Gut: The Inside Story of Our Body's Most Under-Rated Organ

by Giulia Enders

those in the brain — so how much of the relaxing effect of that ‘just one glass of wine’ in the evening actually comes from a sedated gut brain? What about the array of bacteria in the wide range of yoghurt on our supermarket shelves? Is Lactobacillus reuteri better for me than Bifidobacterium animalis? A team of Chinese researchers managed to show in the laboratory that Lactobacillus reuteri is able to inhibit pain sensors in the gut. Lactobacillus plantarum and Bifidobacterium infantis could already be recommended as a pain treatment for patients with irritable-bowel syndrome. Many patients with a low pain threshold in the gut currently take substances designed to treat diarrhoea, constipation, or cramps. That might help with the symptoms, but does not address the cause of the problem. If, after eliminating possible food intolerances and re-stocking the gut flora, there is still no improvement, we must take the problem by the scruff of its neck — or, in this case, by the nerve-cell threshold. So far, very few treatments have been scientifically proven to be effective. Those which have, include cognitive behavioural therapy and hypnotherapy.

The vast majority of our immune system (about 80 per cent) is located in the gut. And with good reason. This is where the main stage at the bacterial Woodstock is situated, and any immune system worth its salt must be there, or be square. The bacteria are confined to a fenced-off area — the mucous membrane of the gut — preventing them from getting too dangerously close to the cells of the gut wall. The immune system is able to play with the cells without ever posing a danger to the body. This allows our defender cells to get acquainted with many previously unknown species.

Practitioners of traditional Chinese medicine who were visiting the institute in Heidelberg at the time of this discovery recognised an opportunity to combine their ancient knowledge with modern medicine. Classical Chinese medical theory has always divided people into three groups, according to how they react to certain medicinal plants, such as ginger. The families of bacteria in our bodies also have different characteristics. They break down food in different ways, produce different substances, and detoxify certain harmful substances but not others. Furthermore, they may also influence the gut flora by either encouraging or attacking bacteria from the other two groups.

The important thing is not to reduce the human body to a two-dimensional cause-and-effect machine. The brain, the rest of the body, bacteria, and the elements in our food all interact with each other in four dimensions. Striving to understand all these axes is surely the best way to improve our knowledge. However, we can more easily tinker with bacteria than with our brain or our genes — and that is what makes microbes so fascinating. The nutrition we receive from our bacteria is not only important for fighting flab, it also affects the levels of fats such as cholesterol in our blood, for example. This realisation could be quite highly charged: obesity and high cholesterol levels are closely connected with the greatest health issues of our time: hypertension, arteriosclerosis, and diabetes.

Cabbage is the classic, but almost any vegetable that can be eaten raw can also be fermented. Carrots and gherkins, for example (gherkins are the pinnacle of pickling, however, since precise procedures must be followed if they are to remain crisp to the bite). Some good bacteria will already be on the cabbage leaves or the skin of the carrots, so there is no need to add any particular bacteria to them. This is why it can be beneficial to buy vegetables that have not been treated with pesticides, etc. Depending on how long you want the fermentation process to take, slice your vegetables thinly or grate them (= one week’s fermentation time) or leave them whole (= four to six weeks’ fermentation time). You need to make sure you avoid contamination as you work. You don’t want just any old kitchen bacteria joining your product in the jar. Add 10 to 15 grams of salt for every kilogramme of vegetables. This slows the growth of bacteria in general, preventing bad germs from commandeering the process before the good ones can do their work. It is important to add the correct amount of salt: too much will prevent the fermentation process altogether; too little can result in the food going off and tasting bad. Sea salt is a good choice, but do not use iodised salt, as the iodine inhibits the bacteria’s growth too much. Knead the mixture with appropriate fervour. This is to mix the salt well into the concoction, and helps to partially break down particularly tough cell walls. The salt ...