Effect of short-term high dietary calcium intake on 24-h energy expenditure, fat oxidation, and fecal fat excretion.
BACKGROUND
Observational studies have shown an inverse association between dietary calcium intake and body weight, and a causal relation is likely. However, the underlying mechanisms are not understood.


OBJECTIVE
We examined whether high and low calcium intakes from mainly low-fat dairy products, in diets high or normal in protein content, have effects on 24-h energy expenditure (EE) and substrate oxidation, fecal energy and fat excretion, and concentrations of substrates and hormones involved in energy metabolism and appetite.


METHODS
In all, 10 subjects participated in a randomized crossover study of three isocaloric 1-week diets with: low calcium and normal protein (LC/NP: 500 mg calcium, 15% of energy (E%) from protein), high calcium and normal protein (HC/NP: 1800 mg calcium, 15E% protein), and high calcium and high protein (HC/HP: 1800 mg calcium, 23E% protein).


RESULTS
The calcium intake had no effect on 24-h EE or fat oxidation, but fecal fat excretion increased approximately 2.5-fold during the HC/NP diet compared with the LC/NP and the HC/HP diets (14.2 vs 6.0 and 5.9 g/day; P < 0.05). The HC/NP diet also increased fecal energy excretion as compared with the LC/NP and the HC/HP diets (1045 vs 684 and 668 kJ/day; P < 0.05). There were no effects on blood cholesterol, free fatty acids, triacylglycerol, insulin, leptin, or thyroid hormones.


CONCLUSIONS
A short-term increase in dietary calcium intake, together with a normal protein intake, increased fecal fat and energy excretion by approximately 350 kJ/day. This observation may contribute to explain why a high-calcium diet produces weight loss, and it suggests that an interaction with dietary protein level may be important.
Jacobsen
R
R
Department of Human Nutrition, Centre for Advanced Food Studies, The Royal Veterinary and Agricultural University, DK-1958 Frederiksberg C, Denmark.
Lorenzen
J K
JK
Toubro
S
S
Krog-Mikkelsen
I
I
Astrup
A
A
D000293:Adolescent; D000328:Adult; D000886:Anthropometry; D001835:Body Weight / Q000187:drug effects* / Q000502:physiology; D002136:Calcium, Dietary / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000494:pharmacology*; D018592:Cross-Over Studies; D003611:Dairy Products / Q000032:analysis; D004032:Diet; D004041:Dietary Fats / Q000493:pharmacokinetics*; D004044:Dietary Proteins / Q000008:administration & dosage; D004734:Energy Metabolism / Q000187:drug effects* / Q000502:physiology; D005243:Feces / Q000737:chemistry; D005260:Female; D006801:Humans; D008055:Lipids / Q000097:blood; D008297:Male; D008875:Middle Aged; D009747:Nutritional Physiological Phenomena / Q000502:physiology; D010084:Oxidation-Reduction / Q000187:drug effects
D002136:Calcium, Dietary; D004041:Dietary Fats; D004044:Dietary Proteins; D008055:Lipids