Associations between the intake of dairy fat and calcium and abdominal obesity.

Abstract

This study evaluates the association between abdominal obesity and the intake of dairy fat and calcium using information from dietary data and the relative content of the fatty acids 14:0, 15:0, and 17 : 0 in serum phospholipids (PL) and adipose tissue (AT), which are suggested biological markers for dairy fat intake. This study also explores how the associations were affected when under-reporters (URs) were separated from the analyses. Cross-sectional study. In all, 301 healthy 63-y-old men with different degrees of fasting-insulin concentrations. Sagittal abdominal obesity (SAD), dietary intake assessed by a 7-day food registration, and the fatty acid composition in serum PL and AT were measured. URs (n=88) and non-under-reporters (non-URs, n=213) were identified by Goldberg's equation, which compares energy intake with energy expenditure, both expressed as multiples of the basal metabolic rate. The intake of dairy fat, expressed as g/100 g fat, was inversely correlated with SAD; however, this association was only observed in the URs (r=-0.36, P=0.001) and not in the non-URs (r=-0.04, P=0.59). The intake of calcium was inversely correlated with SAD in both groups, although the association was weaker in the non-URs. The intake of dairy fat was related to the relative content of the fatty acids 14:0, 15:0, and 17 : 0 in serum PL and AT (r ranging between 0.32 and 0.55). When these fatty acids were correlated to SAD, inverse associations were seen except for 14:0 in PL (r ranging between -0.17 and -0.29. If there is a true inverse association between the intake of dairy fat and SAD, it remains to explain why this association was not seen in the non-URs. The data gave some indications of an inverse association between SAD and the intake of calcium. The diverse findings observed when the URs and non-URs were separated highlight the question of how to use and interpret dietary data in URs when diet-disease relationships are investigated.