Walnuts help lower bad cholesterol

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By David Liu, PHD

Friday Aug 17, 2012 (foodconsumer.org) -- Walnuts, which are high in omega-3 fatty acids,  are known to be able to lower bad cholesterol.  A new study in the Jne 2012 issue of Nutrition, Metabolism and Cardiovascular Disease confirmed that using walnuts can reduce the low density lipoprotein (LDL) or bad cholesterol.  Low LDL cholesterol is considered protective against heart disease.

The study led by N.R. Damasceno of Biomedical Research Institute August Pi i Sunyer, Hospital Clínic, in Barcelona, Spain and colleagues found men and women eating a diet with walnuts for four weeks significantly lowered their LDL cholesterol, which is considered a risk factor for heart disease, compared to the baseline serum level of the cholesterol.

For the study, 18 participants with nine women at a mean average of 56 years and having a body mass index of 25.7 kg/m2, which is considered a healthy body weight, were assigned to use a diet either with virgin olive oil, or walnuts or almonds for one month.  In each diet, 40 percent of fat in the base diet was replaced with Virgin olive oil or walnuts or almonds.  Cholesterol and other markers were measured in the participants who did not have heart disease.

As a result, after the dietary intervention, diets with virgin olive oil, walnuts or almonds were able to lower the LDL cholesterol by 7.3, 10.8 and 13.4 percent, respectively, compared to the baseline levels.

With each diet with either walnuts or olive oil or almonds, total cholesterol and the ratio of LDL cholesterol to high density lipoprotein (HDL) cholesterol decreased in parallel with the decrease in LDL cholesterol greater than predicted from dietary fatty acid and cholesterol exchanges among diets.  Low total cholesterol and low cholesterol ratio are believed protective against heart disease.

All the diets did not change other lipid fractions, oxidation analytes or inflammatory biomarkers. 

The researchers concluded "The results confirm the cholesterol lowering properties of nut-enriched diets. They also suggest that phenolic-rich VOO (Virgin olive oil) has a cholesterol lowering effect independently of its fatty acid content, which clearly deserves further study."

Walnuts, Virgin olive oil and almonds are high in Mediterranean diet, which has been known to be associated with lower risk for heart disease.

In addition to walnuts, olive oil and almonds, many other foods and supplements can be used to control cholesterol. They include soy foods, high fiber foods such as oats, barley and other whole grains, beans, and eggplant and okara, and many fruits such as apples, strawberries, citrus fruits and grapes

Other measures for the protection against heart disease include avoiding use of animal-based fat or oil like butter, and lard.  High intake of soybean oil and corn oil should also be avoided because it is not a good thing to have a high intake of omega-6 fatty acids.

Cholesterol is not the only risk factor for heart disease.  Calcium from certain sources can be risky.  Calcium as a mineral or micronutrient is important, but should preferably come from plant-derived foods like green leafy vegetables.  Calcium supplements are linked with higher risk of heart disease.

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