So-called ‘good bacteria’ that are contained in many popular probiotic drinks are “quite useless,” according to a group of scientists in Israel. Until now, probiotics have been seen as healthy and good for the gut, but the findings of the team from the Weizmann Institute of Science show otherwise. Their study is among the most detailed analyses to date of what happens when we consume probiotics. For their research, the team created a cocktail containing 11 common good bacteria and gave it to 25 healthy volunteers. Samples were then taken from each of the volunteer’s stomachs, as well as their small and large intestines. The scientists were looking to see where the bacteria successfully colonised and whether any changes in the activity of the gut were evident. Publishing their findings in the journal Cell, the scientists said that in half of cases the good bacteria literally went in one end and out the other, without providing any benefits whatsoever. In the rest, they hung around for a bit before being overwhelmed by the bacteria that commonly frequents our bodies. Speaking about the research, Dr Eran Elinav said people should not expect off-the-shelf products to provide them with definitive health benefits. He suggested that the future of probiotics lies in creating bacteria cocktails that are tailored to the specific needs of individuals. “And in that sense just buying probiotics at the supermarket without any tailoring, without any adjustment to the host, at least in part of the population, is quite useless,” he said.
Most people get cravings for high-calories foods, such as chocolate and pizza, from time to time. But new research suggests that such cravings can be reduced by consuming a supplement called inulin-propionate ester. Researchers from Imperial College London and the University of Glasgow found that study participants who drank milkshakes containing the gut bacteria-based supplement were less likely to crave high-calorie foods. Presenting their findings in The American Journal of Clinical Nutrition, the researchers said the supplement works by increasing the amount of propionate in the gut - a compound that is released naturally when a person consumes the fibre inulin, which is found in artichokes, bananas and asparagus. Inulin slows digestion, increase fullness and reduces appetite, and it is already used as a dietary supplement today. For the study, the researchers asked a group of 20 healthy men to drink milkshakes. Half of the group's milkshakes contained inulin-propionate ester, while the other half contained just inulin alone. The researchers then showed the men pictures of different foods; some high calorie, some low calorie. The study participants' brain activities were monitored throughout to see how they reacted to the various pictures. The group that drank the milkshakes containing inulin-propionate ester displayed reduced activity in their brains' reward centres - the caudate and the nucleus accumbens (both associated with food cravings) - but only when they were looking at images of high-calorie foods. In addition to being showed the food images, the men were then given equal-sized bowls of pasta and told to eat as much as they wanted. The inulin-propionate ester group consumed around 10% less than their inulin only counterparts. Dr. Douglas Morrison from the University of Glasgow, who co-authored the study, said that the research illustrates how important gut microbiota signals are for regulating appetite and influencing people's food choices.
New research suggests that the impact of dietary fats on our overall health is likely to be affected by the changes they cause in the stomach’s bacteria ecosystem. The findings, which were obtained by studies in mice, show that diets rich in omega-3 fats, such as fish oil, affect the gut’s balance of bacteria differently to diets rich in lard. Senior researcher Professor Fredrik Bäckhed, from the University of Gothenburg’s faculty of Health Sciences, also known as the Sahlgrenska Academy, led the team of European researchers who discovered that changes in gut microbiota are responsible for some of their health benefits. “We wanted to determine whether gut microbes directly contribute to the metabolic differences associated with diets rich in healthy and unhealthy fats,” said first study author Robert Caesar from the University of Gothenburg. And, even though the study was done in mice, he said: “our goal is to identify interventions for optimising metabolic health in humans.” Writing in the journal Cell Metabolism, Bäckhed’s team said they obtained their results by feeding either lard or fish oil to a group of mice for a period of 11 weeks. They then monitored the metabolic health of the study mice and found that dietary fat is a major community structure driver, which in turn affects the composition and diversity of gut microbiota. “We were surprised that the lard and the fish oil diet, despite having the same energy content and the same amount of dietary fibre—which is the primary energy source for the gut bacteria—resulted in fundamentally different gut microbiota communities and that the microbiota per se had such large effects on health,” said Bäckhed. Increased lard consumption promoted the growth of Bilophila, bacteria often linked to gut inflammation. In contrast, the fish oil diet increased the growth of Akkermansia muciniphila, bacteria known to reduce weight gain and improve glucose metabolism in mice. The bottom line is that eating a diet rich in fish oils is, as the study suggests, going to help you lose weight, compared to a diet rich in lard.