Vitamins & Supplements Archive

There is little evidence that dietary supplements marketed as performance enhancers do more than following a well-balanced diet. Two nutrients that can help people during extended exercise are carbohydrates and caffeine.

Women over 60 need less iron than they did before menopause, when they lost iron through menstruation. Many conditions can lead to iron loss and iron-deficiency anemia, when the body can’t make enough red blood cells to properly carry oxygen throughout the body. Signs of iron deficiency include pale skin, fatigue, shortness of breath, weight loss, and chest pain. Tests can reveal iron deficiency and underlying reasons for iron loss. People should not take iron supplements without checking with their doctor. Too much iron can damage organs.

Elderberry syrup or tea may help reduce the duration and severity of cold and flu symptoms. But the evidence for these benefits is uncertain, since the studies are small and most did not compare elderberry to standard treatments. Claims that elderberry products can prevent viral infections or boost immunity are unproven. Elderberry supplements appear to be relatively safe; in clinical trials, effects such as nausea, vomiting, or diarrhea were mild and rare.

Vaginal probiotics contain live microorganisms and come in oral and suppository forms. Some ads claim these products can prevent or treat infections. But the vagina regulates its own bacterial mix, so vaginal probiotics aren’t necessary.

In the US, more than a quarter of children and adolescents have ready-to-eat cereal for breakfast most days of the week. Advertising touts cereal as a healthy choice, but a recent study disputes this.

In a 2025 randomized trial of about 1,000 people (ages 50 or older), followed for four years, those who took 2,000 international units of vitamin D₃ per day showed cellular signs that suggested they were aging more slowly compared with people who did not take the supplement. It’s unclear if this benefit would continue from taking daily pills longer than four years. Scientists do know that taking vitamin D₃ supplements is important for people with osteoporosis or with vitamin D deficiency (as determined by a blood test).

Taking 2,000 International Units of supplemental vitamin D₃ daily may help slow the cellular aging process, according to a 2025 study.

Magnesium is a mineral the human body needs to function properly — especially for a healthy cardiovascular system, nerves, muscles, and bones — though the benefits of supplements are largely oversold. While most people get enough magnesium from their diet, in certain instances people should take a supplement.

Taking a daily multivitamin helps fill in nutritional gaps and some studies have found a link to better cognitive fitness. Adding a vitamin D supplement may help maintain bone health and a B₁₂ supplement is suitable for people who might have difficulty getting this vitamin from food.