People use dietary supplements for a wide assortment of reasons. Some seek to compensate for diets, medical conditions, or eating habits that limit the intake of essential vitamins and nutrients. Other people look to them to boost energy or to get a good night's sleep. Postmenopausal women consider using them to counter a sudden drop in estrogen levels.
When it comes to omega-3 fatty acids (omega = ω) such as EPA and DHA, children may be given cod liver oil and served fish and/or other seafood 2-3 times a week. It is important to check the dose of vitamin A supplied, as it can be toxic in high doses, especially for children. One problem with cod liver oil today is that vitamin D has been removed during processing, thus changing the natural ratio of the two vitamins so that we ingest relatively too much of vitamin A. 
The U.S. Food and Drug Administration is currently deliberating on how to enhance the usefulness to consumers of point-of-purchase nutrition information. This includes information on the main display panel of food products, called "front-of-pack" labeling. The new labeling provides 65 million parents in America with easy access to the information they need to make healthy choices for their children.
Protein-containing supplements, either ready-to-drink or as powders to be mixed into water, are marketed as aids to people recovering from illness or injury, those hoping to thwart the sarcopenia of old age, to athletes who believe that strenuous physical activity increases protein requirements, to people hoping to lose weight while minimizing muscle loss, i.e., conducting a protein-sparing modified fast, and to people who want to increase muscle size for performance and appearance. Whey protein is a popular ingredient, but products may also incorporate casein, soy, pea, hemp or rice protein.
How did I accomplish this? While I was inclined to go crazy and cut it out at first, I found that just didn’t work. So, I started slow. The first day, I removed about 1/2 tablespoon of sugar from my normal amount. The, when I got used to that after a few days, I removed another 1/2 tablespoon. Then, I started using unsweetened creamers, like half and half. Each time, I removed a small piece of what was unhealthy and, slowly, I became less and less dependent on the coffee and creamer I had become so obsessed with.
Also limit the amount of cholesterol you consume. Cholesterol is a fat-like substance found in every cell of the body. It helps digest some fats, strengthen cell membranes and make hormones. But too much cholesterol can be dangerous: When blood cholesterol reaches high levels, it can build up on artery walls, increasing the risk of blood clots, heart attack and stroke. Although dietary cholesterol can contribute to heart disease, the greater risk comes from a diet high in saturated and trans fats.
Most Americans get far more protein than they really need. In theory, that may not be wise. Like carbohydrates, protein provides 4 calories per gram, and excess calories from any source will be stored as body fat. Excess dietary protein increases calcium loss in the urine, perhaps raising the risk for osteoporosis ("thin bones," more a worry for women) and kidney stones (a particular worry for men).
Carbohydrates are one of your body’s main sources of energy. But most should come from complex, unrefined carbs (vegetables, whole grains, fruit) rather than sugars and refined carbs. Cutting back on white bread, pastries, starches, and sugar can prevent rapid spikes in blood sugar, fluctuations in mood and energy, and a build-up of fat, especially around your waistline. Learn more »
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.