Role of Gut Microbiota in the Aetiology of Obesity: Proposed Mechanisms and Review of the Literature

Table 2

Studies looking at differences in SCFA in faecal or caecal samples in obese versus lean phenotypes in animal and human studies.

Reference	Technique used	SCFA differences	Gut microbiota differences
Turnbaugh et al. 2006 [4]	GC-MS, pyrosequencing	↑ caecal acetate and ↑ butyrate in obese ob/ob mice compared to lean	↑ Firmicutes and lower Bacteroidetes in obese than lean mice. No differences in genera level diversity
Zhang et al. 2009; [23]	GC, qPCR, and pyrosequencing	↑ acetate in obese compared to lean and gastric bypass group	↑ M. smithii and Prevotellaceae in obese compared to lean and gastric bypass
Schwiertz et al. 2010; [18]	GC and qPCR with SYBR Green	↑ total SCFA and propionate (conc.  &  %) in obese compared to lean	↑ Bacteroides and ↓ Firmicutes, ↓ Ruminococcus flavefaciens, ↓ Bifidobacterium, and ↓ Methanobrevibacter in obese compared to lean
Payne et al. 2011; [24]	qPCR, TGGE, and HPLC	↑ butyrate, propionate, and isobutyrate in obese compared to lean; ↑ lactate and valerate in lean compared to obese; No difference in acetate and total SCFA	No difference in Firmicutes and Bacteroidetes, Firmicutes/Bacteroides ratio, Bifidobacteria, Enterobacteriaceae, and sulphate reducing bacteria between lean and obese children; ↑ Roseburia/E. rectale in obese; Highly variable banding pattern on TGGE for both obese and healthy
Yang et al. 2013; [25]	GC	↑ ratio of molar propionate: total SCFA and ↓ acetate : SCFA ratio in obese versus lean	Not measured
Teixeira et al. 2013; [26]	GC	↑ acetate, propionate, and butyrate in obese versus lean women; SCFA correlated with body fat, blood pressure, waist circumference, insulin, and HOMA index	Not studied
Belobrajdic et al. 2012; [27]	GC	Increase in total SCFA pool and stool energy irrespective of obese or lean phenotype (obesity prone or obesity resistant) in response to 0, 4, 12, and 16% resistant starch diet for 4 weeks	Not studied
Rahat-Rozenbloom et al. 2014; [28]	GC	↑ total SCFA, acetate, and butyrate in obese compared to lean; No differences in isobutyrate, isovalerate, and valerate	↑ Firmicutes : Bacteroidetes ratio in obese. Firmicutes correlated with SCFA in obese
Fernandes et al. 2014; [29]	GC, qPCR	Significantly ↑ propionate and valerate; Marginally ↑ acetate and butyrate	Escherichia Coli higher in lean than obese; No difference in Bacteroides/Prevotella, Clostridium coccoides and C. leptum group, Bifidobacteria, and total bacteria, F/B ratio
Li et al. 2013; [30]	GC	Higher SCFA in obese than lean	↑ Firmicutes and lower Bacteroidetes in obese

GC: gas chromatography, GC-MS: gas chromatography-mass spectrometry, SPME-GCMS: solid phase microextraction-gas chromatography mass spectrometry, v1-v2: variable regions 1 and 2, HPLC: high performance liquid chromatography, TGGE: temperature gradient gel electrophoresis, CHO: carbohydrate, EU: European Union, qPCR: quantitative polymerase chain reaction, and F/B ratio: Firmicutes to Bacteroidetes ratio.