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Beta Carotene Provides A Boost to Immune System in Elderly Men

By Greg Arnold, DC, CSCS, January 11, 2012, abstracted from “Natural killer cell activity in elderly men is enhanced by beta-carotene supplementation” in the American Journal of Clinical Nutrition, l996;64:772-7.

The cells in our body that make up our immune system (white blood cells) work in a number of ways to help fight infection. One way is during exposure to an infection like a virus and producing proteins called antibodies that will better fight the infection when the next exposure occurs (just like with vaccines) (1).

Another type of immune protection by white blood cells is our earliest form of immunity and does not require exposure to infection. These types of white blood cells are called “natural killer cells” and have been found to provide “early protection against tumor transformation and [infection].” (2). Now research (3) has started to show that beta-carotene, an antioxidant found in orange, red, and dark green fruits and vegetables (carrots, cantaloupe, apricots, sweet potatoes, pumpkin, mangos, collard greens) (4) may positively affect natural killer cell function in elderly men.

In the study, 2 groups of men (38 “middle-aged” men between the ages of 51 and 64 and 21 “elderly” men between the ages of 65-86) participating in the Physicians’ Health Study (5) for 12 years (1983-1995) were given either beta carotene (50 mg every other day) or placebo throughout the course of the study. At the completion of the study, researchers obtained blood samples to determine natural killer cell activity.

When looking at natural killer cell activity (measured in what’s called a “lytic unit” (6)), the elderly men on beta carotene had 59% higher natural killer cell activity than the placebo group (63.5 vs 39.8 Lytic Units). No improvement was seen in the middle-age group with beta-carotene supplementation, with the placebo group actually having 53% higher natural killer cell activity compared to the placebo group (156.3 vs 102. Lytic Units). The researchers could not explain these results but did admit that the results from the middle-age group differs from earlier research showing 3 months of 30 mg/day of beta carotene to significantly increase natural killer cell activity in similarly-aged patients (7).

Although they admit they do not know exactly how beta-carotene enhances natural killer cell activity, the researchers conclude that “long-term, low-dose beta-carotene supplementation enhanced natural killer cell activity in healthy elderly men when compared with placebo.”

Greg Arnold is a Chiropractic Physician practicing in Hauppauge, NY. You can contact Dr. Arnold directly by emailing him at PitchingDoc@msn.com or visiting his web site at www.PitchingDoc.com

Reference:

1. “10 Things You Need to Know About Immunization” - http://www.cdc.gov/vaccines/vac-gen/10-shouldknow.htm

2. Cheent K. Natural killer cells: integrating diversity with function. Immunology. 2009 April; 126(4): 449–457. doi: 10.1111/j.1365-2567.2009.03045.x

3. Santos MS. Natural killer cell activity in elderly men is enhanced by beta-carotene supplementation. Am J Clin Nutr l996;64:772-7.

4. “Vitamin A and Carotenoids” - http://ods.od.nih.gov/factsheets/vitamina/

5. “Physician’s Health Study” - http://phs.bwh.harvard.edu/phs1.htm

6. Pollock RE. Lytic units reconsidered: pitfalls in calculation and usage. Clin Lab Anal1990;4(4):274-82.

7. Prabhala RH, Garewal HS, Hicks MI, Sampliner RE, Watson RR. The effects of 13-cis retinoic acid and /3-carotene on cellular immunity in humans. Cancer 1991;67:1556-60.