Taking large doses of single vitamins and minerals also carries risks. Excessive levels of zinc, for example, can disrupt the body’s uptake of copper, increasing the likelihood of anemia. Vitamin D is not metabolized efficiently without an adequate level of magnesium, and in high doses it can be toxic.
Vitamins and herbal supplements can also interact with prescription medications, dampening their effectiveness or, in the case of blood thinners, for example, raising concentrations to dangerously high levels.
There are times when taking a supplement can be very useful, such as during pregnancy or to address a clear nutrient deficiency. But for healthy adults who are worried about the coronavirus, eating a nutritious diet and getting proper sleep and exercise are the best ways to strengthen your immune system, said Linda Van Horn, chief of nutrition in the department of preventive medicine at the Northwestern University Feinberg School of Medicine.
Whole foods like fruits, vegetables, fish, poultry, nuts, legumes and milk contain a wide range of vitamins, minerals and phytochemicals — including zinc and vitamin D — that work in synergy to protect your health.
“This is an ideal time to look at what you’re eating,” said Dr. Van Horn. “We all know that grocery stores have been experiencing some limitations. But for the most part people are still able to find fresh produce and other healthy foods.”
Ms. Koff, the dietitian in Ohio, said she tells people it is fine to take a multivitamin to address any gaps in their nutrition. But she encourages people to focus on their diet, stress levels and sleep and warns them not to overload their systems with large doses of supplements.
“This is the time to start implementing behaviors that support your health, not going and taking high amounts of things that are incorrectly listed as immune boosters,” she said.