Need of Multivitamins

If you take a multivitamin , it’s probably because you want to do everything you can to protect your health. But there is still limited evidence that a daily cocktail of essential vitamins and minerals actually delivers what you expect. Most studies find no benefit from multivitamins in protecting the brain or heart. But There are potential benefits and no risks from a one daily standard multivitamin.

So, is it worth considering a multivitamin as part of a healthy lifestyle? Start with asking yourself why you would consider taking a multivitamin. If you suspect your diet is nutritionally lax, focus your efforts there.

What we know about multivitamins so far

Despite all the research on vitamins and health, we have only a handful of rigorous scientific studies on the benefits of a “true” multivitamin: a pill that provides essential vitamins and minerals at the relatively low levels that the body normally requires.

The Physicians’ Health Study II is the best study completed so far. It was the first and only large-scale randomized clinical trial to test a commonly taken multivitamin like the ones most people take, containing the daily requirements of 31 vitamins and minerals essential for good health.

A large group of male physicians took either a multivitamin or a placebo pill for more than a decade. The results have been mixed, with modest reductions in cancer and cataracts, but no protective effect against cardiovascular disease or declining mental function. Is it safe?

Multivitamin advocates point to the lack of any strong proof that taking a multivitamin for many years is dangerous. While the likelihood of harm is small, the likelihood of a clear health benefit is also very small—and also we have no clear proof yet of such benefit.

The optimists say despite no clear evidence of health benefit, multivitamin supplementation is low risk and low cost. And it helps to fill potential gaps in the diet that people might have.

For now, you can take certain steps:

• Ask your doctor if you really need to take a multivitamin. Could you have a vitamin deficiency?
• Assess your diet. Do you eat as healthy as you could? Is anything lacking?
• Do you want expert nutritional advice? See a dietician. Also, Medicare beneficiaries get an annual “wellness” visit with their primary care providers.
• Do not take high doses of specific vitamins, especially A and E. These may actually be harmful.

Researchers looked at the effect of long-term multivitamin use in healthy men on various aspects of health. Here is what they found:

Cancer

Men were 8% less likely to be diagnosed with cancer. The protective effect was greatest in men with a history of cancer.

Vision

Lower risk of developing cataracts.

Cardiovascular disease

No protection against heart attacks, strokes, or death from cardiovascular disease.

Brain

No protection against declining memory or mental skills.

Caveat

Because of PHSII’s design, the findings on memory loss and vision are somewhat more likely to be chance findings than the cancer and cardiovascular disease results.

• While classic nutrient deficiency diseases like rickets and scurvy are now rare in the U.S., inadequate levels of certain micronutrients can still impair a wide range of biological functions.

• For example, you’ve probably heard that inadequate intake of calcium and vitamin D over time can contribute to osteoporosis later in life, or that low folic acid intake among pregnant women increases the risk of neural tube defects in newborns.

• What you may not have considered, though, is that micronutrient inadequacies can also increase susceptibility to illness and chronic diseases, such as cancer, heart disease, type 2 diabetes, age-related macular degeneration and cognitive dysfunction. Not getting enough of certain micronutrients can also lead to impaired immune function, making you increasingly susceptible to infection. I recently even argued that inadequate magnesium status may increase the risk of COVID-19 infection and severity, due to its various roles like activating vitamin D in the body.

• To date, though, there’s only two large, long-term clinical trials of multivitamins. The Physicians Health Study II was the first to assess the long-term efficacy of multivitamins in preventing chronic disease. It tested four supplements (including a multivitamin) on the prevention of certain diseases among nearly 15,000 male physicians over the age of 50. Over an average of 11 years, the study found multivitamin use decreased risk of cancer by 8% and cataracts by 9%, with no effects on cardiovascular disease, cognitive decline or age-related macular degeneration. Not exactly a slam dunk, but remember this study didn’t find any noteworthy drawbacks to taking a multivitamin, either.  

• The more recent  COSMOS randomized clinical trial in The American Journal of Clinical Nutrition assessed shorter-term efficacy of multivitamins on prevention of cancer and cardiovascular disease in over 21,000 participants.  Over an average of 3.6 years, the study failed to show effects of multivitamin use on total cancer or cardiovascular disease, although the relatively short duration of the study likely limits its ability to detect any small to moderate effects on cancer incidence. COSMOS did show a statistically significant reduction in lung cancer incidence.  

• The study provides consistent evidence with the Physician’s Health II study that a daily multivitamin likely has little to no influence on development of cardiovascular disease, but also lacks any drawbacks to health (note that the multivitamin tested in both clinical trials was Centrum).

• Although more research is needed, many researchers in the field (including myself) speculate that when micronutrient intakes are lower than recommended levels, immediate short-term requirements for micronutrients in metabolic reactions take precedence over long-term needs—which could lead to irreversible, long-term damage in exchange for keeping your short-term needs met. Think of it like only ever replying to the newest three emails in your inbox. For these reasons, taking a daily multivitamin makes practical sense to me.