Keeping up with the latest scientific developments on probiotics and human health is becoming very challenging because every month there are new and very exciting findings.
Recently, there have been several reports on how intestinal bacteria play a role in nutrition, obesity and diabetes.
Here are a few of the results of those studies:
- Patients who received probiotics after gastric bypass surgery lost more weight than those who received a placebo (1).
- Women who took probiotics starting in the first trimester of pregnancy were less likely at one year postpartum to have central or abdominal obesity as compared to the control group who did not take a probiotic (2).
- In a study of overweight adolescents who went on a weight loss diet, those who were successful at losing weight had a healthy change in the composition of the intestinal bacteria (3).
These and others studies in humans and animals have discovered that our intestinal bacteria affect the amount of calories we extract from the food we eat, and how we store or use those calories. The studies further suggest that obese and lean people have different intestinal bacterial flora.
Probiotics’ Regulation of Obesity and Type 2 Diabetes
There are ongoing scientific investigations aimed at determining how the gut bacteria participate in the regulation of our weight and the development of obesity and Type 2 diabetes.
In a series of experiments, it was found that mice fed a normal diet had 40% higher body fat content than germ-free mice fed a similar diet (4). The bacteria in the colon, particularly Bifidobacteria, can metabolize certain starches in our diet that we can’t digest otherwise. These extra calories harvested by the bacteria contribute to our net calorie balance. A mere 1-2% increase in calorie absorption on a daily basis can add up to many extra pounds over a year.
These studies are a little confusing. If a healthy gut flora includes Bifidobacteria, why don’t the lean individuals who have more of the Bifidobacteria gain weight?
Scientists are trying to sort out these conflicting results. To understand how the good bacteria can help control weight gain, it is important to briefly review a little biochemistry.
Whole grain foods contain starches that are resistant to digestion in the small intestines. These starches enter the colon where they are used as fuel by Bifidobacteria and Lactobacillus. The bacteria break the starches down and produce short chain fatty acids (SCFA) by a process called fermentation. The SCFA are absorbed in the colon and contribute to the calories in the diet. But the SCFA also have other effects.
One proposed mechanism is that the short chain fatty acids produced by the Bifidobacteria stimulate the release of intestinal hormones that slow the stomach emptying after a meal (5). This results in a sense of fullness or satiety with less calorie intake; it takes less to fill you up. It may be that people with the healthy bacteria who consume whole grain foods don’t eat as much.
In addition, the healthy bacteria in lean individuals suppress the proliferation of a group of bacteria called “gram negative bacteria.” Gram negative bacteria can produce a substance called lipopolysaccharide (LPS) that causes the liver to convert ingested carbohydrate calories into fat instead of burning the calories as an energy source (6). The fat is then stored in our adipose or fat tissues.
Finally, LPS has been shown to lessen our cells’ sensitivity to the insulin our pancreas produces (6). This can result in Type 2 diabetes. Studies have shown that modifying the bacterial content of the intestines can lessen the production of LPS and the potential for developing diabetes.
The evidence indicates that the gut bacteria composition can be different between healthy individuals and those who are obese and have Type 2 diabetes. The challenge is how to manipulate the intestinal bacteria to lessen these metabolic disorders.
Take home message. Eat whole grain foods, avoid high fatty diets and consider a probiotic like EndoMune. You may just avoid weight gain and the risk of developing diabetes.
Eat healthy and live well.
Lawrence J Hoberman, MD
(1) Probiotics Improve Outcomes After Roux-en-Y Gastric Bypass Surgery: A Prospective Randomized Trial: Woodard G, Encarnacion B, Downey J, et al:J Gastrointest Surg. 2009 Apr 18
(2) Probiotics May Help Ward Off Obesity, Laitinen K: Study In Pregnant Women. European Association for the Study of Obesity; Presented 2009 May 8
(3) Interplay Between Weight Loss and Gut Microbiota Composition in Overweight AdolescentsSantacruz A, Marcos A, Wärnberg J, Martí A, Martin-Matillas M, Campoy C, Moreno LA, Veiga O, Redondo-Figuero C, Garagorri JM, Azcona C, Delgado M, García-Fuentes M, Collado MC, Sanz Y. Obesity (Silver Spring). 2009 Apr 23
(4) The gut microbiota as an environmental factor that regulates fat storage. Backhed F, Ding H, Wang
T, et al. Proc Natl Acad Sci U S A. 2004 Nov 2;101(44):15718-15723
(5)Oligofructose and long-chain inulin:influence on the gut microbial ecology of rats associated with a human faecal flora. Kleessen B, Hartmann L, Blaut M. Br J Nutr. 2001;86(2):291-300
(6) Metabolic endotoxemia initiates obesity and insulin resistance. Cani PD, Amar J, Iglesias MA, et al
Diabetes. 2007 Jul;56(7):1761-1772. Epub 2007 Apr 24.