beta-Carotene and selenium supplementation enhances immune response in aged humans
Abstract
BACKGROUND: Nutritional research has focused on the effects of specific nutrients' ability to cause or prevent cancer. While beta-carotene and selenium (both important for antioxidant systems) have cancer prevention capabilities, their antineoplastic mechanism(s) remains to be elucidated.
METHODS: In a prospective, randomized study design we evaluated immunological changes in free-living, healthy aged humans (57-84 years of age) given a placebo, beta-carotene (45 mg/day), and/or selenium (400 µg/day) supplement for 6 months and after 2 months of discontinuation. Peripheral blood lymphocytes were evaluated and subtyped using flowcytometry. Natural killer (NK) cell cytotoxicity was determined by a fluorescent method. Plasma diene conjugates were assessed to evaluate changes in oxidative stress.
RESULTS: Selenium and selenium plus beta-carotene supplementation caused an increase in total T cells by 27% and 31%, respectively (p < .05). The only group that was different (in T lymphocytes) from the controls (placebo group) after 6 months of supplementation (p < .05) was the selenium-supplemented group (+65%). Much of this increase was the result of an increase in CD4(+) T-cell subsets. Selenium or beta-carotene supplementation for 3 months increased NK cell cytotoxicity over pretreatment levels by 58% and 34%, respectively; however, these levels returned to +12% and -6% of pretreatment levels after 6 months supplementation. Selenium plus beta-carotene supplementation caused an increase in the percentage of NK cell by 121% and 161% at 3 and 6 months, respectively. However, the increased numbers of NK cells were not correlated with NK cell activity.
CONCLUSIONS: We found that selenium enhanced immune function (NK cell cytotoxicity) and phenotypic expression of T-cell subsets, whereas beta-carotene affected only immune function. Increased NK cell cytotoxicity may last for only a short period of supplementation and was not sustained throughout the 6 months of supplementation. Supplemental selenium and beta-carotene seemed to affect immune function in aged subjects by different mechanisms.
See also:
- Official Web Site: The Di Bella Method;
- Beta-Carotene or β-carotene in Solution of retinoids in vitamin E in the Di Bella Method biological multitherapy;
- The Di Bella Method (A Variable Part - Selenium methonine, 40 μg capsules, twice a day);
- The Di Bella Method (A Fixed Part - Calcium, 2 grams per day, orally);
- The Di Bella Method (A Fixed Part - Vitamin C/Ascorbic Acid, 2–4 grams, twice a day orally);
- Solution of retinoids in vitamin E in the Di Bella Method biological multitherapy;