Skin and hair

Your skin and hair are an important barrier and the body's first line of defence against mechanical damage, microorganisms and ultraviolet radiation. Thus, the health of your skin and hair is important for overall wellbeing. The health of your skin, hair and nails can be affected by the quality of your diet. Nutritional deficiencies, food allergies and occasionally an excess in certain food groups can affect your skin, hair and nails. Therefore, it is important to eat a balanced diet to maintain good skin, hair and nails.

Skin damage

Antioxidants such as beta-carotene, lycopene and vitamin C, that are found naturally in fruit and vegetables, offer protection against the toxic effects of ultraviolet radiation found in sunlight, which can cause premature skin ageing, dry skin and skin cancer. Vitamin A and its derivatives are commonly used to treat acne.

Skin disorders

Nutritional deficiencies often have minor symptoms, however, changes to the skin and hair may be the first sign. Pellagra, a condition caused by vitamin B3 (or niacin) deficiency, is characterised by skin and hair changes including inflammation of skin (dermatitis), sensitivity to sunlight, scaling of skin and hair loss.

Skin disorders can increase the requirements for nutrients such as folate and protein. Dietary intake of fish oil has also been suggested to help manage psoriasis and eczema.

Food allergies can cause skin disorders such as atopic dermatitis, which is a chronic inflammatory disorder of the skin. Specific components in foods, such as eggs, cow's milk, soy, wheat, fish, peanuts and shellfish can trigger an allergic reaction. Removing trigger foods from the diet has been shown to improve the condition in both children and adults. Excluding gluten from your diet also helps relieve the itchy bumps and blisters associated with dermatitis herpetiformis, a condition caused by gluten intolerance.

Healthy food.A variety of healthy foods. 

Protein, energy and malnutrition

Kwashiorkor is a protein energy malnutrition disorder that results in swelling (oedema), inflammation of the skin (dermatitis) and changes in the colour or texture of hair and skin pigment.


Zinc has been shown to decrease hair loss and increase hair density. Zinc deficiency can result in weeping, inflamed skin (dermatitis), poor wound healing and fragile or sparse hair on the head and in the pubic region. Chronic iron deficiency can result in hair loss, and itching and inflammation at the corners of the mouth.


There are different types of vitamins. Some are fat-soluble, such as vitamin A, which when deficient can result in thick, rough skin, as well as blocked sweat glands. It can also result in dry skin, darker skin and fragile hair.

Then there are water-soluble vitamins such as vitamin C, which is important in the synthesis of collagen, so a vitamin C deficiency can result in a reduced production and increased fragility of collagen. The deficiency can also cause scurvy, a condition characterised by bleeding gums and a generally unwell feeling.

Excess intake of some nutrients can also cause problems. For example, too many carotenoids in the blood can cause yellow skin. Carotenoids are yellow, lipid-soluble compounds present in yellow, orange and red fruit and vegetables.


A type of vitamin B involved in the creation of DNA and RNA. It plays a key role in cell growth and reproduction.


A mixture of proteins that occur in wheat, barley, rye and similar grains.

Vitamin A

A fat-soluble vitamin essential for skeletal growth, good vision and reproduction.

Vitamin B3

A water-soluble vitamin, which is essential for the breakdown and use of nutrients in the body. It supports the health of the skin, nervous and digestive systems and sex hormones. Known as vitamin B3 or niacin.

Vitamin C

A water-soluble vitamin essential for the formation of connective tissue. It also aids in fighting bacterial infections. Also known as ascorbic acid.


Nails are made up of mostly a hair-like hard keratin, as well as some epithelial-like soft keratin. Nails grow roughly two to three millimetres every month and are fully replaced every six to nine months. Nutritional deficiencies can result in abnormal nail growth.

Protein, energy and malnutrition

Protein deficiency, or malnutrition caused by chronic alcoholism can result in linear depressions that run across the nail bed, called Beau's lines.

Malnutrition can also result in:

  • Soft, brittle nails;
  • Brown or black lines that run up and down the nail, and;
  • Terry's nails - although it can be seen during liver disease, it can also result from malnutrition. It is usually seen in the elderly and is characterised by most of the nail turning white and having a ground-glass appearance, so that the crescent white area normally at the tip of the nail is indistinguishable from the rest of the nail.

Deficiency in albumin in the blood can cause narrow, paired lines that run across the nails, called Muehrcke's lines.


A pale appearance of the nail bed can be a sign of iron deficiency. Iron deficiency is also known to cause brittle or broken nails and can sometimes even cause the nails to detach from the nail bed.

Severe calcium deficiency can result in white bands, called transverse leukonychia, that tend to occur around the same position across multiple nails. Zinc deficiency can also cause a similar pattern of white bands.

Magnesium deficiency can result in soft, flaky nails that are liable to break. Selenium deficiency causes nails to turn white. Iodine deficiency causing cretinism results in the clubbing of fingers and nails.


Vitamin A and D deficiency can result in soft nails. Vitamin D deficiency can also result in brown or black bands that run up and down the nail.

Vitamin B deficiencies can cause nails to crack and split, become indented (convex), or the top of nails to soften and thin. Vitamin C deficiency can also cause indented and soft nails, as well as red or black lines that run up and down the nail bed (splinter haemorrhages).

Clubbing of fingers

An abnormal enlargement of the tips of fingers, or toes, and a change in the angle where the nails emerge.

Vitamin D

A vitamin that is important for the health of bones and teeth as it promotes absorption of calcium from the diet.

Vitamin B

A group of eight water-soluble vitamins found in foods, such as cereals and milk. They are important for production of energy and red blood cells.

Vitamin A

A fat-soluble vitamin essential for skeletal growth, good vision and reproduction.

Vitamin C

A water-soluble vitamin essential for the formation of connective tissue. It also aids in fighting bacterial infections. Also known as ascorbic acid.

When to see a doctor

Most of the time you can get all the essential vitamins and minerals you need from eating a balanced diet rich in fruit, vegetables and protein. However, if you are malnourished, or have an underlying condition, you may need nutritional supplements as prescribed by your doctor. If you are maintaining a healthy diet and still experience problems with your skin, hair and nails, it's also a good idea to see your doctor.


  1. Carotenaemia (carotenemia) carotenosis. DermNet NZ. Accessed 28 August 2014 from link here
  2. Dermatitis herpetiformis. Coeliac disease. DermNet NZ. Accessed 28 August 2014 from link here
  3. DIET IN DERMATOLOGY: PRESENT PERSPECTIVES. Accessed 28 August 2014 from link here
  4. Melanonychia. DermNet NZ. Accessed 27 August 2014 from link here
  5. Nails in nutritional deficiencies Seshadri D De D - Indian J Dermatol Venereol Leprol. Accessed 27 August 2014 from link here
  6. Nutrition and nail disease. Accessed 28 August 2014 from link here
  7. Nutrition and nutritional supplementation. Accessed 28 August 2014 from link here

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