- Not all living foods are probiotic, but they offer some benefits.
- Keeping your gut healthy requires prebiotics, like fibre.
- Fibre feeds and strengthens the gut barrier function that protects against disease.
Humans aren't completely, well, human. Our bodies consist of 30 trillion human cells which make up only 43% of the total cells in our bodies. The other 57% are microbial cells, the tiny bacteria that help keep their hosts in good working condition.
One of the best ways to keep those microbes happy – and us healthy – is through probiotics. Many know it as the supplement with live organisms, which you take when on antibiotics to ensure that the medication doesn't kill all the good bacteria in the gut. Probiotics also come in food form, like yoghurt, amasi, kombucha, kimchi and sourdough bread.
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What is a probiotic?
But just because a food contains living bacteria, it doesn't automatically mean it's a probiotic, says Andrea Hardy, a registered dietitian and gut health expert from Canada who spoke at the recent One Health Summit Webinar.
According to the World Health Organisation, a proper probiotic has to be characterised as such; be proven safe for use; have a sufficient number of organisms to be beneficial; be able to survive the shelf life; and be supported by at least one peer-reviewed human trial study.
While yoghurt is the most popular probiotic food suitable for lactose intolerant people, in South Africa, it's actually illegal to label yoghurt as a probiotic.
Unregulated fermented foods
Some fermented foods also do not meet the criteria to be classified as probiotics.
Hardy says these foods touted as "probiotics" are not held to the same standards as other supplements and probiotic foods. Because the types and numbers of microbes differ widely between brands and even between batches, it's difficult to reliably track their benefits.
But that doesn't mean they don't offer other health benefits, including vitamins, minerals, fibre, phytochemicals and increased exposure to good microbes while suppressing the bad ones.
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How to treat probiotics right
The best way to introduce probiotics to your system is by ingesting them with food. It's also important to remember that it takes 14 days for the gut to recover from a course of antibiotics. This means taking probiotics while taking antibiotics and carrying on afterwards until your gut bacteria are back to normal.
When taking supplements, you should also make sure you're taking the right probiotic strain for the right reasons. You also need to know if you want to pep up existing microbes or introduce new organisms to increase diversity.
The importance of fibre
Before getting to probiotics, it's also important to remember the prebiotics. These are substances that help feed existing microbes and sustain diversity. According to Hardy, one of the most important of these is fibre.
Fibre helps maintain our gut barrier function – a defensive shield against invaders while nutrients are absorbed into the body. This barrier is created by gut microbes that digest the things we can't, which in turn, produces short-chain fatty acids (SCFA) that feed the epithelial cells. This whole system has a major effect on the immune system and immune tolerance.
This mechanism is very dependent on our diet – more so than medication and disease – and maintaining it requires a healthy intake of a variety of plants and dairy products. A traditional western diet high in fat and sugar can lead to a dysfunctional gut barrier, while a flexitarian approach with high plant, omega-3 and fibre intake, has a much more beneficial effect.
While not all fibre is prebiotic, it does help to increase SCFA production, thickening the barrier and reducing gut transit time and inflammation.
She recommends 25 to 38 grams of fibre a day. Other prebiotics you can include in your diet are onion, garlic, ginger, turmeric, oregano and cayenne pepper.
"If you don't feed your gut microbiota, they will feed on you."
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(Infographic: Gabi Zietsman)
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