Written by Aisling Moran BSc (Hons)
22nd Jul 2022 • 7 minute read
Dr Noel Young
Reviewed by
Dr Noel Young MBBS BSc, Medicine

Vitamins are essential nutrients that enable your body to work properly and to stay healthy. Most vitamins are in your food, or you can get them from vitamin supplements. Learn what vitamins your body needs, their roles, and how to check for vitamin deficiencies.

Why are vitamins important?

Vitamins are vital for maintaining your health because they perform hundreds of roles. The nutrients that you get from vitamins help your body to carry out essential functions, like:

  • support the maintenance of skin, bone, and muscle
  • supporting of your immune function
  • maintenance and repair of cells, tissues, and organs
  • converting food into energy

There’s a wide range of vitamins, with most of them having multiple functions. Some of the most common types are: 

The solubility of a vitamin determines how that vitamin acts within your body, and it can either be fat-soluble or water-soluble.

You can check your vitamin levels at home with a vitamins blood test. And you can treat a deficiency with our premium supplements.

What are fat-soluble vitamins?

These vitamins can dissolve in fat (lipid). They're absorbed in fat globules that travel into general blood circulation through the lymphatic system of your small intestine.

Once within your body, usually stored in your liver and fatty tissues, they tend to stay there for future use.

Fat-soluble vitamins include:

Vitamin A 

Vitamin A helps your immune and reproductive system function properly and keeps your skin healthy. It can also help your vision in low lighting.

Vitamin A deficiency symptoms can include:

  • night blindness (nyctalopia) — you might struggle to see well in poor lighting or in the dark
  • conjunctival xerosis — extremely dry eyes
  • Bitot spots — foam-like marks on the whites of both eyes

There are two forms of vitamin A in our diets — preformed vitamin A (like retinol) and provitamin A (carotenoids). Preformed vitamin A is found in animal foods. While provitamin A is a plant pigment that your body converts into vitamin A, beta-carotene is the most common.

Good sources of vitamin A are:

  • cheese
  • eggs
  • oily fish — like salmon and mackerel
  • milk
  • yoghurt
  • liver and liver paté — you should avoid these if you're pregnant
  • sweet potatoes
  • carrots
  • spinach

Vitamin D

Your body needs vitamin D for healthy bones, muscles, and a strong immune system. Low vitamin D levels are linked to conditions like osteoporosis, heart disease, diabetes, cancer, and a low mood.

Your body can make vitamin D itself — when your skin is exposed to sunlight. You can also get vitamin D from food, but most people don’t get enough this way. These foods include:

  • red meat
  • egg yolks
  • liver
  • oily fish — like salmon and mackerel
  • mushrooms
  • fortified foods — like some dairy milk, plant milk, cereals, and orange juices

When sunlight levels are low during winter, Public Health England advises everyone to consider taking a 10 mcg (400 IU) daily vitamin D supplement to prevent low vitamin D levels from October to March. 

If you have a deficiency, you can treat it with our premium vitamin D supplements.

You should check with your GP before taking any supplements if you have certain medical conditions. 

These conditions include: 

  • sarcoidosis — when inflammatory cells grow in parts of your body, like your lungs, skin, heart, and eyes
  • kidney disease
  • hyperparathyroidism — when the parathyroid glands in your neck (found below your thyroid gland) produce excess levels of a hormone called parathyroid

Vitamin E

Vitamin E is an antioxidant that can help to protect your cells from damage. The protective effect of antioxidants might help prevent chronic diseases — like heart disease and cancer. Vitamin E is also important for your immune function, blood vessels, skin, and eyes, 

Vitamin E is found naturally in:

  • almonds
  • sunflower seeds
  • avocados
  • spinach
  • kiwifruit
  • broccoli
  • fish — like shrimp and trout
  • plant oils — like sunflower and rapeseed

Vitamin K

Vitamin K is a group of vitamins essential for blood clotting (helping wounds heal) and bone health. You should get all the vitamin K your body needs by eating a varied and balanced diet with lots of green leafy vegetables, vegetable oils, and some fruits. Bacteria in your gut also produce some vitamin K that your body can absorb.

Vitamin K is found in:

  • broccoli
  • green leafy vegetables — like kale, cabbage, and spinach
  • soybeans and soybean oil
  • pumpkin
  • fermented foods — like natto

What are water-soluble vitamins?

These vitamins can dissolve in water. Most water-soluble vitamins aren't stored in your body, meaning you need to eat them daily to replenish supplies. Once the nutrients are absorbed, your body quickly removes any excess, normally in the urine.

Water-soluble vitamins and their sources include:

Vitamin C (ascorbic acid)

Vitamin C helps protect your cells and maintains healthy skin, blood vessels, and bones. It also helps with healing wounds.

Good dietary sources of vitamin C include:

  • oranges
  • kiwifruit
  • strawberries
  • peppers
  • broccoli
  • potatoes
  • brussels sprouts
  • tomatoes

It’s important to note that cooking will reduce the amount of vitamin C in your food, as it’s destroyed by heat. 

Vitamin B1 (thiamin)

Vitamin B1 helps your body to use carbohydrates for energy.

Good sources include:

  • pork
  • fish — like salmon, tuna, and mussels
  • green peas
  • black beans
  • brown rice
  • asparagus

Vitamin B2 (riboflavin)

Vitamin B2 keeps your skin, eyes, and nervous system healthy and helps your body release energy from food. You'll find it in foods like:

  • eggs
  • low-fat dairy milk
  • avocados
  • yoghurt
  • meat — especially pork and beef
  • green vegetables — like spinach
  • almonds
  • mushrooms
  • fish — like salmon

Vitamin B3 (niacin)

There are 2 forms of vitamin B3 found in food — nicotinic acid and nicotinamide. Nicotinic acid helps to lower LDL cholesterol and increase HDL cholesterol, while nicotinamide helps increase niacin levels if you’re deficient.

Vitamin B3 helps your body release energy from food and keeps your nervous system and skin healthy.

Good sources of vitamin B3 are:

  • meat — like lean chicken and pork
  • fish — like tuna
  • brown rice
  • eggs
  • peas
  • sweet potatoes
  • avocados

Vitamin B6 (pyridoxine)

Vitamin B6 is required for over 100 enzyme reactions involved in metabolism. It also supports brain development during pregnancy. 

Good sources of vitamin B6 are:

  • chickpeas
  • meat — like lean chicken, pork and beef
  • fish — like tuna and salmon
  • some fruits — like banana, cantaloupe and oranges
  • some fortified breakfast cereals
  • some vegetables — especially dark leafy greens

Vitamin B12 (cobalamin)

Vitamin B12 is essential for making red blood cells that carry oxygen from your lungs to the rest of your body. B12 also keeps your brain and nervous system healthy and helps you to release energy from food. Vitamin B12 is naturally only found in animal products, so deficiencies can occur if you are on a vegan or vegetarian diet. 

Deficiencies can also be due to pernicious anaemia. This is an autoimmune condition that causes you to have issues absorbing vitamin B12 in your stomach. You can treat a deficiency with our premium vitamin B12 supplements.

Vitamin B12 can be found in:

  • meat
  • fish
  • low-fat milk
  • eggs
  • cheese
  • some fortified foods — like breakfast cereals, tofu, and soymilk

It's important to take vitamin B12 supplements if you are following a vegan or vegetarian diet and are consuming less than the required 2.4 mcg per day. 

Vitamin B5 (pantothenic acid) 

Pantothenic acid helps turn the food you eat into energy — it plays a particularly important role in making and breaking down fats. Pantothenic acid can be found in:

  • shiitake mushrooms
  • fish — like salmon
  • meat — like lean chicken and beef
  • eggs
  • avocado
  • whole milk
  • sweet potatoes
  • lentils

Vitamin B9 (folate)

Folate is the naturally occurring form of vitamin B9. While folic acid is the synthetic version of vitamin B9, which is what’s found in fortified foods and supplements. Vitamin B9 is essential for making red blood cells, which are vital for energy.

Vitamin B9 is found in small amounts of:

  • leafy green vegetables — like cabbage, kale, spring greens, broccoli, and spinach
  • asparagus
  • lentils
  • edamame
  • sweetcorn
  • brussels sprouts
  • peas
  • chickpeas
  • kidney beans

Find out more about folate deficiency.

How to test your vitamin levels at home

If you’re worried you might have a vitamin deficiency, it’s possible to check some of your vitamin levels with a vitamins blood test

Find out more about our premium supplements.