Gut microbiome associated with some blood lipid levels

By Will Boggs MD

The gut microbiome is associated with body mass index (BMI) and blood levels of high-density lipoprotein (HDL) cholesterol and triglycerides, according to results from the Dutch LifeLines-DEEP cohort.

"We were surprised to observe the gut bacteria contributed substantial variation in BMI, HDL, and triglycerides, but very little in LDL (low-density lipoprotein) and total cholesterol," Dr. Jingyuan Fu, from University Medical Center Groningen, the Netherlands, told Reuters Health by email. "Lipid metabolism is far more complicated than we expected and so far hundreds of lipid species are identified in humans."

Gut microbiota have been linked to lipid metabolism through their role in bile acid metabolism, but so far no large studies have assessed the association between lipids and microbiota and their association with development of cardiovascular disease (CVD).

Dr. Fu's team used data from 893 participants in LifeLines-DEEP to assess which gut bacteria were associated with BMI and blood lipids and how much the variation in blood lipids could be explained independently by the gut microbiome.

The researchers identified 148 unique bacterial sequences (OTUs) that were identified with BMI and blood lipids: 66 were associated with BMI, 114 with triglycerides, and 34 with HDL.

Twelve OTUs were shared by all three traits, 29 were shared by BMI and triglycerides, and four were shared by BMI and HDL, while 21 were specifically associated with BMI, 64 with triglycerides, and nine with HDL.

The OTUs explained 2.74% of the variation in BMI, 3.83% in triglycerides, and 2.46% in HDL.

The combination of age, gender, genetics, and the gut microbiome explained 11.3% of the variation in BMI, 17.1% in triglycerides, and 25.9% in HDL, with the microbiome making a significant independent contribution to the explained variation in each.

There were no significant associations at OTU level for LDL or total cholesterol, according to the September 10 Circulation Research online report.

"Gut bacterial community can be shaped by many factors, including diet, probiotics, medication, and fecal transplantation," Dr. Fu explained. "However, this field is still at its infancy."

"Our results highlight the potential of therapies that alter the gut microbiome to control body mass, triglycerides, and HDL in cardiovascular disease prevention," the researchers concluded. "In moving from potential to action, it will be essential to identify the causal axis of microbiome-lipids-CVD and to gain more mechanistic insight into the gut bacteria functions."

Dr. Max Nieuwdorp, from Academic Medical Center, Amsterdam, the Netherlands, told Reuters Health by email, "The fecal microbiome has a small but important contribution to clinical cardiovascular risk factors like lipids and BMI. However, as lipid metabolism is mainly taking place in the small intestine, more prospective studies also including small intestinal bacteria composition (which are different than the fecal microbiota used in this study) and more focus on long-term diet of included subjects are needed to establish the role of gut microbiota in cardiovascular disease."

Several organizations supported this research. The authors reported no disclosures.

SOURCE: http://bit.ly/1Y8GEH1

Circ Res 2015.

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