Vitamin D, glucose tolerance and insulinaemia in elderly men

Abstract

We have been interested in environmental factors which may contribute to the development of non-insulin-dependent diabetes mellitus (NIDDM). Previous analysis of dietary factors in a cohort of elderly Dutch people has shown that regular fish eating reduced the 4-year risk of glucose intolerance in normoglycaemic individuals [1]. Experimentally vitamin D is required for normal insulin secretion and glucose tolerance [2]. Since fish can be an important dietary source of vitamin D this sub-study was designed to determine whether variation in vitamin D status relates to glucose intolerance. Subjects, materials and methods Study population:In 1960 a population-based random sample of 878 men (born 1900-1920) were enrolled in the Zutphen Study, the Dutch contribution to the Seven Countries Study. Clinical examinations and dietary surveys were conducted initially and at regular intervals thereafter. In 1990 all living participants (314) were invited for the 30-year follow-up and 238 (77 %) agreed. Men known by then to have diabetes were excluded (n = 29). Complete data on diet and BMI from both the 10-and 30-year surveys and on glucose tolerance at the 30-year survey were available on 158 subjects. Serum for 25-hydroxyvitamin D (25(OH)D) analysis was available on 142 of those who formed the study group.Protocol: All men were examined as in previously reported surveys [3]. At the 30-year follow-up an OGTT conforming to World Health Organization (WHO) guidelines [4] was performed with samples at 0, 1 and 2 h after the glucose load. Plasma glucose was measured in fluoridated samples using hexokinase methodology. WHO criteria were used to classify the men into those with newly diagnosed NIDDM, impaired glucose tolerance or as normoglycaemic [4]. Serum total insulin was assayed by radioimmunoassay (Pharmacia Diagnostics, Uppsala, Sweden; cross-reaction with proinsulin 100 %).Clinical examinations and anthropomorphic measurements were made by physicians specifically trained for the study as

Vitamin D deficiency in early life accelerates Type 1 diabetes in non-obese diabetic mice

“…In vivo, however, clear glucose intolerance was observed already at 100 days of age in female and even more pronounced in male vitamin D-deficient NOD mice. There are several reports on the link between vitamin D deficiency and the pathogenesis of insulin resistance, impaired glucose intolerance and even Type 2 diabetes in humans [45,46]. Therefore the impaired glucose intolerance found in the vitamin Ddeficient NOD mice at 100 days of age might be explained in part by an increased insulin resistance in these animals, since insulin secretion and synthesis were comparable to those found in vitamin D-sufficient NOD mice.…”

Hypovitaminosis D in Type 2 Diabetes Mellitus: Association with Microvascular Complications and Type of Treatment

“…This finding further suggests that hypovitaminosis D is associated with severe glucose intolerance and insulin-dependency in diabetic subjects. Experimentally, vitamin D is required for normal insulin secretion and glucose tolerance [30], and hypovitaminosis D may be a significant risk factor for glucose intolerance in diabetic patients [8]. It has recently been reported that positive correlation of serum 25-OHD concentration with insulin sensitivity and a negative effect of hypovitaminosis D on β cell function were found in normal population, and that subjects with hypovitaminosis D had a greater prevalence of components of metabolic syndrome than did subjects without hypovitaminsosis D [31].…”

“…In type 1 diabetes, it is apparent that osteopenia occurs especially in the young-onset type 1 diabetes, and that the demineralization process seems to be related to fasting blood glucose concentrations and HbA1c [5][6][7]. Moreover, it has also been suggested that hypovitaminosis D may be a significant risk factor for glucose intolerance [8]. High prevalence of hypovitaminosis D in type 2 diabetes patients has been reported [9,10], whereas Ishida et al [11] could not find any difference in such patients from the control, suggesting that more precise analysis of the relationship between the 25-OHD level and the clinical manifestations of type 2 diabetes is needed.…”

Food consumption and the incidence of type II diabetes mellitus

“…Findings of several studies suggest that higher intake of polyunsaturated fat and possibly long-chain n-3 fatty acids could be beneficial in prevention of type II diabetes, whereas higher intake of saturated fat and trans-fat may be detrimental (Hu et al, 2001b). Other dietary factors that have been related to reduced risk of type II diabetes include coffee (van Dam & Feskens, 2002;Tuomilehto et al, 2004), dairy products , and vitamin D (Baynes et al, 1997).…”