Weighing two to four pounds, the “friendly” microbes in your colon are considered so important, some of the best scientists in America have been enrolled by the National Institutes of Health to explore their association with health and disease.

They affect us in multiple ways including production of vitamins, neurotransmitters and hormones; detoxification; the ability to resist infection; what kind of mood we are in and even our weight.

Our whole physical and emotional health hinges on the condition of the trillions of cells that make up the gut microbiome. So what’s the best thing you can do to support them? Here’s a recent finding.

The study was conducted to find out the best way to build healthy gut flora. Should we buy probiotic drinks, a fermented drink called kefir, or eat foods that feed the good bacteria?

The findings were fascinating.

For the study, UK science journalist and medical doctor Michael Mosley teamed up with Dr. Paul Cotter from the Teagase Research Center in Cork, Ireland and scientists from the University of Roehampton.

30 volunteers were divided into three groups taking either an off-the-shelf probiotic drink containing a few species of bacteria, a fermented milk product called kefir which contains multiple strains of friendly bacteria, or foods rich in inulin, a prebiotic fiber that feeds the good bacteria already living in the intestines.

Kefir Comes Out on Top

At the end of four weeks, those consuming the probiotic drink saw an increase in a type of bacteria called Lachnospiraceae that is known to help in reducing weight. But the change was too small to be considered significant.

The group eating foods containing inulin (onions, leeks, garlic, chicory root, Jerusalem artichokes) saw significantly greater amounts of a bacterium known to improve the general health of the gut.

Other studies have reported the same outcome.

However, by far the biggest change was seen in those drinking kefir. Here there was an increase in a group of bacteria called Lactobacillates. Some of these are known to help in conditions such as lactose intolerance and traveler’s diarrhea, but they are also beneficial for the overall health of the gut.

Microbes in Fermented Foods Survive Stomach Acid

Commenting on the kefir findings Dr. Cotter said, “Fermented foods by their very nature are quite acidic and so these microbes have had to evolve in order to cope with these sorts of environments, so they’re naturally able to survive in acid.

“That helps them to get through the stomach in order to then have an influence in the intestine below.”

After completing the study, the researchers went on to compare a range of fermented foods that can be bought in shops with homemade varieties made according to traditional principles.

Shop-Bought Products Found Wanting

They found some marked differences. While the homemade fermented products contained a diversity of bacteria, some of the shop-bought ones contained scarcely any.

According to Dr. Cotter, “Typically, with commercial varieties, they would be subjected to pasteurization after preparation to ensure their safety and extend their shelf life which can kill off the bacteria, whereas that wouldn’t be the case for the homemade varieties.”

If you would like to ferment your own foods, there are plenty of YouTube videos that can show you how. It’s not hard.

If you are interested in purchasing kefir, bear in mind that it is tart and fizzy and the taste does not appeal to everyone, although it can be blended with banana and sweetened with stevia.

Because the best kefir is very strong, live, active and continues to ferment in the bottle, the fermentation gases will be ready to burst out of the bottle, so be very careful when opening for the first time.

The recommended dose is six fluid ounces a day taken first thing in the morning.


  1. http://www.bbc.co.uk/news/health-38800977