The guidelines also establish ranges (called acceptable macronutrient distribution ranges or AMDR) for fat, carbohydrates and protein, instead of exact percentages of calories or numbers of grams. The report maintains that since all three categories serve as sources of energy, they can, to some extent, substitute for one another in providing calories.
Do you wonder if you need a dietary supplement? Maybe you do, but usually not. Ask yourself why you think you might want to take a dietary supplement. Are you concerned about getting enough nutrients? Is a friend, a neighbor, or someone on a commercial suggesting you take one? Some ads for dietary supplements in magazines, online, or on TV seem to promise that these supplements will make you feel better, keep you from getting sick, or even help you live longer. Often, there is little, if any, good scientific research supporting these claims. Supplements may cost a lot, could be harmful, or simply might not be helpful. Talk to your doctor or a registered dietitian for advice.
Animal products, such as meat, fish and poultry are good and important sources of iron. Iron from plant sources are found in peas and beans, spinach and other green leafy vegetables, potatoes, and whole-grain and iron-fortified cereal products. The addition of even relatively small amounts of meat or foods containing vitamin C substantially increases the total amount of iron absorbed from the entire meal.
To make it easy to find reliable information, NIH has fact sheets on dietary supplements at ods.od.nih.gov/factsheets/list-all/. NIH also recently launched an online Dietary Supplement Label Database at www.dsld.nlm.nih.gov. This free database lets you look up the ingredients of thousands of dietary supplements. It includes information from the label on dosage, health claims and cautions.
Women, as we age, are also more susceptible to the breakdown of our bones, which may result in osteoporosis over time. Genetically, women have a particularly high risk of osteoporosis compared to men, so it’s recommended that women monitor their calcium intake to be sure they’re getting enough. Weight training is another great way (and my favorite!) to build bone density, which is another great reason you should hit the weights!
Because observational studies may not fully control for dietary factors, exercise habits, and other variables, they can't prove whether the treatment is responsible for the health benefits. "People who take supplements tend to be more health conscious, exercise more, eat healthier diets, and have a whole host of lifestyle factors that can be difficult to control for fully in the statistical models," Dr. Manson says.
Reduced nutritional density in many foods, combined with the use of refined "foods" like sugar, white flour and refined oils, places a greater priority on eating the most nutritious foods. Farm produce grown organically generally has higher levels of essential nutrients such as trace minerals because the soil contains higher levels of trace minerals and the produce grows slower and thus has more time to absorb nutrients from the soil. Examples of nutrient dense foods are sardines, wild salmon, shellfish, eggs, liver, kale, collards and spinach, sea plants (seaweed), garlic, blueberries, and dark chocolate. 
Fresh, Frozen, or Canned Fruits ― don’t think just apples or bananas. All fresh, frozen, or canned fruits are great choices. Be sure to try some “exotic” fruits, too. How about a mango? Or a juicy pineapple or kiwi fruit! When your favorite fresh fruits aren’t in season, try a frozen, canned, or dried variety of a fresh fruit you enjoy. One caution about canned fruits is that they may contain added sugars or syrups. Be sure and choose canned varieties of fruit packed in water or in their own juice.
A healthy vegetarian diet falls within the guidelines offered by the USDA. However, meat, fish and poultry are major sources of iron, zinc and B vitamins, so pay special attention to these nutrients. Vegans (those who eat only plant-based food) may want to consider vitamin and mineral supplements; make sure you consume sufficient quantities of protein, vitamin B12, vitamin D and calcium. You can obtain what you need from non-animal sources. For instance:
One exception, he says, is seniors, who may need additional B-12 because as we get older, we absorb less of it. Most of us should skip the supplements and get our Bs from grains, dark green vegetables, orange juice, and enriched foods. People with certain medical conditions or who take drugs that interfere with vitamin absorption may also require supplementation.
If you do decide to diet, you still need to maintain good nutrition. You want to cut back on calories, not nutrients. And while you want to reduce fat, don't eliminate it entirely. Some studies suggest that older women who maintain a higher body-fat percentage are less likely to suffer from osteoporosis and other conditions associated with menopause. Fat cells also retain estrogen, which helps maintain the calcium in your bones. Younger women should be careful, too: a low body fat percentage can lead to infertility; below 17 percent may lead to missed periods, also known as amenorrhea.
However, some herbal supplements may not be safe. They could contain unlisted ingredients that make you sick. Drugs that aren’t listed on the label can include, steroids or estrogens. Products may even contain toxic, or poisonous, substances. Examples include, as arsenic, mercury, lead, and pesticides. Supplements must be recalled if they are found to contain toxic ingredients.
Protein-containing supplements, either ready-to-drink or as powders to be mixed into water, are marketed as aids to people recovering from illness or injury, those hoping to thwart the sarcopenia of old age, to athletes who believe that strenuous physical activity increases protein requirements, to people hoping to lose weight while minimizing muscle loss, i.e., conducting a protein-sparing modified fast, and to people who want to increase muscle size for performance and appearance. Whey protein is a popular ingredient, but products may also incorporate casein, soy, pea, hemp or rice protein.