A coenzyme is a small organic molecule that combines with an enzyme and causes that enzyme to become active or which facilitate its activity. In general, molecules that combine with enzymes in this way are called cofactors, but when the molecules are organic, rather than simple ions of elements, they are called coenzymes. Even though they are organic molecules, coenzymes are not proteins, as enzymes are, and they are not catalytically active themselves, which perhaps makes cosubstrate or cofactor a less confusing name for them. In many reactions catalyzed by enzymes, electrons or groups of atoms are transferred from one compound to another, and this usually involves a coenzyme, which temporarily accepts the group being transferred.
Continue Reading » What are Coenzymes?
By Ken Adams, M.D. and Scott E. Conard, M.D.
Sources and Physiologic Functions
Liver, kidney, muscle meats, eggs, cheese, milk, and fish are excellent sources of vitamin B12. It is not found in plant foods or in yeast. Fermented foods such as soy sauce, tempeh, and miso, and fortified foods such as soymilk are also good sources of this vitamin.
Continue Reading » Vitamin B12 (Cyanocobalamine) - When, How, and Why to Supplement
Vitamin B12 is essential for DNA synthesis and for cellular energy production. This review aims to outline the metabolism of vitamin B12, and to evaluate the causes and consequences of sub-clinical vitamin B12 deficiency. Vitamin B12 deficiency is common, mainly due to limited dietary intake of animal foods or malabsorption of the vitamin. Vegetarians are at risk of vitamin B12 deficiency as are other groups with low intakes of animal foods or those with restrictive dietary patterns. Malabsorption of vitamin B12 is most commonly seen in the elderly, secondary to gastric achlorhydria. The symptoms of sub-clinical deficiency are subtle and often not recognized. The long-term consequences of sub-clinical deficiency are not fully known but may include adverse effects on pregnancy outcomes, vascular, cognitive, bone and eye health.
Continue Reading » Vitamin B12 In Health And Disease
In recent years vitamin B6 has become a focus of research describing the compound’s critical function in cellular metabolism and stress response. For many years the sole function of vitamin B6 was considered to be that of an enzymatic cofactor. However, recently it became clear that it is also a potent antioxidant that effectively quenches reactive oxygen species and is thus of high importance for cellular well-being. In view of the recent findings, the current review takes a look back and summarizes the discovery of vitamin B6 and the elucidation of its structure and biosynthetic pathways. It provides a detailed overview on vitamin B6 both as a cofactor and a protective compound. Besides these general characteristics of the vitamin, the review also outlines the current literature on vitamin B6 derivatives and elaborates on recent findings that provide new insights into transport and catabolism of the compound and on its impact on human health.
Continue Reading » Vitamin B6: Functions, Complexities, and History
Sports success is dependent primarily on genetic endowment in athletes with morphologic, psychologic, physiologic and metabolic traits specific to performance characteristics vital to their sport. Such genetically-endowed athletes must also receive optimal training to increase physical power, enhance mental strength, and provide a mechanical advantage. However, athletes often attempt to go beyond training and use substances and techniques, often referred to as ergogenics[[footnote]]Ergogenic aids are any external influences that can be determined to enhance performance. These include mechanical aids, pharmacological aids, physiological aids, nutritional aids, and psychological aids.
Continue Reading » Vitamins and Sports Performance