This research study will test the effects of Blueberries on immune functions in overweight older men and postmenopausal women

This study will examine the effects of Blueberries on clinically relevant markers of immune function. Eligible and selected participants will be randomized to one of two groups at the baseline clinic visit. The Blueberry group participants will consume blueberries (2 packets of blueberry freeze-dried powder equivalent to 2 cups of fresh blueberries) added to the habitual diet and the Control group participants will abstain from blueberries (with instructions to limit the consumption of other berries and polyphenol rich foods) but otherwise continue their habitual diet. During the study, clinic visits will occur at 4-week intervals (baseline, weeks 4, 8 and 12) for a total of 4 visits at the Loma Linda University Nutrition Research Center. Blood samples taken at baseline and at week 12 will be assayed for changes in immune function and inflammatory markers.

Inclusion Criteria:

1. Older men and post-menopausal women aged 50-70 year
2. Have BMI of 25-32
3. Able to commute to Loma Linda University
4. Consuming a typical American Diet low in polyphenols

Exclusion Criteria:

1. Intolerance or allergy to Blueberries
2. Regular intake of Blueberries and other berried (>2 ounces/week)
3. Immune system insufficiency or disease
4. Using immune boosting supplements
5. Exposure to antibiotics and corticoids immediately prior to study
6. Uncontrolled chronic diseases and relevant psychiatric illness, including major depression
7. Flu vaccination and or Covid Vaccination less than 3 months ago from the start of the study

The investigator, participant, care provider, outcomes assessor will not be aware of which participant is in which arm