Probiotics and mental health: 'A promising area for our future research' — Yakult

Speaking at our first Probiota Asia summit, the company’s senior researcher Toshihisa Ota outlined the vast array of trials that had featured Yakult’s Lactobacillus Casei Shirota​ strain over its 80-year history.

He pointed to positive results for gut health, diabetes, irritable bowel disease, immunity, and cancer care.

But he said cognitive health, and especially mental health, was now worthy of further examination.

In his presentation, he focused on a recent trial​ that showed the strain's beneficial effects on subjects with physical stress.

Ota elaborated on three double-blind, placebo-controlled trials conducted to examine the effects of the probiotics on psychological and physiological stress responses in healthy medical students facing exam stress.

Stress suppressed

Subjects received LcS-fermented milk or a placebo daily for eight weeks prior to taking a national exam.

Subjective anxiety scores, salivary cortisol levels, and the presence of physical symptoms during the intervention were pooled and analysed.

"Academic stress-induced increases in salivary cortisol levels and the rate of physical symptoms were significantly suppressed in the probiotics group," ​said Ota.

Meanwhile, studies carried out on rats suggested that probiotics suppressed water avoidance stress-induced increases in plasma corticosterone.

The paper, published in the journal Neurogastroenterol Motility​, stated: "These findings suggest that LcS may prevent hypersecretion of cortisol and physical symptoms under stressful conditions, possibly through vagal afferent signalling to the brain and reduced stress reactivity in the ​paraventricular nucleus."​

Ota told the summit, organised by NutraIngredients-Asia and held in Singapore, that future research could assess the impact of the strain on depression and autism.

"We have 80 years of history behind us, but there is still so much we don't yet know about the positive effects of Yakult,"​ he added.

Ota said Yakult has research institutes in Japan and Europe, while the Shirota strain now has more than 100 published papers to its name.