Dairy, Magnesium, and Calcium Intake in Relation to Insulin Sensitivity: Approaches to Modeling a Dose-dependent Association

Abstract

Dairy intake has been inversely associated with insulin resistance, which may be partly due to the specific effects of calcium and magnesium. Data from the Insulin Resistance Atherosclerosis Study (1992-1999) for 1,036 US adults without diabetes at baseline were examined to evaluate the cross-sectional association of habitual dairy, magnesium, and calcium intake with insulin sensitivity at baseline and after 5 years of follow-up. Insulin sensitivity was directly measured with a validated, 12-sample, insulin-enhanced, intravenous glucose tolerance test with minimal model analysis. Dietary intake was assessed by a validated food frequency interview, and dietary supplement dose was confirmed by reviewing the supplement label. Several statistical approaches were used to ensure appropriate modeling of the dose-dependent association. No association was found between dairy intake and insulin sensitivity (p=0.41); however, associations were positive for magnesium and calcium intake (p=0.016) after adjusting for demographic, nondietary lifestyle and dietary factors, and food groups. Furthermore, magnesium intake was associated with insulin sensitivity in a threshold fashion, with a Bayesian method-estimated threshold (325 mg) (beta=0.0607/100 mg, p=0.0008 for <325 mg of magnesium/day; and beta=-0.001/100 mg, p=0.82 for >or=325 mg of magnesium/day). This study suggests that magnesium and calcium intake specifically, but not dairy intake, is associated with insulin sensitivity.

Calcium consumption and insulin resistance syndrome parameters. Data from the Epidemiological Study on the Insulin Resistance Syndrome (DESIR)

“…Finally, Ma et al also found a relationship between calcium intake and insulin sensitivity, but not with dairy intake [10].…”

“…Bowen et al report no effect of dietary calcium or protein sources on weight loss, and Thompson et al in a randomised trial, shows similar results [8][9]. Lastly, Ma et al find that calcium intake, but not dairy intake, is associated with insulin sensitivity [10]. Thus, the impact of dietary calcium on the insulin resistance syndrome parameters is a subject of debate.…”

Calcium, vitamin D and dairy intake in relation to type 2 diabetes risk in a Japanese cohort

“…Calcium deficiency leads to the secretion of parathyroid hormone and increases calcium inflow from the extracellular fluid into intracellular regions, resulting in cellular calcium overload and impaired insulin sensitivity [5,23]. In epidemiological studies, calcium intake was positively associated with insulin sensitivity [24][25][26]. Vitamin D is also involved in insulin regulation [3,4].…”

Magnesium intake and colorectal cancer risk in the Netherlands Cohort Study

“…It may be relevant that reported magnesium intake levels are lower in Sweden than in the Netherlands: median intakes in lowest and highest quintiles were 198 and 268 mg day À1 (Larsson et al, 2005), and 236 and 349 mg day À1 in Dutch women, respectively. Magnesium intake of up to 325 mg day À1 was recently found to be associated with insulin sensitivity, and intakes above this level might not provide further benefits; sex-specific data were not presented (Ma et al, 2006). We observed no further decrease in risk in our subsite-specific analyses (Table 2) in quintile 5 (4350 mg day À1 ; median 375) compared to quintile 4 (321 -350 mg day À1 ; median 313), which is in line with the threshold finding.…”