Topical Area: Nutritional Epidemiology
Objectives : To determine if consuming walnuts daily for 2 years would improve the omega-3 index in healthy elderly compared to habitual diet without walnuts.
Design: Secondary analysis of the Walnuts and Healthy Aging (WAHA) study, a 2-year, randomized controlled clinical trial, conducted in Loma Linda University, CA, USA and Hospital Clinic, Barcelona, Spain. Subjects were randomly assigned to either a walnut or a control group.
Study Population: Included 193 WAHA study subjects from the Loma Linda center only, whose blood samples were collected and analyzed for RBC fatty acids.
Statistical analysis: To assess whether the changes of the Omega-3 index from baseline to year 1 and baseline to year 2 are significantly different between the walnut and control groups. Unstructured covariance model best fitted the data and was utilized. Then, repeated measures analyses were conducted to assess the delta change differences based on generalized least squares model.
Results : Omega-3 index did not significantly change between baseline and year 1 in either group. The index significantly increased by 1.5% (P < 0.001) in walnut group and by 1.8% (P < 0.001) in control group between baseline and year 2. This between-group difference was not statistically significant (P > 0.05).
Conclusions : Preliminary findings suggest that consuming walnuts, a rich source of ALA, may not be adequate to improve the omega-3 index compared to a walnut free habitual diet. Background intake of EPA and DHA may have a more pronounced influence on the index and needs to be further explored.
Funding Sources : California Walnut Commission, Folsom, CA