Immunological Impact of High Olive Oil Consumption
Condition: Immune Factors
Study type: Interventional

Summary: 
      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.
    

Detailed description: 
      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:

        1. in vivo indices of T cell-mediated function [delayed type hypersensitivity (DTH)],

        2. plasma inflammation markers (such as IL-1b, IL-6, TNF-a, CRP, MCP-1, sICAM-1, and
           sVCAM-1),

        3. ability of T cells and their subsets (such as CD4 and CD8, naïve and memory) to
           proliferate,

        4. Ex vivo production cytokines and PGE2 by immune cells.

        5. Gene expression of relevant pathways using transcriptomics analysis in circulating
           mononuclear cells.

        6. The CANTAB (Cambridge Cognition Ltd, Tunbridge Court, Tunbridge Lane, Bottisham,
           Cambridge, CB25 9TU, UK) is a computerized cognitive assessment, and

        7. 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.
    

Intervention name(s): Olive Oil
Intervention type(s): Other
Intervention description(s): 3 months intervention
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Investigator)
Primary purpose: Prevention
Keywords: Olive oil; DTH; elderly