[The role of oils containing triacylglycerols and medium-chain fatty acids in the dietary treatment of obesity. The effect on resting energy expenditure and serum lipids].

BACKGROUND: Treatment of obesity with strict reducing diets is as a rule associated with the development of energetic efficiency manifested among others also by a decline of energy expenditure. The objective of the trial was to test whether addition of oils containing triacylglycerols with medium-chain fatty acid can prevent this decline and whether their administration can affect the lipid spectrum.

METHODS AND RESULTS: Sixty obese patients were served for a four-week period of hospitalization at the obesitology unit a low-energy diet REDITA (Promil Co., N. Bydzov) providing 1596 kJ, 37 g protein, 50 g carbohydrate and 3 g fat. Part of the treatment was regular aerobic exercise, behavioural therapy to teach correct dietary habits and physical activity; physical activity was monitored by means of pedometers. From this group during the 3rd and 4th week 11 patients with similar characteristics were separated (age, body weight, BMI and energy expenditure at rest) as in the basic group. These patients were given daily 15 ml oil containing triacylglycerols with medium-chain fatty acids, MCT OIL (Mead Johnson, Evansville), providing 545 kJ. The resting energy expenditure was assessed in all patients every morning on fasting, immediately after awakening, using indirect calorimetry and it was corrected with regard to the respiratory quotient and excretion of catabolic nitrogen. The body composition was assessed at the beginning and at the end of the trial by hydrostatic weighing. Administration of oil containing triacylglycerols with medium-chain fatty acids (MCT OIL) prevented the decline of the resting energy expenditure (130.0 +/- 9.2 kJ/kg lean body mass/day, as compared with 126.5 +/- 7.2 kJ/kg lean body mass/day in the basic group: the difference is statistically not significant). Although addition of oil increased the energy intake by 545 kJ/day, the drop of body weight and BMI was comparable with that in the group of obese patients who did not receive the oil (10.3 +/- 1.1 kg vs. 10.6 +/- 0.5 kg). While during administration of the oil the resting energy expenditure did not change (5.97 +/- 0.30 kJ/min. vs. 5.24 +/- 0.58 kJ/min.), in obese patients who were only on the strict reducing diet it declined from 5.45 +/- 0.18 kJ/min. to 4.44 +/- 0.22 kJ/min. (p < 0.01). The significant drop of total cholesterol achieved by dietotherapy alone (5.41 +/- 0.21 mmol/l vs. 6.26 0.20 mmol/l before treatment) was not affected by administration of oil (4.86 +/- 0.28 mmol/l vs. 5.69 +/- 0.35 mmol/l before treatment). HDL-cholesterol, on the other hand, declined only in obese patients with dietotherapy (1.40 +/- 0.04 mmol/vs. 1.22 +/- 0.04 mmol/l after treatment, p < 0.01). The triacylglycerol values declined significantly in both groups (p < 0.01).

CONCLUSIONS: It appears that administration of thermogenetically acting triacylglycerols with medium-chain fatty acids can prevent diet-induced energetic efficiency and can improve the long-term success of dietotherapy of obese patients.