Giving extra leucine, glutamine, arginine and vitamins to elderly persons who are ill improves their immune system. According to researchers at the University of Tokyo, such a supplement increases the activity of the Natural Killer cells.
You can compare the Natural Killer cells in your body to a somewhat rough but highly effective unit of Marines who come into action when acting quickly is more important than acting correctly.
Natural Killer cells attack deviating cells, such as cells that become cancerous or cells infected by a virus. Scientists consider Natural Killer cells as part of the innate immune system, which is commonly referred to as 'natural resistance'. This natural resistance is a more primitive part of our immune system.
The more advanced part of our immune system is capable of learning. It collects information about new intruders and develops specialised cells to eliminate these intruders. But this is not the subject of this article.
Twice a day for 8 weeks, researchers gave a group of 70- and 80-year-old ill persons a supplement whose composition is shown below. The supplement supplied 1200 mg of leucine, 600 mg of glutamine and 500 mg of arginine daily. It was administered as a powder that the subjects had to dissolve in water.
After 4 weeks [Mid-point] and again after 8 weeks [Post-point] the researchers drew blood from the subjects and extracted the Natural Killer cells, which they added to foreign material. They discovered that, as the supplement period continued, the cells reacted more strongly. The supplement did not increase the number of Natural Killer cells.
Among the group of subjects who were hospitalised, the supplement reduced the number of days when these subjects had fever [Febrile frequency]. However, the reduction was not statistically significant. In this same period, the number of days of fever in a control group increased, an increase that was statistically significant.
The researchers are not exactly sure about how the supplement works. In earlier studies, vitamin C and glutamine improved the response of the immune system, but the doses in those studies were much higher than those used by the Japanese researchers.
J Clin Biochem Nutr. 2012 Mar;50(2):162-8.