Probiotics cannot compensate for an unhealthy diet or lifestyle, but solid research suggests that they can be an effective part of a treatment plan for a variety of illnesses:
Irritable bowel syndrome: A meta-analysis of 20 probiotic trials found that probiotics improved IBS symptoms, including diarrhea, bloating, gas, and abdominal pain.
Ulcerative colitis: One review of studies found that active ulcerative colitis responded well to a combination of Lacto-Bifido probiotics and an anti-inflammatory medication.
Mood disorders: A meta-analysis of 10 clinical trials reported that probiotics improved mood in those presenting with mild to moderate depressive symptoms, while another meta-analysis concluded that probiotics were associated with a significant reduction in -depression for people under 60.
The effect of probiotics on anxiety symptoms is less decisive; in one review, about half of the studies examined found that probiotics eased anxiety. (For more on using probiotics to treat mood disorders, see “Psychobiotics: Using Gut Bacteria to Treat Mental Illness”.)
Leaky gut syndrome: A randomized, double-blind, placebo-controlled trial of Lactobacillus to treat children who had acute gastroenteritis noted that the probiotic helped rebuild intestinal integrity after infection. Another study of a soil-based probiotic found it reduced symptoms associated with leaky gut in adults.
Microbiome imbalances: Evidence suggests that some probiotics are as effective as antifungal drugs in preventing the overgrowth of candida and other fungi in premature infants and can help reduce bacterial overgrowth in patients with small intestine bacterial overgrowth, or SIBO.
In addition, there is limited but encouraging evidence that probiotics can address numerous issues: sleep, lactose intolerance, autoimmunity, atopic dermatitis, allergies, blood pressure, and cholesterol.