Walnuts Prevent Heart Disease

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Harvard Health

Publicationshttp://www.health.harvard.edu/medline/Heart/H0800c.html

 

Harvard Health Online

Harvard Heart Letter

August 2000

 

Can Walnuts Prevent Heart Disease?

People worried about heart disease are continually told about all the things

they shouldn't eat. But how often do they hear about foods (other than

fruits and vegetables) that might actually reduce their risk of heart

disease? Recent evidence suggests that nuts in general - and walnuts, in

particular - might be a heart-healthy part of the diet, even though every

mouthful of nuts is rich in calories and fat. Researchers believe the reason

for this rests in the type of fat found in nuts. Walnuts are especially rich

in monounsaturated and polyunsaturated fats; such fats, when they replace

the saturated fats found in meats and dairy products, can lower a person's

LDL ( " bad " ) cholesterol levels and raise the HDL ( " good " ) cholesterol.

 

Some epidemiological data have shown lower rates of heart disease among

people who eat large amounts of walnuts. That finding, however, may reflect

other factors of lifestyle or habit that are shared by those with higher

rates of nut consumption, in which case nut-eating itself would not account

for the generally improved cardiovascular health. At the same time, other

studies have questioned whether walnut consumption can improve lipid

profiles. Over the last several years, the California Walnut Commission (a

group with an obvious vested interest in promoting walnut consumption) has

sponsored research to evaluate the effects of these nuts on lipids and heart

disease.

 

The most recent information on this issue comes from Barcelona, Spain. The

study included 49 volunteers with high LDL cholesterol levels (greater than

130 mg/dL), who were enrolled at a lipid clinic. The subjects were taught to

eat two diets, each for six weeks. The first diet was a Mediterranean-type,

low-fat diet, as is often recommended to people with high cholesterol

levels. Red meat and eggs are limited in this eating plan, while vegetables

and fish are emphasized. Olive oil is used for cooking and nuts are

prohibited.

 

During the other six weeks, the volunteers ate a diet in which walnuts

partially replaced olive oil and other fatty foods. Prepackaged daily

supplies of raw shelled walnuts were given to the patients to eat as snacks

or with meals. The walnut diet had the same number of calories as the

Mediterranean diet, but walnuts accounted for 18% of the total calories and

35% of the total fat.

 

Blood tests obtained throughout the study indicated that the walnut diet had

heart-healthy effects. The subjects' average total cholesterol levels fell

by 9% (about 25 mg/dL) while on the walnut diet; the " control " Mediterranean

diet led to a smaller decline of 5%, or 14 mg/dL. LDL cholesterol fell by

11% or 22 mg/dL while the subjects were on the walnut diet, versus 6% or 11

mg/dL with the control diet. The two diets had essentially the same effect

on HDL (no significant change). Body weight did not change - thus these

results cannot be explained by a loss of appetite during the walnut-diet

phase of the study. (Annals of Internal Medicine, Vol. 132, No. 7, pp.

538-46.)

 

Overall, the volunteers appeared not to mind the walnut diet. About half of

the subjects reported that their stools were soft while on the walnut diet,

and three of the volunteers said they had some mild sensations of heaviness

and bloating. However, these symptoms did not prompt anyone to quit the

study.

 

These data confirm findings from previous research on the effects of

walnuts, and help add credibility because the volunteers were not eating a

carefully controlled diet in a laboratory. Instead, these people were " free

living, " so the results probably reflect " real-world " circumstances.

However, before filling the snack bowl with walnuts, keep in mind that the

subjects in this study replaced other fats in their diets with walnuts. If

you just add walnuts to your diet - and thus, extra calories and fats - don'

t expect the same kind of positive results.

©2000 President and Fellows of Harvard College

[Guest guest]

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" Elaine121 " <Elaine121

<Undisclosed-Recipient:;@connect.com.au>

Sunday, November 25, 2001 4:16 PM

Walnuts Prevent Heart Disease

 

 

> Can Walnuts Prevent Heart Disease?

 

Hi Elaine,

 

Walnuts are the richest nut source for Omega 3 LNA. Flax is still very much

superior.

========================

Good Health & Long Life,

Greg Watson, gowatson

USDA database (food breakdown) http://www.nal.usda.gov/fnic/foodcomp/

PubMed (research papers) http://www.ncbi.nlm.nih.gov/entrez/query.fcgi

DWIDP (nutrient analysis) http://www.walford.com/dwdemo/dw2b63demo.exe

KIM (omega analysis) http://ods.od.nih.gov/eicosanoids/KIM_Install.exe