"Walnuts add a happy crunch to life, and they may even help prolong
it", NY Times, 28 Sept 94, p. B1

Summary of newspaper article:  Despite the perception of nuts' being
full of fat, walnuts are popular and, in one study, proven to lower
blood cholesterol levels.  Included are descriptions of the varieties
of walnuts and recipes for walnuts.

"Effects of walnuts on serum lipid levels and blood pressure in normal
men", J. Sabate et al., NEJM 4 March 93, v. 328, pp. 603-607.

Background:  A follow-up study shows that frequent consumption of nuts
is associated with a reduced risk of ischemic heart disease.

Objective:  To explore the effects of walnut consumption on serum
lipids and blood pressure.

Kind of study:  Crossover designed experiment

Subjects:  18 free-living healthy men

Setting:  Nutrition-research kitchen of university mostly (other meals
controlled but eaten anywhere)

Treatments:  (a) reference (cholesterol-lowering) diet (negative
control), (b) similar diet but modified to use walnuts without
increasing percentage of calories from fat (positive control).

Treatment assignment:  Reference diet for first 5 days.  Then both
treatments applied to each subject for 56 days.  Random assignment of
the order of treatments (one diet for first period, the other for
second period), with stratification on the basis of age, base-line
serum cholesterol level, and body-mass index.

Outcome measurements:  Blood pressure, body weight, and
high/low-density lipoprotein and total cholesterol levels during
run-in period and each treatment.

Blindness:  Subjects were not blind.  Personnel analyzing were blinded
to subjects' diet sequence.

Population:  Male volunteers responding to campus and community
advertisements.  Out of those responded, 24 were selected by the
criteria that they did not eat nuts frequently, did not have known
food allergies, did not smoke, did not have a history of hypertension
or atherosclerotic or metabolic disease, did not take medication on a
regular basis, did not have serum cholesterol values below the 20th
percentile or above the 80th percentile for specific age range, and
were not considered unable to comply with the criteria.

Statistical methods used:  Two-tailed t-tests for comparison of changes
in outcome variables in response to treatment and diet period and for
possible interaction between treatment and diet period (carry-over
effect).  Comparison of means for all descriptive values.  4 tables
and 1 plot.

Stated conclusions:  Mean blood-pressure values did not change for each
period.  Levels of total, HDL, and LDL cholesterol (12.4%, 16.3%, and
4.9% respectively) and the ratio of LDL cholesterol to HDL cholesterol
(p<0.001) were lowered by the walnut diet.

Nonresponse:  5 withdrew during run-in period and 1 missed a blood
drawing and excluded.

Confounding variables:  None (randomized experiment).

Difficulties of generalizing to the real world:  Those who hate
walnuts.  Walnuts eaten as a dietary supplement and effects of
oil-roasted nuts may show different results.  Maintaining intake of
total fat and calories while having walnuts not realistic in everyday
purposes.  Results do not apply to women and those with
hypercholesterolemia.

Other problems:  Newspaper article said the subjects were divided into
two groups of 9, but the journal reported the subjects were divided
into two groups of 10 and 8, based on factors (i.e. age).

How does this relate to the rest of the scientific literature:  Results
of this study about blood pressure do not agree with previous studies
that intake of unsaturated fats lowers blood pressure.  Also, these
results of walnuts agree with other studies that show nuts are
beneficial in many health aspects.