B Vitamins

The  B Vitamins are a group or as I call them library of eight different vitamins.

They are manufactured in plants.

Some foods are high in one while other foods are high in another.

Leafy greens, whole grains and lentils are good sources of B vitamins.

Fruits, vegetables, nuts and legumes are also good sources of vitamin B.

None of them contain significant amounts of B12, which is found in meat and dairy.

Brewers yeast and its Australian incarnation, Vegemite are high in B vitamins.

Avocado, pomegranate, dates, watermelon and berries are high in B-complex vitamins. Leafy greens and vegetables such as well as avocados, bok choy, Swiss chard, kale, Brussels sprouts, potatoes, squashes and parsnips are also high in B vitamins.

Legumes are high in B vitamins.

Soy beans, black-eye peas and edamame contain the highest amounts of B9 or folate.

Vitamin B complex is found naturally in many high-protein foods like meat, dairy and legumes.

Processed foods and grains, such as cereals and breads, have much of them removed in the processing so manufacturers add vitamins to their products.


B vitamins are a group of water-soluble vitamins that play a role in cell metabolsm. They are often involved in energy transactions.

Thiamin - Vitamin B1

  • The disease beriberi was recognized in China as early as 2600 BC and is the earliest documented deficiency disorder. Thiamin acts as a coenzyme in the decarboxylation reaction of the branched chain amino acids, valine, leucine and isoleucine.
  • Thiamin also functions in the formation of acetyl-CoA, the two-carbon fragment that provides the link between carbohydrate, fat and protein metabolism.
  • Thiamin requirements increase with exercise, high carbohydrate diets and high metabolic rates. Thiamin requirements on the other hand are reduced when protein and fats comprise a higher caloric proportion of the diet.
  • Thiamin requirements are also lower for sedentary people. Thiamin is transformed in the liver to thiamin pyrophosphate, the active co-enzyme form of the vitamin. A deficiency of thiamin results in an increase in blood lactic acid levels, which have important implications for athletes.


Riboflavin - Vitamin B2

Riboflavin or Vitamin B2 is converted to two active coenzyme forms, flavine mononucleotide (FMN), and flavine adenine dinucleotide (FAD).  These coenzymes function as hydrogen carriers (flavoproteins) in the mitochondria electron transport system (respiratory chain). Riboflavin is involved with thyroid hormone production, fatty acid metabolism and the citric acid cycle.

Niacin B3

Niacin functions as part of a coenzyme complex. Within the complex Niacin acts as a hydrogen donor in oxidation-reduction reactions. Niacin plays an essential role in glycolysis, fatty acid metabolism, and the citric acid cycle. Niacin is also neede for protein synthesis.

Niacin blocks the release of fatty acids from adipose tissue thus preventing its use as a source of energy. Consequently, glycogen depletion is accelerated and a drop in blood glucose occurs (hypoglycemia). In all likelihood, the impairment of fatty acid mobilization precludes its use as a supplement for athletes.


Pantothenic Acid B5

Pantothenic acid is a structural component of coenzyme A (CoA). CoA occupies an essential place in energy metabolism and is linked to energy utilization in transacetylation reactions. In this capacity, CoA is involved with carbohydrate, fat and protein metabolism through the formation of acetyl coenzyme A (acetyl CoA). Supplementation with pantothenic acid can reduce the need for oxygen by lowering the lactate level of athletes.


Pyridoxine - Vitamin B6

Pyridoxine is a cofactor in deamination and decarboxylation reactions.  Consequently, Vitamin B6 requirements become higher when high-protein diets are consumed, since these reactions occur during amino acid transformation.

Vitamin B6 is important in all aspects of amino acid metabolism and is especially important in brain metabolism. Vitamin B6 is involved with the formation of brain amines (epinephrine, dopamine, and serotonin), which are responsible for neuronal synaptic transmissions.  Since low carbohydrate diets cause early glycogen depletion, Vitamin B6 supplements may aid athletes who insist on following a high protein diet.

Cobalamin - Vitamin B12

Vitamin B12 functions in a variety of reactions: DNA synthesis, folic acid metabolism, neural tissue development, hemoglobin and RBC formation. It is the most abused vitamin among athletes. There is  no need to supplement an athlete’s diet with Vitamin B12.


Folic Acid - Vitamin B9

Folic acid or Vitamin B9 functions in various coenzyme forms. Its main metabolic function is in donating or accepting one-carbon units.

Folate or Folic acid is important in cell division and nucleotide metabolism. Folic acid also plays a role in fatty acid metabolism and is intricately involved with erythrocyte (Red Blood Cell) formation.

Folic acid in its coenzyme form aids in the conversion of homocysteine to methionine. High homocysteine levels are associated with atherosclerosis. High homocysteine levels are also an independent risk factor for cardiovascular disease. An increased level of Folic acid lowers homocysteine levels.



Choline is an accessory nutrient that is included with the B vitamins. Choline acts as a methyl donor. That is, it provides carbon atoms in the form of (CH3). Choline is required in higher amounts during periods of growth necessitating its inclusion in infant milk formulas. Choline and pantothenic acid (vitamin B5) are combined to produce acetylcholine,

Choline is a component of lecithin and acetylcholine (ACh). Acetylcholine is a neurotransmitter. Lecithin is chemically known as phosphatidylcholine and commercially represents a natural mixture of lipids. Phosphatidylcholine helps maintain cell membrane fluidity and support for the protective sheath that surrounds the brain. Choline is also needed for cell membrane integrity and helps move fats in and out of cells

Biotin - Vitamin H

Biotin is also a member of the water-soluble B vitamins. It functions as a coenzyme, and has a metabolic role in energy and amino acid metabolism.  Biotin is necessary for the conversion of pyruvate, (the three-carbon compound formed from glucose metabolism) to acetyl-CoA. Acetyl-CoA is the two-carbon unit that enters the citric acid cycle during aerobic metabolism. Biotin is necessary for metabolism and growth

The citric acid (tricarboxylic acid) cycle is a recycling system of two carbon units. These units are, in the form of acetyl-CoA. These units combine with the four-carbon skeleton of oxaloacetic acid to produce the six-carbon compound, citric acid. In the process of returning to the original four-carbon compound, carbon dioxide is released. The release of CO2 is coupled to an energy transfer to the high-energy phosphate bonds of ATP. In addition, each spin of the cycle releases electrons that enter the respiratory chain. Each cascade of electrons in the respiratory chain produces more high-energy bonds. The bonds of ATP are used as the energy currency in biological reactions.


Ascorbic Acid - Vitamin C

Vitamin C (ascorbic acid) has multiple functions in the body. Ascorbic acid is a water-soluble antioxidant important in exercise. Vitamin C is necessary for the synthesis of collagen, adrenaline, carnitine, and serotonin. Vitamin C has a role in steroid synthesis and is aids in steroid release (cortisol) from the adrenal gland.

There is an interrelationship between Vitamin C and heat, stress and exercise.

The importance of maintaining adequate levels of Vitamin C is important for healing, performance and long term health. Athletes are advised to supplement their diet with high doses of C to insure a high level during exercise.


More in this category: « Minerals Carbohydrates »