Two New Studies Deemed Supplements Ineffective — Here's Why This Doctor Disagrees

Photo: Tatjana Zlatkovic

Sometimes it's hard to know whether or not vitamins are worth your money. Some studies show they can boost your mood, improve your health, and decrease your risk for chronic disease, while others find they just pass through the body unabsorbed, conferring none of these benefits and essentially just making "expensive urine." With the cluttered nutrition research landscape and conflicting headlines in the news, it can be hard to know what to believe and which advice to take.

Two recent headlines about vitamins caught my attention: "Omega-3 Supplements Don’t Protect Against Heart Disease" and "Vitamin Pills and Supplements Aren’t Helping Most People." It would appear these two stories drive more nails into the vitamin coffin. As a medical professional who recommends high-quality multivitamins to my patients when necessary—and who regularly takes them myself—I understand that these headlines might be disconcerting. However, taking a closer look at these news stories and the accompanying studies sheds some light on the complex, and somewhat controversial, relationship between medical journals and the pharmaceutical industry and why there are so many conflicting reports on vitamins.

So, how can you decipher what's good science? Here's are my two best tips for looking past the headlines and knowing when there might be more to the story, especially when it comes to natural therapies like vitamins.

Follow the money: funding, reprints, and conflicts of interest.

It's important to keep in mind that just like other businesses, pharmaceutical companies need to sell their product—medications—in order to make a profit and stay in business. For this reason, pharmaceutical companies have a keen interest in funding and promoting studies that indicate beneficial results for the drugs they produce or that seem to indirectly support their product by debunking "natural" therapies like vitamins.

One way in which pharmaceutical companies can promote favorable studies is through reprints. This is the practice of purchasing reprinted copies of a study from the medical journal in which it was published to distribute to medical professionals. Pharmaceutical companies can, and regularly do, advertise in medical journals. In fact, the former editor of the British Medical Journal, Richard Smith, is of the opinion that these practices are so widespread that medical journals have just become an extension of pharmaceutical companies marketing arm, which is definitely something we should keep in mind as we're evaluating new research.

In addition, studies that favor pharmaceutical companies may be more likely to be published in the first place. An analysis published last fall revealed that more than 50 percent of journal editors received payment from pharmaceutical companies in exchange for favorable publication, which can make it hard to tell if the publication of a study may have been influenced behind the scenes. Although it can be hard to determine the presence of this type of funding, it's good to be aware that it can happen. Next time you see a sensational headline about the surprising findings of a new study, be sure to check for the funding sources and use a critical eye whenever you read about scientific studies.

Photo: Tatjana Zlatkovic

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Take a closer look at the study behind the story.

When it comes to determining the legitimacy of a study's results, the study design can offer important insights. A well-conducted study, or analysis of multiple studies, will have clearly stated criteria for inclusion in the study, use uniform and proven dosages of the studied therapy, and have a standard of quality for tested compounds to reduce bias. Unfortunately, the studies behind the two anti-vitamin headlines I mentioned do not seem to pass the test. Here's why.

In the large meta-analysis that spurred the headline "Omega-3 Supplements Don’t Protect Against Heart Disease," the range of omega-3 doses studied varied greatly. A combined EPA/DHA omega-3 dosage of 1,800 mg daily or higher is usually needed for a therapeutic outcome in subjects with diseases, which many of the participants had. And yet, there was no minimum daily dosage of omega-3 supplementation required to enter the analysis, and some of the studies supplied as little as 200 mg of omega-3. Also, some of the analyzed studies provided no DHA, which is a critical form of the omega-3 fatty acid known to lower inflammation. Can you imagine an analysis of the effectiveness of 1 mg of aspirin for heart attack prevention? Of course it would find low or no effect!

Similarly, in the study of multivitamins that led to the headline "Vitamin Pills and Supplements Aren’t Helping Most People," the type, quality, and doses of vitamins studied ranged widely. For example, when looking at the health effects of vitamin D, the study authors combined studies on vitamin D2, a version of the vitamin generally thought to be far less effective than vitamin D3, and vitamin D3, the form more commonly used in functional medicine clinics. This could have diluted the data and biased the results to show that vitamin D supplementation has no effect, when in fact it could be that the data on the effectiveness of vitamin D3 was negated by the data on the ineffectiveness of vitamin D2. Another way in which this study's results may have been biased is that when analyzing the effect of B vitamins, the authors pooled results from studies using inactive forms like cyanocobalamin B12 and active forms like folinic acid and methylcobalamin.

To me, it's pretty clear that both of these studies had design flaws that biased them to show negative results. Unfortunately, these and other studies like them tend to garner considerable press coverage, further confusing the public and stirring up distrust in vitamins and natural therapies.

So, back to the big question: Should you take vitamins? I believe that obtaining minerals, vitamins, and omega-3 fatty acids from diets rich in fruits, vegetables, whole grains, legumes, and sources like flaxseed, chia seeds, hemp seeds, and nuts is the optimal route for nutrition. However, nutritional deficiencies are widespread with all dietary patterns, and certain disease conditions respond to supplements. Doing your research, identifying specialty providers of supplements, and asking for advice from health professionals with a focus on nutrition and micronutrients is wise. For me, I take high-quality supplements daily based on nutritional testing verified by follow-up testing.

Curious about starting a supplement regimen? Check out this guide to vitamins, their benefits, and how to incorporate them into your existing routine.

Joel Kahn, M.D.

Cardiologist & Best-Selling Author
Dr. Kahn is the founder of the Kahn Center for Cardiac Longevity. He is a summa cum laude graduate of the University of Michigan School of Medicine and is a professor of medicine at Wayne State University School of Medicine. He is owner of GreenSpace Cafe in Ferndale, Michigan. His books, The Whole Heart Solution, Dead Execs Don't Get Bonuses, and Vegan Sex, all No. 1 best-sellers, are available for sale now. His public TV special, The Whole Heart Solution, is playing nationally now.
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Joel Kahn, M.D.

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