Having two-three servings of tree nuts such as walnuts daily can lower the risk of cardiovascular disease, says a study."Consuming tree nuts lowers total cholesterol, triglycerides and LDL (bad) cholesterol," said lead researcher Michael Falk from the Life Sciences Research Organisation in the US.Tree nuts contain important nutrients such as unsaturated fats, protein, vitamins and minerals."Walnuts are the only nut that provide a significant amount of alpha-linolenic acid (ALA) - the plant-based form of Omega-3s," Falk added.More than any other nut reviewed in this study, walnuts were investigated in 21 of the 61 trials.The researchers found that consuming at least two servings (60 grams) per day of tree nuts has stronger effects on total cholesterol and LDL and may be particularly important for lowering the risk of heart disease in individuals with Type 2 diabetes.More than two decades of research has shown that walnuts may help lower cardiovascular risk factors by decreasing LDL cholesterol and blood pressure.In addition to Omega-3s, walnuts also deliver a convenient source of fibre and protein, said the study published in the American Journal of Clinical Nutrition.