Vitamin B Complex - It's Deficiency and Defects
Healthy Living

Vitamin B Complex - It's Deficiency and Defects

Elina Dawoodani profile Authored by Elina Dawoodani on 23 May 2014 - 21:40.

Vitamins are organic compounds available in small amounts in different natural foods and are vital for growth and maintenance of the human body. Vitamin B in specific is soluble in nature, which are absorbed quickly into the body while the excess of this vitamin which is not utilized is excreted through the urine. They help the body in the process of making energy from the food we eat and help form red blood cells.

They are very essential for the body and found in fish, poultry, meat and eggs and also in leafy green vegetables, beans, and peas.

There are 8 vitamins under this group of vitamin B-Complex, namely:

1. Thiamine (Vitamin B1)

2. Riboflavin (Vitamin B2)

3. Niacin (Vitamin B3)

4. Pyridoxine

5. Pantothenic Acid (Vitamin B5)

6. Folic Acid

7. Biotin (Vitamin B7)

8. Cyanocobalamin (Vitamin B12)

These vitamins help in utilization of energy consumed from various foods. Not consuming adequate amounts of these nutrients can cause various types of deficiency diseases.

This article sheds some light on the roles of some of these vitamins in our body, their food sources and the impact of their deficiency in our body.

1. Thiamine

Thiamine is also known as Vitamin B1 and is widely known for its role in preventing the deficiency disease beriberi. The basic function of thiamine as a coenzyme is release of energy and its storage as fat, thus it makes energy available for normal growth and other bodily functions.  The major functions of thiamine in the body are related to three systems:

a. Cardiovascular system: Thiamin is required for the normal functioning of the heart. Insufficient quantities of this vitamin, affects the muscles of the heart and may lead to heart failure.

b.Gastrointestinal system: Thaimin helps in the production of energy needed by cells of smooth muscles and secretory glands of the gastrointestinal system. Lack of this vitamin leads to poor appetite, indigestion, constipation etc.

c. Nervous system: Glucose is the primary source of energy for the central nervous system. In case of thiamine deficiency, glucose is not broken down sufficiently, and may lead to mal functioning of the nerves. This results in poor response and alertness, apathy, fatigue and irritability. It can also lead to paralysis.

Food sources:

  • Nuts and oilseeds
  • Pulses, especially green peas
  • Whole grain cereals, especially parboiled rice
  • Green leafy vegetables
  • Milk
  • Eggs
  • Fish
  • Meat

Deficiency Defects:

a. Digestive system is disturbed, thus resulting in loss of appetite (anorexia), constipation and poor muscles.

b. Nervous system is also affected. Mental depression, moodiness, irritability, forgetfulness etc is generally seen.

c. Beriberi is disease that occurs due to severe thiamine deficiency. If it occurs in infants, it leads to cyanosis, i.e. the accumulation of carbon dioxide which causes the skin to turn blue. In adults, it can show oedema, palpitation and low cardiac output.


2.     Riboflavin

Riboflavin is also known as Vitamin B2. It produces two co-enzymes that participate in the electron transport chain. They are responsible for release of energy from glucose, fatty acids and amino acids. It also plays a role in cell division and growth.

Food sources:

  • Milk
  • Milk products like yogurt, buttermilk, milk powder etc
  • Liver
  • Kidney
  • Pulses
  • Green leafy vegetables
  • Eggs

Deficiency Defects:

a. Eyes: Eyes become sensitive to sunlight and eyelids become rough.

b. Skin: skin around mouth, lips, tongue and nose become dry and scaly.

c. Lips: Lips become inflamed and cracks are seen.

d. Tongue: Tongue becomes red, sore and swollen.

3.     Niacin

Niacin functions as a component of two coenzymes that are involved in tissue respiration and synthesis and the breakdown of glucose to produce energy. It also aids in cell metabolism and is necessary for growth.

Food sources:

  • Groundnuts
  • Liver
  • Cereals
  • Garden-cress seeds
  • Beef muscle
  • Barley
  • Almond
  • Radish leaves
  • Prawns

Deficiency Defects:

a. Niacin deficiency is manifested through a disease termed as “Pellagra”. Skin symptoms have been observed. The typical clinical features of pellagra are: dermatitis, diarrhoea and dementia.

b. Other effects of niacin deficiency include: irritability, anxiety, insomnia, anorexia, nausea and other digestive and neurological disorders.

4.     Pyridoxine (Vitamin B6):

Vitamin B6 is a co-factor for many enzymes connected with the metabolism of amino acids. It plays a role in formation of antibiotics.

Food sources:

  • Rice polishing
  • Wheat bran
  • Wheat germ
  • Liver
  • Whole cereals
  • Legumes
  • Nuts and oilseeds
  • Milk powder, whole
  • Milk powder, skimmed
  • Eggs, whole
  • Meat
  • Milk
  •  Leafy vegetables

Deficiency Defects:

a.     Peripheral neuritis:  It’s a neural disorder that impairs movement and sensation.

b.     Anaemia: The deficiency of iron leading to low oxygen supply to the cells is termed as anaemia. Fatigue and weakness is observed.

c.      Glossitis: Soreness and inflammation of the tongue is termed as glossitis.

d.     Angular cheilitis: Angular Cheilitis is fungi infection at the corners of lips causing cracks, inflammation and soreness.

5.     Cyanocobalamin (Vitamin B12):

Vitamin B12 is required for proper functioning of many parts of the body. It is the most potent vitamin. It is responsible for DNA formation and production of red blood cells.

Food sources:

  • Liver
  • Organ meats
  • Milk
  • Eggs
  • Muscle meat
  • Fish

Deficiency Problems:

a.     Sore tongue

b.     Apathy

c.      Loss of weight

d.     Tingling of extremities

e.     Mental and other nervous abnormalities

f.       Megaloblastic anaemia

g.     Pernicious anaemia

The problem with Vitamin B12 is, it is found in abundance only in animal products. Plants do not contain Vitamin B12. Hence, for vegetarians, supplementation of this vitamin becomes necessary.

If you are suffering from B – Complex vitamin deficiency, consult your doctor/nutritionist and get guidance on diet and supplementation.




1.     Advanced textbook on Food and Nutrition by Dr. Swaminathan

2.     Nutrition Science by B. Srilakshmi

3.     Fundamentals of Foods, Nutrition and Diet Therapy by S. R. Mudambi and M. V. Rajagopal

*Disclaimer: This is not medical advice. The content is for educational purposes only. Please contact your doctor for any health care issues.