Study supports probiotic yogurt’s immune boosting effects

12-Jun-2017 - Last updated on 19-Jun-2017 at 11:23 GMT

Yogurt containing two probiotic strains plus heat-treated bacteria may boost the activity of immune cells called natural killer (NK) cells in people over 60, says a new study.

Twelve weeks of consuming yogurt containing a combination of Lactobacillus paracasei ssp. paracasei (L. paracasei), Bifidobacterium animalis ssp. lactis (B. lactis) and heat-treated Lactobacillus plantarum (L. plantarum) also led to significant increases in levels of immunoglobulin (Ig) G1 (a type of antibody), compared to placebo.

“The results suggest that daily consumption of dairy yogurt containing L. paracasei, B. lactis and heat-treated L. plantarum could improve immune function by enhancing NK cell activity,” wrote scientists from Yonsei University and Purmil Co., Ltd. in Nutrients.

Study details

The Korea-based scientists recruited 200 non-diabetic elderly people to participate in their randomized, open-label, placebo-controlled study. The volunteers were randomly assigned to consume placebo or a yogurt with 1.2 billion CFUs per day of L. paracasei (L. casei 431, Chr Hansen), 1.2 billion CFUs per day of B. lactis (BB-12, Chr Hansen) and 0.0175% heat-treated L. plantarum (Biogenics Korea Co) for 12 weeks.

Results showed that, compared to baseline values, significant increases in NK cell activity were observed, as were levels of interleukin (IL)-12 (a “communicator” molecule in the immune system) and IgG1.

Compared to placebo, NK cell activity, and levels of IgG1 and interferon (IFN)-gamma were increased.

Immune-enhancement

“NK cells provide a substantial defense against viral infection, and low NK cell activity was shown to be associated with the development of infections in healthy elderly subjects,” wrote the researchers. “In a murine experiment, NK cells were shown to be a major source of IFN-gamme, a potent immune-stimulatory cytokine also known for its antiviral, immunoregulatory, and anti-tumor properties.

“IFN-gamma also has an effect on NK cell regulation; therefore, the increase in serum IFN-gamma concentration accompanying the increase in NK cell activity measured in the test group in this study could have contributed to the immune-enhancing action of supplementation with dairy yogurt containing L. paracasei, B. lactis and heat-treated L. plantarum.”

Source: Nutrients
2017, 9(6), 558; doi:10.3390/nu9060558
“Consumption of Dairy Yogurt Containing Lactobacillus paracasei ssp. paracasei, Bifidobacterium animalis ssp. lactis and Heat-Treated Lactobacillus plantarum Improves Immune Function Including Natural Killer Cell Activity”
Authors: A. Lee et al.