Dietary supplements are substances you might use to add nutrients to your diet or to lower your risk of health problems, like osteoporosis or arthritis. Dietary supplements come in the form of pills, capsules, powders, gel tabs, extracts, or liquids. They might contain vitamins, minerals, fiber, amino acids, herbs or other plants, or enzymes. Sometimes, the ingredients in dietary supplements are added to foods, including drinks. A doctor’s prescription is not needed to buy dietary supplements.
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. 
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).
In general, healthy eating ingredients are found around the outer edges of most grocery stores, while the center aisles are filled with processed and packaged foods that aren’t good for you. Shop the perimeter of the store for most of your groceries (fresh fruits and vegetables, fish and poultry, whole grain breads and dairy products), add a few things from the freezer section (frozen fruits and vegetables), and visit the aisles for spices, oils, and whole grains (like rolled oats, brown rice, whole wheat pasta).
The U.S. Public Health Service recommends that all women of childbearing age consume 400 mcg of folic acid (a B vitamin) daily to reduce their risk of having a pregnancy affected with spina bifida or other neural-tube defects. Women who are actively trying to get pregnant should consume 600 mcg, and lactating women should consumer 500 mcg. Women of childbearing age should also take care to meet the daily requirements for calcium, fiber, iron, protein and vitamin D. Discuss supplements with a health care professional, however. Iron and vitamin D in particular can be dangerous in high amounts.
Omega-3 fatty acids — essential to health and happiness, reviewed by Dr. Mary James, MD. From conception to old age, every cell in our bodies needs omega-3’s. Learn how omega-3 fatty acids benefit every body system — from the brain to the heart, breast, bones, colon, skin and more, this is one nutrient that can make all the difference to our health, our happiness, and — perhaps best of all — our longevity.
Consumers can make wise choices for nutritional supplementation by consulting professional nutritionists and naturopathic physicians. Nutritional supplements are best added into the diet slowly, starting with small dosages and working up to the manufacturers' recommended amounts over time. Also, some supplements, such as herbal medications that may stimulate processes in the body, are best taken intermittently, allowing the body occasional rest periods without the supplement. To avoid unfavorable interactions, nutritional supplements are best used moderately and individually, rather than taking handfuls of capsules and tablets for various needs and conditions at the same time. Finally, consumers should be wary of excessive or grandiose health claims made by manufacturers of nutritional supplements and rely on scientific information to validate these claims.
Dietary fiber is found in plant foods like whole-grain breads and cereals, beans and peas, and other vegetables and fruits. At least one study suggests that women who eat high amounts of fiber (especially in cereal) may have a lower risk for heart disease. High-fiber intake is also associated with lower cholesterol, reduced cancer risk and improved bowel function. And one long-term study found that middle-aged women with a high dietary fiber intake gained less weight over time than women who ate more refined carbohydrates, like white bread and pasta.
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.
Because observational studies may not fully control for dietary factors, exercise habits, and other variables, they can't prove whether the treatment is responsible for the health benefits. "People who take supplements tend to be more health conscious, exercise more, eat healthier diets, and have a whole host of lifestyle factors that can be difficult to control for fully in the statistical models," Dr. Manson says.
The total fat in your daily diet should average no more than 30 percent of your total calories consumed. And saturated fat should be no more than 10 percent of those 30 percent of calories. The amount of fat and saturated fat you eat depends on the foods you select and consume that have fat in them. Consider consulting with a nutrition professional to learn more about how to calculate your fat needs and to not exceed what are healthy amounts. There are many tools available to help you determine how much fat you should consume each day based on your current energy and nutrition needs. Reading food labels is one way to begin to identify where and how much fat is in particular food items.
Over the past decade, many studies have revealed the importance of the gut microbiome in disease development and treatment, including in cancer. Because both host genetics and the gut microbiome can influence host phenotype and treatment outcome, there is an urgent need to develop precision medicine and personalize dietary supplementation based on an individual’s microbiome.
Having a treat now and then is a great way to make sure your healthy eating plan stays on track. Now, you might be thinking, how can eating a piece of cake or a donut help my eating habits? By not making anything completely off limits, registered dietitians explain that you're less likely to wind up feeling deprived—which means you're also less likely to find yourself in a binge-eating episode.
Herbs can supplement the diet to aid in overall health or to stimulate healing for specific conditions. For instance, ginseng is used as a general tonic to increase overall health and vitality, while echinacea is a popular herb used to stimulate the body's resistance to colds and infections. Herbs come in many forms. They can be purchased as capsules and tablets, as well as in tinctures, teas, syrups, and ointments.
The saturated fat, sodium, and added sugars found in foods and beverages are important for you to think about as you build your healthy eating style. Saturated fat and sodium are sometimes found naturally in foods and beverages. Sugars, sodium, and ingredients high in saturated fat can also be added during processing or preparing foods and beverages.
Considering average dietary needs and the prevalence of certain health conditions, some basic guidelines may provide the foundation for the effective use of nutritional supplements. First, a high quality, broad-spectrum multivitamin and mineral supplement, taken once per day, is recommended to provide a range of nutrients. This should contain the B-complex vitamins B6, B12, and folic acid, which may help prevent heart disease, and the minerals zinc and copper, which aid immunity. In addition to a multivitamin, antioxidants can be added to a supplementation routine. These include vitamin A (or beta-carotene), vitamin C, and vitamin E, and the mineral selenium. Antioxidants may have several positive effects on the body, such as slowing the aging process, reducing the risks of cancer and heart disease, and reducing the risks of illness and infection by supporting the immune system. Coenzyme Q10 is another antioxidant in wide usage, as studies have shown it may improve the health of the heart and reduce the effects of heart disease. Essential fatty acids, particularly omega-3, are also recommended as they are involved in many important processes in the body, including brain function. Calcium supplementation is recommended for the elderly and for women, to strengthen bones and prevent bone loss. Calcium supplements that are balanced with magnesium have a less constipating effect and are better absorbed.
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.