Cast of characters: From vitamin A to zinc
This chapter features a broad overview of the best-known vitamins and minerals. For each nutrient described here, you’ll find the following information:
- the Recommended Dietary Allowance (RDA) or adequate intake (AI) for people ages 19 and older (with sex and age differences noted when applicable) and a brief description of the nutrient’s role in the body. An RDA is the average daily amount of a nutrient that is sufficient to meet the nutrient requirements of nearly all healthy people. An AI is an amount of a nutrient thought to be enough and is used when there isn’t enough evidence to identify an RDA.
- a summary of the data pointing to health benefits of that nutrient. If a condition is not listed, that means there is insufficient evidence to support a connection.
- recommendations about taking the nutrient in supplement form.
- a table of selected food sources containing the nutrient, with an emphasis on the best sources in commonly consumed foods.
As a rule, your best strategy is to start by getting vitamins and minerals from foods, not supplements. A vast amount of research has shown that you can cut your risk for chronic disease and disability by following a healthy diet, as well as by exercising regularly, maintaining a healthy weight, and not smoking. The evidence for taking high-dose, individual vitamin and mineral supplements is much less convincing.
Before taking a supplement that delivers more than the recommended daily amount of any nutrient, discuss your decision with your doctor. Your medical history, genetic profile, and medications may affect the dosages and types of supplements you can safely take.
