ALICE CALLAHAN

Nearly eight in 10 adults in the US take at least one dietary supplement, with one in three regularly consuming protein powders, bars, or drinks, according to a survey by the Pew Research Center. Yet, as the global supplement industry expands to an estimated $228 billion, medical experts warn that the vast majority of these over-the-counter products offer no tangible health benefits.

"I would guess that well over 80% to 90% of supplement consumption doesn't offer any proven benefit to the person who's taking it," says Dr Pieter Cohen, an associate professor of medicine at Harvard Medical School.

The survey of 3,554 US adults found vitamins and minerals to be the most common choice, taken by 67% of participants. Meanwhile, 31% reported taking protein supplements, with usage highest among those under 50. Omega-3, fish oil, and krill oil supplements accounted for 25%, while nearly 20% took herbal remedies, including ginseng and ashwagandha, an Ayurvedic staple now gaining massive global traction.

Dr Eric Topol, a cardiologist and founder of the Scripps Research Translational Institute, notes that targeted supplementation is essential for specific medical reasons, such as treating nutrient deficiencies or preventing birth defects. "But that's the minority," he stresses. Millions take omega-3 capsules expecting heart or brain protection, yet large-scale clinical trials consistently fail to support these claims.

Protein obsession is similarly misplaced. Influencer culture on social media has fuelled a widespread belief that daily diets fall short, prompting excessive intake. However, Dr Topol explains that balanced meals easily provide adequate protein for most people.

Interestingly, the survey revealed higher protein supplement usage among women than men. Stuart Phillips, a professor of kinesiology at McMaster University in Canada, attributes this shift to targeted social media campaigns and the growing use of GLP1 weight-loss medications, where extra protein is advocated to prevent muscle loss. However, Phillips emphasises that resistance training, not powder, is key to preserving muscle, and whole foods offer superior nutritional value. "Supplements are convenient, but they are not necessary," he says.

Long-term trends mirror this rise. Research led by Elizabeth Kantor, an epidemiologist at Memorial Sloan Kettering Cancer Centre, showed that US adult supplement use grew from 51% in 1999 to 60% by 2023. Usage peaks among adults aged 65 and older, who are frequently advised to take calcium or vitamin D, despite mixed clinical evidence.

Crucially, experts warn that supplement makers are not required to prove safety or efficacy before bringing products to market. Unsupervised consumption carries real risks, including vitamin toxicity, organ damage from certain herbal formulations, and drug interactions.

As social media drives longevity crazes and unverified health claims, doctors urge consumers to rely on food first. "Most of these are a waste of money," Dr Topol warns. "There's no data to support them, but it enriches your urine."