Introduction

Vitamins appear everywhere in conversations about health — on food packaging, supplement bottles, advertisements and social media.

But vitamins are not simply products you buy in a bottle. They are essential micronutrients that the body needs for normal growth, metabolism and everyday functioning.

Different vitamins perform different jobs. Some contribute to normal vision and skin, some help with energy metabolism, while others are involved in blood formation, bone health, nervous-system function or normal immunity.

The body needs them in relatively small amounts, and eating more than you need does not necessarily provide additional benefits.

For most people, the starting point should be a varied, balanced diet that provides nutrients from a range of foods.

Vitamins are organic compounds required by the body in small amounts for normal physiological functions.

There are 13 recognised essential vitamins: vitamins A, C, D, E and K, together with eight B vitamins.

Each has particular functions, although many nutrients work together rather than acting independently.

For example, vitamin D contributes to calcium absorption and bone health, while vitamin C has roles in collagen formation and normal immune function.

The B vitamins participate in processes including energy metabolism, red blood cell formation and nervous-system function.

Vitamins A, D, E and K are known as fat-soluble vitamins.

Unlike most water-soluble vitamins, they can be stored in the body's liver and fatty tissues.

Vitamin A is important for normal vision, immune function, growth and cell development. Sources include eggs, dairy products and foods containing carotenoids such as carrots and dark-green vegetables.

Vitamin D contributes to calcium absorption, normal bones and muscle function. The body can produce vitamin D when skin is exposed to sunlight, and it can also come from certain foods and supplements.

Vitamin E functions as an antioxidant and is found in foods including nuts, seeds and vegetable oils.

Vitamin K is involved in normal blood clotting and bone metabolism and can be obtained from foods such as leafy green vegetables.

Vitamin C and the B-group vitamins are generally classified as water-soluble.

The B-vitamin family includes thiamine (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), vitamin B6, biotin (B7), folate (B9) and vitamin B12.

These vitamins have a wide range of functions, including helping the body release energy from food and supporting normal nervous-system and blood-cell function.

Vitamin C contributes to collagen formation, antioxidant protection and normal immune function. Fruits and vegetables are important dietary sources.

Although excess amounts of many water-soluble vitamins can be excreted through urine, this does not mean unlimited supplemental doses are safe.

No single everyday food naturally provides every vitamin in ideal amounts.

That is one reason dietary variety is important.

Vegetables and fruits provide vitamins such as vitamin C, folate and carotenoids that the body can convert to vitamin A.

Whole grains, legumes, nuts and seeds contribute several B vitamins and other nutrients.

Eggs, fish, meat and dairy products can provide vitamins including B12 and, depending on the food, vitamins A and D.

Fortified foods can also contribute important nutrients. Some products have vitamins added during manufacturing to help improve nutrient intake.

WHO recommends a varied diet based largely on minimally processed foods, including vegetables, fruits, whole grains, legumes, nuts and appropriate protein sources.

Does Cooking Destroy Vitamins?

Cooking can reduce the amount of some vitamins in food, particularly certain water-soluble vitamins that are sensitive to heat or can move into cooking water.

However, this does not mean raw food is always nutritionally superior.

Cooking makes many foods safer and easier to digest and can improve the availability of certain nutrients.

Using different preparation methods — including steaming, stir-frying, boiling, roasting and eating suitable foods raw — can form part of a varied diet.

Yes. Vitamin deficiencies can develop when intake or absorption is inadequate or when the body's requirements increase.

The risk depends on the nutrient and individual circumstances.

People with highly restrictive diets, certain gastrointestinal conditions or problems absorbing nutrients may be at increased risk of particular deficiencies.

Pregnancy also changes nutritional requirements, while older adults may have different risks depending on diet, health and nutrient absorption.

Vitamin B12 deserves particular attention for people following a strict vegan diet because naturally occurring B12 is found mainly in animal-derived foods.

Symptoms of vitamin deficiency vary considerably and can overlap with many other medical conditions. Diagnosis should therefore not be based only on symptoms found online.

Not everyone needs a daily multivitamin.

People who eat a varied and balanced diet may already obtain many of the vitamins they need from food.

However, supplements can have an important role in particular circumstances.

For example, specific nutrients may be recommended during pregnancy, for people with diagnosed deficiencies, certain restrictive diets or medical conditions affecting nutrient absorption.

The appropriate supplement and dose depend on the individual.

A multivitamin should also not be viewed as insurance against an otherwise poor diet.

Yes.

The fact that vitamins are essential does not mean that increasingly large doses are increasingly healthy.

Excessive intake of certain vitamins can cause adverse effects.

High supplemental intakes of some fat-soluble vitamins are particularly concerning because they can accumulate in the body.

Supplements may also interact with medicines or be inappropriate for certain medical conditions.

Problems can arise when people combine several products without realising that each contains the same nutrient.

Are “Natural” Vitamins Better?

The word “natural” on a supplement label does not automatically tell you whether a product is safer, more effective or necessary.

The body ultimately uses vitamins according to their chemical forms and biological availability.

Food offers an additional advantage because it provides combinations of nutrients, fibre and other food components rather than isolated vitamins alone.

Supplements can still be useful when there is a genuine need, but marketing terminology should not replace evidence-based advice.

For most healthy adults, building a varied diet is a sensible foundation for meeting vitamin requirements.

Try to include vegetables and fruit regularly, vary your protein sources and include whole grains, legumes, nuts or seeds where appropriate.

There are situations where food alone may not provide enough of a particular vitamin, and supplementation can then be valuable.

The important distinction is that supplements should address a genuine nutritional need rather than simply being taken because a product promises more energy, stronger immunity or better health.

Good nutrition is a pattern built over time — not a collection of pills.