The Ultimate Guide To Your Gut

The bacteria in your intestines affect whether you’ll have allergies, your risk of depression— and even how well your medication works

- Vanessa Milne

A DECADE AGO, Kaitlyn, a 28-year-old support worker living in Ontario, Canada, became very ill. She had painful constipation and was contracting fevers and losing weight. “If I ate too much, I would vomit,” she says.

After tests ruled out Crohn’s disease and colitis, Kaitlyn’s family doctor diagnosed her with irritable bowel syndrome (IBS), a chronic disorder that causes cramping, pain and bloating along with constipation or diarrhoea.

While IBS can’t be cured, it can be managed through lifestyle changes. A dietitian suggested to Kaitlyn that the bacteria that lived in her intestines— collectively known as the gut microbiome—might be out of balance, contributing to her condition. She recommended Kaitlyn take probiotics—pills that contain specific strains of bacteria—to help put things in order.

After only a few days of taking the probiotics, Kaitlyn felt a lot better. “The pain and fevers went away, and I was able to eat without getting sick,” she says. She still needed to avoid specific foods that trigger her condition, but gained back some of the weight she had lost.

The state of our gut microbiome impacts many facets of our physical and mental health. But what is it, exactly?