Vitamin Functions, Deficiency Symptoms & Natural Sources

Updated on November 14, 2017

What Are Vitamins?

A vitamin is an organic compound, found in food and other natural sources, that our body needs for basic function and health. Many vitamins are available to us in food. For example, citrus fruits are an abundant source of Vitamin C. Other vitamins are present in food but also in other sources. We get Vitamin D by eating fish, eggs, and mushrooms, for example, but exposure to sunlight is also an important source of that vitamin.

There are 13 essential vitamins:

  1. Vitamin A
  2. Vitamin B1 (thiamine)
  3. Vitamin B2 (riboflavin)
  4. Vitamin B3 (niacin)
  5. Pantothenic acid (B5)
  6. Vitamin B6
  7. Biotin (B7)
  8. Folate (folic acid and B9)
  9. Vitamin B12 (cyanocobalamin)
  10. Vitamin C
  11. Vitamin D
  12. Vitamin E
  13. Vitamin K

Here is a brief overview of the roles that these vitamins play in our health, how we can know when we are deficient, and where vitamins can be found in food.

How Do You Get Your Vitamins?

How do you get your vitamins?

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Essential Vitamin Functions and Sources

Vitamin
Functions
Sources
1. Vitamin A
Form and maintain teeth, bones, tissue, and skin.
Ripe yellow fruits, carrots, oranges, paprika, squash, red peppers, leafy green vegetables, cayenne, pumpkin, chili powder, spinach, soy milk, and sweet potatoes.
2. Vitamin B1 (thiamine)
Essential to help cells turn carbohydrates into energy.
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.
3. Vitamin B2 (riboflavin)
Maintains red blood cells and body growth.
Bananas, dried herbs, asparagus, almonds, wheat bran, dried spices, green beans, sesame seeds, dried roasted soybeans, sun-dried tomatoes, dried peppers, and popcorn.
4. Vitamin B3 (niacin)
Maintains healthy skin and nerves.
Rice bran, wheat bran, paprika, peanuts, sun-dried tomatoes, mushrooms, and tree nuts.
5. Pantothenic acid (B5)
Essential for metabolism of food.
Broccoli, wheat bran, avocado, rice bran, sunflower seeds, whey powder, mushrooms, cheese, corn, broccoli, caviar, sun-dried tomatoes, squash, and fish.
6. Vitamin B6
Form and maintain red blood cells and brain function.
Tree nuts, dried spices, wheat bran, sesame seeds, bananas, rice bran, dried herbs, pistachios, raw garlic, sunflower seeds, molasses, sorghum syrup, filberts, and hazelnuts.
7. Biotin (B7)
Essential for metabolism of protein and carbohydrates.
Oil-roasted peanuts, oil-roasted sunflower seeds, soy beans, dried yeast, 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.
8. Folate (folic acid or B9)
Forms red blood cells and essential to production of DNA.
Leafy green 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.
9. Vitamin B12 (cyanocobalamin)
Forms red blood cells and maintains central nervous system.
Clams, oysters, mussels, liver, caviar, octopus, fish, crab, lobster, beef, beef, mutton (especially shoulder), cheese (especially Swiss), and eggs.
10. Vitamin C
An antioxidant that promotes healthy teeth and gums.
Red chili peppers, guava, green chili peppers, bell peppers, fresh herbs (thyme and parsley), dark leafy greens (garden cress, kale, and mustard), broccoli, cauliflower, Brussels sprouts, kiwi, papaya, strawberries, oranges, and clementines.
11. Vitamin D
Essential for development of healthy teeth and bones.
Fish, eggs, liver, mushrooms, and sunshine.
12. Vitamin E
Helps form red blood cells and process Vitamin K.
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 (basil and oregano), dried apricots, pickled green olives, and cooked spinach.
13. Vitamin K
Essential for blood coagulation and bone health.
Dried herbs, prunes, pickled cucumber, dark leafy herbs, spring onion, Brussels sprouts, broccoli, chili powder, curry, paprika, cayenne, asparagus, and cabbage.
 
 
 
Carrots are an excellent source of Vitamin A, which promotes healthy vision.
Carrots are an excellent source of Vitamin A, which promotes healthy vision.

Signs of Vitamin Deficiency

Vitamin A Deficiency

  • Vitamin A deficiency causes impaired vision, particularly in reduced light. This condition is commonly known as night blindness.
  • Deficiency can also lead to hyperkeratosis, which is a thickening of the stratum corneum, or the outermost layer of skin. This appears as white lumps at the hair follicles.
  • Deficiency of Vitamin A also causes keratomalacia, an eye disorder.

Signs of Vitamin B1 Defiency

  • Vitamin B1 deficiency can cause beriberi, a condition that produces symptoms including loss of appetite, weakness, pain in the limbs, shortness of breath, and swollen feet or legs.
  • B1, or thiamine, deficiency can also lead to Wernicke-Korsakoff syndrome, which manifests as vision disturbances, mental confusion, and unsteady walking.
  • Cataracts
  • Alzheimer’s disease
  • Heart failure
  • Excessive consumption of alcohol can lead to B1 deficiency, as alcohol flushes the vitamin out of the body.

A man with beriberi, which can result from Vitamin B1 (thiamine) deficiency.
A man with beriberi, which can result from Vitamin B1 (thiamine) deficiency.

Signs of Vitamin B2 Deficiency

  • Digestive problems
  • Frequent dizziness
  • Hair loss
  • Skin rashes
  • Eye problems
  • Insomnia
  • Slow mental response
  • Ariboflavinosis, which manifests with lesions around the mouth, weakness, weight loss, and anemia

Signs of Vitamin B3 Deficiency

  • Pellagra (diarrhea, dermatitis, dementia, aggression, red skin lesions, insomnia, weakness, and confusion)

Signs of Vitamin B5 Deficiency

  • Paresthesia (a burning sensation in the hands and feet, muscle cramps, numbness, tingling sensations, irritability, fatigue, diarrhea, vomiting, sleep disturbances, and restlessness).

Broccoli is an excellent natural source of Vitamin B5.
Broccoli is an excellent natural source of Vitamin B5.

Vitamin B6 Deficiency

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

Raw garlic is an excellent source of Vitamin B6.
Raw garlic is an excellent source of Vitamin B6.

Signs of Vitamin B7 Deficiency

  • Dermatitis
  • Enteritis (inflammation of the intestine)
  • Hair loss
  • Fatigue
  • Depression
  • Nausea
  • Muscle pains
  • Anemia

Walnuts are rich in Vitamin B7.
Walnuts are rich in Vitamin B7.

Signs of Folate, or Vitamin B9, Deficiency

  • Magaloblastic anemia
  • Heart problems
  • Age-related hearing loss
  • Age related macular degeneration
  • Depression
  • Neural tube defects and other birth defects

Vitamin B12 Deficiency

  • Megaloblastic anemia
  • Heart problems
  • Weakness
  • Rapid breathing
  • Tiredness
  • Light-headedness
  • Rapid heartbeat
  • Pale skin
  • Sore tongue
  • Weight loss
  • Diarrhea

Vitamin C Deficiency

Vitamin C deficiency causes scurvy. Symptoms include fatigue, mood swings, joint pain, dry skin, weight loss, bruising, muscle pain, dental problems, dry hair, and infection.

Oranges are an abundant source of Vitamin C.
Oranges are an abundant source of Vitamin C.

Vitamin D Deficiency

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

Sunlight is an excellent source of Vitamin D.
Sunlight is an excellent source of Vitamin D.

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.

Almonds are an abundant source of Vitamin E.
Almonds are an abundant source of Vitamin E.

Vitamin K Deficiency

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

Brussels sprouts are rich in Vitamin K.
Brussels sprouts are rich in Vitamin K.

Many vitamin supplements are available in the market. However, it is always advisable to obtain vitamins from their natural sources by eating foods rich in vitamins daily.

Quick Vitamin Facts

  • Vitamins are organic compounds.
  • An otherwise healthy person can get all the vitamins they need from a healthy diet.
  • There is debate about whether supplements are beneficial. Some supplements can lead to complications when combined with certain medications or when taken before surgery.
  • Some vitamins are water-soluble while others are fat-soluble.
  • Vitamin A deficiency can cause night blindness.
  • Vitamin B1, or thiamin, deficiency can cause beriberi. This condition is most common in regions where polished rice (where the husk is removed) is a staple food.
  • Dark, leafy, green vegetables are excellent sources of many vitamins, including A, C, E, and K.
  • Vitamin C deficiency can lead to scurvy.
  • Sunlight is an excellent source of Vitamin D.

Recommended Daily Dosages of Essential Vitamins

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.

© 2013 Srikanth R

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    • srirad0675 profile image
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      Srikanth R 8 days ago

      Thank you.

    • profile image

      Jaideep sharma 9 days ago

      NYC SIR simple and Clear topic on Vitamins

    • srirad0675 profile image
      Author

      Srikanth R 2 months ago

      Welcome.

    • profile image

      Rushikesh Sathe 2 months ago

      Thanx SIR

    • srirad0675 profile image
      Author

      Srikanth R 2 months ago

      Welcome.

    • profile image

      Prerna 2 months ago

      Thxx alot Sir it really helped me with my projects such a simple n easy language

    • srirad0675 profile image
      Author

      Srikanth R 6 months ago

      Thank you.

    • profile image

      Rudra Teja Reddy 6 months ago

      This is such a simple way to know vitamins and their function. It is easy to know thank you for this information. Done a great job.

    • srirad0675 profile image
      Author

      Srikanth R 8 months ago

      Welcome.

    • profile image

      Genesis Johnson 8 months ago

      Nice Work and very imformative

      Thanks

    • srirad0675 profile image
      Author

      Srikanth R 16 months ago

      Welcome!

    • profile image

      PHANI KUMAR M V 16 months ago

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

    • srirad0675 profile image
      Author

      Srikanth R 17 months ago

      Welcome!

    • profile image

      Brian Koome 17 months ago

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

      Thank you much.

    • ahmed abelgaid profile image

      ahmed abdelgaid 3 years ago from egypt

      I absolutely will have to after reading this.

    • srirad0675 profile image
      Author

      Srikanth R 4 years ago

      Thank you!

    • profile image

      LAKSHMI.S 4 years ago

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

    • srirad0675 profile image
      Author

      Srikanth R 4 years ago

      Ok. :-)

    • dwelburn profile image

      David 4 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 4 years ago

      I am glad you liked the article. Thank you.

    • srirad0675 profile image
      Author

      Srikanth R 4 years ago

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

    • dwelburn profile image

      David 4 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 :)