ZEIST, THE NETHERLANDS. A healthy skin begins from the inside, but little information is available as to how nutrition actually affects skin health and appearance. A group of Dutch researchers has now taken a preliminary step towards discovering the relationship between diet and skin health. Their study involved 149 men (aged 19-73 years) and 153 women (aged 18-73 years). All participants completed food frequency questionnaires and had blood samples drawn for analysis of vitamin A (retinol), vitamin E (alpha- tocopherol), vitamin C (ascorbic acid), beta-carotene, lycopene, lutein, zeaxanthin, and beta-cryptoxanthin.
The degree of skin hydration, the skin content of sebum, and the surface pH (acidity) of the skin were also measured. Adequate hydration is important for a smooth and soft skin, sebum helps maintain hydration by providing a protective layer on the skin surface that reduces fluid loss, and a low pH (higher acidity) helps protect the skin from bacteria and other disease-causing pathogens.
The researchers found that men tended to have higher hydration values and sebum content, but lower pH
than did women. There was a clear inverse correlation between the concentration of vitamin A in the blood
serum and sebum content and pH, i.e. the higher the vitamin A level the lower the sebum and pH values.
There was no correlation between blood levels of vitamin C and vitamin E and skin conditions. A higher
beta-cryptoxanthin level was found to correspond to an increase in hydration level in men. An increased
fluid intake, somewhat surprisingly, had very little effect on skin hydration, but was associated with a barely
significant decrease in surface pH among men, but not among women. Total fat intake was negatively
associated with hydration with saturated and monounsaturated fats decreasing hydration the most.
Monounsaturated fats were also associated with a significant increase in surface pH among men.