A Dietitian’s Stance on Supplements

Post by Paula Jahn, Dietitian and Co-owner at Nourish Northwest

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I was going to write a blog post on my most frequently asked questions as a registered dietitian. The worth of dietary supplements is probably at the top of that list. So, I decided to devote an entire post to this topic. There are varying views on this within the health profession and even within the field of dietetics. This is my opinion based on what I know from research and what fits into my philosophy of food and nutrition. And like most things in the world of nutrition, my answer to the supplement question is ever-changing and lands somewhere in the gray.


So many choices!
So many choices!

Besides being a potential waste of money, below are the main reasons I advise against vitamin and mineral supplements for most people (exceptions always apply).


Supplements are not regulated. Unlike medications, there is no governing body that oversees the production of dietary supplements. A corrupt company could very well put sugar (or worse) in a pill, slap a health claim on the bottle and sell that product at the local drug store. There are some companies that choose to go through a voluntary verification process to ensure the quality, purity, and potency of their product. The U.S. Pharmacopeial Convention is a private company that tests products and verifies them. I tell clients who take supplements to look for USP on the label.


Scientific research is limited. Rigorous clinical trials have been conducted on many vitamins and mineral supplements. While some studies show a link between certain supplements and health outcomes (e.g.,vitamin D and calcium for bone health), most studies are inconclusive at best or even show a harmful effect. A study conducted in 2008 was stopped short when researchers discovered that vitamin E and selenium actually increased the risk of prostate cancer in men. Similarly, the CARET study was stopped ahead of schedule in January 1996 because participants who were randomly assigned to receive vitamin A supplements were found to have a 28% increase in incidence of lung cancer, a 17% increase in incidence of death and a higher rate of cardiovascular disease mortality compared with participants in the placebo group.


Gives license to continue unhealthful eating habits. This isn’t always the case, but some people are looking for a magic pill for health and resist making significant changes in lifestyle. We know that the foundation of health is a balanced diet full of plants (fruit, vegetables, nuts, seeds, whole grains, legumes) and physical activity. There is not a pill or a combination of pills that comes close to the power of those two things.

While I’m not against a person taking a multi-vitamin as a sort of “insurance policy,” I do think that most people can get adequate nutrients from food. When vitamins, minerals and anti-oxidants are obtained through food, there is the added benefit of fiber and other nutrients that accompany the whole food. There is a mysterious synergy that exists when nutrients are absorbed together in their natural form; I don’t think that manufacturers will ever be able to mimic that magic.


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