Does glutamine have the “right stuff” to help us build a healthy microbiome? And will the right population of wee beasties and microorganisms help us reach a healthy weight?
That’s the good news from Brazil where a pilot study showed that a daily dose of 30 grams of glutamine significantly reduced the ratio of Firmicutes to Bacteroidetes bacteria in obese and overweight people. The F to B ratio has been a hot area of research at least since 2005 when Jeffrey Gordon and colleagues at Washington University in St. Louis discovered lower levels of Bacteroidetes and higher levels of Firmicutes in obese mice compared to lean mice. A year later Gordon’s team announced similar findings in obese humans.
The recent glutamine study involved 33 overweight or obese adults aged 23 to 59 with a BMIs (body mass index) ranging from 26 to 47. The researchers found that F to B ratio decreased from 0.85 to 0.57 in the glutamine group and increased from 0.91 to 1.12 in the control group, which received 30 grams of L-alanine. What the Brazilian study didn’t show was weight loss, which is hardly surprising given the fact that the study lasted all of fourteen days. Whether a long-term — or even longer-term — study will result in metabolic changes leading to permanent weight loss remains to be seen.
Another relevant study on glutamine and the microbiome was published in 2012 by Zhao-Lai Dai and colleagues at the Laboratory of Gastrointestinal Microbiology at Nanjing Agricultural University in Nanjing, China. It suggested glutamine regulates how gut bacteria assimilate and utilize amino acids, particularly arginine. Because supplemental glutamine can fulfill the needs of pathogenic bacteria, glutamine feeding can minimize their detrimental effect on amino acid availability for the host, with overall improvements in health.
The finding that glutamine may benefit gut microbiota adds to a long list of beneficial health effects found for glutamine by researchers over many years. Muscle loss, accelerated wound healing, gut healing, immune system modulation, and the production of human growth hormone are just a few of those many benefits. Although the research may drive supplement sales, readers of Nourishing Broth know glutamine is the third most abundant amino acid found in bone broth and gelatin.
Textbooks tell us it’s a “non essential” amino acid because the body can manufacture it as needed. The ability to manufacture it easily and abundantly, however, is probably true only of those rare people who enjoy radiant good health. In reality, most people today are so stressed physically and mentally that they can benefit greatly from increasing their supply of glutamine. Obviously glutamine supplements are an option, but those of us in the broth-making community know the “real food” source is bone broth.
De Souza AZ, Zambom AZ, et al. Oral supplementation with l’glutamine alters gut microbiota of obese and overweight human adults: a pilot study. Nutrition Journal, Published Online: January 29, 2015, http://www.nutritionjrnl.com/article/S0899-9007(15)00035-0/abstract Full text available at Research Gate: https://www.researchgate.net/publication/272198125_Oral_Supplementation_with_L-Glutamine_Alters_Gut_Microbiota_of_Obese_and_Overweight_Human_Adults_A_Pilot_Study
Ley RE, Turnbaugh PJ, Klein S, Gordon JI. Microbial ecology: human gut microbes associated with obesity. Nature. 2006 Dec 21;444(7122):1022-3.
Turnbaugh PJ, Ley RE, Mahowald MA, Magrini V, Mardis ER, Gordon JI.An obesity-associated gut microbiome with increased capacity for energy harvest. Nature. 2006 Dec 21;444(7122):1027-31.
Ley RE, Bäckhed F, Turnbaugh P, Lozupone CA, Knight RD, Gordon JI. Obesity alters gut microbial ecology.Proc Natl Acad Sci U S A. 2005 Aug 2;102(31):11070-5
Jumpertz R, Le DS, Turnbaugh PJ, Trinidad C, Bogardus C, Gordon JI, Krakoff J.Energy-balance studies reveal associations between gut microbes, caloric load, and nutrient absorption in humans Am J Clin Nutr. 2011 Jul;94(1):58-65.
Dai ZL, Li XL, Xi PB, Zhang J, Wu G, Zhu WY. L’Glutamine regulates amino acid utilization by interstinal bacteria. Amino Acids. 2013 Sep;45(3):501-12.
Photo of bacteria, courtesy of Shutterstock ©RomanenkoAlexey
Ball and stick model of glutamine molecule Wikipedia Jynto