Overall diet is an important first consideration for those considering nutritional supplementation. Healthy dietary habits can help optimize nutrition and the absorption of supplements, and nutritional supplements cannot substitute for a diet that is not nutritionally balanced in the first place. Supplements are best used moderately to supply any extra nutritional requirements. Sound diets contain a variety of wholesome foods. At least five servings per day of fruits and vegetables are recommended, as well as the inclusion of whole grains in the diet. Variety in the diet is important to provide a full range of vitamins and minerals. Overeating inhibits digestion and absorption of nutrients, while regular exercise contributes to sound nutrition, by improving metabolism and digestion. Drinking plenty of clean water prevents dehydration, improves digestion, and helps the body flush out impurities.
There's not much doubt about this one: Women need more iron than men, because they lose iron with each menstrual period. After menopause, of course, the gap closes. The RDA of iron for premenopausal women is 18 mg a day, for men 8 mg. Men should avoid excess iron. In the presence of an abnormal gene, it can lead to harmful deposits in various organs (hemochromatosis). Since red meat is the richest dietary source of iron, it's just as well that men don't need to wolf down lots of saturated fat to get a lot of iron.
Eat all the foods you enjoy—but the key is to do it in smaller quantities, says Elisa Zied, RDN, who has lost and kept off more than 30 pounds since her highest weight in high school. In fact, she says it's the number one change she made that's helped her maintain her smaller frame. "I didn't want to feel deprived as I had in previous attempts to lose weight," she says. The worst thing you can do is be too strict, then rebound by overeating because you're not satisfied.
An important take-home message is to focus on the types of foods you eat and your overall dietary pattern, instead of on individual nutrients such as fat, dietary cholesterol, or specific vitamins. There are no single nutrients or vitamins that can make you healthy. Instead, there is a short list of key food types that together can dramatically reduce your risk for heart disease.
For example, while increased consumption of fruits and vegetables are related to decreases in mortality, cardiovascular diseases and cancers, supplementation with key factors found in fruits and vegetable, like antioxidants, vitamins, or minerals, do not help and some have been found to be harmful in some cases. In general as of 2016, robust clinical data is lacking, that shows that any kind of dietary supplementation does more good than harm for people who are healthy and eating a reasonable diet but there is clear data showing that dietary pattern and lifestyle choices are associated with health outcomes.