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Prevotella-to-Bacteroides ratio predicts body weight and fat loss success on 24-week diets varying in macronutrient composition and dietary fiber: results from a post-hoc analysis.
Hjorth, MF, Blædel, T, Bendtsen, LQ, Lorenzen, JK, Holm, JB, Kiilerich, P, Roager, HM, Kristiansen, K, Larsen, LH, Astrup, A
International journal of obesity (2005). 2019;(1):149-157
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Abstract
BACKGROUND/OBJECTIVES Individuals with high pre-treatment bacterial Prevotella-to-Bacteroides (P/B) ratio have been reported to lose more body weight on diets high in fiber than subjects with a low P/B ratio. Therefore, the aim of the present study was to examine potential differences in dietary weight loss responses between participants with low and high P/B. SUBJECTS/METHODS Eighty overweight participants were randomized (52 completed) to a 500 kcal/d energy deficit diet with a macronutrient composition of 30 energy percentage (E%) fat, 52 E% carbohydrate and 18 E% protein either high (≈1500 mg calcium/day) or low ( ≤ 600 mg calcium/day) in dairy products for 24 weeks. Body weight, body fat, and dietary intake (by 7-day dietary records) were determined. Individuals were dichotomized according to their pre-treatment P/B ratio derived from 16S rRNA gene sequencing of collected fecal samples to test the potential modification of dietary effects using linear mixed models. RESULTS Independent of the randomized diets, individuals with high P/B lost 3.8 kg (95%CI, 1.8,5.8; P < 0.001) more body weight and 3.8 kg (95% CI, 1.1, 6.5; P = 0.005) more body fat compared to individuals with low P/B. After adjustment for multiple covariates, individuals with high P/B ratio lost 8.3 kg (95% CI, 5.8;10.9, P < 0.001) more body weight when consuming above compared to below 30 g fiber/10MJ whereas this weight loss was 3.2 kg (95% CI, 0.8;5.5, P = 0.008) among individuals with low P/B ratio [Mean difference: 5.1 kg (95% CI, 1.7;8.6, P = 0.003)]. Partial correlation coefficients between fiber intake and weight change was 0.90 (P < 0.001) among individuals with high P/B ratio and 0.25 (P = 0.29) among individuals with low P/B ratio. CONCLUSIONS Individuals with high P/B lost more body weight and body fat compared to individuals with low P/B, confirming that individuals with a high P/B are more susceptible to weight loss on a diet rich in fiber.
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Effect of calcium from dairy and dietary supplements on faecal fat excretion: a meta-analysis of randomized controlled trials.
Christensen, R, Lorenzen, JK, Svith, CR, Bartels, EM, Melanson, EL, Saris, WH, Tremblay, A, Astrup, A
Obesity reviews : an official journal of the International Association for the Study of Obesity. 2009;(4):475-86
Abstract
Observational studies have found that dietary calcium intake is inversely related to body weight and body fat mass. One explanatory mechanism is that dietary calcium increases faecal fat excretion. To examine the effect of calcium from dietary supplements or dairy products on quantitative faecal fat excretion, we performed a systematic review with meta-analysis. We included randomized, controlled trials of calcium (supplements or dairy) in healthy subjects, where faecal fat excretion was measured. Meta-analyses used random-effects models with changes in faecal fat excreted expressed as standardized mean differences, as the studies assessed the same outcome but measured in different ways. An increased calcium intake resulted in increased excretion of faecal fat by a standardized mean difference of 0.99 (95% confidence intervals: 0.63-1.34; P < 0.0001; expected to correspond to approximately 2g day(-1)) with moderate heterogeneity (I(2) = 49.5%) indicating some inconsistency in trial outcomes. However, the dairy trials showed homogeneous outcomes (I(2)=0%) indicating consistency among these trials. We estimated that increasing the dairy calcium intake by 1241 mg day(-1) resulted in an increase in faecal fat of 5.2 (1.6-8.8) g day(-1). In conclusion, dietary calcium has the potential to increase faecal fat excretion to an extent that could be relevant for prevention of weight (re-)gain. Long-term studies are required to establish its potential contribution.
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Effect of dairy calcium on fecal fat excretion: a randomized crossover trial.
Bendsen, NT, Hother, AL, Jensen, SK, Lorenzen, JK, Astrup, A
International journal of obesity (2005). 2008;(12):1816-24
Abstract
BACKGROUND Evidence suggests that dietary calcium intake may be inversely related to body weight. One explanatory mechanism is that dietary calcium increases fecal fat excretion, due to either calcium soap formation and/or binding of bile acids (BAs) in the intestine. OBJECTIVE To examine the effect of calcium from low-fat dairy products on fecal fat excretion. DESIGN A randomized crossover study with 11 subjects, comparing two 7-d diets: one high in calcium from low-fat dairy products (high-Ca; 2300 mg Ca per d) and one low in calcium (low-Ca; 700 mg Ca per d). MEASUREMENTS All feces were collected during the last 5 days of each diet period and analyzed for fat, energy and calcium content and fatty acid (FA) and BA composition. RESULTS Dairy calcium significantly increased the total fecal fat excretion from 5.4+/-0.5 g d(-1) on the low-Ca diet to 11.5+/-1.4 g d(-1) on the high-Ca diet (P<0.001). The fecal energy excretion increased almost correspondingly. Saturated, monounsaturated and polyunsaturated FAs were all excreted in larger amounts on the high-Ca diet (P<0.001 for all), with the effect of calcium being greater for monounsaturated than for saturated FAs. The fecal excretion of BAs was unaffected of calcium intakes. CONCLUSIONS Increasing the intake of calcium from low-fat dairy products by 1600 mg d(-1) for 7 days doubled total fecal fat excretion, but did not affect the excretion of BAs. The results may partially explain why a high-calcium diet can produce weight loss.