This is a prospective, randomized controlled nutrition intervention trial to determine immunological impact of high olive oil consumption in elderly. Aging is associated with impaired immune response which contributes to higher incidence of infections in elderly. Previously we have shown that the type of fatty acids in the diet influences the immune response. In particular, reducing consumption of fats high in n-6 fatty acids has been shown to improve the immune response in aged. Very few studies have evaluated the role of olive oil, the main oil consumed as part of the Mediterranean diet on the immune response of elderly. We hypothesize that high olive oil consumption will improve immune function in elderly. In addition, we will investigate the effect of high olive oil consumption on gene expression of relevant pathways in circulating mononuclear cells, as well as on cognitive function.~Subject recruitment and enrollment will be conducted at the USDA HNRCA. Following screening, 40 eligible overweight or obese participants aged 65 and above will be randomized into one of two nutrition intervention groups for a period of 12 weeks: [1] Control Typical American Diet A, (N=20) and [2] Experimental Diet B (N=20).~Participants on the Control Diet A will be consuming a low-fiber, high-fat typical American Diet. Those on Diet B will consume a similar diet as the typical American diet, but they will be asked to replace their oil intake with extra virgin olive oil. Dietary counseling will be provided by the study dietitian at the Metabolic Research Kitchen of the Jean Mayer USDA Human Nutrition Research Center on Aging (HNRCA) at Tufts University on where the study oils will be replacing oils in the subjects' diets. Subjects will be followed regularly by the study dietitian throughout the intervention period to provide support and ensure compliance to study protocol. Data collection will take place at baseline, and after the subjects have been on the study diets for a period of three months. Data collection for the study outcome measures of interest will comprise blood drawing, anthropometric measurements, and cellular and immune factors. Specifically, measures will include:~in vivo indices of T cell-mediated function [delayed type hypersensitivity (DTH)],~plasma inflammation markers (such as IL-1b, IL-6, TNF-a, CRP, MCP-1, sICAM-1, and sVCAM-1),~ability of T cells and their subsets (such as CD4 and CD8, naïve and memory) to proliferate,~Ex vivo production cytokines and PGE2 by immune cells.~Gene expression of relevant pathways using transcriptomics analysis in circulating mononuclear cells.~The CANTAB (Cambridge Cognition Ltd, Tunbridge Court, Tunbridge Lane, Bottisham, Cambridge, CB25 9TU, UK) is a computerized cognitive assessment, and~Beck Depression Inventory.~This study will be conducted by the Nutritional Immunology Lab, with Dr. Simin Meydani as the PI and Drs. Barnett (Project director), Wu (Lab Director), Dallal (Biostatistician), Saltzman (Study Physician), Sen, Scott, and Ordovas as Co-Investigators. Dr. Ascension Marcos of the Scientific National Research Council (CSIC) is also a Co-I of this study.
This is a prospective, randomized controlled nutrition intervention trial to determine immunological impact of high olive oil consumption in elderly. Aging is associated with impaired immune response which contributes to higher incidence of infections in elderly. Previously the investigators have shown that the type of fatty acids in the diet influences the immune response. In particular, reducing consumption of fats high in n-6 fatty acids has been shown to improve the immune response in aged. Very few studies have evaluated the role of olive oil, the main oil consumed as part of the Mediterranean diet on the immune response of elderly. The investigators hypothesize that high olive oil consumption will improve immune function in elderly. In addition, the investigators will investigate the effect of high olive oil consumption on gene expression of relevant pathways in circulating mononuclear cells, as well as on cognitive function.