Relation between calcium intake and fat oxidation in adult humans.
OBJECTIVE
To determine if total calcium (Ca(2+)) intake and intake of Ca(2+) from dairy sources are related to whole-body fat oxidation.


METHODS
: Cross-sectional study.


METHODS
A total of 35 (21 m, 14 f) non-obese, healthy adults (mean+/-s.d., age: 31+/-6 y; weight: 71.2+/-12.3 kg; BMI: 23.7+/-2.9 kg m(-2); body fat: 21.4+/-5.4%).


METHODS
Daily (24 h) energy expenditure (EE) and macronutrient oxidation using whole-room indirect calorimetry; habitual Ca(2+) intake estimated from analysis of 4-day food records; acute Ca(2+) intake estimated from measured food intake during a 24-h stay in a room calorimeter.


RESULTS
Acute Ca(2+) intake (mg. kcal(-1)) was positively correlated with fat oxidation over 24 h (r=0.38, P=0.03), during sleep (r=0.36, P=0.04), and during light physical activity (r=0.32, P=0.07). Acute Ca(2+) intake was inversely correlated with 24-h respiratory quotient (RQ) (r=-0.36, P=0.04) and RQ during sleep (r=-0.31, P=0.07). After adjustment for fat mass, fat-free mass, energy balance, acute fat intake, and habitual fat intake, acute Ca(2+) intake explained approximately 10% of the variance in 24-h fat oxidation. Habitual Ca(2+) intake was not significantly correlated to fat oxidation or RQ. Total Ca(2+) intake and Ca(2+) intake from dairy sources were similarly correlated with fat oxidation. In backwards stepwise models, total Ca(2+) intake was a stronger predictor of 24 h fat oxidation than dairy Ca(2+) intake.


CONCLUSIONS
Higher acute Ca(2+) intake is associated with higher rates of whole-body fat oxidation. These effects were apparent over 24 h, during sleep and, to a lesser extent, during light physical activity. Calcium intake from dairy sources was not a more important predictor of fat oxidation than total Ca(2+) intake.
Melanson
E L
EL
Center for Human Nutrition, University of Colorado Health Sciences Center, Denver 80262, USA. Ed.melanson@uchsc.edu
Sharp
T A
TA
Schneider
J
J
Donahoo
W T
WT
Grunwald
G K
GK
Hill
J O
JO
D000328:Adult; D002136:Calcium, Dietary / Q000008:administration & dosage* / Q000494:pharmacology; D002153:Calorimetry, Indirect; D003430:Cross-Sectional Studies; D003611:Dairy Products / Q000032:analysis; D004734:Energy Metabolism / Q000502:physiology; D015444:Exercise / Q000502:physiology; D005260:Female; D006801:Humans; D050356:Lipid Metabolism; D008066:Lipolysis / Q000187:drug effects / Q000502:physiology; D008297:Male; D010084:Oxidation-Reduction / Q000187:drug effects; D012890:Sleep / Q000502:physiology
D002136:Calcium, Dietary