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Vitamins: Their functions, deficiency symptoms and natural sources

Updated on July 18, 2016

Joined: 5 years agoFollowers: 42Articles: 73

What are vitamins?

Vitamins are organic compounds that are necessary for overall health and general well-being. These vital nutrients have diverse biochemical functions. Vitamins are classified by their biological and chemical activity, not by their structure.

Here is a brief overview of various functions of vitamins, symptoms of their deficiency and their natural sources.

Vitamin sources

How do you get your vitamins?

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Vitamin A

Functions of vitamin A

Vitamin A (retinol, retinal and four carotenoids including beta carotene) is a fat soluble vitamin. It performs many functions in the human body. It promotes growth and development of the body. It maintains the immune system. It is very important for healthy eyes.

Medical conditions caused by vitamin A deficiency

Deficiency of vitamin A causes impaired vision, particularly in reduced light. This condition is commonly known as night blindness. Hyperkeratosis, thickening of the stratum corneum (outermost layer of the epidermis) is another condition caused by vitamin A deficiency. You notice white lumps at hair follicles. Deficiency of vitamin A also causes keratomalacia, an eye disorder.

Natural sources of vitamin A

Ripe yellow fruits, carrot, orange, paprika, squash, red pepper, leafy vegetables, cayenne, pumpkin, chili powder, spinach, soy milk and sweet potatoes are some natural sources of vitamin A.

Carrot

Vitamin facts

  • Vitamins are organic compounds.
  • Vitamins are classified by their biological and chemical activity, not by their structure.
  • Vitamins have diverse biochemical functions.
  • Some vitamins are water soluble while others are fat soluble.
  • Vitamin A deficiency causes night blindness.
  • Vitamin B1 deficiency causes beriberi.
  • Vitamin B5 plays a major role in the manufacture of RBC.
  • Leafy vegetables are excellent sources of vitamins.
  • Vitamin C deficiency causes scurvy.
  • Sunlight is an excellent source of vitamin D.

Vitamin B1

Functions of vitamin B1

Vitamin B1 (thiamine) is a water soluble vitamin. This means the human body does not store this vitamin. Vitamin B1 plays a significant role in the healthy functioning of the nervous system. It strengthens the immune system and helps the body cope with stress.

Medical conditions caused by vitamin B1 deficiency

Vitamin B1 deficiency causes beriberi, Wernicke-Korsakoff syndrome, cataracts and Alzheimer’s disease. It may also cause heart failure. Excessive consumption of alcohol flushes vitamin B1 out of the body.

Beriberi patient

Natural sources of vitamin B1

Whole grains, enriched cereals, brown rice, sesame seeds, sunflower seeds, dried herbs and spices, pine nuts, pistachios, macadamia nuts, pecans, legumes, wheat germ, bran, brewer’s yeast and blackstrap molasses are some natural sources of vitamin B1

Vitamin B2

Functions of vitamin B2

Vitamin B2 (riboflavin) is a water soluble vitamin. It is necessary for proper functioning of cells. It plays an important role in energy metabolism. It is required for metabolism of carbohydrates, proteins, ketone bodies and fats.

Medical conditions caused by vitamin B2 deficiency

Vitamin B2 deficiency affects the digestive system. The person may experience dizziness frequently, hair loss, skin rashes, eye problems and insomnia. Slow mental response is another common symptom of vitamin B2 deficiency. Ariboflavinosis is another medical condition caused by deficiency in this vitamin.

Natural sources of vitamin B2

Banana, dried herbs, asparagus, almonds, wheat bran, dried spices, green beans, sesame seeds, dried roasted soybeans, sun dried tomatoes, dried peppers and popcorn are some natural sources of vitamin B2.

How much vitamins do you require

Vitamin
Daily requirement
Vitamin A
600 µg
Vitamin B1
Men: 1.2 mg; Women: 1 mg
Vitamin B2
1,6 mg
Vitamin B3
18 mg
Vitamin B5
6 mg
Vitamin B6
2 mg
Vitamin B7
7 µg
Vitamin B9
400 µg
Vitamin B12
6 µg
Vitamin C
75 mg
Vitamin D
5 µg
Vitamin E
10 mg
Vitamin K
80 µg
Daily vitamin requirement chart.

DNA

Vitamin B3

Functions of vitamin B3

Vitamin B3 (niacin and niacinamide) is a water soluble vitamin. It plays a major role in conversion of carbohydrates to glucose. It is important for normal cellular growth and division. It repairs damaged DNA. It plays a significant role in normal production of sex hormones and stress hormones.

Medical conditions caused by vitamin B3 deficiency

Vitamin B3 deficiency causes pellagra. Diarrhea, dermatitis, dementia, aggression, red skin lesions, insomnia, weakness, confusion, ataxia and dilated cardiomyopathy are some common symptoms of this medical condition. Pellagra can cause death.

Natural sources of vitamin B3

Rice bran, wheat bran, paprika, peanuts, sun dried tomatoes, vegetables, mushrooms and tree nuts are some natural sources of vitamin B3. It is definitely advisable to include them in your daily diet.

Broccoli is an excellent natural source of vitamin B5

Vitamin B5

Functions of vitamin B5

Vitamin B5 (pantothenic acid) is a water soluble vitamin. It plays a major role in the manufacture of red blood cells (RBC). It helps in breakdown of fats and carbohydrates in the body.

Medical conditions caused by vitamin B5 deficiency.

Vitamin B5 deficiency causes paresthesia. First sign of vitamin B5 deficiency is burning sensation in the hands and feet. Muscle crams, numbness, tingling sensation, irritability, fatigue, tiredness, apathy, diarrhea, vomiting, sleep disturbance and restlessness are other symptoms of vitamin B5 deficiency.

Natural sources of vitamin B5

Broccoli, wheat bran, avocado, rice bran, sunflower seeds, whey powder, mushrooms, cheese, corn, broccoli, caviar, sun dried tomatoes, squash and fish are some foods that are rich in vitamin B5.

Raw garlic is an excellent source of vitamin B6

Vitamin B6

Functions of vitamin B6

Vitamin B6 (pyridoxine, pyridoxamine and pyridoxal) is a water soluble vitamin. It is involved in many aspects of macronutrient metabolism. It plays a significant role in amino acid metabolism, gluconeogenesis and lipid metabolism.

Medical conditions caused by vitamin B6 deficiency

Anemia and peripheral neuropathy are caused by deficiency in vitamin B6. Inflammation of the skin, sore tongue, depression, cognitive problems and convulsions are some symptoms associated with vitamin B6 deficiency.

Natural sources of vitamin B6

Tree nuts, dried spices, wheat bran, sesame seeds, bananas, rice bran, dried herbs, pistachios, raw garlic, sunflower seeds, molasses, sorghum syrup, filberts and hazelnuts are some natural sources of vitamin B6.

Walnuts are rich in vitamin B7

Vitamin B7

Functions of vitamin B7

Vitamin B7 (biotin) is a water soluble vitamin. Also known as vitamin H, this nutrient is a coenzyme for carboxylase enzymes, involved in synthesis of valine, fatty acids and isoleucine. It is also involved in gluconeogenesis.

Medical conditions caused by vitamin B7 deficiency

Dermatitis and enteritis are medical conditions that are caused by deficiency in vitamin B7. Hair loss, fatigue, depression, nausea, muscle pains and anemia are some signs of vitamin B7 deficiency.

Natural sources of vitamin B7

Oil-roasted peanuts, oil-roasted sunflower seed, soy beans, dried yeast, nuts, oatmeal, walnuts, baker’s yeast, mustard powder, salted peanut, salted sunflower seeds, salted hazelnuts, dried peanuts, instant coffee, oil-roasted hazel nuts and green laver are some good sources of vitamin B7.

Spinach is rich in vitamin B9

Vitamin B9

Functions of vitamin B9

Vitamin B9 (folic acid and folinic acid) is a water soluble vitamin. It helps in conversion of carbohydrates into glucose. It is very much necessary for the proper functioning of the brain. It promotes healthy skin, eyes, hair and liver. It aids in the production of DNA and RNA.

Medical conditions caused by vitamin B9 deficiency

Magaloblastic anemia, heart problems, age-related hearing loss, age related macular degeneration, depression, cancer, neural tube defects and other birth defects are caused by vitamin B9 deficiency.

Natural sources of vitamin B9

Leafy vegetables, pasta, bread, cereal, spinach, dark leafy greens, asparagus, turnip, beets, mustard greens, Brussels sprouts, lima beans, soybeans, brewer’s yeast, root vegetables, whole grains, wheat germ, bulgur wheat, kidney beans, white beans, mung beans, orange juice and avocado are some sources of vitamin B9

Swiss cheese

Vitamin B12

Functions of vitamin B12

Vitamin B12 (cyanocobalamin, hydroxycobalamin and methylcobalamin) is a water soluble vitamin. It works with folate in making body’s genetic material. It is necessary for the production of red blood cells. It also keeps the amino acid homocysteine in check.

Medical conditions caused by vitamin B12 deficiency

Vitamin B12 deficiency causes megaloblastic anemia and heart problems. Weakness, rapid breathing, tiredness, light headedness, rapid heartbeat, pale skin, sore tongue, weight loss and diarrhea are some symptoms of vitamin B12 deficiency.

Natural sources of vitamin B12

Clams, oysters, mussels, liver, caviar, octopus, fish, crab, lobster, beef, beef, mutton (especially shoulder), cheese (especially Swiss cheese) and eggs (raw yellow) are good sources of vitamin B12.

Vitamin C

Functions of vitamin C

Vitamin C (ascorbic acid) is a water soluble vitamin. This essential nutrient is a cofactor in at least eight enzymatic reactions, including several collagen synthesis reactions that, when dysfunctional, cause the most severe symptoms of scurvy.

Vitamin C promotes heaving of wounds and prevents bleeding from capillaries. It is an excellent antioxidant and prevents many harmful medical conditions. It is required for many metabolic reactions.

Medical conditions caused by vitamin C deficiency

Vitamin C deficiency causes scurvy. Fatigue, mood swings, joint pain, dry skin, weight loss, bruising, muscle pain, dental conditions, dry hair and infections are some signs of vitamin C deficiency.

Scurvy

Natural sources of vitamin C

Red hot chili peppers, guava, green hot chili peppers, bell peppers, fresh herbs (like thyme and parsley), dark leafy greens (like garden cress, kale and mustard greens), broccoli, cauliflower, Brussels sprouts, kiwi fruits, papaya, strawberries, oranges and clementines are very good sources of vitamin C

Oranges

Vitamin D

Functions of vitamin D

Vitamin D (cholecalciferol) is a fat soluble vitamin. It plays a major role in maintaining strong and healthy bones. It promotes absorption and use of calcium and phosphates for healthy bones and teeth.

Medical conditions caused by vitamin D deficiency

Vitamin D deficiency causes rickets and osteomalacia. People with deficiency in this vitamin are more likely to be affected by cardiovascular diseases and cancer. Older adults may suffer from cognitive impairment. Children with vitamin D deficiency may be affected by severe asthma.

Rickets

Sunlight is an excellent source of vitamin D

Sun light
Sun light

Almonds

Vitamin E

Functions of vitamin E

Vitamin E (tocopherols and tocotrienols) is a fat soluble vitamin. It is an antioxidant and stops the production of reactive oxygen species formed when fat undergoes oxidation in the body.

Medical conditions caused by vitamin E deficiency

Vitamin E deficiency is very rare. It may cause mild hemolytic anemia in newborn infants. Spinocerebellar ataxia, myopathies, peripheral neuropathy, ataxia, skeletal myopathy and retinopathy are other conditions caused by vitamin E deficiency.

Natural sources of vitamin E

Corn oil, sunflower seeds, paprika, soybean oil, margarine, safflower oil, wheat germ oil, sunflower oil, red chili powder, cooked taro root, almonds, pine nuts, peanuts, dried herbs (like basil and oregano), dried apricots, pickled green olives and cooked spinach are rich in vitamin E.

Brussels sprouts

Vitamin K

Functions of vitamin K

Vitamin K (phylloquinone and menaquinones) is a fat soluble vitamin. Human body needs this vitamin for posttranslational modification of certain proteins required for blood coagulation. It promotes healthy bones and tissues.

Medical conditions caused by vitamin K deficiency

Deficiency in vitamin K causes bleeding diathesis. Newborn infants are more likely to be affected by vitamin K deficiency.

Natural sources of vitamin K

Dried herbs, prunes, pickled cucumber, dark leafy herbs, fresh herbs, spring onion, Brussels sprouts, broccoli, chili powder, curry, paprika, cayenne, asparagus and cabbage are natural sources of vitamin K.

Many vitamin supplements are available in the market. However, it is always advisable to obtain vitamins from their natural sources. Including foods rich in vitamins in your daily diet ensures good health.

Vitamin quiz

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    • dwelburn profile image

      David 3 years ago from Chesterfield, UK

      An excellent and very comprehensive hub on vitamins. Vitamin D can also be obtained from some food sources such as oily fish and eggs. And I couldn't do your quiz at the top because my answer is both :)

    • srirad0675 profile image
      Author

      Srikanth R 3 years ago

      Well... That question and options were created keeping the importance of sunlight as a source of vitamin D in mind.

    • srirad0675 profile image
      Author

      Srikanth R 3 years ago

      I am glad you liked the article. Thank you.

    • dwelburn profile image

      David 3 years ago from Chesterfield, UK

      No; sorry srirad. I meant your question at the top which says 'How do you get your vitamins? through natural sources because that is the right way, or I take vitamin supplements'. Presumably that is talking about all vitamins? And my answer to that is 'both'. :)

    • srirad0675 profile image
      Author

      Srikanth R 3 years ago

      Ok. :-)

    • LAKSHMI.S 3 years ago

      IT IS A FINEST INFORMATION ABOUT VITAMINS AND THEIR FUNCTIONS,SOURCES

    • srirad0675 profile image
      Author

      Srikanth R 3 years ago

      Thank you!

    • ahmed abelgaid profile image

      ahmed abdelgaid 2 years ago from egypt

      I absolutely will have to after reading this.

    • Brian Koome 5 months ago

      The article is quite informative. I have now known some things I didn't know.

      Thank you much.

    • srirad0675 profile image
      Author

      Srikanth R 5 months ago

      Welcome!

    • PHANI KUMAR M V 4 months ago

      SIMPLY SUPERB. Covered most of the information a layman needs. Thank you.

    • srirad0675 profile image
      Author

      Srikanth R 4 months ago

      Welcome!

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