Can dietary supplements put your health at risk?

Written by: Emily Russo, MS, RD, CDN

When it comes to nutritional supplements, how do we know which ones are most helpful and which ones won’t make much of an impact? Better yet, what’s harmful and should be avoided all together?

When it comes to nutritional supplements, how do we know which ones are most helpful and which ones won’t make much of an impact? Better yet, what’s harmful and should be avoided all together?

Have you seen advertisements for deer antler supplements? No, this is not a punch line for a joke.

Referred to as “deer velvet” they supposedly can treat a wide variety of ailments from toothaches, asthma, and high cholesterol, to increasing sex drive while also improving strength and endurance.

Try saying that with a straight face! But many people do.

We see all kinds of nutritional supplements just about everywhere, and they all come with promises. They line the aisles of our grocery stores, are advertised on social media, and are on topic when we hang out with friends. Perhaps you’ve even attended events or like one of those home parties where supplements are presented and sold right then and there.

We assume that because supplements are commonplace, they are harmless. One study noted that 84% of consumers are “confident” dietary supplements are safe and effective.

But are they?
Personally, I have worked with patients admitted to the hospital with organ failure which they developed from adding supplemental powders to smoothies at their local juice stand; and just last month, my friend was diagnosed with liver toxicity after months of taking a daily cocktail of the popular supplements turmeric, matcha, and digestive enzymes.

When I asked a local GI physician to weigh in, she said liver toxicity due to supplement use in NOT uncommon. A local oncology nurse agreed and told me she tells her patients to stay away from all unnecessary supplements. 

For some reason (it’s my opinion that the bottom line is a huge motivating factor!) we hear more about the benefits of supplements – this will relieve inflammation, that will give us more energy, help us sleep, etc. – than we do the risks. So, I outlined a few key concerns below, as well as my own recommendations for supplement use.

Dietary supplements are not intended to treat, diagnose, mitigate, prevent, or cure disease. Only drugs can legally make this claim.

Ironically, this is the motivation behind buying supplements in the first place! In fact, a study featured in the Journal of the Academy of Nutrition and Dietetics found that adults were “two and a half times more likely” to use dietary supplements while taking prescription medication compared to adults without a diagnosed medical condition.

It is understandable that people who are sick want to feel better. But supplements can be especially problematic for this population.

High doses of vitamins and/or minerals in dietary supplements have the potential to either decrease or increase the effectiveness of medications. They can also be taxing on our organs (like our kidneys…more on this later) that are responsible for the breakdown, absorption, and excretion of vitamins and minerals.

Doesn’t our body just excrete what we don’t need?
It depends. In some cases, high dose supplements can build up in the body and become toxic. As one of many examples, those with impaired kidney function need to avoid Vitamin C because it can quickly build up and further damage the kidney.

No one, other than your own medical team, should tell you to start taking a supplement.

Each individual has unique nutritional needs, so there is no one specific supplement I would recommend to everyone. If someone does recommend a supplement to a whole group of people, that’s a red flag. And if they are selling something on the spot….run!

Exercise instructors, guest speakers, podcast personalities, social media influencers, a store employee, or your neighbor doesn’t know your full medical history. My friend told me the topic on her text chain of friends was “what’s your daily vitamin regimen?” And everyone was hoping to pick up tips from each other as casually as one would seek advice on how to handle potty training a toddler.

Since supplements are OTC and seem relatively innocuous, people often try them without consulting a physician first. But this is a mistake. There’s no downside to a sidebar with your medical team BEFORE trying any new supplement.

Ask follow-up questions when it comes to claims that supplements are good for inflammation or your microbiome (clearly a hot topic right now), for example. Small observational study results do not equate to solid evidence, so ask to see large, long-term, randomized controlled trials for results that can be more informative.

Better (or easier) yet, check out the NIH Fact Sheet that lists all supplements and objective information on efficacy and potential side effects, as well as contraindications.

Don’t go rogue! Only take the amount that is recommended.

More doesn’t often equate to better. At best, taking too much is wasteful. As with the Vitamin C noted above, it’s literally like flushing your money down the toilet! At worst, taking too much can be toxic.

Read labels with the finest tooth comb you can find.

Have Allergies? Even though pills and powders don’t seem like food, supplements often use various extracts or fillers to make them palatable and easy to package. Read all the ingredients just to make sure there aren’t any surprises.

What do I need to take…exactly? Sometimes a physician will recommend a supplement but not go into specifics, like with fish oil, for example. This is a particularly broad topic, so ask exactly what ingredients to look for and how much to take.

Do I really need 237% of that? Supplements that supply >100% of daily value (DV) are providing more than is recommended daily. On top of that, because you are also eating food, you may end up getting much more than is recommended.

Rules and regulations around dietary supplements are not straightforward.
Technically the FDA oversees supplements, but not proactively.

They don’t pre-test or pre-approve supplements going on the market. And unlike drugs, supplements aren’t required to go through a rigorous research study protocol in people to prove they are safe. The FDA’s role is to investigate complaints made about supplements – like innocent until proven guilty!

What does this mean for consumers?

There are a wide variety of loopholes available to companies aiming to get their products on the market. For example, some companies will add the term “natural” to labels. While this is keen marketing, there is no definition of “natural” when it comes to supplements.

Even more concerning is that supplements may contain toxic add-ins that the consumer is not aware of. This includes heavy metals like lead and arsenic, bacteria, and fungi. There are cases where one herb has even been replaced with another. We won’t know this from reading the label.

Moreover, supplements are typically taken every day, often in high doses. This differs from something we eat occasionally, which may have unwanted ingredients (and think about how scrutinizing we can be about ingredients in our food!).

✅ So, what do I recommend?
There are very few instances in which supplements are warranted or have solid scientific evidence to support recommending their use. Appropriate use cases are in those who are not able to consume adequate nutrition and/or have a noted deficiency (such as iron for anemia, B12 for those on vegan diets, or Vitamin D for those living in changing seasons). The exception to this is folic acid, which is recommended preventatively during pregnancy.

Other checkpoints to consider when looking at supplement options:

  • Get blood work done to check your levels and reassess whether supplements are really necessary long-term. Avoid taking supplements if they aren’t medically necessary.
  • Look for identification of a third-party quality review (not the supplement company reviewing its own product). This includes USP, NSF, or They do unannounced inspections of products to give consumers better peace of mind.

Refer to reliable sources for objective information on specific supplements and dietary supplement laws:
NIH Fact Sheet provides evidence-based safety and efficacy information for every supplement
– FDA provides a rolling list of consumer updates 
-Academy of Nutrition and Dietetics (AND)’s position paper outlines the FDA’s role in overseeing       dietary supplements and their usage in general.

Lastly, spoiler alert: Deer velvet may not live up to the hype.

Key Takeaway

There are few instances in which dietary supplements are warranted, especially for long-term usage. Consider the dangers of taking dietary supplements by checking labels, speaking with your medical provider prior to purchase, and relying on trusted resources for objective information.

How do you manage your own risk versus benefit when it comes to dietary supplements? Share your experiences and/or questions below. We love hearing from you!

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  1. Anne Sweeney Sedlis

    Great article Emily…..I totally agree that baseline bloodwork is very important, as well as including your physician when considering any supplement. Would love a future article about pre and probiotics…..another questionable “supplement.”

    1. Emily Post author

      Thanks for reading, Anne! Love the live bacteria conversation too. I have an older article on the blog called “Should I take Probiotics?” which is a good start, but there’s always more to elaborate on that topic!