Doctors describe using six supplements for specific needs, while stressing that food, personal health factors and possible risks matter.
Some physicians take supplements, but their choices tend to be tied to a particular need rather than a belief that everyone should take them. That distinction matters: supplements can help fill a nutritional gap, but they don’t replace a balanced diet or medical care, and a clinician’s personal routine isn’t a recommendation for every reader.
About half of adults and one-third of children in the United States take supplements regularly, according to the Office of Dietary Supplements. Yet many clinicians are cautious about the category. Most recommend getting nutrients from food when possible, and supplements aren’t reviewed for safety and effectiveness by the FDA before they reach store shelves. Jeffrey Linder, MD, MPH, a general internist and professor at Northwestern University’s Feinberg School of Medicine, told SELF that “a vast majority of supplements are probably worthless.”
Still, some supplements may serve a purpose when someone’s intake is low or they have a specific health concern. Eight doctors interviewed by SELF described using some of the six below. Their accounts offer examples, not a universal checklist: whether a supplement makes sense depends on a person’s diet, health, medications and other circumstances.
Vitamin D: a nutrient that can be hard to get from food
Vitamin D supports bone health and immune function. Low levels have been associated with a range of conditions, including cancer, autoimmune and infectious diseases, cardiovascular issues and seasonal affective disorder. An association does not establish that low vitamin D causes these conditions, or that supplements prevent or treat them.
Deficiency is more common among people with darker skin and those who live in northern latitudes, where winter sunlight is limited. Few foods contain substantial amounts, which can make it difficult to get enough through diet alone. Lawrence Green, MD, a dermatologist and clinical professor at George Washington University School of Medicine and Health Sciences, described vitamin D as one of the relatively few nutrients people may need to supplement. Nearly all eight doctors interviewed said they take it, particularly during winter; their routines and amounts differed.
When choosing between forms, the article notes that studies have found vitamin D3, also called cholecalciferol, more effective than D2, or ergocalciferol, at raising blood vitamin D levels. Vitamin D is fat-soluble, so taking it with a meal containing fat may help the body absorb it. The doctors’ accounts don’t establish a suitable amount for any individual; that can depend on personal needs and health circumstances.
Calcium: food first, with attention to bone health
Calcium helps maintain bones and teeth. Rachel Pessah-Pollack, MD, an endocrinologist at NYU Langone Health and clinical professor at the NYU Grossman School of Medicine, said women in their 40s approaching menopause should pay attention to getting enough. The changes associated with perimenopause and menopause can increase bone loss, which can contribute to conditions such as osteoporosis.
Pessah-Pollack said she tries to get calcium from food, including dairy products, but takes a combined calcium and vitamin D supplement when her diet falls short. Vitamin D helps the body absorb calcium. The form of calcium also affects how it is taken: calcium carbonate needs stomach acid for absorption and should be taken with food, while calcium citrate can be taken with or without food.
Magnesium: different forms may suit different needs
Magnesium is involved in several functions in the body. Doctors interviewed said they use it for reasons including sleep and migraine symptoms. Raquel Zemtsov, MD, MPH, a family medicine physician and assistant professor at the University of Pittsburgh School of Medicine, takes it to help prevent migraines. Sara Velayati, MD, an obesity medicine specialist at Montefiore Einstein, and reproductive endocrinologist Sheeva Talebian, MD, and internal medicine physician Kathleen Jordan, MD, described taking it at bedtime for sleep.
There isn’t one form that suits every purpose. Velayati said some forms may be better tolerated by people prone to side effects. Jordan noted that magnesium glycinate may cause less gastrointestinal upset than magnesium oxide or citrate. Zemtsov keeps magnesium oxide on hand for migraine prevention, reflecting that the form used can depend on the reason for taking it. Taking magnesium with food may also help reduce stomach discomfort. These examples don’t show that magnesium will improve sleep or prevent migraines for everyone.
Omega-3s: a popular option with practical drawbacks
Omega-3 fatty acids are polyunsaturated fats associated with cardiovascular health. Fish oil and krill oil are common supplement sources. Jordan, Talebian and Velayati said they take omega-3s. Jordan cited their anti-inflammatory properties and association with brain health; Velayati said she takes fish oil selectively and that the right amount depends on the goal. She doesn’t consider it necessary for everyone.
Fish oil can leave a fishy aftertaste, and the body’s absorption of these fats may be a consideration. Since omega-3s are fat-soluble, taking fish oil with a meal containing fat may help. Krill oil is sometimes said to cause less aftertaste, and the article reports evidence suggesting it may be better absorbed. Those points don’t establish that krill oil is the better choice for every person.
Iron: useful when intake or levels are low
Iron is needed to make hemoglobin, the protein in red blood cells that carries oxygen to organs and tissues. Not getting enough can lead to anemia. Menstruation can raise the risk of iron deficiency for women, as blood loss reduces the body’s iron stores.
Zemtsov said she sometimes develops iron deficiency despite trying to eat iron-rich foods. When that happens, she uses ferrous gluconate, a form of iron, every other day to treat or prevent anemia. She cited research suggesting that this schedule can improve absorption and reduce side effects. Jordan also takes iron, citing sleep, hair health and energy. These accounts don’t establish that iron is appropriate for people without a deficiency; a clinician can help assess whether it’s needed.
Vitamin C can help the body absorb iron. Zemtsov pairs her supplement with food containing vitamin C or a vitamin C supplement. People considering iron can ask a clinician or pharmacist how it fits with their diet and any medicines they take.
Fiber: build intake gradually
Fiber supports digestion, helps with fullness and regular bowel movements, and can help stabilize blood sugar and lower LDL cholesterol. Jordan said she takes a fiber supplement as needed on days when she doesn’t meet her daily target of 25 to 30 grams. She also cited personal reasons, including prediabetes and rising cholesterol. Her experience is not evidence that a fiber supplement will address these issues for everyone.
A sudden increase in fiber can cause gas and bloating, particularly for someone whose usual intake is low. Gradually increasing fiber can make the change easier to tolerate. Adequate water also matters, since fiber needs water to work.
Choosing supplements with care
Velayati recommends having a specific reason for taking a supplement, such as a confirmed nutrient deficiency. Her view is that supplements can fill a gap, while nutrition, sleep, exercise and evidence-based medical care remain important parts of health.
Before starting a supplement, discuss it with a primary care clinician, especially if you take other medicines. “Natural” on a label doesn’t guarantee safety. Product quality can vary, and some organizations offer independent testing; Zemtsov suggested looking for products tested by the U.S. Pharmacopeia’s certifying organization or NSF International’s Certified for Sport program.
More isn’t always better. Excess calcium may increase the risk of kidney stones and cardiovascular issues, and too much vitamin D can also cause problems, in part because it increases calcium absorption. A clinician or pharmacist can help weigh a supplement’s possible benefits, risks and interactions for your circumstances. The most useful starting point is a clear reason for considering it and a conversation about whether it addresses a real gap.
