B Healthy: Roles of B Vitamins and Symptoms of Deficiency

B vitamins (Thiamine, Riboflavin, Niacin, Pantothenic Acid, Pyridoxine, Biotin, Folic Acid and Cobalamin) help convert other nutrients into energy so support healthy metabolism, nerve function, eye health, skin health, liver function and foetal growth during pregnancy. A less-than-optimum diet may put individuals at risk of insufficient intake of B vitamins which are important to help prevent fatigue, anaemia, poor memory, mood disorders, etc. Additionally, a number of pharmaceuticals may affect body levels of B vitamins.

Each of these 8 water-soluble B vitamins has specific functions in the body. Each is a cofactor for (or precursor for) key metabolic processes. Since high doses of any one single B vitamin may deplete other B vitamins, a B complex is generally recommended.

All B vitamins are useful for countering stress and fatigue. There are many other benefits of B vitamins. Below is a brief description of some of these benefits.

B vitamins:

  • Contribute to reduction of tiredness and fatigue (B2, B3, B5, B6, B12, Folate)
  • Contribute to normal energy-yielding metabolism (B1, B2, B3, B5, B6. B12, biotin)
  • Contribute to normal psychological function (B1, B3, B6. B12, Folate, biotin)
  • Contribute to normal functioning of the nervous system (B1, B2, B3, B6, B12, biotin)
  • Contribute to normal functioning of the immune system (B6, B12, Folate)
  • Contribute to normal function of the heart (B1)
  • Contribute to normal metabolism of iron (B2)
  • Contribute to protection of cells from oxidative stress (B2)
  • Contribute to maintenance of normal skin (B2, B3, biotin)
  • Contribute to maintenance of normal mucous membranes (B2, B3, biotin)
  • Contribute to maintenance of normal hair (biotin)
  • Contribute to maintenance of normal vision (B2)
  • Contribute to normal red blood cell formation (B6. B12)
  • Contribute to maintenance of normal red blood cells (B2)
  • Contribute to normal blood formation (Folate)
  • Contribute to normal mental performance (B5)
  • Contribute to normal synthesis and metabolism of steroid hormones, vitamin D and some neurotransmitters (B5)
  • Contribute to normal homocysteine metabolism (B6, B12, Folate)
  • Contribute to normal protein and glycogen metabolism (B6)
  • Contribute to normal amino acid synthesis (Folate)
  • Contribute to the regulation of hormonal activity (B6)
  • Have a role in the process of cell division (B12, Folate)
  • Contribute to normal cysteine synthesis (B6)
  • Contribute to maternal tissue growth during pregnancy (Folate)
  • Contribute to normal macronutrient metabolism (biotin)

And below is a brief mention of symptoms of vitamin B deficiency.

Symptoms of Vitamin B1 (Thiamine) deficiency: fatigue, irritability, nerve damage, tingling, blurry vision, loss of appetite, nausea/vomiting. Beriberi is caused by vitamin B1 deficiency. 

Symptoms of Vitamin B2 (Riboflavin) deficiency: fatigue, blurred vision, depression, swollen throat, skin itching/cracking/dermatitis around the mouth, hair loss. 

NOTE that Riboflavin is the B vitamin that, if taken in excess, can excrete via the kidneys causing fluorescent yellow/green urine.

Symptoms of Vitamin B3 (Niacin) deficiency: fatigue, constipation/diaorrhea, vomiting, bright red tongue, aggressive/paranoid behaviour, rough skin that reddens/brown in the sun, hallucinations.  Pellagra is caused by vitamin B3 deficiency. NOTE: vitamin B3 is aka Niacin (the generic name), nicotinic acid and nicotinamide. 

Note that some supplemental forms of niacin may cause a flushing reaction

Symptoms of Vitamin B5 (Pantothenic acid) deficiency: fatigue, headache, irratibility, restlessness, disturbed sleep, numbness in hands/feet, muscle cramps, nausea/vomiting

Symptoms of Vitamin B6 (Pyridoxine) deficiency: fatigue, microcytic anaemia, scaling of the lips and cracks in corners of the mouth, dermatitis, red scaly rash, pins and needles, swollen tongue, depression, confusion. The active form of Vitamin B6 is Pyridoxal-5-Phosphate (P-5-P).

CAUTION: Long-term daily intake (several months to years) of high amounts (500mg or more) of vitamin B6, or shorter-term daily doses of higher amounts (e.g. 2000mg or more) have been shown to cause nerve toxicity including pins and needles.  Also note that high doses of B6 should be avoided in the last trimester of pregnancy and during breast-feeding. 

Biotin is also known as Vitamin H, however it is considered a B vitamin (aka vitamin B7 or sometimes B8) and an essential coenzyme.  Biotin is manufactured in the body by intestinal bacteria, but dietary intake is still needed to achieve levels sufficient for health. Symptoms of Biotin deficiency include: fatigue, dry eyes, dry scaly skin, red rashes on skin, hair loss, brittle hair, loss of appetite, difficulty sleeping.

Folic Acid, sometimes referred to as Vitamin B9, is essential for proper cell replication and particularly important for the development and maintenance of the nervous system. Evidence suggests deficiency of this important nutrient during pregnancy associates with neural tube defects; preventive supplementation is typically recommended during pregnancy (and pre-conceptually for those planning pregnancy). The active form of folic acid is methylfolate. The form of folic acid naturally found in foods is folate. Symptoms of Folic Acid deficiency include: fatigue, symptoms related to anaemia, diarrhoea, muscle weakness, depression, reduced sense of taste, numbness/tingling in feet/hands. 

Vitamin B12 (Cobalamin) is another essential coenzyme. The active forms are methylcobalamin and adenosylcobalamin.  Deficiency of vitamin B12 can result in pernicious (megaloblastic) anaemia. Symptoms of Vitamin B12 deficiency include: extreme fatigue, lethargy (lack of energy), breathlessness, megaloblastic anaemia, weakness, constipation, feeling faint, headaches, pale skin, palpitations, loss of appetite and weight loss

NOTE: vegetarian and vegan diets may be low in Vitamin B12.