Endogenous fat oxidation during medium chain versus long chain triglyceride feeding in healthy women.
OBJECTIVE
To compare the effect of medium chain triglycerides (MCT) vs long chain triglycerides (LCT) feeding on exogenous and endogenous oxidation of long chain saturated fatty acids (LCSFA) in women.


METHODS
Twelve healthy female subjects (age 19-26 y, body mass index (BMI) 17.5-28.6 kg/m2)


METHODS
In a randomized cross-over design, subjects were fed weight maintenance diets providing 15%, 45% and 40% of energy as protein, carbohydrate and fat, respectively, with 80% of this fat comprising either a combination of butter and coconut oil (MCT) or beef tallow (LCT). Following 6 days of feeding, subjects were given daily oral doses of 1-(13)C labelled-myristic, -palmitic and -stearic acids for 8 days. Expired 13CO2 was used as an index of LCSFA oxidation with CO2 production assessed by respiratory gas exchange.


RESULTS
No difference in exogenous LCSFA oxidation was observed as a function of diet on day 7. On day 14, greater combined cumulative fractional LCSFA oxidation (16.9 +/- 2.5%/5.5 h vs 9.1 +/- 1.2%/5.5 h, P < 0.007), net LCSFA oxidation (2956 +/- 413 mg/5.5 h vs 1669 +/- 224 mg/5.5 h, P < 0.01), and percentage dietary LCSFA contribution to total fat oxidation (16.3 +/- 2.3%/5.5 h vs 9.5 +/- 1.5%/5.5 h; P < 0.01) were observed in women fed the MCT vs LCT diet. With the MCT diet, but not the LCT diet, combined cumulative fractional LCSFA oxidation (P < 0.03), net LCSFA oxidation (P < 0.03), and percentage dietary LCSFA contribution to total fat oxidation (P < 0.02) were increased at day 14 as compared to day 7. Day 14 results indicated increased endogenous LCSFA oxidation during MCT feeding.


CONCLUSIONS
The capacity of MCT to increase endogenous oxidation of LCSFA suggests a role for MCT in body weight control over the long term.
Papamandjaris
A A
AA
School of Dietetics and Human Nutrition, Faculty of Agricultural and Environmental Sciences, McGill University, Ste-Anne-de-Bellevue, Quebec, Canada.
White
M D
MD
Raeini-Sarjaz
M
M
Jones
P J
PJ
D000328:Adult; D001944:Breath Tests; D002247:Carbon Isotopes; D018592:Cross-Over Studies; D004041:Dietary Fats / Q000008:administration & dosage*; D005227:Fatty Acids / Q000378:metabolism*; D005260:Female; D006801:Humans; D019814:Myristic Acid / Q000378:metabolism; D010084:Oxidation-Reduction; D019308:Palmitic Acid / Q000378:metabolism; D011659:Pulmonary Gas Exchange; D013229:Stearic Acids / Q000378:metabolism; D014280:Triglycerides / Q000008:administration & dosage* / Q000737:chemistry*
D002247:Carbon Isotopes; D004041:Dietary Fats; D005227:Fatty Acids; D013229:Stearic Acids; D014280:Triglycerides; D019814:Myristic Acid; D019308:Palmitic Acid