 study to investigate the possible effects on anxiety, depression, stress, and coping strategies in healthy human volunteers, a probiotic containing Lactobacillus helveticus R0052 and Bifidobacterium longum R0175 (Probio’Stick®) alleviated psychological distress, particularly depression, anger-hostility, and anxiety, and improved problem solving when taken for 30 days. The researchers concluded that L. helveticus R0052 and B. longum R0175 have beneficial psychological effects in healthy humans.
Psychobiotics can also help boost mood and ease anxiety in people suffering from various chronic diseases. The same probiotic studied above (Lactobacillus casei strain Shirota) was used in another double-blind, placebo-controlled trial in patients with chronic fatigue syndrome.
Patients were randomized patients to receive either 24 billion colony forming units of Lactobacillus casei strain Shirota or a placebo daily for two months. The people taking the probiotic had a significant decrease in anxiety symptoms.
Many additional psychobiotics have been shown to treat depression and anxiety in animal studies. Lactobacillus plantarum strain PS128, for example, is known to increase dopamine and serotonin and decrease depression-like behaviors in mice. In depressed mice that have been subjected to early-life stress, this same psychobiotic decreases cortisol, normalizes the stress response system (the HPA axis), and decreases depression.
Both Bifidobacterium longum 1714 and Bifidobacterium breve 1205 reduce anxiety-like behavior and improve performance on cognitive tests in anxious mice.[12,13]
Psychobiotics for Stress
Psychobiotics have also been shown to help people and animals undergoing stress. A fermented milk drink (kefir) that contained Lactobacillus casei strain Shirota prevented stress-related cortisol increases and raised serotonin levels in stressed medical students. Moreover, the probiotic drink decreased stress-related physical symptoms such as abdominal pain and cold symptoms.
The study authors concluded that taking Lactobacillus casei strain Shirota “…may exert beneficial effects preventing the onset of physical symptoms in healthy subjects exposed to stressful situations.”
Lactobacillus helveticus NS8 was compared to the SSRI, citalopram, in rats with depression, anxiety, and cognitive dysfunction due to chronic stress. The probiotic worked better than citalopram in reducing stress-induced anxiety, depression, and cognitive dysfunction. It lowered cortisol and restored serotonin and other brain neurochemical levels to normal.
Other Lactobacillus helveticus-containing probiotics have also been shown to reduce stress-related depression and anxiety by affecting serotonin, cortisol, and other neuroactive compounds in animal studies. For example, Lactobacillus helveticus R0052 combined with Lactobacillus rhamnosus R0011 normalized anxiety-like behavior and learning and memory impairments in immune-deficient rats with HPA-axis dysfunction.