Dr. Dwayne Jackson

The Vital Science Blog

Starting Living Your Best

Top off your B vitamins and get an A+ in health and performance

B complex vitamins are a group of water-soluble vitamins that exist together in many food sources. They work to support metabolism by acting as coenzymes that convert protein and carbohydrates into energy in the body. As well, they maintain skin and muscle tone, support the immune system, maintain nerve function and support cellular growth. The B complex vitamins are best supplemented in a formulation that contains them all in balance. Most daily multivitamin supplements created for athletes include an abundance of B complex vitamins. 


Supplement research over the years has noted the importance of B vitamins in exercise performance, which is primarily due to the involvement of B vitamins in energy production. In the general population, the body’s vitamin and mineral needs are met with a healthy well balanced diet, however the latest evidence suggests that many athletes are vitamin deficient. 


Vitamin deficiencies in athletes, especially bodybuilders and strength athletes, are predicted to occur for several reasons:


  1. Strength athletes tend to follow strict and limited diets with very little variety, especially during the competitive season. 
  2. The body’s energy producing metabolic pathways are pushed to the limit during intense training; as such, the requirements for some of the vitamins used in these pathways may increase. 
  3. As your body’s metabolism adapts to heavy training your micronutrient requirements tend to increase. 
  4. Exercise can lead to a loss of micronutrients in sweat, urine, and feces. 
  5. Vitamin requirements increase with greater muscle mass. 


If you can relate to any or all of the 5 points above, then we suggest you read on to find out more about the world of B vitamins!


Thiamine (Vitamin B1) maintains metabolism, and promotes cells in our body’s to produce energy from carbohydrates. Thiamine also plays a role in muscle contraction and conduction of nerve signals.  

Sources: Whole grains, legumes, pork, liver

Signs of deficiency: Muscle weakness and wasting, weight loss, impaired growth, mental confusion, and edema. Drinking alcohol can deplete the body’s thiamin levels. 

Recommended Daily Allowance: 1.2 mg 

Recommended Athletic Dose: 100 mg twice daily 


Riboflavin (Vitamin B2) promotes carbohydrate metabolism and fatty acid oxidation (fat burning), maintains healthy skin and vision.

Sources: Eggs, green vegetables, whole grain products, liver, milk

Signs of deficiency: Cracks in lips, sensitivity to sunlight, inflammation of tongue

Recommended Daily Allowance: 1.3 to 1.7 mg 

Recommended Athletic Dose: 100 mg twice daily


Niacin (Vitamin B3) helps the digestive system, skin, and nerves to function properly. It plays an important role in metabolizing food to produce energy. Some research suggests that taking too much niacin blunts fat burning during aerobic exercise. However, when taken in adequate daily doses it may reduce cholesterol, enhance thermoregulation, and improve energy availability during exercise. 

Sources: Dairy products, eggs, enriched breads and cereals, fish, lean meats, legumes, nuts

Signs of deficiency: Niacin deficiency leads to a disease called pellagra, leading to digestive problems, inflamed skin, mental impairment. 

Recommended Daily Allowance: 16 mg 

Recommended Athletic Dose: 100 mg twice daily 

* Niacin is one of the few B vitamins that are harmful when taken in great excess—overdose can cause liver damage, skin rashes, and peptic ulcers. 


Pantothenic Acid (Vitamin B5) acts as a coenzyme for acetyl coenzyme A (acetyl CoA). Acetyl CoA plays a central role in energy production— it is known as the “hub of metabolism”. In addition, B5 plays an important role in the breakdown of fats and carbohydrates for energy, and is critical to the manufacture of red blood cells, as well as sex and stress-related hormones produced in the adrenal glands (which are situated on top of the kidneys). Vitamin B5 helps to maintain a healthy digestive tract, and it helps the body use other vitamins, particularly B2 or riboflavin. 

Sources: Corn, cauliflower, kale, broccoli, tomatoes, avocado, legumes, lentils, egg yolks, beef (especially organ meats such as liver and kidney), turkey, duck, chicken, milk, peanuts, soybeans, sweet potatoes, sunflower seeds, whole grains, lobster, salmon.

Signs of deficiency: fatigue, insomnia, depression, irritability, vomiting, stomach pains, burning feet, and upper respiratory infections

Recommended Daily Allowance: 5 mg

Recommended Athletic Dose: 100 mg twice daily


Pyridoxine (Vitamin B6) promotes protein metabolism and absorption, helps with red blood cell production, and promotes fat metabolism. B6 is needed for the production of serotonin (in the brain), which increases focus and mental health. As well, it is involved in norepinephrine production (in the body), which regulates blood flow to skin and muscle, and fat metabolism in fat cells. 

Sources: Pork, liver, dairy, green leafy vegetables, legumes, whole grains

Signs of deficiency: Anemia, kidney stones, cracks in lips, skin disorders, nausea

Recommended Daily Allowance: 1.3 mg 

Recommended Athletic Dose: 100 mg twice daily


Biotin (Vitamin B7 or Vitamin H) plays an important role in cell growth and metabolism of fats and amino acids. It has been shown to increase insulin sensitivity and help regulate blood glucose levels.

Sources: Peanuts, almonds, walnuts, sweet potato, salmon, eggs, onions, tomatoes, carrots. 

Signs of deficiency: Biotin deficiency is rare, as the body’s intestinal bacteria can produce it. However, eating raw egg whites has been shown to decrease biotin levels in the body.  Furthermore, a few digestive diseases may limit the body’s biotin production and absorption leading to hair loss, conjunctivitis (e.g., pink eye), dermatitis, depression, tiredness, hallucination, and numbness and tingling of the extremities.

Recommended Daily Allowance: No RDA established 

Recommended Athletic Dose: 300 mcg twice daily


Folic Acid (Vitamin B9 or Vitamin M) plays a key role in DNA (gene) synthesis and repair. It is also an important contributor to protein metabolism and red blood cell formation. It is especially important under conditions of rapid cell division and growth (hence why its important for women to take during pregnancy). Finally, folic acid decreases homocysteine levels, which reduces the risk of cardiovascular disease. 

Sources: Beef (especially organ meats such as liver and kidney), green leafy vegetables, bananas, melons, lemons, legumes, orange juice.

Signs of deficiency: Diarrhea, depression, confusion, anemia. Drinking alcohol can deplete the body’s folic acid levels. 

Recommended Daily Allowance: 400 mcg

Recommended Athletic Dose: 400 mcg twice daily


Cobalamin (Vitamin B12) is a coenzyme involved in the production of DNA and serotonin. Its role in DNA production makes B12 an important player in protein and red blood cell synthesis. Based on its several roles, adequate vitamin B12 is needed for increasing muscle mass, the oxygen-carrying capacity of blood, and decreasing anxiety.

Sources: Beef (especially organ meats such as liver and kidney), eggs, fish, milk, oysters, and shellfish. 

Signs of deficiency: anemia, numbness in fingers or toes, neurological disorders

Recommended Daily Allowance: 2.4 mcg 

Recommended Athletic Dose: At lest 100 mcg twice daily



Kim YN, Choi JY, Cho YO. Regular moderate exercise training can alter the urinary excretion of thiamin and riboflavin. Nutr Res Pract. 2015 Feb;9(1):43-8.

Williams MH. Dietary supplements and sports performance: introduction and vitamins. J Int Soc Sports Nutr. 2004 Dec 31;1:1-6.

Woolf K, Manore MM. B-vitamins and exercise: does exercise alter requirements? Int J Sport Nutr Exerc Metab. 2006 Oct;16(5):453-84.

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