As we age, it is generally believed our immune system deteriorates. It is considered a fact of life. Japanese researchers did a study to investigate the effects of supplementing amino acids and vitamins for both unhealthy and healthier older people for both inpatients and outpatients.

From the article, “Amino acid and vitamin supplementation improved health conditions in elderly participants”, Japanese researchers studied one bedridden inpatient group and one outpatient group.

Daily, a mixture of the amino acids containing leucine (1200 mg/day), glutamine (600 mg/day), and arginine (500 mg/day), plus 11 kinds of vitamins were administrated for 8 weeks. In both groups, general blood biomarkers such as C-reactive protein levels, white blood cell count, and natural killer (NK) cell activity were measured.

The study involved thirteen bedridden inpatients (7 males, 6 females; mean age, 81.8 ± 8 years) and eleven outpatients (7 males, 4 females; mean age, 74 ± 12 years) from the Sansei Hospital (Hyogo Prefecture, Japan).

These same amino acid and vitamins were administered to the inpatients as the outpatients with water twice daily, immediately after dinner and before sleeping.

Results from clinical study on Amino Acids and Vitamins

The researchers found that supplementation of the three amino acids arginine, glutamine, and leucine, and 11 kinds of vitamins had beneficial effects on the health of older people in poor health. The aging process in humans results in a condition called sarcopenia, which involves decreased skeletal muscle mass and function which is associated with metabolic diseases such as obesity and type 2 diabetes.

In this study, immune parameters were also evaluated. Of these, NK cell activity, an index of innate immunity, increased in both outpatients and inpatients. In the immune system, NK cell activity is thought to be one of the important indices for monitoring immunity because innate immunity is the first line of defense against infections. For those inpatients who were administered amino acids, their condition was stable due to increased NK cell activity.

To conclude, this study suggested that “dietary supplementation with the amino acids arginine (500 mg/day), glutamine (600 mg/day), leucine (1200 mg/day), and 11 kinds of vitamins for the elderly in poor health increased NK cell activity, irregardless of the presence of a primary disease and the amount of the daily nutrient intake.”

It was also observed that supplementation with more than 1 g/day of vitamin C enhanced immunity in healthy adults. In addition, vitamin E fostered the immunity for both unhealthy subjects (750 mg/day) and in healthy elderly subjects (800 mg/day).