-1018-2
  • Yannakoulia M et al, "Cognitive health and Mediterranean diet: Just diet or lifestyle pattern?" Ageing Research Reviews, March 2015. DOI: 10.1016/j.arr.2014.10.003
  • Barak Y & Fridman D, "Impact of Mediterranean diet on cancer: Focused literature review." Cancer Genomics & Proteomics, Nov-Dec. 2017. DOI: 10.21873/cgp.20050
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The effective base line here seems be: use data from lifestyle and age groups that are similar to your own. In general I use a conservative approach to diet and supplements and found at least 3 pieces of information that I can use to encourage or in someway utilize for myself. Thank you

Drs. Amitabh Pandey and Eric Topol were skeptical of the value of supplements and yet their conclusions were of no value. After looking at 277 studies, some involving as many as 95,000 people and lasting 8 years, these two “researchers” were not able to tell us if supplements were positive or negative to heart health. Second, they were not able to draw conclusions as to what diet would be of value. In fact they were they started. But their conclusion is to do nothing. This is totally unacceptable and the reason people do not like nor trust doctors.

With the research in abundance, the conventional doctors say we do not know and do nothing. They are like deer in headlights. I have advice based on life expeience or empiricism. Under-eat instead of over-eat, have plenty of fresh veggies, healthy fat avocado, eat less red meat, use less salt, avoid juices and soda, enjoy fresh fruit, take grains, wine, beer in small amounts and water in copious amounts. And party every once in a while (once a month) Love your food and eat in peace and fast in stress.

P.S. Turn off the TV and computer and put down the cell phone when eating. Be grateful that the researchers leave it up to us to figure out what we need to eat, because they do not know.

What about EYE VITAMINS? I have Glaucoma and Macular Degeneration and am told by Doctor to be sure and take Eye VITAMINS.

A large clinical trial substantiated the benefit of a vitamin formulation (called AREDS, after the study) to slow the progression of macular degeneration. Go ahead and follow your doctor’s advice!

Is obesity even a factor in these studies? Clearly, if a person changes eating habits from all processed to all natural and is able to lose weight, there must be a definable difference in their health.

My blood pressure is controlled on herbs and vitamins. Thank goodness. I felt like crap on Coreg and long-acting nitro (which I had to take because the Coreg was giving me chest pains). Traditional meds are good for many things but when you get sick from them there are many other routes to take. Traditional docs do not have the time or the interest to treat patients other than ‘take this for that.’ Do your own research, and ask lots of questions. They are far from gods.

I have salt-sensitive high blood pressure. Reducing my salt intake does make a difference for me. I can measure it. Coke and Pepsi do the same thing. This can tell me what to avoid, but not what to do. Since cardio disease is the #1 killer, it’s good to get some data. But then there’s individual data which is heterogeneous.

Research usually focuses on very simple questions, by necessity. Large numbers can make sense, because if you find something, you know it’s not a fluke. But large number studies can also lead to false negatives (not finding what is actually there) because they homogenize something that is heterogeneous.

Unfortunately, the practice of conventional medicine has trended toward a cookbook approach based on these studies. The insurance companies and diagnostic coding are a big part of the problem. I don’t blame physicians. Most are well-meaning and strive to help their patients. As the profession has become more cookbook oriented, so have the training programs.

What is needed is not a cookbook approach, but a clinical approach where there is enough time and attention given to each patient to understand the whole picture. Complementary and alternative physicians try to do that. They don’t throw out the studies, but use them as one source of evidence. Evidence-based medicine should not be just evidence from research studies, but also individual evidence.

A better understanding of research is something that needs more attention. Doctors need to be better trained in this as a foundation. What are the limitations of a specific piece of research? All research designs have flaws. But which ones are relevant is something that needs to be understood.

Why is so much of this data confused and inconclusive? Is it saying that supplements are worthless and of no value? Big Medicine has been at odds with pro-active nutrition for years.

And thank you for recommending Dr. Tieraona Low Dog’s book!

I think it’s curious that medical studies universally find any form of nutritional intervention in humans to be worthless, while there are thousands of controlled studies in laboratory animals that find just the opposite. The message is: Nutrition is pointless but drugs are effective. Pardon my skepticism.

I read many years ago that only one out of four people had an association between salt and blood pressure. So if you were not one of the four, then your salt intake did not correlate at all with your BP.

Is that still an acknowledged fact? It surely could be clouding the data.

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