Phosphorus Supplementation Recovers the Blunted Diet-Induced Thermogenesis of Overweight and Obese Adults: A Pilot Study

Abstract

Diet-induced thermogenesis (DIT) is believed to be largely related to ATP production, which is dependent on phosphorus (P) availability. We aimed to test the effect of P addition on DIT of lean and overweight/obese healthy subjects. DIT was measured with or without P in 10 lean and 13 overweight/obese adults in a double-blind randomized cross-over pilot study with one week washout period. After 10 h overnight fast, resting metabolic rate, respiratory quotient, and substrate utilization were measured at fasting and every 30 min for 3 h after subjects drank a standardized glucose solution, with P (500 mg) or placebo pills. Subjective ratings of hunger and satiety were assessed before and after the end of each experiment using validated visual analogue scale (VAS) questionnaires. Overweight/obese subjects had a blunted DIT with placebo, while P supplementation induced a 23% increase in their DIT area under the curve (p < 0.05), which was associated with a significant increase in carbohydrate oxidation. Subjects had lower appetite following P supplementation, which was expressed as a significantly (p = 0.02) lower desire to eat a meal (4.0 ± 0.7 cm) compared with placebo (5.8 ± 0.9 cm). P supplementation recovers the blunted diet-induced thermogenesis in overweight and obese subjects and enhances their postprandial satiety.

Keywords: diet induced thermogenesis; energy balance; energy expenditure; obesity; phosphorus; supplementation.

Figure 1

Diet-induced thermogenesis after drinking 75 g glucose solution with and without phosphorus supplementation in lean and obese subjects. (A) Resting metabolic rate at baseline and over 3 h (180 min) after drinking 75 g glucose solution in lean and obese subjects with phosphorus (solid lines) or placebo (dashed lines); (B) Total area under the curve of RMR over 3 h (180 min) after drinking 75 g glucose solution with phosphorus (solid bars) or placebo (dashed bars) in lean and obese subjects. Data are Mean ± SEM. * p < 0.05 vs. placebo (paired t-test); † p < 0.05: within-subjects comparison (repeated measures); NS: not significant (repeated measures); RMR: resting metabolic rate; AUC: area under the curve; SEM: standard error of the mean.

Figure 2

Subjective appetite scores of lean (gray) and obese (black) subjects, 3 h after drinking 75 g glucose solution with phosphorus (solid bars) or placebo (dashed bars) supplementation. Visual analog scale (VAS) questionnaires. Data are Mean ± SEM. * p < 0.05 vs. placebo (paired t-test). SEM: standard error of the mean.

Figure 3

Pearson’s bivariate correlation between BMI of lean and obese subjects pooled together and daily phosphorus intake (mg/1000 kcal) estimated from food frequency questionnaire (FFQ). Pearson’s r = −0.48, p = 0.024. BMI: body mass index.