Friends for the skin: how to fight free radicals

Friends for the skin: how to fight free radicals

Our skin is continuously exposed to the action of mechanical, biological, chemical and physical stimulation, but it knows how to defend itself from any damage that these factors may cause by activating some mechanisms that can protect it.

Among the physical stimulation, an important role is that of the sun and ultraviolet radiation which can, in case of excessive exposure, generate the production of oxygen free radicals that attack the cellular structures of our skin. The skin, however, has various protection systems capable of neutralizing these molecules.

In fact, tanning is the first defense that our skin puts in place whenever it is exposed to ultraviolet radiation. Melanin, in addition to being the most powerful natural solar filter, is also endowed with good antioxidant capacities that allow it to better neutralize free radicals.

The skin has several enzymatic and non-enzymatic antioxidants, such as vitamin C, vitamin E, glutathione, coenzyme Q and polyunsaturated fatty acids w-3, which guarantee its intrinsic photoprotective capacity.

To enhance the natural defense systems, skin trophism and ensure a risk-free and lasting tan, it is important to take these substances in adequate quantities through a balanced diet rich in fruit and vegetables, which continuously replenishes the skin's reserves of antioxidants.

In particular conditions of physical stress, the amount of these elements taken with the diet may be insufficient and therefore it is possible to supplement the requirement with the intake of antioxidant-based supplements. Among the main antioxidant substances present in nature, a key role is played by carotenoids, or precursors of vitamin A, to which beta-carotene belongs, mainly contained in yellow-orange vegetables such as carrots, tomatoes, peppers and oranges.

Beta-carotene accumulates in the skin and acts as a solar filter since it is able to absorb solar radiation in the spectrum of UVA (320-400 nm) and visible light (up to 500 nm).

More recently other carotenoids such as zeaxanthin, lutein and lycopene have been studied. Lutein and zeaxanthin are found in high concentrations in many green leafy vegetables such as spinach, cauliflower and cabbage, and have a greater antioxidant activity than beta-carotene. Vitamin E (or alpha-tocopherol) is the non-enzymatic endogenous antioxidant most represented in cellular lipid membranes, preventing lipid peroxidation. It is mainly contained in vegetable oils, cereals, nuts and green leafy vegetables. The reduced form of alpha-tocopherol, depleted during the performance of its antioxidant activity, is subsequently regenerated by vitamin C.

Several studies have shown that vitamin E and vitamin C act synergistically to counteract the formation of oxygen free radicals. Only the concomitant intake of both vitamins in high doses is able to protect against sunburn, while if these vitamins are taken individually they have no antioxidant or photo protective capacity. Vitamin C is also one of the major antioxidants at the level of extra-cellular fluids and also acts as a co-factor in the regulation of the synthesis of collagen fibers and elastin, thus counteracting the loss of skin tone and elasticity it undergoes. the skin for aging. It is mainly contained in citrus fruits, berries and many vegetables. Among the polyphenols we remember the flavonoids contained in the leaves of green tea (Camellia sinensis). Green tea contains four main polyphenols, of which epigallocatechin-3-gallate (EGCG) is the most active. In experimental animals, the polyphenols in green tea have been shown to have a photoprotective effect, acting through antioxidant, anticarcinogenetic and immunoprotective properties, helping to maintain the integrity of the skin's immune system.

Other plant extracts that have demonstrated antioxidant and photoprotective properties both topically and systemically are silymarin, a milk thistle extract containing a blend of flavonoids, and genistein, an isoflavonoid from soy.

We also recall that some cations, such as selenium and zinc, act as co-factors of antioxidant enzymes and vitamin E. In animal models it has therefore been observed that the intake of selenium reduces the erythema induced by ultraviolet exposure and protects from the onset of skin neoplasms, while the intake of zinc improves skin defenses and tissue trophism, facilitating their repair.

Finally, it should be emphasized that the mixtures of antioxidants administered orally have shown greater effectiveness than the simple intake of the individual active ingredients. This synergism appears to be the result of intrinsic interactions between the described antioxidants. In order for our skin to reap the maximum benefits from systemic photoprotection, it is therefore necessary that the supplementation of these substances is integrated and balanced in the complex system of the physiological antioxidant network.