articLe | DERMONUTRITION | by influencing relevant transcription factors, for example
activator protein‑1 (29) and/or peroxisome proliferator activated receptors (PPAR) (30).
Absorption and benefits The authors had demonstrated that GLA is being absorbed, therefore there is no reason that vitamin E will not be equally absorbed. With regard to its effect on epidermal barrier function, vitamin E is also reported to increase the expression of PPAR, known to increase keratinocyte differentiation, and the keratinocyte differentiation marker transglutaminase‑1 (31). This enzyme is essential for the epidermal differentiation process and for corneocyte maturation when ceramides are covalently attached to involucrin, thereby developing a stronger barrier. Vitamin E in vitro reduces TEWL by up to 19% in living skin equivalents (16). GTPs are also known to stimulate the keratinocyte specific differentiation AP-1 transcription factors to increase the levels of involucrin, which is essential for the formation of barrier function (13). Like the polyunsaturated fatty acids, polyphenols such as catechins—when given in drinks—have been shown to improve stratum corneum barrier function, although at much higher concentrations compared with the current study (14). In other studies, GTPs have been shown to provide a
photoprotective benefit when given orally (32). GTPs have many effects on skin cells either directly, or possibly by their conversion into small aromatic acids (29), which could then function as PPAR ligands. Epigallocatechin gallate (EGCg) has also been shown to stimulate the
keratinocyte‑specific differentiation AP-1 transcription factors to induce keratinocyte differentiation (33). In this regard, GTPs have been shown to increase involucrin levels together with transglutaminase activities, both being important for the differentiation process. These effects probably contribute to the benefit reported here. Atopic disease (eczema linked to a genetic disorder)
the effects observed on
generation in these studies possibly culminate from
epidermal differentiation skin barrier function and nmF
additive or synergistic effects of all the ingredients in the dairy product.
results from an inappropriate and primarily Th2‑type immune response and a switch to IgE production. Lactobacillus rhamnosus GG (LGG) and Bifidobacterium lactis have been reported to reduce atopic eczema after 2months (17). Equally, when pregnant mothers were given LGG for the final 2–4 weeks of pregnancy and during breast‑feeding, the incidence of atopy was lowered significantly— even up to 4 years of age. Infants aged 2–16 months also experienced fewer skin problems within the first month of treatment with LGG (34). To date, improvements in adult eczema via probiotics have not been realised. Nevertheless, improvements in acne have been reported (35). Therefore, skin benefits may be possible for these ingredients. This finding, together with the reports of fermented milks reducing skin inflammation in a murine
model of allergic contact dermatitis (18), or their effects on reducing photoinduced immunosuppression (36), suggests that systemic immunomodulation occurs after eating probiotics and as a result, this offers a tremendous opportunity for delivering unique skin condition benefits that may be enhanced with certain nutrients. LGG has been shown to reduce tumour necrosis factor (TNF)‑α, which if occurs systemically will help with skin inflammatory conditions (37). Therefore, by potentially reducing inflammation generally, probiotics may lead to an improvement in skin barrier function and skin health as a result.
Conclusions The effects observed on epidermal differentiation skin barrier function and NMF generation in these studies possibly culminate from additive or synergistic effects of all the ingredients in the dairy product. Clearly, synergy was observed between the GLA‑containing borage oil and the GTPs in the in vitro studies. The dairy product evaluated in this study had an effect
on skin barrier function in the total population (average improvement in TEWL of 13%). An average improvement in TEWL of approximately 1 g m−2
hr−1 relative to placebo
was observed throughout this study, which is approximately the same level of benefit that a topical lotion provides, but in this case as the subjects were eating a food. This is the first study demonstrating the effect of
42 ❚
dermonutrition on filaggrin synthesis and NMF formation. It is possible that the improvement in filaggrin/NMF and skin barrier function is interlinked. The tortuosity of the stratum corneum, together with its extracellular lipids, dominates skin barrier function. Tortuosity is determined by thickness; that is, the precise number of corneocyte
May 2011 |
prime-journal.com
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