Role of dietary factors in the development of basal cell cancer and squamous cell cancer of the skin

The role of dietary factors in the development of skin cancer has been investigated for many years; however, the results of epidemiologic studies have not been systematically reviewed. This article reviews human studies of basal cell cancer (BCC) and squamous cell cancer (SCC) and includes all studies identified in the published scientific literature investigating dietary exposure to fats, retinol, carotenoids, vitamin E, vitamin C, and selenium. A total of 26 studies were critically reviewed according to study design and quality of the epidemiologic evidence. Overall, the evidence suggests a positive relationship between fat intake and BCC and SCC, an inconsistent association for retinol, and little relation between ß-carotene and BCC or SCC development. There is insufficient evidence on which to make a judgment about an association of other carotenoids with skin cancer. The evidence for associations between vitamin E, vitamin C, and selenium and both BCC and SCC is weak. Many of the existing studies contain limitations, however, and further well-designed and implemented studies are required to clarify the role of diet in skin cancer. Additionally, the role of other dietary factors, such as flavonoids and other polyphenols, which have been implicated in skin cancer development in animal models, needs to be investigated.

Are vitamins A and D important in the development of food allergy and how are they best measured?

Food allergy has a dramatic impact on a child's (and their family's) quality of life and places a major financial burden on the community. It has been hypothesized that the increase in food allergy may relate to the concordant rise in prevalence of vitamin D insufficiency. More recently a second hypothesis has implicated vitamin A sufficiency in the development of immune tolerance. Together, these hypotheses have prompted investigation into the circulating levels of vitamins A and D in relation to food allergy prevalence. This review aims to examine the relationship between vitamins A and D and food allergy. The first part of this review presents the available epidemiological data which proposes a dramatic increase of food allergy and related anaphylaxis during the last two decades. There is some indirect evidence that variation in food allergy prevalence within countries might be linked with ambient ultra violet radiation exposure and thus potentially with vitamin D levels. Only a few studies to date have directly examined the relationship between measured serum vitamin D levels and either food sensitization or allergy. The significance of vitamin A in food allergy prevalence is only provided through a hypothetical association due to its role in the immune system. The second part of this review discusses the relevant aspects of the analytical methods to assess vitamin A and D levels in children. The primary methods utilized relate to measuring the main circulating forms of vitamins A and D in blood i.e. retinol and 25-hydroxy-vitamin-D3 respectively. Chromatographic separation coupled with mass spectrometric detection is considered the gold standard method for both vitamins. These analytical methods should be fully validated for the use in pediatric populations to ensure they are fit for their clinical purpose.

Vitamins D and A can be successfully measured by LC-MS/MS in cord blood diluted plasma

OBJECTIVES: In widely used protocols for the collection and isolation of cord blood mononuclear cells, investigators are left with substantial volumes of diluted plasma which could be used for other measurements. The aim of this study was to ascertain the validity of umbilical cord blood (UCB) diluted plasma samples for vitamin D, A and E analysis compared to UCB serum samples. DESIGN & METHODS: Twenty UCB matched samples of diluted plasma and serum were collected. The samples were analysed by two liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods on two separate occasions. RESULTS: The results of 25(OH)D3 obtained by the two laboratories demonstrated close agreement with a mean difference of 0.14nmol/L [95% confidence interval (95% CI), -6.8 to 7.1]. Both methods demonstrate close agreement for 25(OH)D3 in UCB serum versus diluted UCB plasma; mean difference 2.2nmol/L [95% CI, -9.5 to 13.9] and 4.1nmol/L [95% CI, -14.5 to 6.1] for the results from Lab A and Lab B, respectively. Vitamin A was quantified by Lab A in UCB serum and diluted UCB plasma; mean difference 0.07μmol/L [95% CI, -0.41 to 0.28]. Results of 25(OH)D3 epimer and vitamin E in the diluted UCB plasma were below the limit of quantification, and could not be compared with UCB serum. CONCLUSIONS: Diluted UCB plasma can be used for the quantification of retinol and 25(OH)D3 by LC-MS/MS. By contrast, quantification of 25(OH)D3 epimer and vitamin E in diluted UCB plasma is not supported by this study due to limitations in analytical sensitivity.