Vitamins contribute to metabolic processes throughout the body. A lack of them can manifest as a deficiency, but in many cases, it manifests through changes in the skin and mucous membranes. The following are examples of the links between vitamins and the skin and mucous membranes.Vitamin AIf you lack vitamin A, you will become dehydrated more easily. It is believed that the reason for this is that the functioning of sweat glands and the skin is reduced, leading to reduced sebum production and incomplete keratinization that reduces the moisture-retaining function of keratin. It also increases the occurrence of bacterial infections of the skin, harming the condition of the skin and mucous membranes as a result.Vitamin B₂Vitamin B₂ strengthens blood vessels throughout the body, especially capillaries in the skin, and improves blood circulation. It is well-known that having a deficiency causes inflammation of the lips and corners of the mouth. Vitamin B₂ deficiency causes capillaries to dilate, which increases transparency to sunlight, raising sensitivity to external stimuli and causing extreme sensitivity to sunlight.Vitamin B₆If you lack vitamin B₆, skin conditions such as eczema, seborrheic dermatitis, and inflammation of the tongue and corners of the mouth can appear, so it is believed to be a necessary vitamin for skin.

However, much remains unclear about the mechanism which causes these clinical symptoms to appear.NiacinIf you lack niacin, a type of skin inflammation called pellagra can develop. There are many aspects of the mechanism by which pellagra develops that remain unclear, but it is believed to be caused by a hypersensitive reaction to sunlight by the skin.Vitamin CVitamin C is required for the creation of collagen, which accounts for one-third of the proteins in the body.

Collagen is the main component of the connective tissue that joins cells together, and it gives shape to tissues and organs, including skin. Accordingly, a lack of it presents as scurvy, which results in bleeding from the skin and mucous membranes.

For foods with nutrient function claims, the nutrients which in Japan are permitted to be labeled “This nutrient helps maintain the health of skin and mucous membranes” are vitamin A, beta carotene, vitamins B₁, B₂, and B₆; vitamin C, niacin, pantothenic acid, biotin, and zinc.

The amount of vitamin A adults aged 19 to 64 need is:

• 0.7mg a day for men
• 0.6mg a day for women

You should be able to get all the vitamin A you need from your diet.

Any vitamin A your body doesn’t need immediately is stored for future use. This means you don’t need it every day.

The amount of vitamin E you need is:

• 4mg a day for men
• 3mg a day for women

You should be able to get all the vitamin E you need from your diet.

Any vitamin E your body doesn’t need immediately is stored for future use, so you don’t need it in your diet every day.

There are many different types of vitamin B.

This section has information on:

• thiamin (vitamin B1)
• riboflavin (vitamin B2)
• niacin (vitamin B3)
• pantothenic acid
• vitamin B6
• biotin (vitamin B7)
• folate and folic acid
• vitamin B12

Vitamins are divided into two categories: fat-soluble and water-soluble.

The water-soluble group includes: B vitamins (1, 2, 3, 5, 6, 8, 9 and 12) and vitamin C. They present the following characteristics:

• They dissolve in water.
• They are not stored in the organism.
• Excess amounts are excreted through urine.
• They are destroyed when foods are cooked or boiled.

Fat-soluble vitamins include A, D, E and K, and present the following characteristics:

• They dissolve in fat;
• They can be stored in the body;
• When they accumulate, they can cause problems.

Good sources of vitamin C

Vitamin C is found in a wide variety of fruit and vegetables.

Good sources include:

• oranges and orange juice
• red and green peppers
• strawberries
• blackcurrants
• broccoli
• brussels sprouts
• potatoes

From about late March/early April to the end of September, most people should be able to get all the vitamin D they need from sunlight.

The body creates vitamin D from direct sunlight on the skin when outdoors.

But between October and early March we don’t get enough vitamin D from sunlight. Read more about vitamin D and sunlight.

Vitamin D is also found in a small number of foods.

Sources include:

• oily fish – such as salmon, sardines, herring and mackerel
• red meat
• liver
• egg yolks
• fortified foods – such as most fat spreads and some breakfast cereals

Another source of vitamin D is dietary supplements.

Vitamins have multiple functions and are essential to your well-being and to maintain normal body functions (good eyesight, energy levels, cell growth, bone health, a healthy immune system, blood coagulation, etc.). Your body needs sufficient vitamins to function properly.

The main vitamins associated with metabolizing fat are vitamin B2, niacin, and pantothenic acid. These vitamins are coenzymes of the enzymes necessary for metabolizing fats, so when there is a lack of them, metabolism may be impaired. A lack of vitamin B2 in particular halts the metabolism of fatty acids and their use as energy. While there are many vitamins associated with the metabolism of fatty acids, this is the reason only vitamin B2 is called the “fat metabolism vitamin.” The above vitamins, as well as vitamin B1, are also involved in the breakdown of carbohydrates.