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interleukin (iL‑10), which can then enter the circulatory system and systemically affect immunosuppression. Langerhans cells in the skin are implicated in chronic hypersensitivity, and uV radiation results in a depletion of Langerhans cells in the skin. C3H/Hen mice fed green tea as a sole source of drinking water was found to prevent uVB-induced immune suppression7


. Similar


effects were observed when the animals were fed grape seed proanthocyanidins and silymarin (milk thistle).


Nutrients can alter gene expression the paradigm was once to consider food as a fuel source for energy metabolism and growth. in the more recent age of genomics and proteomics, the revised paradigm is to view nutrients as co-factors for the proper function of enzymes involved in a range of aspects of metabolism and tissue maintenance. it is now known that certain nutrients can selectively alter gene expression through transcription factors. nutrients bind or activate gene transcription factors, which then regulate the activation of specific sets of genes8


. Polyunsaturated fatty acids can alter gene


transcription factors through the peroxisome proliferator-activated receptor (PPAr) system. other nutrients alter the oxidation–reduction status of the cell to indirectly influence transcription factor activity. nF-κ-β, a nuclear transcription factor involved in anti-inflammatory response is an example8


. nutritional compounds, omega-3 fatty acids and


isoflavones, have been shown to alter genes that code for cytokines, growth factors, cholesterol metabolising enzymes, and lipoproteins8


. if nutrients affect expression


of certain genes, either directly or indirectly influencing transcription factors, it is likely that a given nutrient will have a different effect in different individuals. Each individual has a polymorphic gene variation that may alter a binding site for the transcription factor. one polymorphism in the inflammatory gene arachidonic 5-lipoxygenase (5‑LoX) has been associated as a risk factor for cardiovascular disease8


.


Metabolism can also produce transcriptional ligands; certain lipids are converted to eicosanoids that bind to retinoid X receptors (rXrs) or PPArs. in this way, acting as lipid sensor receptors regulating genes that metabolise lipid nutrients8


. Animal studies have shown that green tea polyphenol—


11-epigallocatechin-3-gallate (EGCG) — regulates signal transduction by inhibiting tyrosine phosphorylation of the HEr2/neu receptor and epidermal growth factor receptor8


Declaration of interestThe author has no financial or competing interests with regard to the information contained in this article.


. this receptor is associated with tumour


formation. other studies indicate that oral consumption of EGCG can significantly inhibit uVB and tPA-induced tumourigenesis9


. it should be noted that genetic diversity within populations is responsible for the observed


variability of experimental and clinical variations of an individual’s response to diet8


.


Nutraceuticals Much progress has been made in understanding the pathogenic mechanisms of diseases that impact the appearance of the skin: ■ Autoimmune and non-autoimmune diseases ■ Acne ■ Atopic dermatitis ■ Skin cancer ■ Ageing. However, much remains to be understood. the extent


Animal studies have shown


that green tea polyphenol — 11-epigallocatechin-3-gallate


(EGCG) — regulates signal transduction by inhibiting tyrosine phosphorylation


of the Her2/neu receptor and epidermal growth factor receptor.


to which nutraceuticals can influence the health and appearance of the skin remains a topic of debate. A confounding factor is the multitude of molecules found in the processed food products that many consume. For example, milk contains hormones, growth factors, and prostaglandins. An article published in


1995 listed over 60 molecules found in dairy products including prolactin, somatostatin, growth-releasing hormone, thyroid-stimulating and thyrotropin-releasing hormones, and insulin-like growth factors10


. owing to the


variation in each individual’s diet, it is challenging to conduct well-run studies that eliminate the interaction of these molecules. the consensus among investigators is that more research is needed to fully understand how best to use nutraceuticals with regard to treating a range of skin conditions11


.


Conclusions increased life expectancy has resulted in a desire to maintain a young and healthy looking appearance of the skin. the link between malnutrition, vitamin deficiency, and the appearance of the skin is well established. the effect of nutraceuticals and other dietary factors on the appearance of the skin with regard to the mechanism from a molecular biological is not as well understood. the correct choice of nutrients can help to improve skin appearance and health by preventing disorders, such as wrinkles, uneven skin tone, and atopic dermatitis. Studies have shown that dietary intake of antioxidant compounds can help to protect from endogenous and exogeneous environmental assault1, 7, 9


. References


1. Manchester KL. An orange a day keeps the scurvy away. Trends Pharmacol Sci 1998; 19(5): 167–70


2. Matts PJ, Oblong JE, Bissett


DL. A review of the range of effects of niacinamide in human skin. Int Fed Soc Cos Chem Magazine 2002; 5(4): 285–9


3. Strumia R, Varotti E, Manzato E, Gualandi M. Skin signs in anorexia nervosa. Dermatology 2001; 203(4): 314–7


4. McNaughton SA, Marks GC, Green AC. Role of dietary factors in the development of basal cell cancer and squamous cell cancer of the skin. Cancer Epidemiol Biomarkers Prev 2005; 14(7): 1596–607


5. Köpcke W, Krutmann J.


Protection from sunburn with beta-Carotene—a meta- analysis Photochem Photobiol 2008; 84(2): 284–8


6. Purba MB, Kouris-Blazos A,


Wattanapenpaiboon N et al. Skin wrinkling: can food make a difference? Jour Am Coll Nutri 2001; 20(1): 71–80


7. Katiyar SK. UV-induced


immune suppression and photocarcinogenesis: chemoprevention by dietary botanical agents. Cancer Lett 2007; 255(1): 1–11


8. Meskin MS, Bidlack WR, Randolph RK. Phytochemicals: Nutrient-Gene Interactions. Oxford: Taylor & Francis, 2006


9. Krutmann J, Humbert P.


milk. Vitam Horm 1995; 50: 77–149


Nutrition for Healthy Skin. Germany: Springer-Verlag, 2011


10.Koldovský O. Hormones in


11. Grant-Kels JM. Nutrition and the skin: “You are what you eat” Part II. Clin Dermatol 2010; 28(6): 597


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