Study of the Effects of Blackcurrant Extract and Omega-3 Fats on the Health of the Heart and Blood Vessels

Background: \- Heart disease is the leading cause of death in the United States. Eating fruits and vegetables with chemicals called flavonoids may protect against heart disease and improve blood flow to the heart. They are found in blackcurrant berries. Oils found in fish and mussels called omega-3 fats have also been shown to protect the heart. Researchers want to know if blackcurrant extract and omega-3 fats can improve blood flow, which may increase blood to the heart. They also want to learn about the health of blood vessels and how the heart works. Objective: \- To learn if blackcurrant extract and omega-3 fats will improve blood flow and make the heart beat stronger. Eligibility: \- Healthy adults 55 to 75 years old. Design: * Participants will be screened with medical history, physical exam, and blood tests. * Visit 1 will take 6 7 hours. * Participants will have physical exam and blood and urine tests. * A small device like a microphone will be placed on their arm to take pictures of blood vessels. A blood pressure cuff will be tightened on their arm and more pictures will be taken. * Blood pressure cuffs will be placed on their arms and legs. They will be tightened at the same time and blood pressure will be measured. * Participants will answer questions about their eating and exercise. * Every 8 weeks, participants switch from taking blackcurrant and/or omega-3 tablets to a placebo to no tablets. \ * Every 8 weeks, they will have another shorter clinic visit that will repeat most of visit 1.