A Complete Guide to What are the 13 official vitamins?

October 13, 2025 •

3 min read

The human body requires 13 essential vitamins to function properly, which cannot be synthesized in sufficient amounts and must be obtained through diet. These vital micronutrients are grouped into two categories: fat-soluble and water-soluble, each with distinct roles in metabolism, growth, and overall health.

Quick Summary

This guide covers the 13 essential vitamins, detailing their classification as fat-soluble or water-soluble, individual functions, and common dietary sources for maintaining good health.

Key Points

13 Essential Vitamins: The body needs 13 vitamins—4 fat-soluble and 9 water-soluble—for proper function.
Fat-Soluble Storage: Vitamins A, D, E, K are stored in fat and liver, posing a toxicity risk with over-consumption.
Water-Soluble Excretion: B-complex and Vitamin C are not significantly stored (except B12) and need regular intake.
Diverse Functions: Vitamins support vision, bone health, metabolism, immunity, and blood clotting.
Balanced Diet is Key: A varied diet of whole foods is the best way to get all 13 vitamins.
Deficiency Risks: Lack of vitamins can cause health problems like night blindness or anemia.

Vitamins are organic compounds needed in small quantities for normal cell function, growth, and development. These essential nutrients facilitate vital chemical reactions and processes within the body. They are divided into two main categories based on how they are absorbed and stored: fat-soluble and water-soluble.

The Fat-Soluble Vitamins (A, D, E, K)

Fat-soluble vitamins dissolve in fat and are stored in the body's liver and fatty tissues. Because they can be stored, excess intake can lead to toxicity (hypervitaminosis), making balanced consumption crucial.

Vitamin A (Retinoids and Carotenoids)

Function: Essential for vision, immune function, cell growth, and healthy skin. Sources: Animal products (liver, eggs, dairy) and colorful fruits and vegetables (carrots, spinach).

Vitamin D (Calciferols)

Function: Promotes calcium and phosphorus absorption for strong bones and teeth. Sources: Sunlight exposure, fatty fish, and fortified foods.

Vitamin E (Tocopherols and Tocotrienols)

Function: An antioxidant protecting cells from damage. Sources: Vegetable oils, nuts, seeds, and leafy greens.

Vitamin K (Phylloquinone and Menaquinone)

Function: Crucial for blood clotting and bone health. Sources: Green leafy vegetables and some animal products and fermented foods.

The Water-Soluble Vitamins (C and B-complex)

Water-soluble vitamins dissolve in water and are not significantly stored, except for B12. Excess is typically excreted, requiring regular intake.

Vitamin C (Ascorbic Acid)

Function: Supports immune health, collagen formation, wound healing, and iron absorption. Sources: Citrus fruits, berries, peppers, and broccoli.

The B-Complex Vitamins

This group of eight vitamins supports various metabolic processes.

Vitamin B1 (Thiamine): Converts carbohydrates to energy. Found in whole grains, pork, and legumes.
Vitamin B2 (Riboflavin): Supports energy and cell function. Found in dairy, eggs, and fortified cereals.
Vitamin B3 (Niacin): Vital for energy production and nervous system. Found in meat, fish, and fortified grains.
Vitamin B5 (Pantothenic Acid): Essential for hormone production. Found in chicken, whole grains, and avocados.
Vitamin B6 (Pyridoxine): Involved in protein metabolism and brain function. Found in meat, fish, bananas, and legumes.
Vitamin B7 (Biotin): Assists in metabolizing proteins, carbs, and fats. Found in eggs, whole grains, and soybeans.
Vitamin B9 (Folate/Folic Acid): Crucial for DNA synthesis and red blood cells, especially during pregnancy. Found in leafy greens, legumes, and fortified grains.
Vitamin B12 (Cobalamin): Essential for nerve function, DNA, and red blood cells. Found in animal products and fortified foods.

Comparison of Fat-Soluble and Water-Soluble Vitamins


Feature	Fat-Soluble (A, D, E, K)	Water-Soluble (B-complex, C)
Storage	Stored in the liver and fatty tissues.	Not significantly stored (except B12).
Absorption	Absorbed with dietary fats and bile salts.	Absorbed directly into the bloodstream.
Excretion	Excreted slowly, can accumulate.	Quickly excreted in urine.
Toxicity	Higher risk of toxicity with excess.	Lower risk of toxicity.
Cooking Effects	More stable, less affected by heat.	Sensitive to heat, light, and air.

Ensuring Adequate Intake for a Healthy Diet

To get all 13 essential vitamins, eat a varied diet of nutrient-dense foods like fruits, vegetables, whole grains, lean proteins, legumes, and dairy. Some individuals may need supplements, but consult a healthcare professional first, as excessive fat-soluble vitamins can be harmful. For more on dietary guidelines, consult the National Center for Complementary and Integrative Health.

Conclusion

Understanding what are the 13 official vitamins and their roles helps in making informed dietary choices. A diverse diet of whole foods is key to acquiring these essential nutrients naturally. Consult a healthcare provider about potential deficiencies.

Frequently Asked Questions

Fat-soluble vitamins (A, D, E, K) are absorbed with fat, stored in the body, and can be toxic in excess. Water-soluble vitamins (C, B-complex) dissolve in water, are not stored significantly (except B12), and require regular intake.

The B-complex includes B1, B2, B3, B5, B6, B7, B9, and B12.

Symptoms vary, including night blindness (Vitamin A), scurvy (Vitamin C), bone issues (Vitamin D), and anemia or neurological problems (B vitamins).

Yes, a healthy, varied diet with fruits, vegetables, whole grains, lean proteins, and dairy usually provides all necessary vitamins.

Supplements are often not needed with a balanced diet but may benefit certain groups like pregnant women, older adults, vegans, or those with specific health conditions.

Water-soluble vitamins, especially Vitamin C and some B vitamins, are easily destroyed by heat, light, and air during cooking. Use methods like steaming to minimize loss.

Vitamin B12 is mainly in animal products. Vegans need to get it from fortified foods or supplements to avoid deficiency, which can cause anemia and nerve damage.