Fish oil is rich in omega-3 fatty acids, which are the ultimate anti-aging ingredient. Because our bodies can manufacture them, it's essential to get them through a diet of fatty fish or a supplement. Research tells us that omega-3 fatty acids reduce high cholesterol and high blood pressure, two risk factors for cardiovascular disease. Studies also show that regularly getting these nutrients can boost brainpower, prevent cancer, protect against aging and fight wrinkles. Many of those claims are still being studied, but there are very few side effects of fish oil (minus the potential for fishy burps).