Herbal supplements are added to the diet for both nutritional and medicinal purposes. Herbs have been used for centuries in many traditional medicine systems, and as sources of phytochemicals, or substances found in plants that have notable effects in the body. Chinese medicine and Ayurvedic medicine from India, two of the world's oldest healing systems, use hundreds of herbal medications. Naturopathy and homeopathy, two other systems of natural healing, also rely on herbal preparations as their main sources of medication. The medicinal effects of herbs are getting scientific validation; about one-fourth of all pharmaceuticals have been derived directly from plant sources, including aspirin (found in willow bark), codeine (from poppy seeds), paclitaxel (Taxol), a patented drug for ovarian and breast cancer (from the Pacific Yew tree), and many others.
Foods that contain natural folic acid include orange juice, green leafy vegetables, peas, peanuts and beans. (One cup of cooked kidney beans contains 230 mcg of folic acid.) Fortified foods, such as ready-to-eat breakfast cereals, also contain a synthetic form of folic acid, which is more easily absorbed by your body than the natural form. Folic acid is now added to all enriched grain products (thiamin, riboflavin, niacin, and iron have been added to enriched grains for many years).
Consult your health care professional. Women of childbearing age may want to consider taking folic acid supplements to reduce the risk of having a pregnancy affected with neural tube defects. Many women and teenage girls don't get enough calcium or vitamin D, both of which are critical to healthy bones and avoiding osteoporosis. Some people with diabetes appear to benefit from chromium. Vegetarians, especially vegans, may want to consider supplements to obtain nutrients they aren't getting from animal products.
I have identified a number of arguments in favor of supplementing the modern diet with essential nutrients, here summarized with 7 headlines. Most people should consider taking a multivitamin supplement containing vitamins and minerals even if they eat a nutritionally balanced diet. Additional nutrients may contribute to better health and, in some cases, can be of vital importance in our modern world. The arguments are presented in random order, i.e. the order does not reflect priority.
What you eat and drink is influenced by where you live, the types of foods available in your community and in your budget, your culture and background, and your personal preferences. Often, healthy eating is affected by things that are not directly under your control, like how close the grocery store is to your house or job. Focusing on the choices you can control will help you make small changes in your daily life to eat healthier.
Anemia can deplete your energy, leaving you feeling weak, exhausted, and out of breath after even minimal physical activity. Iron deficiency can also impact your mood, causing depression-like symptoms such as irritability and difficulty concentrating. While a simple blood test can tell your doctor if you have an iron deficiency, if you’re feeling tired and cranky all the time, it’s a good idea to examine the amount of iron in your diet.
Poor nutrition can manifest itself in many ways. The more obvious symptoms of a nutritional deficiency include dull, dry or shedding hair; red, dry, pale or dull eyes; spoon-shaped, brittle or ridged nails; bleeding gums; swollen, red, cracked lips; flaky skin that doesn't heal quickly; swelling in your legs and feet; wasted, weak muscles; memory loss; and fatigue.
Specialty products may offer particular health benefits or are targeted for specific conditions. These products may consist of whole foods or may be isolated compounds from natural or synthetic sources. Examples include antioxidants, probiotics (supplements containing friendly bacteria for the digestive tract), digestive enzymes, shark cartilage, or other animal products, or chemical extracts such as the hormone DHEA (dehydroepiandrosterone) and coenzyme Q10, an antioxidant.
The Natural Nutritional Foods Association estimated that in 2003 nutritional supplements amounted to a $19.8 billion market in the United States. By category, vitamins provided $6.6 billion in sales, herbs $4.2 billion, meal supplements $2.5 billion, sports nutrition products $2.0 billion, minerals $1.8 billion, and specialty and other products totaling $2.7 billion. The nutritional supplement industry provides a huge array of products for consumer needs.
In addition, several independent organizations offer quality testing and allow products that pass these tests to display their seals of approval. These seals of approval provide assurance that the product was properly manufactured, contains the ingredients listed on the label, and does not contain harmful levels of contaminants. These seals of approval do not guarantee that a product is safe or effective. Organizations that offer this quality testing include:
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. 
^ Siscovick DS, Barringer TA, Fretts AM, Wu JH, Lichtenstein AH, Costello RB, Kris-Etherton PM, Jacobson TA, Engler MB, Alger HM, Appel LJ, Mozaffarian D (2017). "Omega-3 Polyunsaturated Fatty Acid (Fish Oil) Supplementation and the Prevention of Clinical Cardiovascular Disease: A Science Advisory From the American Heart Association". Circulation. 135 (15): e867–e884. doi:10.1161/CIR.0000000000000482. PMID 28289069.
Calcium: For adult women aged 19-50, the USDA recommended daily allowance is 1,000 mg/day. For women over 50, the recommended daily allowance is 1,200 mg/day. Good sources of calcium include dairy products, leafy green vegetables, certain fish, grains, tofu, cabbage, and summer squash. Your body cannot take in more than 500 mg at any one time and there’s no benefit to exceeding the recommended daily amount.
It's a cliché, to be sure, but a balanced diet is the key to good nutrition and good health. Following that diet, however, isn't always that easy. One challenge is that women often feel too busy to eat healthfully, and it's often easier to pick up fast food than to prepare a healthy meal at home. But fast food is usually high in fat and calories and low in other nutrients, which can seriously affect your health. At the other extreme, a multimillion dollar industry is focused on telling women that being fit means being thin and that dieting is part of good nutrition.