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.