What Are Vitamins?
Quick answer
Vitamins are organic compounds needed in small amounts for normal body functions. They do not provide calories, and each vitamin has distinct roles, food sources and deficiency risks.
Two broad groups
Vitamins A, D, E and K are fat-soluble. The B vitamins and vitamin C are water-soluble. This affects absorption, storage and the consequences of excessive intake.
Small amount, important role
Vitamins participate in vision, blood formation, energy metabolism, immunity, bone health and many other processes.
Supplements require context
A supplement can help correct a deficiency or meet a specific need, but high doses can be ineffective, interact with medication or cause harm.
Vitamin C in an orange is accompanied by water, fibre and many food compounds. A tablet may provide vitamin C, but it does not reproduce the whole food.
Water-soluble and fat-soluble vitamins
| Group | Vitamins | Useful context |
|---|---|---|
| Water-soluble | Vitamin C and the B vitamins | Generally circulate in body water; regular dietary intake matters |
| Fat-soluble | Vitamins A, D, E and K | Absorbed with dietary fat and can be stored in the body to varying degrees |
Foods provide vitamins in a broader package
Vegetables, fruit, whole grains, legumes, dairy or fortified alternatives, eggs, fish, meat, nuts and seeds can all contribute different vitamins. No single food provides everything, which is why variety matters.
Fortified foods also play an important role in many diets. A food does not have to be “natural” to make a useful nutrient contribution.
More is not always better
Vitamins are essential, but large supplemental doses are not automatically beneficial and can sometimes cause harm or interact with medications. Supplements can be useful in specific situations, but they should not be treated as universally necessary.
Key terms
| Vitamin | An organic micronutrient required in small amounts. |
|---|---|
| Deficiency | Inadequate status that impairs normal function. |
| Fat-soluble | Absorbed with fat and stored to varying degrees. |
| Water-soluble | Dissolves in water and is generally less extensively stored. |
Common mistakes
- Assuming more is always better. Some vitamins can be harmful in high supplemental doses.
- Treating supplements as a substitute for a varied diet.
- Expecting one vitamin to fix a vague symptom without identifying the cause.
Practical takeaway
For most people, food is the starting point. Supplements can be useful in specific situations, but dose and need matter—especially when medications or health conditions are involved.