Study Title:

Nails in nutritional deficiencies

Study Abstract

Nails are not only an important aspect of the external appearance, they are also mirrors of the internal constitution and nutritional status. Nail changes in nutritional deficiencies are mostly minor and non-specific. It is often difficult to suspect a nutritional deficiency state just by observing nail changes. In this article, we have discussed the basic contents of the nail plate and the different nail changes that can be observed in various nutritional deficiency states.

The nail apparatus consists of a horny "dead" product, the nail plate, and four specialized epithelia: the proximal nail fold, the nail matrix, the nail bed, and the hyponychium. [1] The bulk of the nail plate is constituted by hair type (hard) keratins which comprise 80% to 90% of the nail plate. Epithelial type keratins account for 10% to 20%. The overall sulphur content is approximately 10% by weight. The disulfide bonds of cystine in the matrix proteins contribute maximally to nail hardness by gluing the keratin fibers together. Calcium does not contribute to nail hardness and makes up only 0.2% of the nail plate by weight. The lipid content is relatively low compared with the lipid content of the stratum corneum. Glycolic and stearic acids are nail plate lipids and their presence contributes to the water resistance. Despite the water resistance, the hydration status of the nail plate is another factor determining its hardness. The nail plate's water content can vary greatly, with normal content being 18%. Nails become brittle when the water content is less than 16% and become soft when greater than 25%. Minerals are another important aspect of the nail plate's composition; mainly, magnesium, calcium, iron, zinc, sodium, and copper. [2]

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