A Pesco-Mediterranean Diet With Intermittent Fasting

JACC Review Topic of the Week

James H. O'Keefe, MD; Noel Torres-Acosta, MD; Evan L. O'Keefe, MD; Ibrahim M. Saeed, MD; Carl J. Lavie, MD; Sarah E. Smith, PHD; Emilio Ros, MD, PHD


J Am Coll Cardiol. 2020;76(12):1484-1493. 

In This Article

Health Benefits of Mediterranean, Vegetarian, and Pesco-vegetarian Diets

The PREDIMED (Prevención con Dieta Mediterránea) study was a randomized clinical trial (RCT) of primary CVD prevention conducted in Spain in older individuals at high risk but with no CVD at enrollment, testing 3 diets: a Mediterranean diet supplemented with extra-virgin olive oil (EVOO), a Mediterranean diet supplemented with mixed nuts (walnuts, almonds, and hazelnuts), or a low-fat diet.[23] The groups consuming the Mediterranean diet supplemented with EVOO or nuts had statistically significant reductions of 29% for major adverse CVD events —myocardial infarction (MI), stroke, and death from these causes (Figure 1)—and 42% for stroke.[23] During the 4.8-year long PREDIMED study, the dietary changes in the groups randomized to the Mediterranean diet that were significantly different from those in the control group were: 1) increased intake of EVOO and nuts; 2) increased intake of fish/seafood and legumes; and 3) increased total fat intake from 39% to 42%, but a decrease in saturated fat consumption from 10% to 9%. Deviations in the randomization protocol affecting 12% of participants occurred in PREDIMED, but reanalysis of the data did not change the results.[23]

Figure 1.

Primary Endpoint of PREDIMED: Myocardial Infarction, Stroke, or Death From Cardiovascular Causes
CI = confidence interval; EVOO = extra-virgin olive oil; HR = hazard ratio.

Only 2 large RCTs have examined the effects of the Mediterranean diet on hard CVD events: PREDIMED[23] in primary prevention of CVD, and the Lyon Diet Heart study in MI survivors,[24] which also had impressive results (73% reduction in reinfarction rates at 27 months), albeit the intervention arm did not exactly follow a traditional Mediterranean diet (little olive oil consumption and a margarine enriched in alpha-linolenic acid as main dietary fat). Of note, PREDIMED also tested for the first time the effects of the Mediterranean diet on the incidence of other CVD-related outcomes, including peripheral artery disease,[25] atrial fibrillation,[26] and diabetes.[27] Table 1 summarizes the results of these RCTs.

A meta-analysis of 5 prospective dietary studies evaluated long-term coronary artery disease (CAD) mortality rates among vegetarian and nonvegetarian cohorts from Western countries. Compared with regular meat-eaters, CAD mortality was 34% lower in pescatarian (plant-rich diet with seafood as main source of meat), 34% lower in lacto-ovo-vegetarians, 26% lower in vegans, and 20% lower in occasional meat-eaters.[28]

The Adventist Health Study 2 was a 6-year prospective study that enrolled 73,308 subjects in the North American Adventists.[5] This study reported a decreased incidence of all-cause mortality when comparing vegetarians with nonvegetarians. However, when the vegetarians were stratified into vegans, lacto-ovo vegetarians, pesco-vegetarians, and semi-vegetarians, the pesco-vegetarians had lowest risks for all-cause mortality, CVD mortality, and mortality from other causes (Figures 2A to 2C).[5]

Figure 2.

Association of Dietary Patterns With All-Cause, Ischemic Heart Disease, and Other Mortality From Adventist Health Study 2
(A) Association of dietary patterns with all-cause mortality from Adventist Health Study 2. (B) Association of dietary patterns with ischemic heart disease mortality from Adventist Health Study 2. (C) Association of dietary patterns with other mortality from Adventist Health Study 2.

In the European Prospective Investigation into Cancer and Nutrition (EPIC) Oxford study, which included 48,188 participants with 18 years of follow-up, the incidence of CAD was significantly lower among vegetarians and pescatarians when compared with meat eaters.[29] Unexpectedly, vegetarians, but not pescatarians, had significantly higher rates of hemorrhagic strokes and total strokes when compared with meat eaters.[29] However, selection bias and confounding, which may be accounting for some of these findings, are pervasive issues in diet-health studies and may undermine the validity of some findings.