Summary Vitamin B6 and its derivative, pyridoxal 5′-phosphate (PLP), are essential to over 100 enzymes mostly involved in protein metabolism.  (More information) High levels of circulating homocysteine are associated with an increased

Summary Vitamin A is a generic term that refers to fat-soluble compounds found as preformed vitamin A (retinol) in animal products and as provitamin A carotenoids in fruit and vegetables.

Summary Thiamin pyrophosphate (TPP), the active form of thiamin, is involved in several enzyme functions associated with the metabolism of carbohydrates, branched-chain amino acids, and fatty acids.  (More information) Severe thiamin

Summary Riboflavin is the precursor of the coenzymes flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN). FAD and FMN act as electron carriers in a number of oxidation-reduction (redox) reactions

Summary Pantothenic acid — also known as vitamin B5 — is a water-soluble vitamin that is a precursor in the synthesis of coenzyme A. Coenzyme A is essential to many biochemical reactions that sustain

Español Summary Dietary precursors of nicotinamide adenine dinucleotide (NAD), including nicotinic acid, nicotinamide, and nicotinamide riboside, are collectively referred to as niacin or vitamin B3. The essential amino acid tryptophan

Español | 日本語 Summary Naturally occurring forms of vitamin K include phylloquinone (vitamin K1) and a family of molecules called menaquinones (MKs or vitamin K2).  (More information) With limited vitamin K storage capacity,

Summary Naturally occurring tocochromanols include eight fat-soluble forms: α-, β-, γ-, and δ-tocopherol and α-, β-, γ-, and δ-tocotrienol. The body preferentially uses α-tocopherol, and only α-tocopherol supplementation can reverse

Summary Vitamin D can be synthesized in the skin upon exposure to sunlight and is then metabolized in the liver and kidney to the metabolically active form called 1α,25-dihydroxyvitamin D.

Summary Vitamin B12 or cobalamin plays essential roles in folate metabolism and in the synthesis of the citric acid cycle intermediate, succinyl-CoA.  (More information) Vitamin B12 deficiency is commonly associated with