In a thriving multi-billion dollar industry, dietary supplements, and multivitamins have little to no impact on the health of those who are neither pregnant nor nutrient deficient.

The market for dietary supplements in North America was estimated by analysts to be worth $52,874.7 million in 2021, with annual spending predicted to rise by 5.6 percent through 2030.a

A poll done between 2011 and 2014 found that 31% of individuals utilize a multivitamin-mineral supplement, while 52% of adults use at least one dietary supplement each month. To replace vitamin shortages in the diet, "overall health and wellness" was cited as the most frequent justification for taking supplements.

However, studies demonstrate that taking multivitamins in otherwise healthy people has little to no impact on health and may even, in certain situations, raise the risk of illnesses like cancer.

How do multivitamins work?

According to Dr. Sarah Berry, chief scientist at ZOE and reader in nutritional sciences at King's College London, "strictly speaking, the term 'multivitamins' refers to supplements containing solely vitamins." But the majority of supplements mix vitamins, minerals, and additional nutrients like omega-3 fatty acids.

Common misunderstandings

One of the biggest misconceptions about multivitamins, according to Dr. Rachel Kopec, assistant professor of human nutrition at The Ohio State University, is the dose administered. Depending on how they are encapsulated and what they are encapsulated with, the amount of a given micronutrient dose that is actually absorbed into the bloodstream from multivitamins can be quite low for essential minerals like iron and calcium as well as fat-soluble micronutrients like vitamins A, D, E, and K. For instance, once vitamin A has dissolved in the stomach, there is a chance that iron will oxidize it.

Studies on nutrition

Dr. Berry pointed out that there is a lot of misunderstanding on how supplements affect health. She stated that there are two reasons for this.

The first is the wide range of multivitamin supplements, which makes research more challenging. The second is that consuming a single micronutrient could not have the same physiological effects as consuming them as a component of a fruit or vegetable.

She said that research employing food interventions is generally used to infer the health impacts of nutrients. The impact of a nutrient from a portion of food is, however, influenced by the other nutrients in the food as well as the complexity of the food matrix, or the structure of the food.

Those who ought to take multivitamins

According to Dr. Brian Lindshield, a professor in Kansas State University's Department of Food, Nutrition, Dietetics, and Health, those who might experience a micronutrient shortage should take multivitamins.

He said that "taking a multivitamin can compensate for eating a diet low in micronutrients."

"It can help avoid vitamin insufficiency, which is important, but the reason that many people take them is because they desire the health advantages of a micronutrient-rich diet, such the reduction of chronic disease, without having to consume the micronutrient-rich diet. But studies have shown that multivitamins or pills containing only one micronutrient have little to no advantage on the likelihood of developing chronic diseases," he said.

Other than multivitamins

All of the experts concurred that eating a well-balanced diet is essential. Limiting weight gain, engaging in modest physical activity, quitting smoking, limiting alcohol consumption, and eating a healthy, balanced diet are the most crucial factors, according to Dr. Giovanni. The combined impact of these is significant for health.

Limiting the negative consequences of stress is also crucial. Except perhaps for extra vitamin D, multivitamins would be less effective for people who lead healthy lifestyles, he said.