As we age, our immune system gradually deteriorates and we become more susceptible to certain infections. A recent study suggests that yogurt containing the probiotic strains Lactobacillus paracasei ssp. paracasei (L. paracasei), Bifidobacterium animalis ssp. lactis B (B. lactis), and heat-treated Lactobacillus plantarum (L. plantarum) may help increase the activity of natural killer immune cells in people over the age of 60.

Participants in the study included 200 non-diabetic mature adults who were given either yogurt containing 1.2 billion CFUs of L. paracasei, 1.2 billion CFUs of B. lactis, and 0.015% heat-treated L. plantarum daily or a placebo for 12 weeks.

At the conclusion of the study, the researchers noted significant increases in natural killer cell activity in the supplement group. They also noted increases in the immune system communicators interleukin-12 and IgG1.

Researchers from Yonsei University in Korea led the study. It was published on May 31, 2017, in the journal Nutrients.

L. paracasei is a probiotic that has been found in previous studies to aid digestive health and boost the immune system. B. lactis has been found in previous studies to support digestive and immune health, healthy cholesterol levels, and help with ulcerative colitis. Both can be found in fermented foods and dairy products. L. plantarum can be found in fermented foods such as Korean kimchi, sauerkraut, and human saliva. Previous studies have shown it may help with easing symptoms of Irritable Bowel Syndrome, Chrohn’s disease, and colitis.