Vitamin E and tryptophan status is associated with immune function and quality of life in the elderly, in one recent study.
Doctors in a study on inflammation thought low antioxidant levels encourage chronic inflammation that leads to disease as we age. Researchers measured nutrients and inflammation in about 70 senior men and women and found that, compared to those with lower nutrient levels, those with higher blood levels of the antioxidant vitamin E and the essential amino acid tryptophan—which helps control mood, appetite and sleep—had better quality of life, including better physical and mental health, and fewer signs of inflammation.