Vitamins - Types, Functions, Deficiency Diseases, and Sources

Vitamins - Vitamins are vital organic compounds required by our body in small amounts to maintain good health, support growth, and enable the smooth functioning of various biological processes. Unlike carbohydrates, proteins, or fats, vitamins do not provide energy, but they are essential for metabolic reactions that convert food into energy.

This article provides a clear, student-friendly explanation of what vitamins are, how they function, the effects of their deficiency, and the natural sources to obtain them.

What Are Vitamins?

Vitamins are micronutrients that our body cannot produce in sufficient quantities; hence, they must be obtained through diet. Each vitamin plays a specific role in maintaining bodily functions—such as improving immunity, aiding vision, healing wounds, and strengthening bones and teeth.

They are divided into two major groups based on solubility:

1. Fat-Soluble Vitamins: Vitamins A, D, E, and K — stored in the liver and fatty tissues.

2. Water-Soluble Vitamins: Vitamin B-complex and Vitamin C — not stored in the body, hence must be consumed regularly.

Importance of Vitamins

Vitamins are essential for:

Growth and Development: Especially important for children and adolescents.

Immunity: Helping the body fight infections.

Metabolism: Enabling enzymes to convert nutrients into usable energy.

Repair and Maintenance: Assisting in cell regeneration and tissue healing.

Classification of Vitamins

1. Fat-Soluble Vitamins

These vitamins dissolve in fat and can be stored in the body.

Vitamin A (Retinol)

Function: Maintains vision, skin health, and immune system.

Deficiency Disease: Night blindness or Loss of Vision.

Symptoms: Poor vision, difficulty seeing in dim light, dry eyes.

Sources: Carrots, spinach, fish liver oil, butter, and egg yolk.

Vitamin D (Calciferol)

Function: Promotes absorption of calcium and phosphorus for bone health.

Deficiency Disease: Rickets in children and Osteomalacia in adults.

Symptoms: Soft, bent bones; delayed growth.

Sources: Sunlight exposure, milk, egg yolk, cod liver oil.

Vitamin E (Tocopherol)

Function: Acts as an antioxidant and protects cells from damage.

Deficiency Disease: Muscle weakness and neurological problems.

Symptoms: Muscle degeneration, reproductive issues.

Sources: Vegetable oils, nuts, spinach, and whole grains.

Vitamin K

Function: Helps in blood clotting and wound healing.

Deficiency Disease: Hemorrhage (excessive bleeding).

Symptoms: Prolonged bleeding and bruising.

Sources: Green leafy vegetables, broccoli, and liver.

2. Water-Soluble Vitamins

These vitamins dissolve in water and are not stored in the body.

Vitamin B Complex

This group includes eight vitamins, each with distinct roles:

Vitamin	Scientific Name	Function	Deficiency Disease	Symptoms	Sources
B1	Thiamine	Energy metabolism	Beriberi	Weak muscles, fatigue	Whole grains, nuts, pork
B2	Riboflavin	Growth and energy	Ariboflavinosis	Cracked lips, sore throat	Milk, eggs, almonds
B3	Niacin	Improves digestion and skin	Pellagra	Skin rashes, diarrhea	Meat, fish, peanuts
B5	Pantothenic Acid	Hormone and energy synthesis	Rare	Fatigue, insomnia	Eggs, meat, avocados
B6	Pyridoxine	Protein metabolism	Dermatitis, Anemia	Skin issues, confusion	Bananas, poultry, potatoes
B7	Biotin	Cell growth, metabolism	Dermatitis	Hair loss, brittle nails	Egg yolk, soybeans
B9	Folic Acid	DNA synthesis	Anemia	Fatigue, poor growth	Leafy vegetables, citrus fruits
B12	Cobalamin	RBC formation, nerve function	Pernicious anemia	Weakness, numbness	Meat, dairy, fortified cereals

Vitamin C (Ascorbic Acid)

Function: Aids in collagen synthesis, boosts immunity, and heals wounds.

Deficiency Disease: Scurvy.

Symptoms: Bleeding gums, delayed wound healing.

Sources: Citrus fruits, amla, guava, tomatoes, and bell peppers.

Minerals and Their Importance

Vitamins often work alongside minerals—another group of essential micronutrients that play crucial roles in structural and functional processes.

Mineral	Deficiency Disease	Symptoms	Sources
Calcium	Bone and tooth decay	Weak bones, tooth loss	Milk, cheese, sesame seeds
Iron	Anaemia	Weakness, fatigue	Spinach, red meat, legumes
Iodine	Goiter	Swollen neck, mental retardation in children	Iodized salt, seafood, eggs
Phosphorus	Weak muscles	Bone pain	Fish, poultry, nuts
Zinc	Growth retardation	Delayed wound healing	Meat, whole grains, beans

Deficiency Diseases and Their Symptoms (Summary)

Vitamin/Mineral	Deficiency Disease	Key Symptoms
Vitamin A	Loss of Vision	Poor night vision
Vitamin B1	Beriberi	Weak muscles, fatigue
Vitamin C	Scurvy	Bleeding gums
Vitamin D	Rickets	Soft, bent bones
Calcium	Bone & Tooth Decay	Weak bones
Iodine	Goiter	Swollen neck glands
Iron	Anaemia	Weakness, tiredness

How to Prevent Vitamin Deficiency

Eat a balanced diet: Include fruits, vegetables, whole grains, dairy, and proteins.

Sun exposure: Helps produce Vitamin D naturally.

Avoid overcooking: Excess heat can destroy water-soluble vitamins.

Stay hydrated: Water aids vitamin absorption and transportation.

Take supplements cautiously: Only under medical guidance.

Importance of Balanced Nutrition

A diet rich in all essential vitamins and minerals ensures:

• Healthy growth and immunity.
• Proper brain and nerve function.
• Strong bones and teeth.
• Efficient metabolism and energy levels.
• Better resistance to infections.

Deficiency of even a single vitamin can disrupt multiple body functions. Hence, maintaining balance through diet is key to overall well-being.

FAQs About Vitamins

Q1. What are vitamins and why are they important?

Vitamins are organic compounds that help regulate body functions such as metabolism, growth, and immunity. They are essential for maintaining overall health.

Q2. How are vitamins classified?

They are classified as fat-soluble (A, D, E, K) and water-soluble (B complex, C).

Q3. Which vitamin deficiency causes night blindness?

Vitamin A deficiency causes night blindness and poor vision.

Q4. What are common sources of Vitamin C?

Citrus fruits like oranges, lemons, and amla are rich in Vitamin C.

Q5. Can vitamin supplements replace natural food?

No. Supplements can help in deficiency, but natural food sources are always preferred for overall nutrition.

Q6. Which vitamin is produced when we are exposed to sunlight?

Vitamin D is synthesized in the skin when exposed to sunlight.

Q7. What are the symptoms of iron deficiency?

Fatigue, weakness, and pale skin are common symptoms of anaemia caused by iron deficiency.