Participants were recruited through advertisements in senior citizens homes, hospitals, and newspapers. Approximately 700 elderly were screened for enrollment to the study. Out of them 157 non-demented participants with memory complaints met the previously described inclusion criteria . Briefly, eligible participants were non-demented men or women between the ages of 50 and 90 years, with complaints of memory loss  and no evidence of a condition that could produce cognitive deterioration including AD, Parkinson's disease, stroke, normal pressure hydrocephalus, and other brain lesions including tumors, renal, respiratory, cardiac, and hepatic disease, diabetes mellitus, endocrine, metabolic or hematological disturbances unless well controlled, and malignancy not in remission for more than two years. Concomitant use of drugs or supplements affecting cognitive function was prohibited.
The study was conducted according to the principles of the Declaration of Helsinki and good clinical practice. The protocol was approved by the Ethics Committee of the Sourasky Medical Center, Tel-Aviv, Israel, and all volunteers gave written informed consent prior to participation.
The study was designed as a single-center, randomized, double-blind, placebo-controlled, 15 weeks study, followed by an open-label extension of additional 15 weeks. At the first, double--blind, phase, participants were randomized according to a computerized process based on 6 and 8 blocks, in a 1:1 ratio stratified by gender, to receive three capsules per day of PS-DHA or a matched identically looking placebo (cellulose). The daily PS-DHA dosage provided 300 mg PS and 79 mg DHA+EPA (DHA:EPA ratio of 3:1). During the second, open-label, phase, participants consumed one capsule a day of PS-DHA. The daily dosage provided 100 mg PS and 26 mg DHA+EPA. PS-DHA (Vayacog™) was supplied by Enzymotec, Migdal HaEmeq, Israel.
Safety was evaluated by clinical laboratory assessments including biochemical and hematological parameters at baseline and endpoint of the double-blind phase and by adverse events recording, physical examination and measurement of vital signs and weight at baseline, week 7 and endpoint (week 15) of the double-blind phase and at the end of the open-label extension (week 30).
Blood samples were analyzed by the American Medical Laboratories (AML), Herzliya, Israel. Adverse events were monitored and recorded at each visit and by telephone contact every other week.
Biochemical parameters consisted of potassium, sodium, calcium, phosphorus, chloride, glucose, creatinine, blood urea nitrogen (BUN), bilirubin, total protein and lipid profile (total cholesterol, triglycerides, HDL, and LDL), alanine-aminotransferase (ALT), aspartateaminotransferase (AST), and alkaline phosphatase. Hematology consisted of red blood cell count, hematocrit, hemoglobin, white blood cell count and differential, platelets, MCV, MCH, and MCHC.
The parameters assessed were weight, resting systolic and diastolic blood pressure, and pulse rate.
Two-sided Student's t-test for dependent samples was used to analyze changes between different points in time in the tested parameters, in the whole group and in each gender separately, for both arms.
Two-sided t-test for independent samples was used to analyze differences between arms in the change between baseline and week 15 in blood parameters, vital signs and weight, in the whole group and in each gender separately and to detect any difference between groups in the frequency of adverse events.
Pearson's chi-square test for categorical variables was used to analyze the differences between groups in the number of participants who reported adverse events.
In the analysis of differences between and within groups, P values were adjusted for the number of parameters analyzed using Bonferroni correction. SAS statistical package (version 9.1) was used for all analyses.