INTRODUCTION
The structural integrity, functional capacity, and regenerative
potential of the human skin are known to be influenced,
to a variable extent, by a plethora of factors, which thus greatly affect our appreciation of its overall appearance
and our perception of its health and beauty. Heredity,
sunlight, environmental or occupational exposure, chronic disease, medications, drug abuse, dietary habits, hormonal supplementation, psychosomatic stress, and poor socioeconomic
conditions have all been implicated in the pathophysiology
of skin abnormalities and aging. Nutrition has historically
been one of the earliest and most important factors associated with skin health. However, the degree of its impact upon skin physiology, as well as the mechanisms involved in various nutrition-dependent alterations in skin structure and function, remain highly controversial.
Practical hardships in explicitly establishing a causative association
between consumption of specific nutrients or food products and their potential effects on the skin have been hampered within clinical research, even when this relationship might appear straightforward or highly reasonable.
In this article, we thoroughly analyze available evidence derived
from the most important clinical nutritional studies with regard to the human skin and we provide scientifically sound and clinically relevant conclusions based on emerging knowledge
in this very challenging area of research.
Effects of Nutrition on Specific Skin Diseases
Nutrition and acne
Historically, the association between acne and nutrition has been highly controversial. The studies of Fulton et al,1 in 1969 and Anderson2 in 1971 failed, at the beginning of the second half of the century, to show any associations between diet and acne. The former,1 was a cross-over subject-blind interventional study of 65 adolescents who received either a chocolate bar or a control bar with similar amounts of sugar and fat in both bars; all subjects exhibited a similar glycemic index and glycemic load. The latter,2 a case series study of 27 students did not show any effects of various foods (chocolate, milk, toasted peanuts or cola) during a short study period of only 1 week.
The first serious randomized placebo-controlled dietary study was provided by Smith et al,3 who demonstrated a link between high glycemic load carbohydrate intake and acne. Smith et al,3 demonstrated significant improvement of acne severity in 23 Australian males aged between 15-25 years, adhering to a low glycemic load diet. The low glycemic load diet resulted in significant
reduction in weight, body mass index, free androgen index, and increased IGF binding protein-1 (IGFBP-1) serum
