** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** WALNUTS ARE A NUTRIENT-RICH FOOD THAT PROVIDES MELATONIN AND POLYPHENOLS. WE HAVEEVIDENCE THAT DIETARY INTAKES OF FOODS HIGH IN THESE COMPONENTS CAN HAVE A GOOD IMPACT ON SLEEP BUT WE DON'T KNOW IF INCLUDINGWALNUTS IN THE DIET INFLUENCES SLEEP. WE PROPOSE TO FILL THIS KNOWLEDGE GAP BY TESTING THE EFFECTS OF WALNUT CONSUMPTION ON BLOOD LEVELS OF MELATONIN AND SLEEP. WE EXPECT THAT WALNUT CONSUMPTION FOR 4 DAYS WILL INCREASE MELATONIN LEVELS AND LEAD TO BETTER SLEEP QUALITY COMPARED TO A FOOD WITH A HIGH AMOUNT OF CARBOHYDRATES AND SUGAR (HCHS). THIS IS VERY IMPORTANT FOR THE GENERAL COMMUNITY BECAUSE A LARGE PORTION OF AMERICAN ADULTS EXPERIENCE SLEEP DIFFICULTIES. WITH THIS STUDY, WE WILL BE ABLE TO PROVIDE USEFUL INFORMATION TO THE AMERICAN POPULATION ABOUT THE POTENTIAL BENEFITS OF WALNUTS FOR IMPROVING THEIR SLEEP. TO ACCOMPLISH THIS GOAL, WE WILL CONDUCT A TRIAL IN MIDDLE-AGED TO OLDER ADULTS WHO HAVE SLEEP DIFFICULTIES.ADULTS WILL BE RECRUITED AND TESTED UNDER 2 CONDITIONS: WALNUT OR HCHS. IN EACH CONDITIONTHEY WILL EAT THREE SERVINGS PER DAY OF WALNUTS OR HCHS FOOD FOR FOUR DAYS. SLEEP QUALITY WILL BE MEASURED EVERY NIGHT USING A QUESTIONNAIRE AND A WRIST MONITOR. WE WILL ALSO MEASURE TIME SPENT IN DEEP AND LIGHT SLEEP ON NIGHT 3. OTHER MEASURES OF SLEEP QUALITY WILL BE MEASURED IN THE LABORATORYON DAY 4. THESE WILL INCLUDE BLOOD MELATONIN LEVELS AND BODY TEMPERATURE. WE WILL ALSO MEASURE OVERNIGHT PRODUCTION OF MELATONIN FROM URINE COLLECTED ON THE MORNING OF DAY 5. GIVEN THE EXTENT OF POOR SLEEP, OUR FINDINGS WILL PROVIDE INFORMATION ON NATURAL WAYS TO IMPROVE SLEEP HEALTH FROM INCREASED WALNUT CONSUMPTION. THIS WILL HAVE HIGH PUBLIC HEALTH RELEVANCE GIVEN THE IMPORTANCE OF GOOD SLEEP FOR OVERALL HEALTH AND WELLBEING.