Higashikawa, F., Noda, M., Awaya, T., Nomura, K., Oku, H., & Sugiyama, M. (2010). Improvement of constipation and liver function by plant-derived lactic acid bacteria: A double-blind, randomized trial. Nutrition, 26, 367–374.

To evaluate the effects of yogurts made with different types of lactic acid bacteria (LAB) on the gastrointestinal system.

Participants were recruited via advertisement. Consenting patients were assigned using stratified randomization by defecation frequencies to receive one of three types of yogurt.

• Type A: plant-derived LAB—Lactobacillus plantarum—SN35N (95%) with SN13T (5%)
• Type B: plant-derived LAB—Lb. plantarum—SN13T (98%) with SN35N (2%)
• Type C: animal-derived LAB—Lb. lactis A6 (86.1%), Streptococcus thermophilus 510 (13.8%), and Lb. bulgaricus C6 (0.1%)

Participants consumed 100 g of yogurt daily for a six-week period. Data were collected from clinic visits at two-week intervals.

• The study reported on a sample of 68 patients aged 21 to 65 years.
• The sample comprised 49 women and 19 men.
• Patients were healthy adults with some complaints of intestinal health, such as constipation, diarrhea, abdominal pain, and bloating.

Hiroshima, Japan

This was a randomized, double-blind study.

Bristol Stool Form Scale

• No statistical difference existed between the study types (groups A and B) and the control (group C).
• Total cholesterol decreased significantly in all individuals from 214.3 mg/dl at baseline to 203.2 mg/dl at six weeks (p = 0.012) in group B, but not in groups A and C.
• No participants reported any significant adverse events resulting from yogurt intake during the trial.
• No abnormal changes in urine analysis or serum biochemical parameters were observed during the study.

In healthy adults, Lb. plantarum SN13T may improve serum lipid levels and liver function. Actual effects in relieving constipation are unclear.

• The sample size was small (fewer than 100).
• The study did not include patients with cancer.

Effects in relieving constipation are unclear in healthy adults. Additional studies are warranted that include a larger sample and patients with cancer.