Feeding your friends

The past number of years has seen an explosion of research into ‘the microbiome’, the technical term for the trillions of bacteria living in our guts, and on our skin. After a lot of research, it’s been determined that we are around 76% human, the rest of our genes are bacterial in origin.

We know that diet is a strong influence on these bacteria, on which ones are more active, and how they influence our health. Recently there has been a lot of focus on a type of diet known as the ‘ketogenic diet’, which is a diet with <10% carbohydrate and is up to 70-80% fat. Now, while there is nothing wrong with high fat diets, with any diet it is important to consider that if anything is that high, what loses out? What is replaced?

Unfortunately, while a ketogenic diet can be done well, it is very difficult to do well, and what is happening all too often in the real world is people are eating steak and butter, with minimal veg and no fruit intake. And this approach appears to have profoundly negative effects on the microbiome.

You see, the species of bacteria in the gut which we associated with beneficial influence on of immune system, mood, and digestion, are all species which preferentially feed off carbohydrates that we lack the enzymes to digest, namely fibre. Because we can’t digest fibre, they enjoy free access to this, and as they degrade fibre in our guts they produce beneficial byproducts that we can use for better gut health, amongst other benefits.

When we take fibre out, we shift the composition of the gut bacteria to species that cause inflammation, and are potentially carcinogenic. And research has shown that high fat, higher protein diets that lack fibre cause this shift in gut bacterial composition. So, at this point we have enough evidence of caution against dropping all carbs, which currently we have a real fad movement of doing.

But let’s not confuse chickpeas with a can of Coke: carbohydrate quality matters. So, to keep your gut bugs happy, don’t adopt any diet that mandates that level of carbohydrate restriction. Eat your oats, lentils, chickpeas, and other beans, your dark green leafy veg, fruit, and wholegrains (like brown rice or wholegrain pasta).

Recent research found that consuming 30 different species of plants each week was associated with the most diversity of beneficial bacteria in the gut. So, make that your goal for this week! Diversify your veg, eat a wide variety of fruits, include different seeds, and rotate your starch and wholegrain intake.