These supplement myths do more harm than good

By Alistair Gardiner
Published February 12, 2021

Key Takeaways

Even after decades of study, there’s surprisingly little high-quality evidence to support supplement efficacy outside of certain situations. Despite this, many still expect supplements to make up for gaps in nutrition and boost our health.

According to the Council for Responsible Nutrition’s (CRN’s) 2020 consumer survey, 73% of Americans take dietary supplements, which is an increase from 68% reported in 2015. The survey also found that 43% of those who regularly take supplements reported changing which ones they use since the start of the COVID-19 pandemic. CRN analysts noted that pandemic-induced lifestyle changes, like shopping restrictions and increased concerns over general health, have driven many to start thinking more often about their health, wellness, and immunity. 

But are supplements necessary for good health? Can they make up for a lack of nutrition in our diets? Or are they the dangerous product of clever marketing tactics? Here are five myths about supplements, alongside the most up-to-date evidence, to help you decide whether or not to add them to your diet.

Myth #1: They’re regulated and safe

Dietary supplements are only loosely regulated, undergoing little or no government testing for safety or effectiveness before hitting store shelves.

The FDA regulates dietary supplement products as well as dietary ingredients. Importantly, supplements are regulated under a different set of rules than those that apply to conventional foods and drugs, placing them under the provision of the 1994 Dietary Supplement Health and Education Act (DSHEA)—which shifted much of the responsibility for a supplement’s safety onto its manufacturer.

"A firm is responsible for determining that the dietary supplements it manufactures or distributes are safe and that any representations or claims made about them are substantiated by adequate evidence to show that they are not false or misleading. This means that dietary supplements do not need approval from FDA before they are marketed,” reads a statement on the FDA website. 

While the FDA is responsible for taking action against companies that have mislabeled or produced an unsafe product, dietary supplements do not need approval from the FDA to be sold unless they include a new dietary ingredient.  

Lawmakers updated the DSHEA in 2006, when they approved the Dietary Supplement and Nonprescription Drug Consumer Protection Act, which requires manufacturers to report adverse health issues to the FDA to determine the safety of the products. 

With the onus shifting onto manufacturers, it’s reasonable to question whether many supplements are safe, especially as more hit the market every year, potentially overwhelming the FDA’s ability to keep pace with their claims and safety reports. According to a review published in Nutrients, there were roughly roughly 4,000 supplement products made by 600 manufacturers in 1994, compared with 85,000 in 2018.

Myth #2: Supplements only contain natural ingredients

Dietary supplements should only contain “dietary ingredients,” which include vitamins, minerals, herbs or other botanicals, amino acids, and substances such as enzymes, organ tissues, glandulars, and metabolites. However, according to the FDA, many dietary supplements have been recalled because the harmful effects of certain non-dietary elements found in the products, including microbiological, pesticide and heavy metal contamination; false claims about the amount of the dietary ingredient claimed on the label; or even a complete absence of the advertised dietary ingredient. 

One study, published in late 2020 in Neurology Clinical Practice, also found that several products marketed as dietary supplements contained five unapproved pharmaceutical drugs. Researchers tested 10 of these products using non-targeted liquid chromatography-quadrupole time of flight-mass spectrometry methods, and detected the presence of omberacteam, aniracetam, phenibut, vinpocetine and picamilon, none of which is approved by the FDA. What’s more, some of the products didn’t include many of the ingredients listed on the label. Overall, study results indicated that 75% of declared quantities on the label were inaccurate, potentially exposing unaware consumers to up to four times the doses of the ingredients these supplements’ manufacturers claimed on their products’ labels.

Myth #3: Everyone can benefit from probiotics

According to a 2019 review published in Microorganisms, the global market for probiotics is predicted to exceed $3 billion by 2024. The authors of the review, however, concluded that most people don’t need to be taking these supplements, and they often don’t have any measurable impacts on health. 

This is due in part to the quality of the research used to measure probiotics’ effects. In a review of relevant literature, investigators found that most studies on the efficacy of probiotics suffered a shortage of standardization, incomplete reporting, extended data variance, high patient withdrawal, and a lack of qualified experimental designs. In an attempt to analyze the contradictory results of probiotic effectiveness, researchers found firm evidence to support their use only in cases of respiratory tract infections and antibiotic- and Clostridium difficile-associated diarrhea. Outside of this, probiotics did not demonstrate any difference in outcomes for the likes of constipation, cancer, anxiety, rheumatoid arthritis, urinary tract infections, weight loss, food allergies, and various other conditions.

Misconceptions surrounding probiotics are a product of “real life habits, hopes, and media-directed information overcom[ing] scientific knowledge in real-time,” the authors wrote, adding that more research is required in this area. They also advised that further regulations should be considered for probiotic supplements, due to their potentially harmful effects. Probiotics are prokaryotes, meaning they use hostile characteristics to boost their survival. As such, they are capable of inducing local and systemic adverse effects in the body. In this vein, the authors cited several studies that showed post-antibiotic gut mucosal microbiome reconstruction is impaired by probiotics. 

The conclusions of this review corroborate findings from a 2018 study published in Cell, which found that probiotics produce a transient impact on mucosal community structure and gut transcriptome, which is highly variable from person to person. Probiotic supplements do not appear to have a universal or persistent impact on the gut, they wrote, concluding that a personalized approach to probiotic consumption is probably the best way forward. 

Myth #4: Supplements can replace foods in your diet

You may think that if your diet limits your intake of certain nutrients, dietary supplements can fill the gap. But research indicates that this is not true in most cases.

One study, published in 2019 in Annals of Internal Medicine, sought to evaluate associations between supplement use, nutritional intake, and mortality among US adults. Using data on more than 30,000 individuals from the National Health and Nutrition Examination Survey 1999-2010, researchers examined subjects’ nutritional intake from food and supplements before monitoring various health outcomes, including mortality from all causes, cardiovascular disease, and cancer. The findings indicated that adequate intake of vitamin A, vitamin K, magnesium, zinc, and copper was associated with reduced all-cause or CVD mortality—but those associations were only observed when it came to nutrient intake from actual foods. Notably, the researchers also found that excessive intake of calcium was associated with increased risk for cancer death, and that this intake appeared to be linked to supplement use. They concluded that using dietary supplements is not associated with mortality benefits among US adults. 

Similarly, an analysis published in BMJ in 2020 illustrated that supplements are primarily recommended in low- and middle-income countries, where specific micronutrient deficiencies (like iodine, iron, zinc, and vitamin A) exist. In the United States, however, food fortification (like the addition of vitamin D to milk, and B1 and B3 vitamins to refined flour) means that our diets don’t typically require these vitamin or mineral boosts from non-dietary sources. 

In light of this, many Americans taking supplements are ingesting levels of vitamins and minerals that exceed the tolerable limit. While quality research on the effects of this trend is still limited, concerns linger over possible long-term adverse consequences on general health. 

Myth #5: No one can benefit from supplements

Despite the previous four points, dietary supplements can provide the body with vital nutrients that it may be missing—in a few cases.

For example, according to a 2018 review published in Pharmaceutics, the long-term use of some prescription or over-the-counter drugs can result in clinically relevant micronutrient deficiencies, which can develop over months or years. 

While the authors found that further research is needed to understand all interactions between certain drugs and possible nutrient deficiencies, they found evidence that some populations could be at risk. For these individuals, using supplements alongside a balanced and healthy diet may be an effective way to ensure they’re getting all they need. For example, people with chronic health conditions may benefit from specific dietary and herbal supplements. 

Likewise, patients with the following conditions may want to take supplements, according to a 2019 article published in JAMA Network:

  • When they are pregnant or planning to become pregnant

  • When they have osteoporosis and aren’t able to get enough vitamin D and calcium in their diet

  • When they have a measured B12 deficiency

  • When they have gastroenterological conditions or have had bariatric surgery

Bottom line

Remember, the best way to meet your nutritional requirements is through the food you eat, rather than dietary supplements. But, if supplements are a necessity, remember that it’s important to check nutrition labels carefully and proceed with caution.

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