The research, published in British Journal of Nutrition, finds that continuous intake of milk containing Lactobacillus casei strain Shirota (LcS) reduces the duration of fever caused by norovirus gastroenteritis, but does not offer protection from the illness.
A team of Japanese researchers based at Juntendo University, working in partnership with scientists from the Yakult Central Institute for Microbiological Research, found that elderly people provided with LcS-fermented milk had reduced fever durations after the onset of infectious gastroenteritis caused by norovirus.
“Although the continuous intake of LcS-fermented milk did not prevent infectious gastroenteritis caused by norovirus […] it was found that the fever associated with gastroenteritis was alleviated, and that the internal flora and environment were optimised,” said the researchers, led by Dr Satoru Nagata from Juntendo University
Dr Nagata and colleagues explained that many incidences of norovirus gastroenteritis have been reported in recent years.
According to the Centers for Disease Control and Prevention in the USA, most cases of infectious gastroenteritis caused by norovirus occurred at elderly welfare facilities.
The researchers explained that in infectious gastroenteritis caused by norovirus, “fever is one indicator that the disease may become severe.”
As such, in elderly care facilities, the prevention and management of norovirus gastroenteritis has thus become extremely important, they added.
Nagata and co-workers explained that elderly people are especially prone to infection, as many physiological and immune responses as well as organ functions decline with age.
“An infection under these conditions tends to be refractory and becomes severe. In elder care facilities, it is highly likely that an infection, after it breaks out, will spread easily among residents,” they noted.
“Lactobacillus casei strain Shirota (LcS) is the most common probiotic bacterium and is clinically proven in many reports to have an immuno-enhancing effect, protective effects against post-operative infectious complications, cancer and allergies, and to regulate intestinal function,” wrote the authors.
Seventy seven frail, elderly, care home residents were enrolled in the trial of LcS-fermented milk. Half were given a test diet consisting of fermented milk containing LcS.
The researcher reported that there was no significant difference between the two groups in terms of norovirus incidence, or in terms of the number of days on which diarrhoea and vomiting were observed – indicating that the LcS-fermented milk offered no protection from norovirus infection.
However, Nagata and colleagues reported that the duration of norovirus induced fever was significantly reduced in the LcS fed group.
“Compared with the non-administered group, there were fewer days of fever […] in the LcS-fermented milk-administered group during the same period,” wrote the authors.
“The intestinal flora and environment of the residents of the investigated facility were disturbed, and the possibility that such residents may have been highly susceptible to harmful bacteria in the intestine is strongly suggested; however, with the intake of LcS-fermented milk, the population of Bifidobacteria increased, which significantly optimised the intestinal environment, thereby limiting the growth of harmful bacteria in the intestine based on the findings of previous experimental and clinical studies,” concluded Nagata and co-workers.
“It is therefore suggested that the continuous intake of LcS-fermented milk helps the residents of elderly care,” they added.
Source: British Journal of Nutrition
Published online ahead of print, doi: 10.1017/S000711451100064X
“Effect of the continuous intake of probiotic-fermented milk containing Lactobacillus casei strain Shirota on fever in a mass outbreak of norovirus gastroenteritis and the faecal microflora in a health service facility for the aged”
Authors: S. Nagata, T. Asahara, T. Ohta2, T. Yamad, S. Kondo, L. Bian, et al