Tagore’s “Kabuliwala” the archetypal nut seller has never been as significant as in this modern era, when plethora of information is available that nuts are good for the heart.
Walnuts, are rich in polyunsaturated fatty acids, and have beneficial effect on serum cholesterol.
Replacing 35% of the energy obtained from monounsaturated fats  or 20% of calories  of total diet with walnuts have shown to reduce 4 -12 percent reductions in serum total cholesterol and 6-12 percent reduction in serum bad LDL cholesterol levels.
Walnuts also improve endothelial function in patients with elevated cholesterol 
In one study when almonds were given replacing 20% of energy (68g) in healthy adults and in adults with mildly elevated cholesterol levels, the diet led to marked improvements in lipids within four weeks .
Prospective Adventist Health Study results have shown that individuals who consume nuts more than four times per week have significant reductions in mortality from coronary heart disease and in nonfatal heart attacks compared to those who consumed nuts less than once per week 
Results of Physicians’ Health Study also showed that men who consumed nuts two or more times per week had significant reductions in total coronary deaths and sudden cardiac deaths. 
Almonds, peanuts and walnuts contain Vitamin E and are good for the heart. People who take nuts 5 days a week have 20 per cent less chances of having a heart attack. Patients may also consume nuts and seeds in moderate amounts.
Being plant in origin nuts contains zero cholesterol.
1. Ann Intern Med 2000; 132:538.
2. N Engl J Med 1993; 328:603
3. Circulation 2004; 109:1609.
4. Circulation 2004; 109:1609
5. Am J Clin Nutr 2003; 77:1379.
6. Arch Intern Med 1992; 152:1416