Multivitamins promise glowing skin, better sleep and a longer life. But for whom are supplements really useful? | Donna Lu

Supplements are not a cottage industry: an estimate third Unpleasant almost half of Australians regularly take vitamins or minerals.

Vitamin gummies, promoted by the likes of the Kardashian-Jenner clan, have found popularity in recent years among millennials and zoomers, who are more receptive to supplements in the form of “powders, liquids and gummiesthan older generations. Gwyneth Paltrow’s Goop – no stranger to questionable health trends – sells its own line of such supplements.

On TikTok, influencers selling multivitamin gummies — and more recently vitamin patches that resemble cute, colorful stickers or fine line tattoos — promise glowing skin, luscious locks, energy boosts and better sleep. But if you’re looking for real health benefits, you’re better off saving your pennies.

What does the evidence say about multivitamins?

The average person can be there recommended intake of vitamins (those of plant or animal origin, such as vitamin C and vitamin B12) and minerals (elements such as iron, zinc and iodine) from food alone.

“Someone who is healthy and has access to a balanced diet, especially whole foods, generally does not need vitamin supplements,” says Barbara Mintzes, professor of evidence-based pharmaceutical policy at the University of Sydney.

“In almost all cases, people pay a lot of money for things that provide them with no benefit at all,” agrees Prof Nial Wheate, director of academic excellence and medicine researcher at Macquarie University.

Multivitamins contain a variety of vitamins and minerals. Experts often say that they produce very expensive urine. “Many vitamins are water soluble. So once you’ve satiated your body’s stores, you just pee them out,” says Clare Collins, professor of nutrition and dietetics at Newcastle University.

While specific supplements are important for conditions related to nutrient deficiencies (more on this later), for the general population there is little evidence that multivitamins have any health benefits.

Numerous meta-analyses – in which the results of multiple studies are analyzed – have found multivitamins not improve heart healthreduce the risk of certain cancers or people make live longer. An Australian meta-analysis of the studies in older adults found that multivitamins made no difference in mortality risk.

Collins suspects that multivitamins are so popular because they are considered a kind of insurance policy. “I think this is because people know they probably aren’t eating as healthy as they should.

“Unfortunately, you don’t necessarily get everything you need (from multivitamins), such as dietary fiber and other items… like phytonutrients, which are plant chemicals that occur naturally in a range of foods.”

In some cases, supplements can do more harm than good. Some fat-soluble vitamins, such as vitamin A, are stored in the liver and can build up to dangerous levels when overconsumed, although Collins says this is unlikely with multivitamins. “Damage usually occurs when (people) isolate just one and take mega doses of it.”

For supplements that claim to have specific benefits – such as hair, skin and nail formulations – Dr. Helen Macpherson, a senior research fellow at Deakin University’s Institute for Physical Activity and Nutrition, to be careful with health claims. “Often the ingredients (in concentrations) are simply too low to have any physiological benefit,” she says.

Vitamins marketed specifically for hair, skin, and nail health often contain biotin, a B vitamin one review found had “no proven efficacy in hair and nail growth in healthy individuals.” A American study of 176 products marketed as hair, skin and nail supplements were found to contain 255 different ingredients, including biotin in doses ranging between 100% and 33,333% of the recommended daily intake. American regulators have done that repeatedly warnings issued that biotin can interfere with laboratory tests and produce false results for troponin, a biomarker used to diagnose heart attacks.

In Australia, most multivitamins are regulated by the Therapeutic Goods Administration as “listed” drugs, which are subject to less stringent regulations than drugs classified as “scheduled” drugs, such as prescription drugs. “If someone starts a vitamin company, all they have to do is prove to the government that it is safe. They don’t have to prove that it works,” Wheate says.

According to Wheate, vitamin patches contain very low concentrations of ingredients, and there is no guarantee that they will work at all because not all medications can be administered through the skin. There are currently no vitamin patches listed on the Australian Register of Therapeutic Goods, meaning they cannot be legally supplied in Australia.

And what about the gummies sold by Kourtney Kardashian, which supposedly support “vaginal health, freshness and fragrance?” They “don’t add any health benefits for women,” one expert found in a thorough but bourgeois nonsense.

Who are vitamin supplements good for?

In certain cases, there are clear benefits to taking supplements. For example, vegans are at greater risk of vitamin B12 deficiency because it is the only vitamin that people get exclusively from animal sources – although Collins says it is often added to plant-based milk products.

Iron supplements may be necessary to prevent or treat iron deficiency anemia. Similarly, people at higher risk of osteoporosis, such as postmenopausal women, may be advised to take calcium and vitamin D to supplement dietary intake.

Folic acid, iodine and vitamin D supplements are recommended for pregnant women because they are necessary for normal development of a fetus. Vitamin D supplements may also be necessary for people with dark skin or who don’t get much sun.

And for people with age-related macular degeneration, a combination of zinc and antioxidants known as AREDS2 supplements can reduce the risk of the condition worsening.

“There is definitely a place for taking vitamin supplements,” says Macpherson. “Individuals really need to work with their healthcare provider to address these (nutrient deficiencies). Taking a multivitamin will not be sufficient in those cases.”

• Donna Lu is Guardian Australia’s science writer

• Antiviral is a biweekly column that interrogates the evidence behind health headlines and fact-checks popular wellness claims.