Vanadium  釩

釩是一種必需的微量礦物質（直到最近才被確定為人類真正必需的礦物質）。 正常飲食通常每天提供約 10-30 微克 (mcg) 的釩。 儘管目前尚未制定每日建議攝取量，但這個數字似乎足以滿足大多數健康成年人的需求。 釩的補充形式通常是氧釩基或釩酸鹽形式。 釩被認為在碳水化合物的代謝中發揮作用，並可能在膽固醇和血脂代謝中發揮作用。 對於糖尿病患者，釩補充劑可能對調節血糖水平產生積極作用。 釩的食物來源包括海鮮、蘑菇、一些穀物和大豆。

·  Lowers blood sugar 降血糖

·  Increases muscle mass 增肌肉

·  Increases muscle vascularity and blood flow ("pumped feeling")  增強肌肉血流量

·  Mimics insulin action  模擬胰島素作用

·  Increases glycogen synthesis and storage 增加肝糖合成和儲存 

釩或最常見的補充形式——硫酸氧釩——被認為透過一種尚不清楚的機制來模仿胰島素的生理作用。 透過這種胰島素模擬作用，釩被認為可以促進肝醣合成，維持血糖水平並刺激肌肉合成代謝。

硫酸氧釩補充劑已被證明可以使非胰島素依賴型糖尿病 (NIDDM) 患者的血糖水平正常化並降低糖化血紅蛋白水平。 同樣在 NIDDM 患者中，硫酸釩（每天 100 毫克——大劑量）可以將空腹血糖值降低約 20%，並降低肝臟胰島素抗性。 正常（非糖尿病）受試者通常不會表現出葡萄糖攝取或脂肪分解的顯著變化，但硫酸氧釩可能會急劇刺激氨基酸轉運到骨骼肌。 硫酸氧釩對於減肥和運動表現的研究各不相同，大多數研究表明對身體組成僅產生適度（如果有的話）的影響。 儘管釩已成為健美運動員中流行的膳食補充劑，但支持增加肌肉質量和力量的說法的數據有限。

有關釩毒性的資訊有限。 傳統上，釩被認為對人體相當安全（因為其吸收性差）。 然而，一些研究表明，躁鬱症患者的血液和組織中釩含量升高。 在一項安全性研究中，NIDDM 受試者服用 100 毫克硫酸氧釩（大劑量），持續 4 週（每次 50 毫克，每天兩次）。 75% 的受試者在第一週內出現了胃腸道副作用，但此後補充劑的耐受性良好。 研究的作者得出結論，硫酸氧釩“耐受性良好”，並導致空腹血糖適度降低，但他們警告說，較大劑量和較長時間使用釩補充劑的安全性仍不確定。 人們認為，長期接觸過量的釩可能會導致肌肉痙攣、情緒抑鬱以及神經系統和其他器官的傷害。 一些動物研究表明，長期餵食釩後可能會出現血液學和生化變化、生殖和發育毒性以及對穀胱甘肽、抗壞血酸、脂質和 NADPH 的促氧化作用。

釩是一種必需的微量礦物質，許多多種維生素/礦物質補充劑中不含釩。 然而，人們認為我們從飲食中獲得了足夠的釩。 對於那些關心維持血糖水平的人，例如糖尿病患者或低血糖患者，釩補充劑可能是有益的。 有些健美和糖尿病膳食補充劑含有毫克級的釩——而膳食需求量可能僅為微克（低 1000 倍）。 不建議長期食用高劑量的釩補充劑。

釩沒有每日攝取量 (DV) 或建議飲食攝取量 (RDA)。 釩現在被認為是一種必需的微量礦物質，每天 10 微克（微克）被認為可以滿足身體的需求（我們的飲食中每天可能含有約 10-30 微克釩）。

Vanadium or the most common supplemental form -vanadyl sulfate - is thought to mimic the physiological effects of insulin by a mechanism which remains unclear. Through this insulin-mimetic effect, vanadium is thought to promote glycogen synthesis, maintain blood glucose levels and stimulate muscle anabolism. 

Vanadyl sulfate supplements have been shown to normalize blood glucose levels and reduce glycosylated hemoglobin levels in patients with non-insulin dependent diabetes mellitus (NIDDM). Also in NIDDM patients, vanadium sulfate (100 mg per day – a HUGE dose) can reduce fasting glucose levels by about 20% and decrease hepatic insulin resistance. Normal (nondiabetic) subjects typically do not exhibit a significant change in glucose uptake or lipolysis, but vanadyl sulfate may acutely stimulate amino acid transport into skeletal muscle. Studies of vanadyl sulfate for weight loss and exercise performance have been variable, with most showing only modest (if any) effects on body composition. Although vanadium has become a popular dietary supplement among bodybuilders, there is limited data to support claims of increased muscle mass and strength. 

Limited information is available about vanadium toxicity. Traditionally, vanadium is considered quite safe in humans (because of its poor absorption). Some studies have suggested, however, that patients with manic depression have elevated blood and tissue levels of vanadium. In one safety study, 100mg of vanadyl sulfate (a HUGE dose) was given to NIDDM subjects for 4 weeks (50mg twice per day). Gastrointestinal side effects were experienced by 75% of the subjects during the first week, but the supplements were well tolerated after that. The authors of the study concluded that vanadyl sulfate was "well tolerated" and resulted in modest reductions of fasting plasma glucose – but they cautioned that the safety of larger doses and use of vanadium supplements for longer periods remained uncertain. It is thought that prolonged exposure to excessive vanadium could cause muscle cramps, emotional depression, and damage to the nervous system and other organs. Some animal studies have suggested the possibility of hematological and biochemical changes, reproductive and developmental toxicity, and pro-oxidative effects on glutathione, ascorbic acid, lipids and NADPH following prolonged vanadium feeding. 

Vanadium is an essential trace mineral that is NOT contained in many multi-vitamin/mineral supplements. It is thought, however, that we obtain enough vanadium from our diets. For those individuals concerned with maintaining blood glucose levels – such as diabetics or people with hypoglycemia (low blood sugar), a vanadium supplement may be beneficial. Some bodybuilding and diabetic dietary supplements contain vanadium at milligram levels - when dietary needs are likely to be only in microgram amounts (1000 times lower). Prolonged consumption of high dose vanadium supplements is not recommended. 

There is no Daily Value (DV) or Recommended Dietary Allowance (RDA) for vanadium. Vanadium is now considered to be an essential trace mineral and 10mcg (micrograms) per day is thought to satisfy the bodys needs (our diets probably contain about 10-30mcg of vanadium per day).