Walnut and Immunity Study

Effects of Walnuts on Innate, Acquired and Gut Immunity in Older Adults With Overweight: A Randomized Controlled Trial

The main objective of the study is to determine if eating walnuts enhances immune function, in older free-living men and postmenopausal women with overweight.

The main objectives of our proposed study are to determine the effect of walnut consumption on innate, acquired, and gut immunity by assessing whether the ingestion of walnuts enhances immune function, in older free-living men and postmenopausal women with overweight. To accomplish these objectives, a randomized controlled, parallel design study is proposed with two groups consuming their habitual diet, but with one (Walnut group) receiving 15% of their total energy as walnuts and the other (Control group) abstaining from eating any walnuts and limited amounts of other tree nuts and peanuts (up to <1 serving/wk).

Inclusion Criteria:

• Older men and post-menopausal women aged 55-75 years
• Have a BMI of 25-32
• Being able to commute to Loma Linda University.
• Not taking medication or supplements that affect immunity

Exclusion Criteria:

• Intolerance or allergy to walnuts
• Regular intake of walnuts and/or other nuts (>3 ounces per week).
• Immune system insufficiency or disease.
• Using immune boosting supplements.
• Exposure to antibiotics and corticoids immediately prior to the study.
• Participants with uncontrolled chronic diseases, and relevant psychiatric illness, including major depression will not be included in study
• Flu vaccination or Covid booster within past 6 months