What Are Vitamins? Types, Functions and Benefits Explained

We hear about vitamins from an early age. Vitamin C is associated with fruits and vegetables, vitamin D with sunlight, and B vitamins often appear on the labels of foods and supplements.

But vitamins are much more than names on a nutrition label. These essential micronutrients are involved in processes throughout the body, from normal energy metabolism and immune function to maintaining healthy bones, skin and vision.

So what exactly are vitamins, what do they do and how can you make sure you are getting enough? In this guide, we explore the 13 essential vitamins, the difference between water-soluble and fat-soluble vitamins, their main functions and the foods that provide them.

What Are Vitamins?

Vitamins are organic compounds that the body needs in relatively small amounts to function normally. Most vitamins cannot be produced by the body in sufficient quantities, so they need to come from the diet.

There are 13 essential vitamins:

• Vitamin A
• Vitamin B1 (thiamine)
• Vitamin B2 (riboflavin)
• Vitamin B3 (niacin)
• Vitamin B5 (pantothenic acid)
• Vitamin B6
• Vitamin B7 (biotin)
• Vitamin B9 (folate)
• Vitamin B12 (cobalamin)
• Vitamin C
• Vitamin D
• Vitamin E
• Vitamin K

These vitamins can be divided into two main groups: water-soluble vitamins and fat-soluble vitamins.

What Is the Difference Between Water-Soluble and Fat-Soluble Vitamins?

Water-Soluble Vitamins

The water-soluble vitamins include vitamin C and the eight B vitamins.

Unlike fat-soluble vitamins, most water-soluble vitamins are not stored in large amounts in the body, which means regular dietary intake is important.

Water-soluble vitamins include:

• Vitamin B1
• Vitamin B2
• Vitamin B3
• Vitamin B5
• Vitamin B6
• Vitamin B7
• Vitamin B9
• Vitamin B12
• Vitamin C

Fat-Soluble Vitamins

Vitamins A, D, E and K are fat-soluble. They are absorbed alongside dietary fat and can be stored in the body.

Because these vitamins can accumulate, taking unnecessarily high amounts from supplements should be avoided.

What Do Vitamins Do in the Body?

Each vitamin has different functions. Some contribute to normal energy metabolism, while others are involved in immune function, cell protection, bones, vision, blood formation or the nervous system.

Rather than working independently, vitamins form part of a much larger network of nutrients and physiological processes.

Vitamin A: Vision, Skin and Immunity

Vitamin A contributes to the maintenance of normal vision, normal skin and the normal function of the immune system. It also contributes to normal iron metabolism and the maintenance of normal mucous membranes.

Vitamin A can be obtained directly from animal-derived foods. Certain plant foods contain carotenoids such as beta-carotene, which the body can convert into vitamin A.

Sources of provitamin A carotenoids include carrots, sweet potatoes, pumpkin and dark green leafy vegetables.

B Vitamins: Energy, Nervous System and More

The B vitamin family consists of eight different vitamins. Although they are often grouped together, each has its own functions.

Vitamin B1

Thiamine contributes to normal energy-yielding metabolism, normal psychological function and the normal functioning of the nervous system.

Vitamin B2

Riboflavin contributes to normal energy-yielding metabolism and the reduction of tiredness and fatigue. It also contributes to the maintenance of normal skin and vision and to the protection of cells from oxidative stress.

Vitamin B3

Niacin contributes to normal energy-yielding metabolism, normal psychological function and normal functioning of the nervous system.

Vitamin B5

Pantothenic acid contributes to normal mental performance and normal energy-yielding metabolism. It also contributes to the reduction of tiredness and fatigue.

Vitamin B6

Vitamin B6 contributes to normal energy-yielding metabolism, normal functioning of the nervous system and normal psychological function. It also contributes to normal immune system function and the reduction of tiredness and fatigue.

Biotin

Biotin contributes to normal energy-yielding metabolism and the maintenance of normal hair, skin and mucous membranes.

Folate

Folate contributes to normal blood formation, normal psychological function and normal function of the immune system. It also contributes to the reduction of tiredness and fatigue.

Vitamin B12

Vitamin B12 contributes to normal energy-yielding metabolism, normal functioning of the nervous system and normal psychological function. It also contributes to normal red blood cell formation, normal immune function and the reduction of tiredness and fatigue.

Vitamin B12 occurs naturally primarily in animal-derived foods, so people following vegan diets need to pay particular attention to obtaining sufficient B12 through fortified foods or supplementation.

Vitamin C: Immunity, Collagen and Cell Protection

Vitamin C has several established functions in the body.

Vitamin C contributes to the normal function of the immune system and to the protection of cells from oxidative stress.

It also contributes to normal collagen formation for the normal function of skin, bones, cartilage, blood vessels, gums and teeth.

In addition, vitamin C contributes to normal energy-yielding metabolism, increases iron absorption and contributes to the reduction of tiredness and fatigue.

Good dietary sources include peppers, citrus fruits, berries, kiwi, broccoli and other fruits and vegetables.

Vitamin D: Bones, Muscles and Immunity

Vitamin D is unusual because the body can produce it in the skin following exposure to sunlight.

Vitamin D contributes to the maintenance of normal bones, teeth and muscle function. It also contributes to normal immune system function.

Vitamin D also contributes to normal absorption and utilisation of calcium and phosphorus and to normal blood calcium levels.

Dietary sources include oily fish, egg yolks and certain fortified foods, although obtaining sufficient vitamin D from food alone can be difficult.

Vitamin E: Protection from Oxidative Stress

Vitamin E contributes to the protection of cells from oxidative stress.

Dietary sources of vitamin E include nuts, seeds and vegetable oils.

Vitamin K: Blood Clotting and Bones

Vitamin K contributes to normal blood clotting and the maintenance of normal bones.

Vitamin K can be found in foods including green leafy vegetables such as spinach, kale and broccoli.

Where Do We Get Vitamins From?

A varied and balanced diet can provide many of the vitamins the body needs.

Useful sources include:

• Fruit and vegetables for vitamin C, folate and carotenoids
• Whole grains and legumes for several B vitamins
• Nuts and seeds for vitamin E and other micronutrients
• Eggs and dairy products for several B vitamins and fat-soluble vitamins
• Fish for vitamin D and several B vitamins
• Meat for vitamin B12 and other B vitamins
• Fortified foods for nutrients such as vitamin D and B12

Eating a wide variety of foods is generally more useful than focusing on one individual vitamin or so-called superfood.

How Long Does It Take for Vitamins to Work?

There is no universal timeframe for a vitamin to "start working". It depends on the nutrient, your current nutritional status, the amount consumed, absorption and your individual requirements.

If someone has a nutritional deficiency, correcting that deficiency can take time and should be approached according to the individual situation.

Vitamins should therefore not be viewed as instant solutions. They are nutrients that the body continuously uses as part of normal physiological processes.

Do You Need Vitamin Supplements?

Not everyone needs a vitamin supplement. A varied and balanced diet should provide the foundation of your nutrient intake.

However, supplements can be useful when dietary intake is insufficient, nutritional requirements are increased or certain nutrients are difficult to obtain from a particular diet.

Examples can include vitamin B12 for people following vegan diets or vitamin D when sufficient intake and sunlight exposure are difficult to achieve.

The appropriate supplement depends on individual diet, lifestyle and nutritional requirements.

Can You Take Too Many Vitamins?

Yes. More is not automatically better when it comes to vitamins.

Fat-soluble vitamins can be stored in the body, meaning excessive intake can accumulate over time. High supplemental intakes of some water-soluble vitamins can also be inappropriate.

Always follow the recommended intake of a food supplement and avoid combining multiple products containing the same nutrients without considering your total intake.

What Is the Difference Between Vitamins and Minerals?

Vitamins and minerals are both micronutrients, but they are different types of substances.

Vitamins are organic compounds, while minerals are inorganic elements.

Minerals include nutrients such as magnesium, calcium, zinc, iron, selenium and iodine. Like vitamins, they have different functions throughout the body and need to be obtained in appropriate amounts.

Frequently Asked Questions About Vitamins

How many essential vitamins are there?

There are 13 essential vitamins: vitamins A, C, D, E and K, plus the eight B vitamins.

Which vitamins are water-soluble?

Vitamin C and the eight B vitamins are water-soluble.

Which vitamins are fat-soluble?

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

What vitamins help reduce tiredness and fatigue?

Several vitamins contribute to the reduction of tiredness and fatigue, including vitamins B2, B3, B5, B6, B9, B12 and vitamin C.

Which vitamins support the immune system?

Vitamins A, B6, B9, B12, C and D contribute to the normal function of the immune system.

Which vitamins are important for skin?

Vitamin A contributes to the maintenance of normal skin, while biotin, riboflavin and niacin also contribute to maintaining normal skin. Vitamin C contributes to normal collagen formation for the normal function of skin.

Can vitamins replace a healthy diet?

No. Food supplements should not be used as a substitute for a varied and balanced diet and a healthy lifestyle.

Key Takeaways

• There are 13 essential vitamins.
• Vitamins C and B are water-soluble, while vitamins A, D, E and K are fat-soluble.
• Different vitamins perform different functions throughout the body.
• A varied diet is the foundation for obtaining essential vitamins.
• Vitamin D can be produced in the skin following sunlight exposure.
• People following vegan diets need a reliable source of vitamin B12.
• Supplements can complement the diet when additional nutritional support is appropriate.
• More is not necessarily better, and recommended daily intakes should be respected.

Building a Strong Nutritional Foundation

Vitamins may be required only in relatively small quantities, but they contribute to an impressive range of functions throughout the body.

Rather than focusing on one vitamin at a time, aim for a varied diet containing plenty of vegetables, fruits, whole grains, legumes, nuts, seeds and appropriate sources of protein and healthy fats.

Supplements can complement that foundation where appropriate, but good nutrition starts with the bigger picture: variety, balance and consistency.