Researchers are uncovering how good bacteria stop bad bacteria in their tracks. Your intestinal flora influences cancer development and likely helps you live longer.
Yakult Cripples Bad Bacteria
Probiotic bacteria are known to guard against bad bacteria, but how this works is still not clear. Liévin-Le et al. looked specifically at the motility of two known pathogenic bacteria, Salmonella and Helicobacter pylori, after incubating them with compounds secreted by Lactobacillus casei Shirota YIT9029, the bacteria in the yogurt drink Yakult. They found that after incubation, both strains of bad bacteria were altered in such a way that they couldn’t properly move. The loss of movement prevented them from entering human cells, a process that normally helps them induce disease.
Good Escherichia Coli Don’t Share Their Iron
Iron is good for you, but it’s, unfortunately, also good for the growth of Salmonella, a bacteria that causes food poisoning. While the body does its best to store extra iron safely in cells, Salmonella is well equipped to locate and utilize even small amounts of residual iron. Searching for a solution, researchers at the University of California in Irvine investigated if beneficial bacteria could help. They found that E. coli Nissle 1917 could reduce Salmonella colonization by effectively competing for iron. This could lead to new ways to prevent or treat food poisoning.
Intestinal Flora Trump Genes in Cancer Model
Angelina Jolie’s choice to remove her breasts to prevent cancer highlights how important genes are in the development of certain forms of cancer. However, new research by scientists from the United States and Austria demonstrated that the intestinal flora also is important too. Using a mouse strain that develops B-cell lymphomas due to a genetic disorder, they looked at how different intestinal flora populations could modulate the cancer incidence. They found that a good population of Lactobacillus johnsonii led to less-cancer prone mice.
Reduced Calories and Longer Lives via Bacteria
Calorie restriction is known to increase the life span of many animals. While the current thinking is that the life extension is due to reduced oxidative processes, some intestinal bacteria are often found in animals that live longer. Chinese researchers examined the intestinal microbiota in mice after life-long, calorie restriction. They found that calorie restricted mice had intestinal microflora enriched with bacterial populations associated with a longer lifespan and reductions in those associated with a shorter lifespan. The researchers suspect that the increase in good bacteria may help increase life expectancy by reducing immunological stress.
- Deriu E, Liu JZ, Pezeshki M, Edwards RA, Ochoa RJ, Contreras H, Libby SJ, Fang FC, Raffatellu M. Probiotic bacteria reduce salmonella typhimurium intestinal colonization by competing for iron. Cell Host Microbe. 2013 Jul 17;14(1):26-37.
- Liévin-Le Moal V, Fayol-Messaoudi D, Servin AL. Compound(s) secreted by Lactobacillus casei strain Shirota YIT9029 irreversibly and reversibly impair the swimming motility of Helicobacter pylori and Salmonella enterica serovar Typhimurium, respectively. Microbiology. 2013 Jul 19. [Epub ahead of print]
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- Zhang C, Li S, Yang L, Huang P, Li W, Wang S, Zhao G, Zhang M, Pang X, Yan Z, Liu Y, Zhao L. Structural modulation of gut microbiota in life-long calorie-restricted mice. Nat Commun. 2013 Jul 16;4:2163.