For healthy bones and teeth, women need to eat a variety of calcium-rich foods every day. Calcium keeps bones strong and helps to reduce the risk for osteoporosis, a bone disease in which the bones become weak and break easily. Some calcium-rich foods include low-fat or fat-free milk, yogurt and cheese, sardines, tofu (if made with calcium sulfate) and calcium-fortified foods including juices and cereals. Adequate amounts of vitamin D also are important, and the need for both calcium and vitamin D increases as women get older. Good sources of vitamin D include fatty fish, such as salmon, eggs and fortified foods and beverages, such as some yogurts and juices.
Examples of ongoing government research organizations to better understand the potential health properties and safety of dietary supplements are the European Food Safety Authority, the Office of Dietary Supplements of the United States National Institutes of Health, the Natural and Non-prescription Health Products Directorate of Canada, and the Therapeutic Goods Administration of Australia. Together with public and private research groups, these agencies construct databases on supplement properties, perform research on quality, safety, and population trends of supplement use, and evaluate the potential clinical efficacy of supplements for maintaining health or lowering disease risk.
There are thousands of dietary supplements on the market, including 40+ essential nutrients alone and in various combinations, i.e. vitamins, minerals, trace elements and fatty acids. However, a number of other nutrients are "conditionally essential", meaning that the body normally can make these molecules, but some people do not make optimal amounts. Examples are L-carnitine, alpha-lipoic acid, the methyl donor betaine,  chondroitin sulfate, coenzyme Q10, choline, amino acids such as tyrosine or arginine, and "essential" sugars normally formed in the body. 
Part of the reason why so many women fail to get the amount of iron they need is because one of the best sources of iron is red meat (especially liver) which also contains high levels of saturated fat. While leafy green vegetables and beans are also good sources of iron—and don’t contain high levels saturated fat—the iron from plant foods is different to the iron from animal sources, and not absorbed as well by the body. Other foods rich in iron include poultry, seafood, dried fruit such as raisins and apricots, and iron-fortified cereals, breads, and pastas.
In 1994, the United States Congress passed a law defining nutritional supplements, and requiring them to be labeled as dietary supplements and identified as not intended to be a substitute for certain foods. A nutritional supplement can be defined as a product intended for consumption in tablet, capsule, powder, soft gel, gel cap, or liquid form, and containing vitamin(s), mineral(s), herb(s), other botanicals, amino acids, or any combination thereof.
While women tend to need fewer calories than men, our requirements for certain vitamins and minerals are much higher. Hormonal changes associated with menstruation, child-bearing, and menopause mean that women have a higher risk of anemia, weakened bones, and osteoporosis, requiring a higher intake of nutrients such as iron, calcium, magnesium, vitamin D, and vitamin B9 (folate).
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:
An optimum intake of all nutrients is difficult to achieve even for those who eat almost exclusively an excellent diet of nutrient dense foods, such as meat and innards, fish, shellfish, fowl, eggs, nuts, mushrooms, and vegetables, berries and nutritious fruits. Some nutrients such as folic acid or carotenoids in vegetables are absorbed better from processed than unprocessed foods. Although vegetables are often considered to be a good source of vitamins, for example vitamin A from carrots, vitamin A is only found in animal products such as liver, egg yolk, fish cod and cod liver oil. Although eating raw vegetables is helpful for several reasons (vitamin C, fiber, microbiota), carotenoids (alpha/beta-carotene, lutein, lycopene) in vegetables are less well absorbed from raw than cooked food and better absorbed in the presence of added fat. [38,39]. Nutrients in vegetables are better absorbed when finely chewed, graded, or mashed , and cooking and grinding meat reduces the energy required to digest it  and increases nutrient absorption .
A number of supplements may interact in harmful ways with prescription or over-the-counter drugs. For example, St. John's wort may alter the breakdown of many drugs including antidepressants and birth control pills. Vitamin K, ginkgo biloba, garlic, and vitamin E may interact with blood-thinners. That's why it's essential that you consult your physician before starting a supplement regimen or making changes to your treatment regimen or prescribed medications.
Nutritional supplements are used for many purposes. They can be added to the diet to boost overall health and energy; to provide immune system support and reduce the risks of illness and age-related conditions; to improve performance in athletic and mental activities; and to support the healing process during illness and disease. However, most of these products are treated as food and not regulated as drugs are.