High dietary calcium reduces body fat content, digestibility of fat, and serum vitamin D in rats.
OBJECTIVE
This study investigated which aspect of energy balance was responsible for the decrease in body fat content of rats fed a high-calcium, high-dairy protein diet.


METHODS
Male Wistar rats were fed a control diet (25% kcal fat, 14% kcal protein from casein, 0.4% by weight calcium) or high-calcium diet (25% kcal fat, 7% kcal protein from nonfat dry milk, 7% kcal protein from casein, 2.4% calcium) for 85 days. Body weights, digestible energy intakes, energy expenditures, rectal temperatures, body composition, and serum glucose, insulin, free fatty acids, triglycerides, and 1,25-dihydroxyvitamin D were measured.


RESULTS
Rats fed high-calcium diet gained significantly less weight than controls and had 29% less carcass fat. Gross energy intake was not significantly different between groups, but digestible energy was 90% of gross energy in the high-calcium diet compared with 94% in the control diet because of increased fecal excretion of dietary lipid. The difference in digestible energy intake accounted for differences in carcass energy. Body temperatures and energy expenditures of the rats were not different. The high-calcium diet reduced serum triglycerides by 23% and serum 1,25-dihydroxyvitamin D by 86%.


CONCLUSIONS
These results confirm that a high-calcium diet decreases body weight and fat content due to a lower digestible energy intake caused by increased fecal lipid and a nonsignificant reduction in gross energy intake.
Papakonstantinou
Emilia
E
Department of Foods and Nutrition, University of Georgia, Athens, Georgia 30602, USA.
Flatt
William P
WP
Huth
Peter J
PJ
Harris
Ruth B S
RB
D000273:Adipose Tissue / Q000033:anatomy & histology; D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D001823:Body Composition; D001835:Body Weight; D002117:Calcitriol / Q000097:blood*; D002136:Calcium, Dietary / Q000008:administration & dosage*; D002364:Caseins / Q000008:administration & dosage; D004041:Dietary Fats / Q000008:administration & dosage; D004063:Digestion; D002149:Energy Intake; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005243:Feces / Q000737:chemistry; D007328:Insulin / Q000097:blood; D008055:Lipids / Q000032:analysis; D008099:Liver / Q000033:anatomy & histology; D008297:Male; D008892:Milk; D009929:Organ Size; D051381:Rats; D017208:Rats, Wistar; D014280:Triglycerides / Q000097:blood
D001786:Blood Glucose; D002136:Calcium, Dietary; D002364:Caseins; D004041:Dietary Fats; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D008055:Lipids; D014280:Triglycerides; D002117:Calcitriol