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.
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.
Actually, more people suffer from food intolerances, which don't involve the immune system. However, food intolerance symptoms—such as intestinal distress—may mimic those of a food allergy. If you have a food intolerance, talk to a nutritionist about diagnosis and treatment; if you have food allergies, you need to see an allergist. Whether you have food allergies or intolerance, you will need to develop a diet that fits your needs and avoids foods that trigger a reaction.
Young adults. Teen girls and young women usually need more calories than when they were younger, to support their growing and developing bodies. After about age 25, a woman’s resting metabolism (the number of calories her body needs to sustain itself at rest) goes down. To maintain a healthy weight after age 25, women need to gradually reduce their calories and increase their physical activity.
Our sedate, modern lifestyle reduces the need for energy from food, which implies a lower food intake or obesity. Loren Cordain, PhD, and coworkers have estimated that hunter-gatherers had significantly higher energy needs than the typical modern office worker.  A lower energy intake generally reduces the absolute intake of all nutrients, while the need for some nutrients is not always reduced proportionally with energy intake. Overall this suggests that more exercise along with a more nutritious diet, including supplements of essential nutrients and less carbohydrates, will help to prevent obesity and maintain health.
Dietary supplements are complex products. The FDA has established good manufacturing practices (GMPs) for dietary supplements to help ensure their identity, purity, strength, and composition. These GMPs are designed to prevent the inclusion of the wrong ingredient, the addition of too much or too little of an ingredient, the possibility of contamination, and the improper packaging and labeling of a product. The FDA periodically inspects facilities that manufacture dietary supplements.