It is made up of 90% rigid keratin, which is much stronger than that of the other phanera (hair). Keratin is a protein, belonging to the family of fibrous proteins, made up of sulphur amino acids, including methionine and cystine. This protein constitutes the material making up the translucent and hard part of the nails. It ensures their strength, protection, growth and impermeability. Keratin proteins are manufactured by our body cells from certain vitamins, amino acids and minerals (calcium, selenium, zinc) that we consume.

The nail also contains small amounts of water, fatty acids, calcium (the main mineral constituent of the nail) and iron.

The first role of the nail is a passive one, as a defence against external attacks . The nails protect the back of the fingers and toes from pressure, shock, and temperature changes.

The nail also has roles in cooperation with the skin:

• The nail makes the skin of the fingertip harder by exerting a counter-pressure to the pulpy part. This makes it easier and more efficient to pick up small objects.

• They also play a role in the sensitivity of our sense of touch, due to the intensity of the innervation and vascularisation of the nail bed.

Today, nails also have an aesthetic role, serving as a support for nail polish, for example.

• Soft nails

Soft nails are usually flexible and bend easily. They are caused by demineralisation of the nail and protein deficiency. A deficiency of sulphur, vitamin B, and calcium may also be responsible.

Having your hands in water too long, for example when washing dishes, or washing your hands too often are some of the causes of soft nails. Indeed, some household products are highly harmful to nail health, so it is necessary to avoid direct contact. Remember to wear gloves.

• Brittle nails

Nails sometimes tend to break or split slightly to the side. This is due to dryness of the skin and damage to the keratin caused by frequent contact with water and detergents. Brittle nails can also be a sign of a vitamin, calcium or iron deficiency.

If your nails are brittle, it is best not to cut them. Instead, use cardboard nail polish to gently smooth the surface. You must absolutely ban metal files, which damage the keratin and make your nails more fragile.

• Split nails

Nails split when the keratin layers separate. They are sometimes a sign of vitamin and mineral deficiency.

But most often, this problem occurs as a result of poor nail filing technique. You can also use a nail polish to avoid splitting and flaking. Nail biting (onychophagy) is also a risk factor for split nails. The application of an anti-rodent varnish is the best solution to get rid of this bad habit.

• Grooved nails

The striations on the nails are, in a way, wrinkles. They are caused by the ageing of the nails and are sometimes due to a deficiency of selenium, iodine, iron and vitamin B. Hormonal or stress-related problems may be associated with it.

Some manicure products and techniques can have harmful effects on nails. For example, excessive use of a sander can soften the nail and cause scratches to appear. If you have damaged and ridged nails, avoid harsh manicure products. For example, use mild, acetone-free removers to avoid drying out your nails and making the situation worse when you remove your nail polish.

• Protein :

Consisting of amino acids such as methionine and cysteine, they are necessary for the formation of keratin, which naturally strengthens our nails. They are provided by fish, eggs, meat, whole grains, legumes and dairy products.

• Vitamins :

vitamin A helps to strengthen the nails. It is particularly concentrated in certain foods of animal origin such as fish and dairy products.

vitamin B2 or riboflavin is one of the essential vitamins that our body needs. It is linked to the production of keratin, a major constituent of hair and nails. Vitamin B2 is most abundant in animal products, particularly offal, meat and dairy products.

Similarly, the vitamin B9 (folate), is important for nail growth and health by contributing to the formation of red blood cells and the development of new cells. A folate deficiency can cause a change in pigment in the nails and make them stiff and brittle. Vitamin B9 is found in dark green vegetables, citrus fruits, beans, peas, lentils, nuts, seeds and avocados.

• Minerals and trace elements:

The Zinc helps to stimulate the production of proteins, including keratin and collagen. Zinc is found in seafood, fish, eggs or red meat, while copper is found in wheat, oats or soya.

The iron extract maintains the solidity of the nails, it is essential to ensure optimal growth. An iron deficiency can indeed cause a change in the shape of the nails and their appearance. Meat, fish, eggs and pulses are foods rich in iron.

• Antioxidants :

antioxidant compounds (vitamin E, vitamin C and flavonoids) present in abundance in fruits and vegetables contain a better resistance of the nails to external aggressions: sun, tobacco, pollution.