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Comparative effects of very low-carbohydrate, high-fat and high-carbohydrate, low-fat weight-loss diets on bowel habit and faecal short-chain fatty acids and bacterial populations.
Br J Nutr 2009; 101(10):1493-502BJ

Abstract

Very low-carbohydrate diets are often used to promote weight loss, but their effects on bowel health and function are largely unknown. We compared the effects of a very low-carbohydrate, high-fat (LC) diet with a high-carbohydrate, high-fibre, low-fat (HC) diet on indices of bowel health and function. In a parallel study design, ninety-one overweight and obese participants (age 50.6 (sd 7.5) years; BMI 33.7 (sd 4.2) kg/m(2)) were randomly assigned to either an energy-restricted (about 6-7 MJ, 30 % deficit) planned isoenergetic LC or HC diet for 8 weeks. At baseline and week 8, 24 h urine and faecal collections were obtained and a bowel function questionnaire was completed. Compared with the HC group, there were significant reductions in the LC group for faecal output (21 (sd 145) v. - 61 (sd 147) g), defecation frequency, faecal excretion and concentrations of butyrate (- 0.5 (sd 10.4) v. - 3.9 (sd 9.7) mmol/l) and total SCFA (1.4 (sd 40.5) v. - 15.8 (sd 43.6) mmol/l) and counts of bifidobacteria (P < 0.05 time x diet interaction, for all). Urinary phenols and p-cresol excretion decreased (P < or = 0.003 for time) with no difference between diets (P > or = 0.25). Faecal form, pH, ammonia concentration and numbers of coliforms and Escherichia coli did not change with either diet. No differences between the diets were evident for incidences of adverse gastrointestinal symptoms, which suggests that both diets were well tolerated. Under energy-restricted conditions, a short-term LC diet lowered stool weight and had detrimental effects on the concentration and excretion of faecal SCFA compared with an HC diet. This suggests that the long-term consumption of an LC diet may increase the risk of development of gastrointestinal disorders.

Authors+Show Affiliations

Preventative Health National Research Flagship, Commonwealth Scientific and Industrial Research Organisation - Human Nutrition, Adelaide, South Australia, Australia.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Randomized Controlled Trial
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

19224658

Citation

Brinkworth, Grant D., et al. "Comparative Effects of Very Low-carbohydrate, High-fat and High-carbohydrate, Low-fat Weight-loss Diets On Bowel Habit and Faecal Short-chain Fatty Acids and Bacterial Populations." The British Journal of Nutrition, vol. 101, no. 10, 2009, pp. 1493-502.
Brinkworth GD, Noakes M, Clifton PM, et al. Comparative effects of very low-carbohydrate, high-fat and high-carbohydrate, low-fat weight-loss diets on bowel habit and faecal short-chain fatty acids and bacterial populations. Br J Nutr. 2009;101(10):1493-502.
Brinkworth, G. D., Noakes, M., Clifton, P. M., & Bird, A. R. (2009). Comparative effects of very low-carbohydrate, high-fat and high-carbohydrate, low-fat weight-loss diets on bowel habit and faecal short-chain fatty acids and bacterial populations. The British Journal of Nutrition, 101(10), pp. 1493-502. doi:10.1017/S0007114508094658.
Brinkworth GD, et al. Comparative Effects of Very Low-carbohydrate, High-fat and High-carbohydrate, Low-fat Weight-loss Diets On Bowel Habit and Faecal Short-chain Fatty Acids and Bacterial Populations. Br J Nutr. 2009;101(10):1493-502. PubMed PMID: 19224658.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Comparative effects of very low-carbohydrate, high-fat and high-carbohydrate, low-fat weight-loss diets on bowel habit and faecal short-chain fatty acids and bacterial populations. AU - Brinkworth,Grant D, AU - Noakes,Manny, AU - Clifton,Peter M, AU - Bird,Anthony R, Y1 - 2009/02/19/ PY - 2009/2/20/entrez PY - 2009/2/20/pubmed PY - 2009/7/8/medline SP - 1493 EP - 502 JF - The British journal of nutrition JO - Br. J. Nutr. VL - 101 IS - 10 N2 - Very low-carbohydrate diets are often used to promote weight loss, but their effects on bowel health and function are largely unknown. We compared the effects of a very low-carbohydrate, high-fat (LC) diet with a high-carbohydrate, high-fibre, low-fat (HC) diet on indices of bowel health and function. In a parallel study design, ninety-one overweight and obese participants (age 50.6 (sd 7.5) years; BMI 33.7 (sd 4.2) kg/m(2)) were randomly assigned to either an energy-restricted (about 6-7 MJ, 30 % deficit) planned isoenergetic LC or HC diet for 8 weeks. At baseline and week 8, 24 h urine and faecal collections were obtained and a bowel function questionnaire was completed. Compared with the HC group, there were significant reductions in the LC group for faecal output (21 (sd 145) v. - 61 (sd 147) g), defecation frequency, faecal excretion and concentrations of butyrate (- 0.5 (sd 10.4) v. - 3.9 (sd 9.7) mmol/l) and total SCFA (1.4 (sd 40.5) v. - 15.8 (sd 43.6) mmol/l) and counts of bifidobacteria (P < 0.05 time x diet interaction, for all). Urinary phenols and p-cresol excretion decreased (P < or = 0.003 for time) with no difference between diets (P > or = 0.25). Faecal form, pH, ammonia concentration and numbers of coliforms and Escherichia coli did not change with either diet. No differences between the diets were evident for incidences of adverse gastrointestinal symptoms, which suggests that both diets were well tolerated. Under energy-restricted conditions, a short-term LC diet lowered stool weight and had detrimental effects on the concentration and excretion of faecal SCFA compared with an HC diet. This suggests that the long-term consumption of an LC diet may increase the risk of development of gastrointestinal disorders. SN - 1475-2662 UR - https://www.unboundmedicine.com/medline/citation/19224658/Comparative_effects_of_very_low_carbohydrate_high_fat_and_high_carbohydrate_low_fat_weight_loss_diets_on_bowel_habit_and_faecal_short_chain_fatty_acids_and_bacterial_populations_ L2 - https://www.cambridge.org/core/product/identifier/S0007114508094658/type/journal_article DB - PRIME DP - Unbound Medicine ER -