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.
What aspect of your health are you planning on prioritizing in 2024?
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