The study was a free-living study over the course of 2 years. All the participants ate their own food at home, under normal conditions. Half of the participants were assigned to a group that received a serving of walnuts in their diets each day for two years. The other half refrained from eating walnuts for the same time period.
The study was conducted at two locations, Loma Linda University in the United States and University Hospital Clinic Barcelona Spain. Each study site recruited 350 healthy elderly subjects who made a 2-year commitment to participate in the study. Recruitment began in September of 2012 and continued until 2013.
Memory tests and eye exams were administered to the participants. Blood was drawn to test their general health parameters. Every two months each participant came to Loma Linda University to be weighed and measured and to meet with the study dietitian. During this visit walnuts were provided to those in the walnut group while other incentives were given to those in the control group. At the end of one year blood draw was conducted and at the end of two years memory tests and eye and final blood draw were scheduled.
Eligible participants were:
- Between the ages of 62 to 80 years old
- Reasonably healthy
- Able to read and write English
- Able to come to Loma Linda University every 2 months
They were not:
- Extremely obese
- Had uncontrolled diabetes or hypertension
- Were in the first year of tragic loss
- Were allergic to walnuts