What makes nuts heart healthy?

Nuts are a good source of fat, and they also have protein. Most nuts have at least some of these heart-healthy substances:

• Unsaturated fats. The "good" fats in nuts — both monounsaturated and polyunsaturated fats — seem to lower "bad" cholesterol, although it's not clear why.
• Plant protein. Nuts are a source of plant protein, which is good for the heart and kidneys.
• Omega-3 fatty acids. Many nuts are rich in omega-3 fatty acids. Omega-3s are healthy fatty acids. They may lower the risk of heart attacks and strokes.
• Fiber. All nuts have fiber, which helps lower cholesterol. Fiber also makes you feel full, so you eat less.
• Plant sterols. Some nuts have compounds called plant sterols that can help lower cholesterol. Food makers often add plant sterols to products such as margarine and orange juice for extra health benefits. But nuts are natural sources of sterols.
• L-arginine. Nuts are also a source of a protein building block called L-arginine. Some research suggests that L-arginine may lower blood pressure, improve cholesterol and boost overall blood vessel health.