The purpose of the study is to examine the effect of dietary n-3 polyunsaturated fatty acid supplementation on subjects' pan CD4+ T cell function, cognition, and muscle function. Half of the participants will receive fish oil, while the other half will receive a placebo (olive oil).

Generalized inflammation has been consistently associated with aging and metabolic diseases, often characterized by reduced muscle and cognitive function. Although much of the aging-associated inflammation has been attributed to chronic activation of the innate host defense system, activated CD4+ T cells have been shown to contribute directly to the pathogenesis of several other inflammatory diseases. In humans, dietary n-3 polyunsaturated fatty acids (PUFA), particularly docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), have anti-inflammatory properties and reduce disease symptoms, in part, through suppression of CD4+ T cell activation. Therefore, the Researchers' overall hypothesis is that dietary supplementation with DHA and EPA in humans will ameliorate inflammatory symptoms, in part, by suppressing CD4+ T cell activation, positively affecting muscle and cognitive function.

Inclusion criteria:

1. Healthy male or female according to the investigator/appointed staff judgment
2. 55 years and older
3. Stable body weight for the past 3 months (< 5% change)

Exclusion criteria:

1. History of cardiovascular disease
2. Metabolic diseases, including hepatic or renal disorders
3. Presence of acute illness or metabolically unstable chronic illness (including diagnosis of Insulin Dependent Diabetes Mellitus)
4. Unwilling to stop taking nutritional supplements containing proteins or free amino acids within 5 days of the first study day until study completion
5. Participated in a nutritional supplement study program within the past 4 weeks
6. Any other condition according to the PI or nurse that would interfere with the study or safety of the subject or influence the results
7. Daily use of supplements containing > 1000 mg EPA+DHA 3 months prior to the first test day
8. Known hypersensitivity to fish and/or shellfish, Swanson EFAs Super EPA Fish oil or any of its ingredients, Swanson EFAs Certified Organic Extra Virgin Olive oil or any of its ingredients
9. Presence of fever within the last 3 days
10. Failure to give informed consent
11. (Possible) Pregnancy
12. Unwilling to comply with any other rules set forth in the Informed Consent Form