In the United States, the Dietary Supplement Health and Education Act of 1994 provides this description: "The Dietary Supplement Health and Education Act of 1994 (DSHEA) defines the term “dietary supplement” to mean a product (other than tobacco) intended to supplement the diet that bears or contains one or more of the following dietary ingredients: a vitamin, a mineral, an herb or other botanical, an amino acid, a dietary substance for use by man to supplement the diet by increasing the total dietary intake, or a concentrate, metabolite, constituent, extract, or combination of any of the aforementioned ingredients. Furthermore, a dietary supplement must be labeled as a dietary supplement and be intended for ingestion and must not be represented for use as conventional food or as a sole item of a meal or of the diet. In addition, a dietary supplement cannot be approved or authorized for investigation as a new drug, antibiotic, or biologic, unless it was marketed as a food or a dietary supplement before such approval or authorization. Under DSHEA, dietary supplements are deemed to be food, except for purposes of the drug definition."
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.
Maintaining a healthy weight is important piece of the puzzle to achieve good health. A healthy weight can be determined using the body mass index charts (see web source below). If you find you are overweight or obese, weight loss may be beneficial for you. Before you begin any weight loss efforts, consult with your medical provider and/or consult a registered dietitian to create a weight loss plan. If you are underweight, consult a medical provider to assess your weight status.
The majority of adults in the United States take one or more dietary supplements either every day or occasionally. Today's dietary supplements include vitamins, minerals, herbals and botanicals, amino acids, enzymes, and many other products. Dietary supplements come in a variety of forms: traditional tablets, capsules, and powders, as well as drinks and energy bars. Popular supplements include vitamins D and E; minerals like calcium and iron; herbs such as echinacea and garlic; and specialty products like glucosamine, probiotics, and fish oils.
Vitamin A can become toxic when taken in large amounts (over 100,000 International Units) on a daily basis over time, as can vitamin D. Substituting beta-carotene for vitamin A can alleviate this risk. Very large doses of minerals taken over long periods may have toxic effects in the body. Dosages far exceeding RDA's of vitamins are not recommended, nor are large doses of other supplements.
Nutritional supplements may be designed to provide specialized support for athletes. Some of these consist of high-protein products, such as amino acid supplements, while other products contain nutrients that support metabolism, energy, and athletic performance and recovery. People engaging in intense athletic activity may have increased needs for water-soluble vitamins, antioxidants, and certain minerals, including chromium. Sports drinks contain blends of electrolytes (salts) that the body loses during exertion and sweating, as well as vitamins, minerals, and performance-supporting herbs.
USDA's food icon, MyPlate, serves as a quick visual reminder to all consumers to make healthy food choices when you choose your next meal, built off of the Dietary Guidelines for Americans. MyPlate can help prioritize food choices by reminding us to make half of our plate fruits and vegetables and shows us the other important food groups for a well-balanced meal: whole grains, lean proteins, and low fat dairy.
Among general reasons for the possible harmful effects of dietary supplements are: a) absorption in a short time, b) manufacturing quality and contamination, and c) enhancing both positive and negative effects at the same time. The incidence of liver injury from herbal and dietary supplements is about 16–20% of all supplement products causing injury, with the occurrence growing globally over the early 21st century. The most common liver injuries from weight loss and bodybuilding supplements involve hepatocellular damage with resulting jaundice, and the most common supplement ingredients attributed to these injuries are green tea catechins, anabolic steroids, and the herbal extract, aegeline. Weight loss supplements have also had adverse psychiatric effects.
2. Eat a variety of foods. As we covered earlier, the brain craves novelty. While you may not be able to replicate the crunchy/creamy contrast of an Oreo, you can vary your diet enough to keep things interesting. For example, you could dip a carrot (crunchy) in some hummus (creamy) and get a novel sensation. Similarly, finding ways to add new spices and flavors to your dishes can make eating healthy foods a more desirable experience.
Protein gives you the energy to get up and go—and keep going—while also supporting mood and cognitive function. Too much protein can be harmful to people with kidney disease, but the latest research suggests that many of us need more high-quality protein, especially as we age. That doesn’t mean you have to eat more animal products—a variety of plant-based sources of protein each day can ensure your body gets all the essential protein it needs. Learn more »
"Creatine is one of the most popular supplements, with over 100 studies consistently showing it can work in muscle cell recovery in athletes who engage in high-intensity, short-burst activity such as sprinting or weight lifting," notes Clark. "But it does not work for endurance or recreational athletics." (She cautions anyone taking creatine to be sure they stay well hydrated to avoid cramping.)
The soil in areas with relatively low rainfall may in some cases contain an extremely high concentration of minerals, which is reflected in the plants growing there. This was well documented 70 years ago in the book Tomorrow's Food.  The Dentist George W. Heard found that the soil in Hereford, Texas, was exceptionally rich in minerals. Hereford became known as the "town without a toothache" after a newspaper article from January 29, 1942, reported that Hereford had the lowest incidence of tooth decay of any city in the United States.  Heard found that people in Hereford had exceptionally few dental cavities and also that the soil locally was especially rich in minerals. He emphasized that the population in the county ate unprocessed food and was drinking raw milk. 
Some supplements that were found to have health benefits in observational studies turned out, with more rigorous testing, to be not only ineffective but also risky. Vitamin E, which was initially thought to protect the heart, was later discovered to increase the risk for bleeding strokes. Folic acid and other B vitamins were once believed to prevent heart disease and strokes—until later studies not only didn't confirm that benefit but actually raised concerns that high doses of these nutrients might increase cancer risk.
After basic nutritional requirements are supported, supplements may be used to target specific needs and health conditions. For instance, athletes, men, women, children, the elderly, and vegetarians have differing needs for nutrients, and an informed use of supplements would take these differences into account. People suffering from health conditions and diseases may use specific supplements to target their condition and to support the body's healing capacity by providing optimal amounts of nutrients.
Research from Tufts University nutrition scientists shows that Americans are drinking so much soda and sweet drinks that they provide more daily calories than any other food. Obesity rates are higher for people consuming sweet drinks. Also watch for hidden sugar in the foods you eat. Sugar may appear as corn syrup, dextrose, fructose, fruit juice concentrate or malt syrup, among other forms, on package labels.
Obviously, the best treatment plan for poor nutrition is to change your diet. Most Americans eat too little of what they need and too much of that they don't. For many women, decreasing fat and sugar consumption and increasing fruit, vegetables and grains in your diet can make a big difference. Many women also need to boost consumption of foods containing fiber, calcium and folic acid. Compare your diet to that suggested by the food pyramid and compare your nutrient intake to the suggested daily levels. Adjust accordingly, and you may be able to dramatically improve your health.
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.
If you suspect that you have had a serious reaction from a dietary supplement, let your health care provider know. He or she may report your experience to the FDA. You may also submit a report to the FDA by calling 800-FDA-1088 or completing a form online. In addition, report your reaction to the dietary supplement company by using the contact information on the product label.