Nutritional Deficiencies, Vitamins & Nail Diseases | LearnSkin

Our nails do a lot for us. The fingernails and toenails are considered extensions of the skin that protect the fingers and toes from harm, help us to pick up tiny objects, enhance fine touch, help us when we have a scratch, and improve the visual appearance of the hands and feet.^[1] Dermatologists commonly see patients who are displeased with their nail appearance and nail disorders are a common reason for people to go to the doctor. 

Nails are aesthetically important to many people and make up a huge portion of the beauty industry in ways to improve their appearance and quality. Nail color, luster, size, shape, thickness, and the health of surrounding skin all add to healthy and beautiful nails.  Nail dystrophy, or onychodystrophy, is an umbrella term used to describe abnormal nail changes, including uneven nail ridges, discoloration, texture changes, and overall poor aesthetic appearance. A wide range of factors can lead to an abnormal nail, including genetic nail and skin diseases, cancer and other systemic illnesses, inflammation, infection, and injury. 

Nutrition plays an important role in nail health. Deficiencies in dietary intake of vitamins, minerals, and other nutrients can contribute to nail diseases.^[2]

Nails and Nutrition

There is scientific evidence that various foods, supplements, and nutrients could improve nail health and appearance. On the other hand, malnutrition and deficiencies in some vitamins and minerals can lead to nail disorders. Here are a few nutrients important for nail health.

Vitamin A

Interestingly, too much and too little Vitamin A is associated with nail changes.  It is known that too much vitamin A as well as medications that are vitamin A derivatives, such as isotretinoin, can cause brittle nails. Vitamin A toxicity has also been reported to lead to onycholysis (separation of the nail from the nail bed) and nail ridging.

On the other hand, vitamin A deficiency can also cause fragile and easily broken fingernails.^[3] Many of the symptoms seen in vitamin A toxicity can also be seen in vitamin A deficiency. In vitamin A deficiency, the nails can become thin and brittle, leading to easy splitting. Vitamin A deficiency is most prevalent in developing countries in malnourished youth and adults, but fat malabsorption and liver disease can also increase the risk for vitamin A deficiency.^[4] 

Sources of vitamin A

Dietary vitamin A can be obtained from both animal and plant food sources, including fish, milk, broccoli, squash, carrots, kale, and sweet potatoes.

Vitamin B12

Vitamin B12, also known as cobalamin, is essential for proper metabolism of protein, fat, and carbohydrates.^[5] Vitamin B12 deficiency is associated with darkening of the skin and also the fingernails.^[6,7] Vitamin B12 deficiency affects up to 15% of people in the world and is most common in the elderly and in strict vegans.^[8]

Sources of vitamin B12

In order to get enough vitamin B12 in your diet, aim to increase your intake of dairy, meat, and eggs.  If you are vegetarian or vegan, you can also obtain vitamin B12 from fortified cereals and supplements.

Vitamin C

Vitamin C is a powerful antioxidant that quenches free radicals and is also an essential factor in collagen production, wound healing, bone health, and iron absorption.^[9] Scurvy is the term used to describe the syndrome of vitamin C deficiency and can manifest as easy bruising/bleeding such as bleeding gums, tongue pain, slow wound healing, “corkscrew hairs”, and hyperkeratosis (or thickening of the outermost layer of skin). Low vitamin C shows as bleeding under the nails and a condition called hapalonychia, or “egg shell nails”.^[10][12]

Sources of vitamin C

Vitamin C is abundant in many fruits and vegetables, including oranges, strawberries, bell peppers, broccoli, and dark leafy vegetables like kale.

Iron

It is estimated that 2 billion people in both developed and developing countries have iron deficiency.^[11] Iron is vital for many functions throughout the body including proper red blood cell formation, protein synthesis, and immune system functioning. Iron deficiency is classically associated with a nail condition called koilonychia, also known as “spoon-shaped nails,” in which the nails become thin and have a spoon-shaped convexity.^[12] In addition, iron deficiency can cause the nails to become dry, brittle, and fragile.^[13]

Sources of iron

In order to get enough iron in your diet, increase your intake of lentils, spinach, and fortified breakfast cereals.

Selenium

Selenium is an important trace mineral that is required by antioxidant enzymes throughout the body to neutralize damaging free radicals.^[14] White nail discoloration has been reported in patients with selenium deficiency, who also receive IV feedings. The nail changes improved one month after starting selenium supplementation.^[15] 

Sources of selenium

Brazil nuts, wheat germ, and whole grains are rich in selenium and are delicious healthy foods to include in your regular diet.

Zinc

Zinc deficiency can result from both genetic diseases and lack of adequate zinc intake from foods.  In a rare genetic disease of zinc deficiency, called acrodermatitis enteropathica, patients suffer from multiple symptoms including nail findings of onychodystrophy and skin infections around the nails (called paronychia). Nutritional zinc deficiency is associated with a nail disorder called Lines of Beau, which shows up as grooves across the nails.^[16] Lines of Beau can also develop during periods of psychological or physical stress, such as during severe illness.^[17] 

Sources of zinc

Rich sources of dietary zinc include seafood and fortified cereals.

Conclusion

Adequate dietary intake of vitamins and minerals are important to support proper nail health growth and appearance.  Those who are concerned that they might have a nutritional deficiency should seek testing and recommendations from their healthcare provider.