How Long Chain Omega-3 Fatty Acids Improve the Immune System of Older Adults
The immune system is extremely complex, made up of a disparate group of cells and organs that protect us from pathogens, toxins and the by-products of metabolic processes that can damage cells. Perhaps paradoxically, we may be concerned that the immune system is not functioning well when we catch a cold, but the runny nose and coughing are actually a sign that the immune system is doing its job. Medicines designed to manage the symptoms of a cold actually dampen the immune response. Thus, it is important to have an immune system that can keep out the infectious agents, but not over-react.
In older people, the immune system becomes deregulated, and both the severity of infectious diseases, and the incidence of some autoimmune diseases increase. Old age is also a time when the results of chronic inflammation, an extended period of heightened immune system activity, result in degenerative diseases, cardiovascular disease and malignancies (for a comprehensive review, see Pera et al.). Supplementation with long chain omega-3 fatty acids has been shown to modulate the immune response by improving signaling between immune cells and improving the ability of cells to destroy pathogens. There is hope that omega-3 fatty acids can help keep infections at bay without exacerbating inflammation.
Recently, Rodacki and co-workers looked at the specific effects of fish oil on the immune system of healthy older women (around 65 years of age) participating in a strength training program. 45 women were assigned either to strength training three times per week for 12 weeks, strength training supplemented with fish oil (2 grams per day), or strength training that was preceded by 2 months’ fish oil supplementation that continued throughout the strength training period. The supplements provided 0.4 g EPA and 0.3 g DHA per day.
There were no changes found in the participants in terms of body composition from either the strength training or supplements. The DHA and EPA concentration of plasma increased in the supplemented groups: after two months, the subjects who took the supplements before the training period started had a stable DHA and EPA level. There were some changes in the fish oil supplemented group that were not seen in the control group. There was an increase in cells’ ability to remove zymosan, a molecule found on the surface of fungal cells, an increase in the volume of lysosomes, associated with improved cellular defenses, and increases in hydrogen peroxide, used for immune cell signaling, and superoxide anion production, which deactivates invading microbes. There were changes in the ratio of CD4-lymphocytes to CD8-lymphocytes, such that the number of CD4-lymphocytes was reduced compared to CD8-lymphocytes, despite an increase in levels of both. This is consistent with an improvement in cell-mediated immunity without over-stimulation of the immune system. The authors also found a general reduction in the inflammatory biomarker TNF-alpha with increases in IL-2 and IFN-gamma. This indicates that fish oil could exert a moderating effect on the immune system: inflammatory cells and molecules were reduced, with a resulting increase in immune system components that fight disease.
Interventions that can improve the immune system’s activity to fight infection without resulting in an increase in chronic inflammation could make a considerable impact on the health and well-being of aging adults. While this study was small and conducted over a relatively short period of time, and the results cannot be directly translated to recommendations, it is prudent to consume enough omega-3 fatty acids.
Cintia de Lourdes Nahhas Rodacki, André Luiz Felix Rodacki, Isabela Coelho, Daniele Pequito, Maressa Krause, Sandro Bonatto, Katya Naliwaiko and Luiz Cláudio Fernandes. Influence of fish oil supplementation and strength training on some functional aspects of immune cells in healthy elderly women. British Journal of Nutrition, available on CJO2015. doi:10.1017/S0007114515001555.
Pera A, Campos C, López N, Hassouneh F, Alonso C, Tarazona R, Solana R. Immunosenescence: Implications for response to infection and vaccination in older people. Maturitas. 2015 May 18. pii: S0378-5122(15)00675-1. doi: 10.1016/j.maturitas.2015.05.004. [Epub ahead of print] http://www.ncbi.nlm.nih.gov/pubmed/26044074