If you follow a vegan diet and remove all animal proteins and dairy from your diet, you might develop a deficiency in certain nutrients, particularly vitamin B-12, zinc and iron. Animal proteins and dairy products are the best sources of B-12, zinc and iron. Vegans who take supplements or plan their diets carefully should not become deficient. Vitamin and mineral deficiencies can cause several types of skin problems.
Few sources of vitamin B-12 exist in the vegan diet outside of brewer's yeast or fortified cereals. Supplements can also supply adequate B-12. Skin manifestations of B-12 deficiency include glossitis, a swollen and glassy-looking tongue, mouth sores, particularly stomatitis, cracks in the corners of mouth, hyperpigmentation of the skin and vitiligo, a condition that causes pigmentation loss in areas of the skin.
While plants do contain iron, the iron in plants, called nonheme iron, does not absorb as well as heme iron obtained from meat. Vegans who don't include plants high in iron in their diet could become iron deficient. Although the percentage of vegans with anemia is no higher than that of the general population, vegans have lower iron stores, registered dietitian Reed Mangels reports on the Vegetarian Resource Group website. Skin manifestations of iron deficiency include spoon-shaped nails, vertical white lines in the nails and tongue and mouth cracks similar to those seen in B-12 deficiency.
Although the mineral zinc occurs naturally in some nuts and beans, red meat and poultry supply most of the zinc in the American diet, according to the Office of Dietary Supplements. A vegan who doesn't eat a varied diet may not get the zinc she needs. Zinc deficiency can cause skin rashes, hair loss and delayed wound healing.
A vegan lifestyle can provide a healthy diet and may reduce some health risks, such as heart disease and certain types of cancer, according to pediatrician and author Dr. William Sears. Vegans who pay attention to nutritional requirements and include fortified foods, nuts, legumes and vegetables high in iron, zinc and vitamin B-12 in their daily diet normally do not develop nutritional deficiencies. If you follow a vegan diet and do develop skin rashes or other skin problems, see your doctor so he can diagnose any possible nutritional problems in your diet.