The beneficial bacteria found in fermented milk products strengthen the immune system and improve digestion. But can they influence our mood? This question was answered by cognitive psychologists from two Dutch universities. Details.
The results of the study clearly demonstrated that taking probiotics (food supplements containing beneficial bacteria) improves mood (1). The study was based on data that the intestinal microflora can influence (directly and indirectly) brain processes, and hence cognitive and affective reactions. One known sign of an increased risk of depression is more aggressive or repetitive thoughts as a cognitive response to ordinary sadness.
The experiment of scientists involved 40 healthy people who do not suffer from mood swings, depression or anxiety. Half of them took medications containing eight different types of beneficial bacteria for four weeks, which studies show to alleviate symptoms of depression and anxiety. The second group received a placebo.
Before and after the start of the experiment, the researchers tested all participants on a depression sensitivity scale. Before the experiment, there were no significant differences between the condition of the participants in the two groups. But after four weeks, those who took the probiotics showed a significant decrease in cognitive response to sadness compared to the other group, and thus a lower risk of depression.
Read more:
- Why do we need probiotics
During the experiment, scientists did not set out to determine through which biological mechanisms probiotics affect our mood. It is possible that beneficial bacteria strengthen the epithelium and thereby reduce the permeability of the intestinal wall, and other studies have shown that increased permeability correlates with symptoms of depression. Another hypothesis is that probiotics increase levels of tryptophan, an amino acid that is involved in the production of serotonin, which in turn contributes to our resistance to mood swings…
However, the effect of probiotics on human well-being is still poorly understood, and larger and longer studies are required. But even preliminary results give hope that they may be useful not only for improving digestion, but also for preventing depression.
(1) L. Steenbergen et al. «A randomized controlled trial to test the effect of multispecies probiotics on cognitive reactivity to sad mood», Brain, Behavior, and Immunity, онлайн-публикация от 7 апреля 2015 года.