BackgroundThe association between long-term metformin use and low vitamin B12 levels has been proven. However, the prevalence estimates of metformin-induced vitamin B12 deficiency showed considerable variation among the studies. The potential of the deficiency to cause or worsen peripheral neuropathy in type-2 diabetes mellitus (T2DM) patients has been investigated with conflicting results. The aim of the study was to investigate: 1) the prevalence of vitamin B12 deficiency in T2DM patients on metformin; 2) the association between vitamin B12 and peripheral neuropathy; 3) and the risk factors for vitamin B12 deficiency in these patients.MethodsIn this cross-sectional study, consecutive metformin-treated T2DM patients attending diabetes clinics of two public hospitals in South Africa were approached for participation. Participation included measuring vitamin B12 levels and assessing peripheral neuropathy using Neuropathy Total Symptom Score-6 (NTSS-6) questionnaire. The prevalence of vitamin B12 deficiency (defined by concentrations <150 pmol/L) was determined. Those with NTSS-6 scores >6 were considered to have peripheral neuropathy. The relationship between vitamin B12 and peripheral neuropathy was investigated when the two variables were in the binary and continuous forms. Multiple logistic regression was used to determine risk factors for vitamin B12 deficiency.ResultsAmong 121 participants, the prevalence of vitamin B12 deficiency was 28.1 %. There was no difference in presence of neuropathy between those with normal and deficient vitamin levels (36.8 % vs. 32.3 %, P = 0.209). Vitamin B12 levels and NTSS-6 scores were not correlated (Spearman’s rho =0.056, P = 0.54). HbA1c (mmol/mol) (OR = 0.97, 95 % CI: 0.95 to 0.99, P = 0.003) and black race (OR = 0.34, 95 % CI: 0.13 to 0.92, P = 0.033) were risk factors significantly associated with vitamin B12 deficiency. Metformin daily dose (gram) showed borderline significance (OR = 1.96, 95 % CI: 0.99 to 3.88, P = 0.053).ConclusionsClose to third of metformin-treated T2DM patients had vitamin B12 deficiency. The deficiency was not associated with peripheral neuropathy. Black race was a protective factor for vitamin B12 deficiency.

Peripheral neuropathy (PN) is a primary complication of type 2 diabetes mellitus (T2DM) and a direct manifestation of vitamin B12 deficiency. Examining the effects of metformin use on PN status became imperative following clinical studies that showed the vitamin B12-lowering effect of the medication. The complexity of the topic and the inconsistency of the results warrant consideration of topic-specific perspectives for better understanding of the available evidence and more appropriate design of future studies.

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Aloe vera gel is widely used in the treatment of an array of disturbances, especially skin disorders. The woundhealing effects have been attributed to its moisturiz-ing and anti-inflammatory effects as well as its beneficial effect on the maturation of collagen. The aim of the present study is to compare the effects of topically applied extracts of Aloe ferox with that of Aloe vera on the symptoms as well as IgE levels of a mouse model of atopic dermatitis (AD). Mice were sensitized and challenged with 2,4-dinitrochlorobenzene and treated afterwards for 10 consecutive days with the gels of either A. ferox or A. vera applied topically to the affected areas. A placebo gel was used for the control mice. Blood was collected at the beginning and end of the treatment period to measure serum IgE levels. Although the gels of both the Aloe species inhibited the cutaneous inflammatory response as well as serum IgE levels in the rats, the extracts of A. ferox were superior to that of A. vera in reducing IgE levels. The gels of A. ferox and A. vera, applied topically, may be a safe and useful alter-native to antihistamines and topical corticosteroids, for the treatment of patients suffering from recurring chronic AD.

Vitamin D is a fat-soluble vitamin that plays an important role in bone metabolism and seems to have some anti-inflammatory and immune-modulating properties. For most people sunlight is the most important source of vitamin D. The time required to make sufficient vitamin D varies according to a number of environmental, physical and personal factors, but is typically short and less than the amount of time needed to damage the skin e.g. reddening and burns. Enjoying the sun safely, while taking care not to burn, can help to provide the benefits of vitamin D without unduly raising the risk of skin cancer. Vitamin D supplements and specific foods can aid in maintaining sufficient levels of vitamin D, particularly in people at risk of deficiency. However, there is still a lot of uncertainty around what are “optimal” or “sufficient” levels, how much sunlight different people need to achieve a given level of vitamin D, and whether vitamin D protects against chronic diseases such as cancer, heart disease and diabetes, as well as the benefits and risks of widespread supplementation.