SOURCES: Institute of Medicine Food and Nutrition Board, Dietary Reference Intakes: "Calcium, Phosphorus, Magnesium, Vitamin D and Fluoride." National Academy Press, Washington, D.C., 1999. Journal of Nutrition, October 2005. Position paper of the American Dietetic Association on Food Fortification and Supplementation, Journal of the American Dietetic Association, August 2005. Michael Holick, MD, PhD, professor of medicine, physiology, and biophysics, Boston University Medical Center. Andrew Shoa, PhD, vice president for regulatory affairs, Council for Responsible Nutrition. Alice Lichtenstein, DSc, director and senior scientist, Cardiovascular Nutrition Laboratory, Human Nutrition Research Center on Aging, Tufts University. Dave Grotto, RD, spokesman, American Dietetic Association; author, 101 Foods That Could Save Your Life. Eduardo Baetti, MD, rheumatologist; Kaiser Permanente. Patrick Rea, editorial director, Nutrition Business Journal. Kristine Clark, PhD, RD, director of sports nutrition, Penn State University. Vasilios Frankos, PhD, Division of Dietary Supplement Programs, FDA. Sarubin, A. The Health Professionals Guide to Popular Dietary Supplements, American Dietetic Association, Chicago, IL, 2000. FDA. WebMD Weight Loss Clinic Feature: "Are You Getting Enough Vitamin D?" National Center for Complementary and Alternative Medicine: "Questions and Answers About Homeopathy."
Creating an industry estimated to have a 2015 value of $37 billion, there are more than 50,000 dietary supplement products marketed just in the United States, where about 50% of the American adult population consumes dietary supplements. Multivitamins are the most commonly used product. For those who fail to consume a balanced diet, the United States National Institutes of Health states that certain supplements "may have value."
Eat healthy fats. According to the American Heart Association, women should get at least five to 10 percent of total daily calories from omega-6 fatty acids (equal to 12 to 20 grams), and between 0.5 and 3 grams of omega-3 fatty acids, depending on individual risk for heart disease. Good sources of omega-6 fatty acids include sunflower, safflower, corn, cottonseed and soybean oils. And good sources of omega-3 fatty acids include fatty fish, tofu and other forms of soybeans, canola, walnuts, flaxseed, and their oils. Talk with your health care professional about how much of these beneficial oils you should be getting, how you can best incorporate them into your diet and whether or not you should be taking them in supplement form.
Good sources of iron include liver, kidneys, red meat, poultry, eggs, peas, legumes, dried fruits and dark, green leafy vegetables. Three ounces of cooked chicken liver contains 7.2 mg of iron; a cup of cooked spinach contains 6.4 mg. Your health care professional will probably recommend iron supplements during pregnancy (probably starting at 30 mg per day).
Eat like a tourist in Greece. The sunset over your office park isn't as stunning as the one over an Aegean beach, but a plate of grilled fish and fresh vegetables and a glass of wine is as delicious in Athens, Georgia, as it is in Athens, Greece. All the heart-healthy fats, minerals, and antioxidants in Mediterranean foods like hummus, olive oil, and feta can help lower your risk for heart disease, says Susan Mitchell, Ph.D., coauthor of Fat Is Not Your Fate (Fireside).
Vitamin C protects the brain and nervous system from damage caused by stress because the synthesis and maintenance of chemical neurotransmitters such as adrenaline and noradrenaline requires adequate levels of vitamin C.  Vitamin C is also needed to repair collagen which is essential for skin, blood vessels, bones and joints, and muscles. When these are damaged by physical stress, extra vitamin C is necessary. A controlled trial of 91 adults who experienced increased anxiety and stress 2-3 months after an earthquake in New Zealand in 2011 was divided into three groups, two were given a broad spectrum supplement of micronutrients in low or higher doses.  The supplements were found to alleviate the experience of stress, with the biggest dose having the biggest effect.
The need for efficient detoxification and excretion is greatly increased by environmental pollution from the chemical industry, herbicides and pesticides used by industrial agriculture, antibiotic treatment of animals, transport, and plastic packaging.  In our polluted world, the increased toxic load may be compensated for by an increase in nutrients to promote detoxification. One can respond by taking large doses of supplements of essential nutrients, for example, antioxidants vitamin C and E, and an adequate dose of selenium, which help the body detoxify harmful chemicals. Also helpful is regularly taking sauna baths, fasting periodically, and eating an excellent diet that includes generous portions of dark green leafy vegetables and colorful vegetables and fruits. 
In 2015, the Australian Government's Department of Health published the results of a review of herbal supplements to determine if any were suitable for coverage by health insurance. Establishing guidelines to assess safety and efficacy of botanical supplement products, the European Medicines Agency provided criteria for evaluating and grading the quality of clinical research in preparing monographs about herbal supplements. In the United States, the National Center for Complementary and Integrative Health of the National Institutes of Health provides fact sheets evaluating the safety, potential effectiveness and side effects of many botanical products.