Practices & Lifestyle
Biotin (Vitamin B7): A Practical Guide
Overview Biotin is a water-soluble B vitamin (B7) that functions as a covalently attached cofactor for five mammalian carboxylase enzymes, all involved in critical metabolic pathways: gluconeogenesis, fatty acid synthesis, amino acid catabolism, and the citric acid cycle. Biotin is widely…
Choline: A Practical Guide
Overview Choline is an essential nutrient (though not a traditional vitamin) critical for phospholipid synthesis, neurotransmitter production, methyl group donation, and lipid transport. The Institute of Medicine established it as an essential nutrient in 1998. Despite its importance, surveys…
Folate (Methylfolate / Folic Acid): A Practical Guide
Overview Folate is a water-soluble B vitamin (B9) essential for one-carbon metabolism — the biochemical foundation of DNA synthesis, DNA repair, methylation reactions, and amino acid interconversions. The term "folate" covers all biologically active forms; folic acid is the synthetic oxidized…
NADH: A Practical Guide
Overview NADH (reduced nicotinamide adenine dinucleotide) is the active, electron-carrying form of NAD+. It is the primary electron donor in mitochondrial oxidative phosphorylation and participates in hundreds of metabolic reactions — most critically in the citric acid cycle and the electron…
PABA (Para-Aminobenzoic Acid): A Practical Guide
Overview Para-aminobenzoic acid (PABA) is an organic compound that was once considered a B vitamin (sometimes labeled vitamin Bx) but is no longer classified as a vitamin because it has no defined essential function in human metabolism that cannot be met by other means. PABA is a precursor to…
PQQ (Pyrroloquinoline Quinone): A Practical Guide
Overview Pyrroloquinoline quinone (PQQ) is a redox-active quinone compound found in trace amounts in many foods (especially natto, green peppers, kiwi, and breast milk) and in soil bacteria. It was identified as a bacterial cofactor for some oxidoreductases and was initially proposed as a…
SAMe (S-Adenosylmethionine): A Practical Guide
Overview S-adenosylmethionine (SAMe) is a naturally occurring molecule synthesized in every cell from methionine and ATP. It is the primary methyl-group donor in human biochemistry, participating in over 200 enzymatic reactions — methylating DNA, RNA, proteins, phospholipids, and…
Vitamin A (Retinol & Retinyl Esters): A Practical Guide
Overview Vitamin A is a fat-soluble micronutrient essential for vision, immune function, cellular differentiation, and reproductive health. The term "Vitamin A" encompasses a family of structurally related compounds: preformed vitamin A (retinol, retinyl esters, retinoic acid — found in animal…
Vitamin B12 (Cobalamin): A Practical Guide
Overview Vitamin B12 (cobalamin) is a water-soluble B vitamin and the largest, most structurally complex of all vitamins. It is the only vitamin containing a metal ion (cobalt), hence its chemical name. B12 is essential for DNA synthesis, myelin formation, red blood cell maturation, and…
Vitamin E (Tocopherols & Tocotrienols): A Practical Guide
Overview Vitamin E is a family of eight fat-soluble antioxidant compounds: four tocopherols (alpha, beta, gamma, delta) and four tocotrienols (alpha, beta, gamma, delta). Alpha-tocopherol is the most biologically active form in humans and the primary form measured in serum. It is the only form…
Vitamin K1 (Phylloquinone): A Practical Guide
Overview Vitamin K1 (phylloquinone) is the primary dietary form of vitamin K, synthesized by plants and found abundantly in leafy green vegetables. It is distinct from vitamin K2 (menaquinones), which is covered in a separate monograph. Vitamin K is essential for the carboxylation of glutamate…