Dietary supplements can provide nutrients individually or in combination in order to increase the quantity of their consumption. Nutrients includes vitamins, minerals, fiber, fatty acids, or amino acids. Dietary supplements can also contain substances that have not been confirmed as being essential to life but are marketed as having a beneficial biological effect. These are also sold individually and in combination, and also in combination with nutrient ingredients. In the United States, dietary supplements are considered a subset of foods and are regulated accordingly. The European Union has also established harmonized rules to help insure that food supplements are safe and properly labeled. In other countries dietary supplements may be classified as drugs or another classification of products.
There are more than 50,000 dietary supplement products marketed in the United States, and more than half of the adult population consume dietary supplements, with most common ones being multivitamins. For those who fail to consume a balanced diet, the U.S. National Institutes of Health states that certain supplements "may have value."
In the U.S. it is against federal regulations for the companies selling the products to claim that these products prevent or treat any disease. Companies are allowed to use what is referred to as "Structure/Function" wording if there is some scientific evidence. An example would be "_____ helps maintain healthy joints." The Food and Drug Administration (FDA) enforces these regulations, and also prohibits the sale of supplements and supplement ingredients that are dangerous, or supplements not made according to standardized good manufacturing practices (GMPs).
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Definition
According to the U.S. FDA, dietary supplements are products which are not pharmaceutical drugs, food additives like spices or preservatives, or conventional food, and which also meet any of these criteria:
- The product is intended to supplement a person's diet, despite it not being usable as a meal replacement.
- The product is or contains a vitamin, dietary element, herb used for herbalism or botanical used as a medicinal plant, amino acid, any substance which contributes to other food eaten, or any concentrate, metabolite, ingredient, extract, or combination of these things.
- The product is labeled as a dietary supplement.
In the United States, the FDA has different monitoring procedures for substances depending on whether they are presented as drugs, food additives, food, or dietary supplements. Dietary supplements are eaten or taken by mouth, and are regulated in United States law as a type of food rather than a type of drug. Like food and unlike drugs, no government approval is required to make or sell dietary supplements; the manufacturer checks the safety of dietary supplements but the government does not; and rather than requiring risk-benefit analysis to prove that the product can be sold like a drug, risk-benefit analysis is only used to petition that food or a dietary supplement is unsafe and should be removed from market.
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Medical uses
The intended use of dietary supplements is to ensure that a person gets enough essential nutrients.
Dietary supplements should not be used to treat any disease or as preventive healthcare. An exception to this recommendation is the appropriate use of vitamins.
Supplements may create harm in several ways, including over-consumption, particularly of minerals and fat-soluble vitamins which can build up in the body. The products may also cause harm related to their rapid absorption in a short period of time, quality issues such as contamination, or by adverse interactions with other foods and medications.
Types
There are many types of dietary supplements.
Vitamins
A vitamin is an organic compound required by an organism as a vital nutrient in limited amounts. An organic chemical compound (or related set of compounds) is called a vitamin when it cannot be synthesized in sufficient quantities by an organism, and must be obtained from the diet. The term is conditional both on the circumstances and on the particular organism. For example, ascorbic acid (vitamin C) is a vitamin for anthropoid primates, humans, guinea pigs and bats, but not for other mammals. Vitamin D is not an essential nutrient for people who get sufficient exposure to ultraviolet light, either from the sun or an artificial source, as then they synthesize vitamin D in skin. Humans require thirteen vitamins in their diet, most of which are actually groups of related molecules, "vitamers", (e.g. vitamin E includes tocopherols and tocotrienols, vitamin K includes vitamin K1 and K2). The list: vitamins A, C, D, E, K, Thiamine (B1), Riboflavin (B2), Niacin (B3), Pantothenic Acid (B5), Vitamin B6, Biotin (B7), Folate (B9) and Vitamin B12. Vitamin intake below recommended amounts can result in signs and symptoms associated with vitamin deficiency. There is little evidence of benefit when consumed as a dietary supplement by those who are healthy and consuming a nutritionally adequate diet.
The U.S. Institute of Medicine sets Tolerable upper intake levels (ULs) for vitamins. This does not prevent dietary supplement companies from selling products with content per serving higher than the ULs. For example, the UL for vitamin D is 100 µg (4,000 IU), but products are available without prescription at 10,000 IU.
Dietary minerals
Minerals are the exogenous chemical elements indispensable for life. Four minerals: carbon, hydrogen, oxygen, and nitrogen, are essential for life but are so ubiquitous in food and drink that these are not considered nutrients and there are no recommended intakes for these as minerals. The need for nitrogen is addressed by requirements set for protein, which is composed of nitrogen-containing amino acids. Sulfur is essential, but for humans, not identified as having a recommended intake per se. Instead, recommended intakes are identified for the sulfur-containing amino acids methionine and cysteine. There are dietary supplements which provide sulfur, such as taurine and methylsulfonylmethane.
The essential nutrient minerals for humans, listed in order by weight needed to be at the Recommended Dietary Allowance or Adequate Intake are potassium, chlorine, sodium, calcium, phosphorus, magnesium, iron, zinc, manganese, copper, iodine, chromium, molybdenum, selenium and cobalt (the last as a component of vitamin B12). There are other minerals which are essential for some plants and animals, but may or may not be essential for humans, such as boron and silicon. Essential and purportedly essential minerals are marketed as dietary supplements, individually and in combination with vitamins and other minerals.
Although as a general rule, dietary supplement labeling and marketing are not allowed to make disease prevention or treatment claims, the U.S. FDA has for some foods and dietary supplements reviewed the science, concluded that there is significant scientific agreement, and published specifically worded allowed health claims. An initial ruling allowing a health claim for calcium dietary supplements and osteoporosis was later amended to include calcium supplements with or without vitamin D, effective January 1, 2010. Examples of allowed wording are shown below. In order to qualify for the calcium health claim, a dietary supplement much contain at least 20% of the Reference Dietary Intake, which for calcium means at least 260 mg/serving.
- "Adequate calcium throughout life, as part of a well-balanced diet, may reduce the risk of osteoporosis."
- "Adequate calcium as part of a healthful diet, along with physical activity, may reduce the risk of osteoporosis in later life."
- "Adequate calcium and vitamin D throughout life, as part of a well-balanced diet, may reduce the risk of osteoporosis."
- "Adequate calcium and vitamin D as part of a healthful diet, along with physical activity, may reduce the risk of osteoporosis in later life."
In the same year, the European Food Safety Authority also approved a dietary supplement health claim for calcium and vitamin D and the reduction of the risk of osteoporotic fractures by reducing bone loss. The U.S. FDA also approved Qualified Health Claims (QHCs) for various health conditions for calcium, selenium and chromium picolinate. QHCs are supported by scientific evidence, but do not meet the more rigorous "significant scientific agreement" standard required for an authorized health claim. If dietary supplement companies choose to make such a claim then the FDA stipulates the exact wording of the QHC to be used on labels and in marketing materials. The wording can be onerous: "One study suggests that selenium intake may reduce the risk of bladder cancer in women. However, one smaller study showed no reduction in risk. Based on these studies, FDA concludes that it is highly uncertain that selenium supplements reduce the risk of bladder cancer in women."
Proteins and amino acids
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. The results are not necessarily consistent. Reviews can conclude that a high protein diet, when combined with exercise, will increase muscle mass and strength, or conclude the opposite. The International Olympic Committee recommends protein intake targets for both strength and endurance athletes at about 1.2-1.8 g/kg body mass per day.
The same protein ingredients can be incorporated into meal replacement and medical food products, but those are regulated and labeled differently from supplements. In the United States, "meal replacement" products are foods and are labeled as such. These typically contain protein, carbohydrates, fats, vitamins and minerals. There may be content claims such as "good source of protein", "low fat" or "lactose free." Medical foods, also nutritionally complete, are designed to be used while a person is under the care of a physician or other licensed healthcare professional. Liquid medical food products - example Ensure - are available in regular and high protein versions.
Essential fatty acids
Essential fatty acids, or EFAs, are fatty acids that humans and other animals must ingest because the body requires them for good health but cannot synthesize them. The term "essential fatty acid" refers to fatty acids required for biological processes but does not include the fats that only act as fuel.
Bodybuilding supplements
Bodybuilding supplements are dietary supplements commonly used by those involved in bodybuilding or athletics in which increased muscle mass is desired. The intent is to increase muscle, increase body weight, improve athletic performance, and for some sports, to simultaneously decrease percent body fat so as to create better muscle definition. Among the most widely used are high protein drinks, branched-chain amino acids (BCAA), glutamine, essential fatty acids, creatine, weight loss products and testosterone boosters. Supplements are sold either as single ingredient preparations or in the form of "stacks" - proprietary blends of various supplements marketed as offering synergistic advantages. While many bodybuilding supplements are also consumed by the general public the frequency of use will differ when used specifically by bodybuilders. One meta-analysis concluded that for athletes participating in resistance exercise training and consuming protein supplements for an average of 13 weeks, total protein intake up to 1.6 g per kg body weight per day would result in an increase in strength and fat-free mass, i.e. muscle, but that higher intakes would not further contribute. The muscle mass increase was statistically significant but modest - averaging 0.3 kg for all trials and 1.0 to 2.0 kg, for protein intake >= 1.6 g/kg/day.
Industry
In 2013, the global market of vitamins, minerals, and nutritional and herbal supplements (VMHS) was valued at $82 billion, with roughly 28 percent of that in the U.S., where sales increased by approximately $6 billion between 2007 and 2012.
The vitamins and dietary supplements sector in the U.S. grew 4% in 2015, to reach US$27.2 billion. The U.S. market was highly competitive in 2015, as no single company accounted for more than a 5% share of value sales.
Controversy
According to University of Helsinki food safety professor Marina Heinonen, more than 90% of dietary supplement health claims are incorrect.
Consumer Reports reported unsafe levels of arsenic, cadmium, lead and mercury in several protein powder products. The Canadian Broadcasting Corporation reported that protein spiking, i.e., the addition of amino acids to manipulate protein content analysis, was not uncommon. Many of the companies involved challenged CBC's claim.
Adverse effects
Among general reasons for harmful effects of dietary supplements are: a) absorption in a short time; b) quality and contamination; and c) enhancing both positive and negative effects at the same time. The number of incidents of liver damage from dietary supplements has tripled in a decade. Most of the products causing that effect were bodybuilding supplements. Some of the victims required liver transplants and some died. A third of the supplements involved contained unlisted steroids. Mild to severe toxicity has occurred on many occasions due to dietary supplements, even when the active ingredients were essential nutrients such as vitamins, minerals or amino acids. This has been a result of adulteration of the product, excessive usage on the part of the consumer, or use by persons at risk for the development of adverse effects. In addition, a number of supplements contain psychoactive drugs, whether of natural or synthetic origin.
Physical and chemical properties
Adulteration in North America
BMC Medicine published a study on herbal supplements in 2013. Most of the supplements studied were of low quality, one third did not contain the active ingredient(s) claimed, and one third contained unlisted substances.
An investigation by the New York Attorney General's office reported in 2015 analyzed 78 bottles of herbal supplements from Walmart, Target, Walgreens and GNC stores in New York State using DNA barcoding, a method used to detect labeling fraud in the seafood industry. Only about 20% contained the ingredient on the label.
Some supplements were contamined by rodent feces and urine.
Only 0.3% of the 55,000 U.S. market dietary supplements have been studied regarding their common side effects.
Society and culture
Public health
Work done by scientists in the early 20th century on identifying individual nutrients in food and developing ways to manufacture them raised hopes that optimal health could be achieved and diseases prevented by adding them to food and providing people with dietary supplements; while there were successes in preventing vitamin deficiencies, and preventing conditions like neural tube defects by supplementation and food fortification with folic acid, no targeted supplementation or fortification strategies to prevent major diseases like cancer or cardiovascular diseases have proved successful.
For example, while increased consumption of fruits and vegetables are related to decreases in mortality, cardiovascular diseases and cancers, supplementation with key factors found in fruits and vegetable, like antioxidants, vitamins, or minerals, do not help and some have been found to be harmful in some cases. In general as of 2016, robust clinical data is lacking, that shows that any kind of dietary supplementation does more good than harm for people who are healthy and eating a reasonable diet but there is clear data showing that dietary pattern and lifestyle choices are associated with health outcomes.
As a result of the lack of good data for supplementation and the strong data for dietary pattern, public health recommendations for healthy eating urge people to eat a plant-based diet of whole foods, minimizing processed food, salt and sugar and to get exercise daily, and to abandon Western pattern diets and a sedentary lifestyle.
Legal regulation
United States
The regulation of food and dietary supplements by the U.S. Food and Drug Administration is governed by various statutes enacted by the United States Congress and interpreted by the U.S. Food and Drug Administration ("FDA"). Pursuant to the Federal Food, Drug, and Cosmetic Act ("the Act") and accompanying legislation, the FDA has authority to oversee the quality of substances sold as food in the United States, and to monitor claims made in the labeling about both the composition and the health benefits of foods.
Substances which the FDA regulates as food are subdivided into various categories, including foods, food additives, added substances (man-made substances which are not intentionally introduced into food, but nevertheless end up in it), and dietary supplements. The specific standards which the FDA exercises differ from one category to the next. Furthermore, the FDA has been granted a variety of means by which it can address violations of the standards for a given category of substances.
Dietary supplement manufacture is required to comply with the good manufacturing practices established in 2007. The FDA can visit manufacturing facilities, send Warning Letters if not in compliance with GMPs, stop production, and if there is a health risk, require that the company conduct a recall.
Regulation in European Union
The European Union's Food Supplements Directive of 2002 requires that supplements be demonstrated to be safe, both in dosages and in purity. Only those supplements that have been proven to be safe may be sold in the bloc without prescription. As a category of food, food supplements cannot be labeled with drug claims but can bear health claims and nutrition claims.
The dietary supplements industry in the United Kingdom (UK), one of the 28 countries in the bloc, strongly opposed the Directive. In addition, a large number of consumers throughout Europe, including over one million in the UK, and various doctors and scientists, had signed petitions by 2005 against what are viewed by the petitioners as unjustified restrictions of consumer choice.
In 2004, along with two British trade associations, the Alliance for Natural Health (ANH) had a legal challenge to the Food Supplements Directive referred to the European Court of Justice by the High Court in London.
Although the European Court of Justice's Advocate General subsequently said that the bloc's plan to tighten rules on the sale of vitamins and food supplements should be scrapped, he was eventually overruled by the European Court, which decided that the measures in question were necessary and appropriate for the purpose of protecting public health. ANH, however, interpreted the ban as applying only to synthetically produced supplements, and not to vitamins and minerals normally found in or consumed as part of the diet.
Nevertheless, the European judges acknowledged the Advocate General's concerns, stating that there must be clear procedures to allow substances to be added to the permitted list based on scientific evidence. They also said that any refusal to add the product to the list must be open to challenge in the courts.
Research
Effects of dietary supplements have not necessarily been evaluated via randomized clinical trials. Randomized clinical trials of certain vitamins and antioxidants have found increased mortality rates.
Source of the article : Wikipedia
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