Proteins are chains of amino acids. Nine of these proteinogenic amino acids are considered essential for humans because they cannot be produced from other compounds by the human body and so must be taken in as food. Recommended intakes, expressed as milligrams per kilogram of body weight per day, have been established.[26] Other amino acids may be conditionally essential for certain ages or medical conditions. Amino acids, individually and in combinations, are sold as dietary supplements. The claim for supplementing with the branched chain amino acids leucine, valine and isoleucine is for stimulating muscle protein synthesis. A review of the literature concluded this claim was unwarranted.[36] In elderly people, supplementation with just leucine resulted in a modest (0.99 kg) increase in lean body mass.[37] The non-essential amino acid arginine, consumed in sufficient amounts, is thought to act as a donor for the synthesis of nitric oxide, a vasodilator. A review confirmed blood pressure lowering.[38] Taurine, a popular dietary supplement ingredient with claims made for sports performance, is technically not an amino acid. It is synthesized in the body from the amino acid cysteine.[39]

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.[108] 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.[109] 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.[110]


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 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.
Research from Tufts University nutrition scientists shows that Americans are drinking so much soda and sweet drinks that they provide more daily calories than any other food. Obesity rates are higher for people consuming sweet drinks. Also watch for hidden sugar in the foods you eat. Sugar may appear as corn syrup, dextrose, fructose, fruit juice concentrate or malt syrup, among other forms, on package labels.

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.
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.
Women who have very low levels of sunlight exposure or have naturally very dark skin are at risk of vitamin D deficiency. Those affected may include women who cover most of their body when outdoors, shift workers, those who are unable to regularly get out of their house or women in residential care. Women who have certain medical conditions or are on some medications may also be affected.

Kris Clark, PhD, RD, sports nutrition director at Penn State University, says she very carefully uses select sports supplements with collegiate athletes: "I rely on the major nutrients in food, timing of meals and fluids to enhance athletic performance, and in general I discourage dietary supplements, other than the use of sport shakes, bars, and gels after practice or events for muscle cell recovery."


Vitamin C protects the brain and nervous system from damage caused by stress because the synthesis and maintenance of chemical neurotransmitters such as adrenaline and noradrenaline requires adequate levels of vitamin C. [25] Vitamin C is also needed to repair collagen which is essential for skin, blood vessels, bones and joints, and muscles. When these are damaged by physical stress, extra vitamin C is necessary. A controlled trial of 91 adults who experienced increased anxiety and stress 2-3 months after an earthquake in New Zealand in 2011 was divided into three groups, two were given a broad spectrum supplement of micronutrients in low or higher doses. [26] The supplements were found to alleviate the experience of stress, with the biggest dose having the biggest effect.
Overall diet is an important first consideration for those considering nutritional supplementation. Healthy dietary habits can help optimize nutrition and the absorption of supplements, and nutritional supplements cannot substitute for a diet that is not nutritionally balanced in the first place. Supplements are best used moderately to supply any extra nutritional requirements. Sound diets contain a variety of wholesome foods. At least five servings per day of fruits and vegetables are recommended, as well as the inclusion of whole grains in the diet. Variety in the diet is important to provide a full range of vitamins and minerals. Overeating inhibits digestion and absorption of nutrients, while regular exercise contributes to sound nutrition, by improving metabolism and digestion. Drinking plenty of clean water prevents dehydration, improves digestion, and helps the body flush out impurities.

You don’t have to spend a lot of money, follow a very strict diet, or eat only specific types of food to eat healthy. Healthy eating is not about skipping meals or certain nutrients. Healthy eating is not limited to certain types of food, like organic, gluten-free, or enriched food. It is not limited to certain patterns of eating, such as high protein.
A review of clinical trials registered at clinicaltrials.gov, which would include both drugs and supplements, reported that nearly half of completed trials were sponsored wholly or partially by industry.[125] This does not automatically imply bias, but there is evidence that because of selective non-reporting, results in support of a potential drug or supplement ingredient are more likely to be published than results that do not demonstrate a statistically significant benefit.[125][126] One review reported that fewer than half of the registered clinical trials resulted in publication in peer-reviewed journals.[127]
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.[108] 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.[109] 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.[110]
×