July 28, 2006
By
Sahar
Bedrood B.S. and Asher Kimchi M.D.
Barcelona, Spain
- The low incidence of coronary artery disease in
Mediterranean countries has been attributed to the
dietary habits of the people in that region. A
multi-center, randomized study by Ramon Estruch, MD,
PhD et al from the Hospital Clinic in Spain compared
the short-term effects of two Mediterranean diets
versus those of a low-fat diet on intermediate
markers of cardiovascular risk. The findings,
published in the July 4, 2006 issue of Annals of
Internal Medicine, found that compared to low-fat
diets, Mediterranean diets supplemented with olive
oil or nuts have beneficial effects on
cardiovascular risk factors.
From October 2003 to March 2004, 930 potential participants
in primary care centers affiliated with 10 teaching
hospitals across Spain were selected. Eligible
participants were community-dwelling men, 55 to 80
years of age, and women, 60 to 80 years of age, who
fulfilled at least 1 of 2 criteria: type 2 diabetes or 3
or more CHD risk factors (current smoking, hypertension
[blood pressure >140/90 mm Hg or treatment with
antihypertensive drugs], low-density lipoprotein [LDL]
cholesterol level 4.14 mmol/L [160 mg/dL] [or
treatment with hypolipidemic drugs], high-density
lipoprotein [HDL] cholesterol level 1.04 mmol/L [40
mg/dL], body mass index [BMI] 25 kg/m2, or a family
history of premature CHD).
Participants were assigned to a low-fat diet (n =
257) or to 1 of 2 Mediterranean diets. Those allocated
to Mediterranean diets received nutritional education and
either free virgin olive oil, 1 liter per week (n =
257), or free nuts, 30 g/d (n = 258). The
authors evaluated outcome changes at 3 months.
The completion rate was 99.6%. Compared with the low-fat
diet, the two Mediterranean diets produced beneficial
changes in most outcomes. Compared with the low-fat
diet, the mean changes of plasma glucose levels in
the Mediterranean diet with olive oil group and the
Mediterranean diet with nuts group were –0.39 mmol/L
(95% CI, –0.70 to – 0.07 mmol/L) and – 0.30 mmol/L
(CI, –0.58 to – 0.01 mmol/L), respectively; systolic
blood pressure changes were: –5.9 mm Hg (CI, –8.7 to –3.1 mm Hg)
and – 7.1 mm Hg (CI, –10.0 to –4.1 mm Hg),
respectively; and for the cholesterol–high-density lipoprotein
cholesterol ratio the changes were: –0.38 (CI, –0.55
to – 0.22) and – 0.26 (CI, –0.42 to –0.10),
respectively,. The Mediterranean diet with olive oil reduced
C-reactive protein levels by 0.54 mg/L (CI, 1.04 to 0.03
mg/L) compared with the low-fat diet.
Overall, the study concluded that Mediterranean diets are
associated with a significant reduction in cardiovascular risk
factors, such as blood pressure, fasting glucose levels and
C-reactive protein levels.
Co-authors: Ramon Estruch, MD, PhD; Miguel Ángel
Martínez-González, MD, PhD; Dolores Corella, PhD; Jordi Salas-Salvadó,
MD, PhD; Valentina Ruiz-Gutiérrez, PhD; María Isabel Covas, PhD;
Miguel Fiol, MD, PhD; Enrique Gómez-Gracia, MD, PhD; Mari Carmen
López-Sabater, PhD; Ernest Vinyoles, MD, PhD; Fernando Arós, MD,
PhD; Manuel Conde, MD, PhD; Carlos Lahoz, MD, PhD; José Lapetra,
MD, PhD; Guillermo Sáez, MD, PhD; Emilio Ros, MD, PhD, for the
PREDIMED Study Investigators*
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