A new large study published in the American Journal of Clinical Nutrition points to Vitamin C's affect upon skin and aging.
Scientists at Unilever used data from the first "National Health and Nutrition Examination Survey" to examine the relationship between dietary nutrient intakes and skin-aging. The study suggests that higher intakes of vitamin C, and lower intakes of fats and carbohydrates, is associated with better skin in older age. This provides further support for the growing number of beauty foods and "cosmeceuticals" which include Vitamin C as an ingredient. The report also mentions linoleic acid as a beneficial ingredient in the same product category.
It is important to note that the original investigation concentrates on dietary intakes of nutrients and not supplements. Still, it shows significant relationships between a number of nutrients and skin aging. Supplement studies concentrate on short term, high-dose nutrients. This team claims that this examination is the first to concentrate on daily nutrient intake as opposed to supplements.
NHANES I was conducted on a nationwide sample of over 30 000 individuals back in the mid-1970s. Information collected includes dietary assessment, height and weight measurements, supplement intake, physical activity level, and sunlight exposure.
In addition, clinical examinations were conducted by dermatologists. In these exams, skin-aging appearance was defined as having a wrinkled appearance, dryness as a result of aging, and skin thinning. In total 4025 females between the ages of 40 and 74 were included in the study.
In particular, lower intakes of vitamin C in the diet were significantly associated with the prevalence of wrinkled appearance and dryness. The researchers hypothesise that this is due the vitamin's antioxidant properties, the role it plays in collagen synthesis and its potential photo-protective qualities.
As a side note, the study found that higher intakes of fats and carbohydrates were associated with increased chances of wrinkled skin appearance and skin atrophy.