Hearing you have an infestation of bacteria growing in your gut may tend to gross you out. And by infestation, I mean that literally. It’s estimated that the human gut contains 100 trillion bacteria—that’s 10 times as many bacteria as there are cells in the entire human body! And the medical community is learning more and more about how these bacteria influence our health. Here’s what you need to know.

Researchers are in the very early stages of understanding how differences in the composition of gut bacteria can influence human health. To date, here are five ways scientists have identified gut flora’s affect on our health and wellness.

  1. OBESITY A recent study found that obese people have less diversity in their gut flora than lean people. Research indicates that an increase in gut bacteria called Firmicutes, and a decrease in a gut bacteria called Bacteroidetes, are linked with obesity. And another study on mice paints an interesting and more conclusive picture. Two groups of mice received “gut bacteria transplants.” The group of mice who received gut bacteria from an obese person gained more weight and fat mass than the mice who received bacteria from a lean person. The transplant also altered the metabolism of the mice! The animals who received gut bacteria from an obese person had metabolic changes linked with obesity in humans (such as increased production of compounds called branched-chain amino acids); while those who received gut bacteria from a lean person had metabolic changes linked with reduced body weight (such as increased breakdown of carbohydrates).
  2. HEART DISEASE When gut bacteria feed on certain foods — including eggs and beef — they produce a compound called trimethylamine-N-oxide (TMAO) that can increase the risk of heart disease. According to a recent study, participants who had high levels of TMAO in their blood were 2.5 times more likely to have a heart attack, stroke or to die over a three-year period compared with people with low levels of the compound.
  3. IMMUNE SYSTEM Your gut is actually an incredibly important barrier between your body and the outside world (second only to your skin). Residing in the gut is the largest group of cells capable of mounting an immune response. The interaction between gut bacteria and your own cells appear to play an important role in the development of a fully-functioning immune system.
  4. YOUR BRAIN Studies suggest a disruption in gut flora may effect the brain, and by extension—behavior. In 2011 researchers performed another study using mice which found that the animals given antibiotics (which kill gut bacteria) became less anxious when their gut bacteria was restored. The mice given the antibiotics also showed changes in their brain chemistry—changes which have been linked to depression. Researchers suspect the bacteria are producing chemicals that can influence the brain. If gut bacteria play a role in human behavior, it is possible that therapies which aim to restore normal gut flora (such as probiotics) may be helpful in correcting behavior and mood changes in people with gastrointestinal diseases.
  5. INFANT COLIC Recent research suggests abnormal gut bacteria in infants may be a cause of colic (excessive crying). In the study, colicky babies (who cry for more than three hours per day without medical reason) had a distinct “bacterial signature.” They had higher numbers of Proteobacteria bacteria in the gut compared to babies without colic. Proteobacteria include bacteria known to produce gas—which may cause pain in infants which results in lengthy crying spells.

Science seems to be on to something big in this arena, but we are only at the tip of the iceberg in terms of our understanding it. With the myriad of health benefits a healthy gut provides, we should all seek to have one, though that aim may prove more complicated than you might think.

Probiotic supplements seem an easy solution, but experts caution about the tricky nature of both food and supplement labeling. Some probiotics have a single strain of organisms, while others contain multiple strains. Different strains of the same species may even be different, and thus have different effects on your health. Concentrations are also a factor. Some supplements may provide a live microbe count “at the time of manufacture,” which does not guarantee this same amount will be available when you buy the product or consume it. And some consumer testing labs found that the less reputable brands far overstate their counts of cultures.

In the coming years we will begin to see a clearer, bigger picture regarding the roll of the gut flora. But given that cold and flu season is just around the corner, it can’t hurt to get a supplement to help boost your immunity (after all probiotics have far better effects than Emergen C). Just ensure you purchase from a reliable supplement manufacturer or health food store. Happy digesting….

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