Seafood ChoiCeS

Seafood Choices: Balancing Benefits and Risks
http://www.nap.edu/catalog/11762.html
00 SEAFOOD ChOICES
effect of EPA/DHA from seafood is difficult to isolate from benefits provided
by other dietary changes.
Randomized Controlled Trials
The effect of fish-oil supplementation has been studied in a metaanalysis
of experimental studies (Geleijnse et al., 2002). The overall results
of 36 trials examined indicate that the mean adjusted net reduction in systolic
and diastolic blood pressure was –2.1 mmHg (95% CI –3.2 to –1.0),
and –1.6 mmHg (95% CI –2.2 to –1.0), respectively. Moreover, systolic and
diastolic blood pressure reductions were significantly greater in older (mean
age ≥45 years) than younger populations, and in hypertensive (blood pressure
≥140/90 mmHg) compared to normotensive populations. Inconsistent
results among studies in women precluded adequate analysis based on sex.
Body mass index, trial duration, and seafood dose did not affect the blood
pressure response noted with fish-oil supplementation. Studies conducted in
diabetic patients were not included in the meta-analysis. The review by Balk
et al. (2004) found only small and inconsistent net effects of EPA/DHA on
blood pressure levels of diabetic patients.
A single RCT with advice to increase seafood intake has been reported.
The Diet and Reinfarction Trial (DART) examined the effect of advice to
consume seafood on blood pressure outcomes at 6 and 24 months in over
2000 men with a history of MI (Ness et al., 1999). The average intake of
the group advised to consume fish was 330 mg of EPA compared to 100 mg
in the control group. There were no significant differences in blood pressure
detected between the groups at either 6 or 24 months.
Obser ational Studies
Appleby et al. (2002) examined the effect of diet and lifestyle factors
on differences between meat eaters, seafood eaters, vegetarians, and vegans
on the prevalence of self-reported hypertension, and mean systolic and diastolic
blood pressure. Data for the analysis was obtained from the Oxford
cohort of the European Prospective Investigation into Cancer and Nutrition
(EPIC-Oxford). More than 11,000 adult men and women were classified
into the four diet groups for analysis. Results showed that age-adjusted
prevalence of self-reported hypertension in men was 15 percent in meat
eaters, 9.8 percent in both seafood eaters and vegetarians, and 5.8 percent
in vegans. In women, the prevalence was 12.1, 9.6, 8.9, and 7.7 percent in
the respective diet groups. After adjustment for body mass index (BMI), the
group differences decreased in both men and women. When seafood eaters
were compared to vegetarians, no benefit was seen that could be attributed
to seafood consumption per se.
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