What you should know about supplements, according to an expert

By Andrea Kane, CNN

Editor’s note: The podcast Chasing Life With Dr. Sanjay Gupta explores the medical science behind some of life’s mysteries big and small. You can listen to episodes here.

(CNN) — Take a walk down the supplement aisle of any local drugstore, and you will be confronted with a floor-to-ceiling wall of choices. Not just the usual suspects — vitamins and minerals — but also items as varied as turmeric, fish oil, probiotics and melatonin — as well as combinations that purport to burn fat (not muscle!), cure erectile dysfunction and boost memory. The deluge of options doesn’t stop there. Endless social media posts claim a life-changing supplement or regimen will help you eliminate “cortisol belly,” protect against the flu or “reset” your hormones.

But exactly how many things do we humans need to buy in the race to optimize our health and live our best life? All this noise around supplements generates confusion and anxiety, obscuring what science there is and making it hard to separate fact from wishful thinking.

In the most basic sense, these products are meant to supplement the food in your diet with extra added “dietary ingredients.” You would not be faulted for thinking that the US Food and Drug Administration regulates supplements — and the agency does, but probably not in the way you might think.

Thanks to a 1994 law called the Dietary Supplement Health and Education Act, or DSHEA, supplements are regulated more like a subcategory of foods, not a subcategory of medicine. This essentially means that the FDA does not have the authority to approve dietary supplements before they are marketed, unlike pharmaceuticals, which must be shown to be both safe and effective in clinical trials.

“DSHEA is the current framework that all dietary supplements are sold in,” supplement safety advocate Dr. Pieter Cohen told CNN Chief Medical Correspondent Dr. Sanjay Gupta recently on his podcast, Chasing Life.

The law, in part, allowed the industry to explode from approximately 4,000 products in 1994, to some 90,000 in 2017, according to estimates in a 2022 AMA Journal of Ethics policy paper.

“Now, that law in 1994 was initially … designed to better regulate vitamins and minerals,” explained Cohen, an associate professor of medicine at Harvard Medical School and an internist at Cambridge Health Alliance, where he leads the Supplement Research Program. “What unfortunately happened — unfortunately, in my opinion — was that that same structure was expanded to include … all nature of botanicals; many different types of extracts, like, let’s say, a cow thyroid extract; live microorganisms, like both bacteria and yeast, that are sold as probiotics; protein powders; amino acids. All this was lumped together under that same framework … and all of them were called ‘dietary supplements’ or ‘dietary ingredients.’”

You can listen to the full episode here.

The FDA does have some power to take action against supplements that are adulterated or misbranded, but only after they are on the market. “The FDA is in the position of looking for problems out in the marketplace after supplements are being sold, and then working to try to identify the products, which is incredibly difficult, because they don’t have an effective system to detect harms, and then to try to remove those dangerous products,” Cohen said.

While regulations exist, “it’s companies selling us whatever they choose to declare and identify as a dietary supplement,” he said. He called it “a system that emphasizes access and minimizes the assurances of safety or at least leaves safety in the manufacturer’s court.”

What should consumers do before plunking down money at the health food store? Cohen explains what you should know about product claims and offers five tips when deciding which supplements to buy, keep or toss.

The truth about supplement product labels

How the FDA can and can’t regulate the supplement industry doesn’t even address the issue of what actually works and what you might actually need.

Some studies show certain well-known vitamins or minerals can help particular conditions, but often recommendations change after new information comes to light. Good-quality clinical trials are expensive and hard to conduct (or data are gathered through epidemiological studies, so cause and effect can’t be definitively proven); they rarely are done on less-well known (or blended) supplements.

The label required on US supplements, in essence, occupies a gray zone, and the average consumer might not know that they are expected to read between the lines.

A product label is permitted to contain a claim about the effect of the supplement on the body’s structure or function (for example, “helps support flexibility”). But the label “may not claim to diagnose, mitigate, treat, cure, or prevent a specific disease or class of diseases,” according to DSHEA.

The law allows manufacturers to make those gray-zone, health-adjacent claims as long as they include a disclaimer that the claim has not been evaluated by the FDA.

The situation is not likely to change any time soon.

“A core concern I have with the current regulatory framework that really inhibits us moving forward is that there is no incentive for manufacturers to conduct carefully done clinical trials,” Cohen said.

“One thing we haven’t talked about yet is that one other part of the law is that supplements can claim to have health effects without it being proven in humans,” he noted. “Since you can do that without doing a clinical trial, what’s the incentive to invest in all that money, millions of dollars, to do a clinical trial?

“The only potential outcome is negative — because if you’re right, you were already advertising it as it was beneficial to your health and all you did was to prove that your claim is correct,” he said. “But more likely, if it turns out it doesn’t really work like you had hoped it did, and all that money is wasted, and then you’ve got a problem. But the good news, I guess, is that you can still keep on selling it as if it does work, even when the studies come out negative.”

Look for a seal of quality

The FDA has certain best practice rules in place when it comes to manufacturing, but it lacks oversight to ensure what is on the label is actually in the supplement, according to Cohen. That’s why it’s essential to choose supplements with a discerning eye.

“Toss away all supplements that do not include the official stamps from NSF (NSF International) or USP (US Pharmacopeia),” said Cohen said via email, referring to two independent, not-for-profit agencies that test supplements and then certify them.

“The FDA does not test supplements before they are sold,” he said. “Unless supplements have been certified by a high-quality third-party organization, such as NSF or USP, it is not possible to know what’s really inside the bottle.”

“Both those groups do deep dives into the quality of manufacturing,” Cohen told Gupta on the podcast. “They look at the original ingredients that are coming (so that) when consumers are going in to purchase this online or in a store, that the label accurately represents what’s in the product.”

Another reputable third-party tester is ConsumerLab.com.

But remember, none of these organizations test for efficacy, that is whether a supplement does what it claims to do.

“If you say something’s good for gut health or will boost your immunity, those claims are not assessed by these companies,” Cohen told Gupta. “The companies are just looking at — is the powder in the bottle the same as what’s on the label?”

Avoid multi-ingredient products

A good rule of thumb when checking ingredient lists for supplements is less is more.

“Toss away all supplements that list two or more botanical ingredients on the label,” Cohen said.

“Manufacturers are not required to share the details of each ingredient when mixing multiple botanical ingredients in the same supplement,” he said. For example, you might not know the ratio of one ingredient to the others, how fresh each one is, or the process by which each is prepared and then blended together.

“The only way to ensure that sufficient information about the botanical is provided on the label, (is to) select only single-ingredient supplements,” he added.

Be skeptical of squishy claims

When you shop for dietary supplements, avoid products that claim in vague language to promote health benefits, Cohen said, such as “boosts immunity” or “improves cognition.”

“Supplement claims are not vetted by the FDA, and manufacturers do not need to perform studies of the supplement to demonstrate any benefit before selling the product,” he noted.

Cohen said it’s best to avoid supplements with these types of claims and instead “obtain information about benefits and risks of supplements from a reliable, independent source, such as the National Institutes of Health’s Office of Dietary Supplements.”

Check for freshness

Supplements can lose potency or, like fish oil, even go bad.

“Toss away all supplements that are past their expiration date,” Cohen said.

“Supplements past their expiration date are unlikely to have the correct amount of active ingredients as listed on the label,” he explained.

Follow your doctor’s orders

It’s important to incorporate any supplements prescribed by your doctor in your routine on a consistent basis. Following your annual wellness visit, your physician might say, for example, that you need more iron or vitamin B12 or vitamin D based on bloodwork.

“Take all the supplements that your doctor recommends,” Cohen said.

“Many vitamin and mineral supplements are key to treating a variety of health conditions, so if your doctor recommends one or more supplements, remember to take them regularly,” he said.

Do you need to take supplements?

Most healthy people probably don’t need to take even a multivitamin, according to Cohen.

“My clinical experience is that regardless of how people are eating, as long as people are not on a highly restrictive diet, that they are going to get sufficient vitamins and minerals,” he told Gupta.

“Even if they’re eating mainly manufactured or processed foods, or they’re growing everything in their own garden, because of supplementation (in the food system), I’m not seeing serious vitamin deficiencies in my practice.”

Of course, it is not a bad idea to check with your doctor before you start a new supplement, and certainly let them know during your annual exam what you are currently taking. Some supplements can interact with certain medications, while others shouldn’t be used by people with certain health conditions.

We hope these five tips help you make better sense of supplements. Listen to the full episode here. Join us next week for a new episode of the Chasing Life podcast.

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