The party inside your belly
There’s a reason the gut microbiome has gotten the lion’s share of attention: of the more than 10,000 distinct species of bacteria (most of which still unidentified) that live in healthy people, at least 4000 of them colonise the gut to help with digestion as well as immunity and overall health. The majority of the bacteria are classified as Firmicutes or Bacteroides, two different phyla. These organisms help the body break down carbohydrates and also make essential nutrients like vitamins B and K. The huge number of good gut organisms help crowd out the harmful ones. As professor of medicine, Dr Cynthia Sears told Discover Magazine, “Just by mere force of numbers, the bad bugs are beat out by the good bugs.”
The parasite in your brain
OK, so this one might be the scariest of all. Typically, the brain is free of the microbes circulating in the body because of the blood-brain barrier – a filter system that allows the brain to get its blood supply without risking infection. “Usually if you have a bacterial infection in the brain, something bad has happened to allow that – a wound got infected, or something broke down in the body’s defence mechanisms,” says Weinstock. But there are organisms that can bypass this barrier, and one of most common is Toxoplasma gondii, a parasite that inhabits the brains of up to 84 per cent of people. What’s particularly interesting (okay, terrifying) about this parasite is that it changes behaviour. “This is a parasitic bacteria that can infect a huge range of animals, including humans,” says Weinstock. “It can crawl inside certain immune cells or nerve cells that cross the blood-brain barrier. It’s a fascinating microbe—it affects behaviour to help it get transmitted.” Cats transmit Toxoplasma, and when mice are infected with the parasite, they become more reckless and take more chances – making them more likely to get caught and eaten by cats. And preliminary studies are finding that humans infected with Toxoplasma may also have slower reaction times and may behave more recklessly.
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Source: RD.com
