According to the Centers for Disease Control and Prevention (CDC), 58% of US adults report taking a dietary supplement in the past 30 days…and one-­quarter of people age 60 and older take four or more daily. In fact, Americans spent nearly $60 billion on dietary supplements in 2020 alone.

There was a time when swallowing handfuls of supplements was seen among older adults as evidence of their dedication to a healthy lifestyle. But we now know that people who consume a balanced diet and are in good health are likely getting all the nutrients they need.

Still, some supplements can fill in nutritional gaps for people who have food allergies…eat lots of junk food and eschew healthy produce…or avoid entire categories of food—picky eaters, vegans or people who skip, say, soy or dairy products because they fear they’re unhealthy (they’re not).

Bottom Line Personal asked integrative medicine specialist Renee Miranda, MD, who should be taking supplements…and which ones.

Do You Need a Supplement?

When a patient asks me about supplementation, my first two questions are, “What does your diet look like?” and “What is your goal?”

What does your diet look like? A varied diet rich in whole foods such as fruits, vegetables, beans and legumes, grains, dairy and protein provides all the required nutrients, so theoretically the only people who need supplementation are those with gaps in their diets. To evaluate your diet: Keep a food log for three consecutive days, including at least one weekend day. Note portion sizes and preparation methods. This log can give you and your doctor an idea of any nutrient gaps.

To improve your diet, a good place to start is the American Heart Association recommendations ( I recommend six to nine servings of fruits and vegetables daily…two to three servings of quality protein mainly from plant sources such as legumes (if you prefer animal products, lean toward unprocessed meats)…one to three servings of whole grains…and an occasional serving of nuts and seeds.

What is your goal? Some people want to improve their heart health, and they have read that a supplement might help…or they have been told that ­multivitamins boost overall wellness. New research is constantly emerging about whether certain supplements live up to the hype. Oftentimes, they don’t.

A 2018 meta-analysis in Journal of the American College of Cardiology determined that supplementing with a multivitamin, vitamin D, calcium or vitamin C does not significantly reduce risk for heart attack or stroke or of dying from any cause. Also, supplementing with large amounts of certain antioxidants—found naturally in fruits and vegetables—may work against your goals by increasing risk for certain types of cancer or chronic diseases. This may be because some fat-soluble vitamins—such as A, D, E and K—are stored in the body for long periods and can accumulate to toxic levels when taken in large doses. And new research suggests that high doses of supplemental antioxidants may even protect cancer cells from the body’s natural cancer-fighting process.

There are, however, instances when supplements make sense. Example: Many older adults are deficient in vitamin B-12, especially those who regularly take acid-suppressing medication, such as esomeprazole (Nexium), omprasole (Prilosec) and lansoprazole (Prevacid). Vitamin B-12 is critical for healthy functioning of the brain and nervous system.

Which Supplements Should You Take?

Here are the supplements that I recommend for certain patients and why…and how to get the most out of them.

Vitamin D does everything from boost calcium absorption from foods (crucial for bone strength) to strengthen the immune system. Yet nearly one-half of Americans are deficient. Reasons: Vitamin D isn’t found in many foods besides oily fish such as salmon, fortified milk and juice, and UV-B-light–boosted mushrooms…we spend so much time indoors (depriving our skin of sunlight, which the body needs to produce vitamin D)…and when we are outside, we use sunscreen. Also: Older adults, people with obesity, darker-skinned individuals and people living in colder, grayer ­climates are at increased risk for deficiency.

What to do: Ask your health-care provider for a blood test to assess your vitamin D level. If it is low, the doctor may recommend 400 international units (IU) to 600 IU daily…or a 50,000-IU pill weekly for four weeks. If your level is around 40 ng/mL—the lower end of normal—and you feel tired, that also suggests supplementation may be useful.

Encouraging: New research shows that older people in China who maintain healthy vitamin D levels had less cognitive impairment and healthier lipid levels than their deficient counterparts.

Note: Vitamin D is fat-soluble—it needs to be combined with a little fat to be absorbed. Swallow the supplement with a plant-based source of fat such as avocado or some almonds, walnuts or other nuts and seeds. Vitamin D also needs magnesium to be activated, so get enough of this mineral.

Vitamin B-12: As you age, the stomach produces less and less hydrochloric acid, a compound needed to absorb B-12 from food. For the same reason, people taking acid-reducing medications may have lower levels of B-12.

Vegans (people who eat no animal products) and some vegetarians (people who don’t eat meat) may need supplemental B-12 because B-12 is available only in animal products or fortified foods such as breakfast cereal and nutritional yeast. Individuals with celiac disease or Crohn’s disease also may be deficient because their gut doesn’t absorb the nutrient efficiently from food.

The average adult needs 2.4 micrograms (mcg) of vitamin B-12 a day. Supplements contain about 1,000 mcg to 2,000 mcg—so you’ll need to supplement only a few times a week. Any excess will be excreted in your urine. Ask your doctor for guidance.

Magnesium: About half the US population is magnesium-deficient, yet this mineral has a hand in dozens of bodily systems. It promotes regular bowel movements, calms anxiety, promotes sleep and more. Magnesium also converts food into energy, so low levels can cause fatigue. Foods high in magnesium: Nuts, seeds, beans, whole grains, leafy green veggies and some fortified foods.

Adults absorb less magnesium as they grow older. People with type 2 diabetes lose magnesium in their urine, and certain medications can reduce magnesium ­levels. These include bisphosphonates such as alendronate (Fosamax) for osteoporosis…loop diuretics such as furosemide (Lasix) for high blood pressure…and prescription proton pump inhibitors such as esomeprazole (Nexium).

A blood test can check for magnesium deficiency, but there’s little risk from supplementing. These supplements come in different forms, including magnesium citrate (recommended for constipation) and magnesium chloride (better suited for sleep and anxiety). Start with 200 mg a day, and see if symptoms improve. You can slowly move up to 400 mg/day. Toxicity symptoms at higher doses or due to inability to eliminate excess magnesium (common among people with kidney disease) include gastrointestinal upset, flushing, weakness and palpitations.

Warning: Start low, and go slow—magnesium citrate supplements can have a laxative effect. If you take any of the previously mentioned medications, space them several hours apart from your supplement.

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