Vitamin/ja: Difference between revisions

| [[proprioception/ja|プロプリオセプション]]障害、神経損傷（100 mg/日を超える用量)

<div lang="en" dir="ltr" class="mw-content-ltr">

==Recommended levels==

In setting human nutrient guidelines, government organizations do not necessarily agree on amounts needed to avoid deficiency or maximum amounts to avoid the risk of toxicity. For example, for vitamin C, recommended intakes range from 40&nbsp;mg/day in India to 155&nbsp;mg/day for the European Union. The table below shows U.S. Estimated Average Requirements (EARs) and Recommended Dietary Allowances (RDAs) for vitamins, PRIs for the European Union (same concept as RDAs), followed by what three government organizations deem to be the safe upper intake. RDAs are set higher than EARs to cover people with higher than average needs. Adequate Intakes (AIs) are set when there is not sufficient information to establish EARs and RDAs. Governments are slow to revise information of this nature. For the U.S. values, with the exception of calcium and vitamin D, all of the data date to 1997–2004.

! rowspan="2" |Nutrient !! rowspan="2" |U.S. EAR!! rowspan="2" |Highest U.S.<br />RDA or AI!! rowspan="2" |Highest EU<br />PRI or AI!! colspan="3" |Upper limit (UL) !! rowspan="2" |Unit

|[[Vitamin A]]|| 625 || 900 || 1300 || 3000 || 3000 || 2700 || µg

|[[Vitamin C]]|| 75 || 90 || 155 || 2000 || ND || ND || mg

|[[Vitamin D]]|| 10 || 15 || 15 || 100 || 100 || 100 || µg

|[[Vitamin K]]|| NE || 120 || 70 || ND || ND || ND || µg

|[[Tocopherol|α-tocopherol]] (Vitamin E) || 12 || 15 || 13 || 1000 || 300 || 650-900 || mg

|[[Thiamin]] (Vitamin B₁) || 1.0 || 1.2 || 0.1&nbsp;mg/MJ || ND || ND || ND || mg

|[[Riboflavin]] (Vitamin B₂) || 1.1 || 1.3 || 2.0 || ND || ND || ND || mg

|[[Niacin (nutrient)|Niacin]] (Vitamin B₃) || 12 || 16 || 1.6&nbsp;mg/MJ || 35 || 10 || 60-85 || mg

|[[Pantothenic acid]] (Vitamin B₅) || NE || 5 || 7 || ND || ND || ND || mg

|[[Vitamin B6|Vitamin B₆]]|| 1.1 || 1.3 || 1.8 || 100 || 25 || 40-60 || mg

|[[Biotin]] (Vitamin B₇) || NE || 30 || 45 || ND || ND || ND || µg

|[[Folate]] (Vitamin B₉) || 320 || 400 || 600 || 1000 || 1000 || 900-1000|| µg

|[[Cyanocobalamin]] (Vitamin B₁₂) || 2.0 || 2.4 || 5.0 || ND || ND || ND || µg

'''EAR''' US Estimated Average Requirements.

'''RDA''' US Recommended Dietary Allowances; higher for adults than for children, and may be even higher for women who are pregnant or lactating.

'''AI''' US and EFSA Adequate Intake; AIs established when there is not sufficient information to set EARs and RDAs.

'''PRI''' Population Reference Intake is European Union equivalent of RDA; higher for adults than for children, and may be even higher for women who are pregnant or lactating. For Thiamin and Niacin the PRIs are expressed as amounts per MJ of calories consumed. MJ = megajoule = 239 food calories.

'''UL or Upper Limit'''  Tolerable upper intake levels.

'''ND''' ULs have not been determined.

'''NE''' EARs have not been established.

<div lang="en" dir="ltr" class="mw-content-ltr">

==Supplementation==

[[File:500 mg calcium supplements with vitamin D.jpg|thumb|upright=1.25|Calcium combined with vitamin D (as calciferol) supplement tablets with fillers.]]

In those who are otherwise healthy, there is little evidence that supplements have any benefits with respect to [[cancer]] or [[cardiovascular disease|heart disease]]. Vitamin A and E supplements not only provide no health benefits for generally healthy individuals, but they may increase mortality, though the two large studies that support this conclusion included [[tobacco smoking|smokers]] for whom it was already known that beta-carotene supplements can be harmful. A 2018 meta-analysis found no evidence that intake of vitamin D or calcium for community-dwelling elderly people reduced bone fractures.

Europe has regulations that define limits of vitamin (and mineral) dosages for their safe use as dietary supplements. Most vitamins that are sold as dietary supplements are not supposed to exceed a maximum daily dosage referred to as the [[tolerable upper intake level]] (UL or Upper Limit). Vitamin products above these regulatory limits are not considered supplements and should be registered as prescription or non-prescription ([[over-the-counter drug]]s) due to their potential side effects. The European Union, United States and Japan establish ULs.

[[Dietary supplement]]s often contain vitamins, but may also include other ingredients, such as minerals, herbs, and botanicals. [[Scientific evidence]] supports the benefits of dietary supplements for persons with certain health conditions. In some cases, vitamin supplements may have unwanted effects, especially if taken before surgery, with other dietary supplements or medicines, or if the person taking them has certain health conditions. They may also contain levels of vitamins many times higher, and in different forms, than one may ingest through food.

{{see also|Megavitamin therapy}}

===Governmental regulation===

Most countries place dietary supplements in a special category under the general umbrella of ''foods'', not drugs. As a result, the manufacturer, and not the government, has the responsibility of ensuring that its dietary supplement products are safe before they are marketed. Regulation of supplements varies widely by country. In the [[United States]], a dietary supplement is defined under the [[Dietary Supplement Health and Education Act]] of 1994. There is no FDA approval process for dietary supplements, and no requirement that manufacturers prove the safety or efficacy of supplements introduced before 1994. The [[Food and Drug Administration]] must rely on its Adverse Event Reporting System to monitor adverse events that occur with supplements.

In 2007, the US [[Code of Federal Regulations]] (CFR) Title 21, part III took effect, regulating Good Manufacturing Practices (GMPs) in the manufacturing, packaging, labeling, or holding operations for dietary supplements. Even though product registration is not required, these regulations mandate production and quality control standards (including testing for identity, purity and adulterations) for dietary supplements. In the European Union, the [[Food Supplements Directive]] requires that only those supplements that have been proven safe can be sold without a prescription. For most vitamins, [[pharmacopoeia|pharmacopoeial standards]] have been established. In the United States, the [[United States Pharmacopeia]] (USP) sets standards for the most commonly used vitamins and preparations thereof. Likewise, monographs of the [[European Pharmacopoeia]] (Ph.Eur.) regulate aspects of identity and purity for vitamins on the European market.

<div lang="en" dir="ltr" class="mw-content-ltr">

==Naming==

|+Nomenclature of reclassified vitamins

! Previous name

! Chemical name

! Reason for name change

| Vitamin B₄

|[[Adenine]]

| DNA metabolite; synthesized in body

| Vitamin B₈

|[[Adenylic acid]]

| DNA metabolite; synthesized in body

| Vitamin B_T

|[[Carnitine]]

| Synthesized in body

| Vitamin F

|[[Essential fatty acid]]s

| Needed in large quantities (does<br /> not fit the definition of a vitamin).

| Vitamin G

|[[Riboflavin]]

| Reclassified as [[B vitamins|Vitamin B₂]]

| Vitamin H

|[[Biotin]]

| Reclassified as [[B vitamins|Vitamin B₇]]

| Vitamin J

|[[Catechol]], [[Flavin group|Flavin]]

| Catechol nonessential; flavin reclassified<br /> as [[B vitamins|Vitamin B₂]]

| Vitamin L₁

|[[Anthranilic acid]]

| Nonessential

| Vitamin L₂

|[[5′-Methylthioadenosine]]

| RNA metabolite; synthesized in body

| Vitamin M or B_c

|[[Folate]]

| Reclassified as [[B vitamins|Vitamin B₉]]

| Vitamin P

|[[Flavonoids]]

| Many compounds, not proven essential

| Vitamin PP

|[[Niacin (nutrient)|Niacin]]

| Reclassified as [[B vitamins|Vitamin B₃]]

| Vitamin S

|[[Salicylic acid]]

| Nonessential

| Vitamin U

|[[S-Methylmethionine]]

| Protein metabolite; synthesized in body

The Danish-speaking scientists who isolated and described vitamin&nbsp;K (in addition to naming it as such) did so because the vitamin is intimately involved in the coagulation of blood following wounding (from the [[Danish language|Danish]] word ''Koagulation''). At the time, most (but not all) of the letters from F through to J were already designated, so the use of the letter K was considered quite reasonable. The table ''Nomenclature of reclassified vitamins'' lists chemicals that had previously been classified as vitamins, as well as the earlier names of vitamins that later became part of the B-complex.

The missing numbered  B vitamins were reclassified or determined not to be vitamins. For example, B₉ is [[folic acid]] and five of the folates are in the range B₁₁ through B₁₆. Others, such as [[4-Aminobenzoic acid|PABA]] (formerly B₁₀), are biologically inactive, toxic, or with unclassifiable effects in humans, or not generally recognised as vitamins by science, such as the highest-numbered, which some [[naturopath]] practitioners call B₂₁ and B₂₂. There are also lettered B substances (e.g., B_m) listed at [[B vitamins]] that are not recognized as vitamins. There are other "D vitamins" now recognised as other substances, which some sources of the same type number up to D₇. The controversial cancer treatment [[laetrile]] was at one point lettered as vitamin B₁₇. There appears to be no consensus on the existence of substances that may have at one time been named as vitamins Q, R, T, V, W, X, Y or Z.

"Vitamin N" is a term popularized for the mental health benefits of spending time in nature settings. "Vitamin I" is slang among athletes for frequent/daily consumption of [[ibuprofen]] as a pain-relieving treatment.

<div lang="en" dir="ltr" class="mw-content-ltr">

== See also ==

{{Portal|Food}}

*[[Vitamin deficiency]]

*[[Hypervitaminosis]]

*[[Human nutrition]]