Probiotics are micro-organisms that have a beneficial effect on their host. They promote intestinal function and digestion and help balance the population of other such organisms that live in all our guts.
To be of benefit, they need to survive the journey through the digestive system to reach the intestines alive.
A simple answer
When I started conducting research into the health effects of probiotics more than a decade ago, I asked a research scientist who had been investigating these micro-organisms for some time if he believed they really improve gastrointestinal health and, if so, which preparation he would recommend.
His answer surprised me. I was expecting to be presented with a bottle of “the world’s most amazing probiotic pills”. Instead, he said yoghurt was possibly the best source of probiotics available on the market.
He recommended I go to the supermarket and select the tub of yoghurt with the longest shelf life, because its probiotic cultures would likely still be viable and able to colonise my gastrointestinal tract.
Labna or labneh is a Middle Eastern cream cheese-like spread made from yoghurt.
I recall asking myself if it could really be that simple, when there are research companies around the world spending millions to create products containing patented strains of probiotic bacteria for targeting specific ailments.
Indeed, the commercial market is flooded with probiotic products that invariably claim they will improve gastrointestinal health. These products include capsules, tablets, yoghurt, gummy lollies, infant formula and beverages, to name just a few.
What’s more, some strains may not possess the robustness to transit through to the colon (the large intestine) because of the bile salts and gastric acids they encounter along the way.
The good news
But it was recently reported that probiotic bacteria found in common fermented foods, such as yoghurt, can reach the gut in high numbers, increasing the likelihood of beneficial effects from consuming these foods.
Consistent with this are other reports that probiotics may lead to improved immunity and a reduction in infectious and inflammatory diseases by enhancing various components of the immune system.
And there’s more good news. A recent study published in the British Journal of Nutrition suggests some probiotics may even help women lose weight. For reasons that remain unclear, the same effect wasn’t found for men.
Another study found a substantial reduction in the risk of developing type 2 diabetes among people who ate yoghurt compared to those who didn’t.
Although all this doesn’t prove that probiotics confer a health benefit, the study authors speculate that probiotic bacteria and a special form of vitamin K associated with fermentation may at least contribute to this effect.
So are probiotics good for the digestive system and health generally, or do those that appear to be effective simply exert a placebo effect? And what is the best form to have them in?
Let them eat yoghurt
A growing body of scientific evidence suggests some commercially available probiotics are effective, while others don’t lead to the claimed health benefits. The problem is telling them apart.
Given this and the remaining question marks over whether probiotics have expected health-related effects, the answer may lie with what my senior researcher told me all those years ago.
Many people like eating yoghurt, which is one of the fermented products containing probiotics that do confer a benefit. And given it is a good source of many essential nutrients, including protein, calcium, vitamin A, vitamin B12 and riboflavin, there are also sound nutritional reasons for consuming this product.
Of course, people who are lactose-intolerant should be careful about how much and what kind of yoghurt they eat, if any. Some lactose-intolerant people find they can consume certain types of yoghurt with little or no resulting discomfort because traditional methods of production involve reducing milk’s lactose content.
But some commercial brands have added milk solids, which contain lactose. So, look at the ingredient list carefully if you are lactose-intolerant, and enjoy the form of probiotics with the greatest known benefit.
Chris Forbes-Ewan, Defence Science and Technology Organisation, receives funding from the NHMRC.
Paul Capela, Defence Science and Technology Organisation, does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations.