Q. What is the microbiome and what does it do?

A. The microbiome is the collection of up to one trillion microorganisms that populate the human gastrointestinal tract. Weighing in at around three kilograms, it contains both good and bad microbes. And we do need both: it's only when the pathogenic types are allowed to multiply that they become a problem. A good healthy microbiome improves immunity, and offers some protection against disease. Our microbiome is damaged by: high-fat diets, diets high in meat and processed meats, and hand sanitising.

Determining the health of our microbiome is difficult, as currently only limited – and expensive – testing is available. One possible indicator of upset microbiome is a tendency to crave more carbohydrates, and possibly increased wind and gas, constipation or loose bowel motions. However, these symptoms also relate to other conditions, so consult a healthcare professional.

The best way to protect our microbiome is by eating well. Legumes, whole grains, and organic, fresh, whole fruit and vegetables (minimum two fruits and five vegetables per day) boost fibre intake, which is particularly important for a healthy microbiome. Inulin-containing foods such as onions feed a special type of immune-promoting bacteria called actinobacteria. Probiotics may be beneficial, but seek professional advice as probiotic strains and genus need to be rotated. Prebiotics also help, so eat fermented foods such as kombucha, sauerkraut, kimchi, along with ground seeds, asparagus and garlic, provided you can tolerate it. Garlic is both anti- and prebiotic, fostering the growth of healthy microbes and eliminating unhealthy ones. Gardening is good for your gut health, because the microbe exposure you get when working with soil is very beneficial for our microbiome.

ATMS member Teresa Mitchell-Paterson BHSc (CompSci) MHSc (HumNut) AdvDipNat is a member of the Australian Traditional Medicine Society.