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Primary Prevention of Cardiovascular Disease with a Mediterranean Diet
- The traditional Mediterranean diet is characterized by a high intake of olive oil, fruit, nuts, vegetables, and cereals; a moderate intake of fish and poultry; a low intake of dairy products, red meat, processed meats, and sweets; and wine in moderation, consumed with meals.1 In observational cohort studies2,3 and a secondary prevention trial (the Lyon Diet Heart Study),4 increasing adherence to the Mediterranean diet has been consistently beneficial with respect to cardiovascular risk.2-4 A systematic review ranked the Mediterranean diet as the most likely dietary model to provide protection against coronary heart disease.5 Small clinical trials have uncovered plausible biologic mechanisms to explain the salutary effects of this food pattern.6-9 We designed a randomized trial to test the efficacy of two Mediterranean diets (one supplemented with extra-virgin olive oil and another with nuts), as compared with a control diet (advice on a low-fat diet), on primary cardiovascular prevention.
Methods
Study Design
The PREDIMED trial (Prevención con Dieta Mediterránea) was a parallel-group, multicenter, randomized trial. Details of the trial design are provided elsewhere.10-12 The trial was designed and conducted by the authors, and the protocol was approved by the institutional review boards at all study locations. The authors vouch for the accuracy and completeness of the data and all analyses and for the fidelity of this report to the protocol, which is available with the full text of this article at NEJM.org.Supplemental foods were donated, including extra-virgin olive oil (by Hojiblanca and Patrimonio Comunal Olivarero, both in Spain), walnuts (by the California Walnut Commission), almonds (by Borges, in Spain), and hazelnuts (by La Morella Nuts, in Spain). None of the sponsors had any role in the trial design, data analysis, or reporting of the results.Participant Selection and Randomization
Eligible participants were men (55 to 80 years of age) and women (60 to 80 years of age) with no cardiovascular disease at enrollment, who had either type 2 diabetes mellitus or at least three of the following major risk factors: smoking, hypertension, elevated low-density lipoprotein cholesterol levels, low high-density lipoprotein cholesterol levels, overweight or obesity, or a family history of premature coronary heart disease. All participants provided written informed consent.Beginning on October 1, 2003, participants were randomly assigned, in a 1:1:1 ratio, to one of three dietary intervention groups: a Mediterranean diet supplemented with extra-virgin olive oil, a Mediterranean diet supplemented with nuts, or a control diet. Randomization was performed centrally by means of a computer-generated random-number sequence.Interventions and Measurements
The dietary intervention 8,10-13. The specific recommended diets are summarized in Table 1Table 1Summary of Dietary Recommendations to Participants in the Mediterranean-Diet Groups and the Control-Diet Group. . Participants in the two Mediterranean-diet groups received either extra-virgin olive oil (approximately 1 liter per week) or 30 g of mixed nuts per day (15 g of walnuts, 7.5 g of hazelnuts, and 7.5 g of almonds) at no cost, and those in the control group received small nonfood gifts. No total calorie restriction was advised, nor was physical activity promoted.
For participants in the two Mediterranean-diet groups, dietitians ran individual and group dietary-training sessions at the baseline visit and quarterly thereafter. In each session, a 14-item dietary screener was used to assess adherence to the Mediterranean diet 8,14 so that personalized advice could be provided to the study participants in these groups.Participants in the control group also received dietary training at the baseline visit and completed the 14-item dietary screener used to assess baseline adherence to the Mediterranean diet. Thereafter, during the first 3 years of the trial, they received a leaflet explaining the low-fat diet on a yearly basis. However, the realization that the more infrequent visit schedule and less intense support for the control group might be limitations of the trial prompted us to amend the protocol in October 2006. Thereafter, participants assigned to the control diet received personalized advice and were invited to group sessions with the same frequency and intensity as those in the Mediterranean-diet groups, with the use of a separate 9-item dietary screener .A general medical questionnaire, a 137-item validated food-frequency questionnaire,15 and the Minnesota Leisure-Time Physical Activity Questionnaire were administered on a yearly basis.10 Information from the food-frequency questionnaire was used to calculate intake of energy and nutrients. Weight, height, and waist circumference were directly measured.16 Biomarkers of compliance, including urinary hydroxytyrosol levels (to confirm compliance in the group receiving extra-virgin olive oil) and plasma alpha-linolenic acid levels (to confirm compliance in the group receiving mixed nuts), were measured in random subsamples of participants at 1, 3, and 5 years.End Points
The primary end point was a composite of myocardial infarction, stroke, and death from cardiovascular causes. Secondary end points were stroke, myocardial infarction, death from cardiovascular causes, and death from any cause. We used four sources of information to identify end points: repeated contacts with participants, contacts with family physicians, a yearly review of medical records, and consultation of the National Death Index. All medical records related to end points were examined by the end-point adjudication committee, whose members were unaware of the study-group assignments. Only end points that were confirmed by the adjudication committee and that occurred between October 1, 2003, and December 1, 2010, were included in the analyses.Statistical Analysis
We initially estimated that a sample of 9000 participants would be required to provide statistical power of 80% to detect a relative risk reduction of 20% in each Mediterranean-diet group versus the control-diet group during a 4-year follow-up period, assuming an event rate of 12% in the control group.10,17 In April 2008, on the advice of the data and safety monitoring board and on the basis of lower-than-expected rates of end-point events, the sample size was recalculated as 7400 participants, with the assumption of a 6-year follow-up period and underlying event rates of 8.8% and 6.6% in the control and intervention groups, respectively.Yearly interim analyses began after a median of 2 years of follow-up. With the use of O'Brien–Fleming stopping boundaries, the P values for stopping the trial at each yearly interim analysis were 5×10−6, 0.001, 0.009, and 0.02 for benefit and 9×10−5, 0.005, 0.02, and 0.05 for adverse effects.18 The stopping boundary for the benefit of the Mediterranean diets with respect to the primary end point was crossed at the fourth interim evaluation; on July 22, 2011, the data and safety monitoring board recommended stopping the trial on the basis of end points documented through December 1, 2010.All primary analyses were performed on an intention-to-treat basis by two independent analysts. Time-to-event data were analyzed with the use of Cox models with two dummy variables (one for the Mediterranean diet with extra-virgin olive oil and another for the Mediterranean diet with nuts) to obtain two hazard ratios for the comparison with the control group. To account for small imbalances in risk factors at baseline among the groups, Cox regression models were used to adjust for sex, age, and baseline risk factors. We tested the proportionality of hazards with the use of time-varying covariates. All analyses were stratified according to center. Prespecified subgroup analyses were conducted according to sex, age, body-mass index (BMI), cardiovascular-risk-factor status, and baseline adherence to the Mediterranean diet.Results
Baseline Characteristics of the Study Participants
From October 2003 through June 2009, a total of 8713 candidates were screened for eligibility, and 7447 were randomly assigned to one of the three study groups . Their baseline characteristics according to study group are shown in Table 2 Baseline Characteristics of the Participants According to Study Group.. Drug-treatment regimens were similar for participants in the three groups, and they continued to be balanced during the follow-up period.
Participants were followed for a median of 4.8 years (interquartile range, 2.8 to 5.8). After the initial assessment, 209 participants (2.8%) chose not to attend subsequent visits, and their follow-up was based on reviews of medical records. By December 2010, a total of 523 participants (7.0%) had been lost to follow-up for 2 or more years. Dropout rates were higher in the control group (11.3%) than in the Mediterranean-diet groups (4.9%). As compared with participants who remained in the trial, those who dropped out were younger (by 1.4 years), had a higher BMI (the weight in kilograms divided by the square of the height in meters; by 0.4), a higher waist-to-height ratio (by 0.01), and a lower score for adherence to the Mediterranean diet (by 1.0 points on the 14-item dietary screener)Compliance with the Dietary Intervention
Participants in the three groups reported similar adherence to the Mediterranean diet at baseline and similar food and nutrient intakes. During follow-up, scores on the 14-item Mediterranean-diet screener increased for the participants in the two Mediterranean-diet groups . There were significant differences between these groups and the control group in 12 of the 14 items at 3 years. Changes in objective biomarkers also indicated good compliance with the dietary assignments.Participants in the two Mediterranean-diet groups significantly increased weekly servings of fish (by 0.3 servings) and legumes (by 0.4 servings) in comparison with those in the control group . In addition, participants assigned to a Mediterranean diet with extra-virgin olive oil and those assigned to a Mediterranean diet with nuts significantly increased their consumption of extra-virgin olive oil (to 50 and 32 g per day, respectively) and nuts (to 0.9 and 6 servings per week, respectively). The main nutrient changes in the Mediterranean-diet groups reflected the fat content and composition of the supplemental foods . No relevant diet-related adverse effects were reported . We did not find any significant difference in changes in physical activity among the three groups.End Points
The median follow-up period was 4.8 years. A total of 288 primary-outcome events occurred: 96 in the group assigned to a Mediterranean diet with extra-virgin olive oil (3.8%), 83 in the group assigned to a Mediterranean diet with nuts (3.4%), and 109 in the control group (4.4%). Taking into account the small differences in the accrual of person-years among the three groups, the respective rates of the primary end point were 8.1, 8.0, and 11.2 per 1000 person-years (Table 3Table 3Outcomes According to Study Group.). The unadjusted hazard ratios were 0.70 (95% confidence interval [CI], 0.53 to 0.91) for a Mediterranean diet with extra-virgin olive oil and 0.70 (95% CI, 0.53 to 0.94) for a Mediterranean diet with nuts (Figure 1Figure 1Kaplan–Meier Estimates of the Incidence of Outcome Events in the Total Study Population.) as compared with the control diet (P=0.015, by the likelihood ratio test, for the overall effect of the intervention).The results of multivariate analyses showed a similar protective effect of the two Mediterranean diets versus the control diet with respect to the primary end point (Table 3). Regarding components of the primary end point, only the comparisons of stroke risk reached statistical significance (Table 3, and Fig. S6 in the Supplementary Appendix). The Kaplan–Meier curves for the primary end point diverged soon after the trial started, but no effect on all-cause mortality was apparent (Figure 1). The results of several sensitivity analyses were also consistent with the findings of the primary analysis .Subgroup Analyses
Reductions in disease risk in the two Mediterranean-diet groups as compared with the control group were similar across the prespecified subgroups (Figure 2). In addition, to account for the protocol change in October 2006 whereby the intensity of dietary intervention in the control group was increased, we compared hazard ratios for the Mediterranean-diet groups (both groups merged vs. the control group) before and after this date. Adjusted hazard ratios were 0.77 (95% CI, 0.59 to 1.00) for participants recruited before October 2006 and 0.49 (95% CI, 0.26 to 0.92) for those recruited thereafter (P=0.21 for interaction).Discussion
In this trial, an energy-unrestricted Mediterranean diet supplemented with either extra-virgin olive oil or nuts resulted in an absolute risk reduction of approximately 3 major cardiovascular events per 1000 person-years, for a relative risk reduction of approximately 30%, among high-risk persons who were initially free of cardiovascular disease. These results support the benefits of the Mediterranean diet for cardiovascular risk reduction. They are particularly relevant given the challenges of achieving and maintaining weight loss. The secondary prevention Lyon Diet Heart Study also showed a large reduction in rates of coronary heart disease events with a modified Mediterranean diet enriched with alpha-linolenic acid (a key constituent of walnuts). That result, however, was based on only a few major events.4,19,20There were small between-group differences in some baseline characteristics in our trial, which were not clinically meaningful but were statistically significant, and we therefore adjusted for these variables. In fully adjusted analyses, we found significant results for the combined cardiovascular end point and for stroke, but not for myocardial infarction alone. This could be due to stronger effects on specific risk factors for stroke but also to a lower statistical power to identify effects on myocardial infarction. Our findings are consistent with those of prior observational studies of the cardiovascular protective effects of the Mediterranean diet,2,5 olive oil,21-23 and nuts24,25; smaller trials assessing effects on traditional cardiovascular risk factors6-9 and novel risk factors, such as markers of oxidation, inflammation, and endothelial dysfunction6,8,26-28; and studies of conditions associated with high cardiovascular risk — namely, the metabolic syndrome6,16,29 and diabetes.30-32 Thus, a causal role of the Mediterranean diet in cardiovascular prevention has high biologic plausibility. The results of our trial might explain, in part, the lower cardiovascular mortality in Mediterranean countries than in northern European countries or the United States.33The risk of stroke was reduced significantly in the two Mediterranean-diet groups. This is consistent with epidemiologic studies that showed an inverse association between the Mediterranean diet2,34 or olive-oil consumption22 and incident stroke.Our results compare favorably with those of the Women's Health Initiative Dietary Modification Trial, wherein a low-fat dietary approach resulted in no cardiovascular benefit.35 Salient components of the Mediterranean diet reportedly associated with better survival include moderate consumption of ethanol (mostly from wine), low consumption of meat and meat products, and high consumption of vegetables, fruits, nuts, legumes, fish, and olive oil. 36,37 Perhaps there is a synergy among the nutrient-rich foods included in the Mediterranean diet that fosters favorable changes in intermediate pathways of cardiometabolic risk, such as blood lipids, insulin sensitivity, resistance to oxidation, inflammation, and vasoreactivity.38Our study has several limitations. First, the protocol for the control group was changed halfway through the trial. The lower intensity of dietary intervention for the control group during the first few years might have caused a bias toward a benefit in the two Mediterranean-diet groups, since the participants in these two groups received a more intensive intervention during that time. However, we found no significant interaction between the period of trial enrollment (before vs. after the protocol change) and the benefit in the Mediterranean-diet groups. Second, we had losses to follow-up, predominantly in the control group, but the participants who dropped out had a worse cardiovascular risk profile at baseline than those who remained in the study, suggesting a bias toward a benefit in the control group. Third, the generalizability of our findings is limited because all the study participants lived in a Mediterranean country and were at high cardiovascular risk; whether the results can be generalized to persons at lower risk or to other settings requires further research.As with many clinical trials, the observed rates of cardiovascular events were lower than anticipated, with reduced statistical power to separately assess components of the primary end point. However, favorable trends were seen for both stroke and myocardial infarction. We acknowledge that, even though participants in the control group received advice to reduce fat intake, changes in total fat were small and the largest differences at the end of the trial were in the distribution of fat subtypes. The interventions were intended to improve the overall dietary pattern, but the major between-group differences involved the supplemental items. Thus, extra-virgin olive oil and nuts were probably responsible for most of the observed benefits of the Mediterranean diets. Differences were also observed for fish and legumes but not for other food groups. The small between-group differences in the diets during the trial are probably due to the facts that for most trial participants the baseline diet was similar to the trial Mediterranean diet and that the control group was given recommendations for a healthy diet, suggesting a potentially greater benefit of the Mediterranean diet as compared with Western diets.In conclusion, in this primary prevention trial, we observed that an energy-unrestricted Mediterranean diet, supplemented with extra-virgin olive oil or nuts, resulted in a substantial reduction in the risk of major cardiovascular events among high-risk persons. The results support the benefits of the Mediterranean diet for the primary prevention of cardiovascular disease. References
Willett WC ,Sacks F ,Trichopoulou A , et al. Mediterranean diet pyramid: a cultural model for healthy eating. Am J Clin Nutr 1995;61:Suppl:1402S-1406SSofi F ,Abbate R ,Gensini GF ,Casini A . Accruing evidence on benefits of adherence to the Mediterranean diet on health: an updated systematic review and meta-analysis. Am J Clin Nutr 2010;92:1189-1196
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CrossRef | Web of Science | Medlinede Lorgeril M ,Salen P ,Martin JL ,Monjaud I ,Delaye J ,Mamelle N . Mediterranean diet, traditional risk factors, and the rate of cardiovascular complications after myocardial infarction: final report of the Lyon Diet Heart Study. Circulation 1999;99:779-785Mente A ,de Koning L ,Shannon HS ,Anand SS . A systematic review of the evidence supporting a causal link between dietary factors and coronary heart disease. Arch Intern Med 2009;169:659-669Esposito K ,Marfella R ,Ciotola M , et al. Effect of a Mediterranean-style diet on endothelial dysfunction and markers of vascular inflammation in the metabolic syndrome: a randomized trial. JAMA 2004;292:1440-1446Vincent-Baudry S ,Defoort C ,Gerber M , et al. The Medi-RIVAGE study: reduction of cardiovascular disease risk factors after a 3-mo intervention with a Mediterranean-type diet or a low-fat diet. Am J Clin Nutr 2005;82:964-971Estruch R ,Martinez-Gonzalez MA ,Corella D , et al. Effects of a Mediterranean-style diet on cardiovascular risk factors: a randomized trial. Ann Intern Med 2006;145:1-11Shai I ,Schwarzfuchs D ,Henkin Y , et al. Weight loss with a low-carbohydrate, Mediterranean, or low-fat diet. N Engl J Med 2008;359:229-241[Erratum, N Engl J Med 2009;361:2681.]- 10
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Zazpe I ,Sanchez-Tainta A ,Estruch R , et al. A large randomized individual and group intervention conducted by registered dieticians increased the adherence to Mediterranean-type diets: the PREDIMED study. J Am Diet Assoc 2008;108:1134-1144Schroder H ,Fito M ,Estruch R , et al. A short screener is valid for assessing Mediterranean diet adherence among older Spanish men and women. J Nutr 2011;141:1140-1145Fernandez-Ballart JD ,Pinol JL ,Zazpe I , et al. Relative validity of a semi-quantitative food-frequency questionnaire in an elderly Mediterranean population of Spain. Br J Nutr 2010;103:1808-1816Salas-Salvado J ,Fernandez-Ballart J ,Ros E , et al. Effect of a Mediterranean diet supplemented with nuts on metabolic syndrome status: one-year results of the PREDIMED randomized trial. Arch Intern Med 2008;168:2449-2458ALLHAT Officers and Coordinators for the ALLHAT Collaborative Research Group . Major outcomes in moderately hypercholesterolemic, hypertensive patients randomized to pravastatin vs usual care: the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT-LLT). JAMA 2002;288:2998-3007- 18
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Bendinelli B ,Masala G ,Saieva C , et al. Fruit, vegetables, and olive oil and risk of coronary heart disease in Italian women: the EPICOR Study. Am J Clin Nutr 2011;93:275-283
CrossRef | Web of Science | Medline Samieri C ,Feart C ,Proust-Lima C , et al. Olive oil consumption, plasma oleic acid, and stroke incidence: the Three-City Study. Neurology 2011;77:418-425Buckland G ,Travier N ,Barricarte A , et al. Olive oil intake and CHD in the European Prospective Investigation into Cancer and Nutrition Spanish cohort. Br J Nutr 2012;108:2075-2082Kris-Etherton PM ,Hu FB ,Ros E ,Sabate J . The role of tree nuts and peanuts in the prevention of coronary heart disease: multiple potential mechanisms. J Nutr 2008;138:1746S-1751SRos E ,Tapsell LC ,Sabate J . Nuts and berries for heart health. Curr Atheroscler Rep 2010;12:397-406Fito M ,Guxens M ,Corella D , et al. Effect of a traditional Mediterranean diet on lipoprotein oxidation: a randomized controlled trial. Arch Intern Med 2007;167:1195-1203Mena MP ,Sacanella E ,Vazquez-Agell M , et al. Inhibition of circulating immune cell activation: a molecular antiinflammatory effect of the Mediterranean diet. Am J Clin Nutr 2009;89:248-256- 28
Fuentes F ,Lopez-Miranda J ,Sanchez E , et al. Mediterranean and low-fat diets improve endothelial function in hypercholesterolemic men. Ann Intern Med 2001;134:1115-1119
CrossRef | Web of Science | Medline Kastorini CM ,Milionis HJ ,Esposito K ,Giugliano D ,Goudevenos JA ,Panagiotakos DB . The effect of Mediterranean diet on metabolic syndrome and its components: a meta-analysis of 50 studies and 534,906 individuals. J Am Coll Cardiol 2011;57:1299-1313Esposito K ,Maiorino MI ,Ceriello A ,Giugliano D . Prevention and control of type 2 diabetes by Mediterranean diet: a systematic review. Diabetes Res Clin Pract 2010;89:97-102Salas-Salvado J ,Bullo M ,Babio N , et al. Reduction in the incidence of type 2 diabetes with the Mediterranean diet: results of the PREDIMED-Reus nutrition intervention randomized trial. Diabetes Care 2011;34:14-19Martinez-Gonzalez MA ,de la Fuente-Arrillaga C ,Nunez-Cordoba JM , et al. Adherence to Mediterranean diet and risk of developing diabetes: prospective cohort study. BMJ 2008;336:1348-1351Muller-Nordhorn J ,Binting S ,Roll S ,Willich SN . An update on regional variation in cardiovascular mortality within Europe. Eur Heart J 2008;29:1316-1326Kastorini CM ,Milionis HJ ,Ioannidi A , et al. Adherence to the Mediterranean diet in relation to acute coronary syndrome or stroke nonfatal events: a comparative analysis of a case/case-control study. Am Heart J 2011;162:717-724Howard BV ,Van Horn L ,Hsia J , et al. Low-fat dietary pattern and risk of cardiovascular disease: the Women's Health Initiative Randomized Controlled Dietary Modification Trial. JAMA 2006;295:655-666Trichopoulou A ,Bamia C ,Trichopoulos D . Anatomy of health effects of Mediterranean diet: Greek EPIC prospective cohort study. BMJ 2009;338:b2337-b2337Buckland G ,Mayen AL ,Agudo A , et al. Olive oil intake and mortality within the Spanish population (EPIC-Spain). Am J Clin Nutr 2012;96:142-149Jacobs DR Jr ,Gross MD ,Tapsell LC . Food synergy: an operational concept for understanding nutrition. Am J Clin Nutr 2009;89:1543S-1548S
Something New under the Sun? The Mediterranean Diet and Cardiovascular Health
Sarah W. Tracy, Ph.D.
- Increasingly, the Mediterranean diet has become the standard for healthy eating. Adherence to it appears to reduce the risk of cardiovascular disease, cancer, Alzheimer's disease, and Parkinson's disease, as well as the risk of death due to cardiovascular disease or cancer and even premature death overall.1 Largely plant-centered, with high intakes of olive oil, fruit, nuts, and whole-grain cereals, moderate consumption of fish and poultry, low intakes of dairy, red meat, and sweets, and often moderate drinking of red wine, the “classic” Mediterranean diet is younger than the region's history suggests. In fact, this dietary pattern was first observed in Greece, Italy, and Spain in the decade after World War II — an artifact of postwar impoverishment that proved beneficial to health. Unfortunately, it is currently under siege in southern Europe from the globalization of fast foods rich in refined carbohydrates, sweets, and red meat.In this issue of the Journal, Estruch et al. (pages 1279–1290) report the positive results of PREDIMED (Prevención con Dieta Mediterránea), a randomized trial of the Mediterranean diet (supplemented with either extra-virgin olive oil or nuts) for the primary prevention of cardiovascular events. The data are impressive and seem to support the high ranking of the Mediterranean diet and its constituent foods among various cardioprotective vegetable- and fruit-rich regimens, such as DASH (Dietary Approaches to Stop Hypertension) and Japanese and traditional vegetarian diets. Yet in many ways, that is old news. The history of dietary guidelines for heart health — a project begun in the 1950s when the United States felt threatened by a perceived “epidemic” of heart attacks — reveals that the Mediterranean diet's cardiovascular benefits have been recognized for decades. As early as 1948, the Rockefeller Foundation assessed the health, economic, and social status of Cretan Greeks and noted that their “impoverished” diet was rich in cereal grains, legumes, wild greens and herbs, and fruits, paired with limited meat, milk, and fish. Meals were said to be “swimming” in olive oil and prepared simply in ways that “preserved the nutritive value of the food rather well.”2The first epidemiologic data supporting the Mediterranean diet came from the Seven Countries Study (SCS), a prospective investigation of diet and other cardiovascular-disease risk factors in 16 cohorts totaling nearly 13,000 men in the United States, Italy, Greece, Yugoslavia, Finland, the Netherlands, and Japan, which began in 1958. The PREDIMED results would come as little surprise to the man behind the SCS, American physiologist and epidemiologist Ancel Keys, who advanced the low-fat diet and the low-saturated-fat Mediterranean diet for the primary and secondary prevention of heart disease. Keys “discovered” the Mediterranean diet's health benefits in the early 1950s, when visiting the region as a medical scientist concerned about the widely reported increase in heart attacks in the United States. After spending several years exploring the dietary patterns and cardiovascular status of men in Italy, Spain, and Crete, Keys launched the SCS. Study data (which are still being collected from elderly “survivors”) offered strong population-level support for the effects of dietary fat and fatty acids on serum cholesterol levels and cardiovascular disease risk.The still-unfolding story of dietary fat has proven more complicated than Keys envisioned, but his observations about dietary patterns in various cultures — Mediterranean, northern European, and Asian — appear prescient today. The nutritional properties of whole foods and food patterns — rather than macronutrients (such as protein, carbohydrate, and fat) and micronutrients (such as vitamins and minerals) — are an important focus of recent research. Many who study diet's effects on disease note that we do not eat isolated nutrients. Instead, we form food patterns, consuming diets rich in fruits, nuts, vegetables, and oils or, alternatively, in highly processed foods, and these constituent foods interact synergistically.3 Sometimes these synergies confer long-term benefits.This holistic turn in nutrition science represents something of a paradigm shift. Early in the 20th century, research focused on the roles of micronutrients, often specific vitamins, and the prevention of deficiency diseases such as beriberi, pellagra, and scurvy. By midcentury, chronic diseases such as atherosclerosis, hypertension, and cancer were recognized as the dominant health threats in the developed world. Yet the reductionism that guided the early studies continued to influence explorations of diet and heart disease. In the 1950s and 1960s, biochemists, clinical scientists, and epidemiologists focused on macronutrients as potential contributors to cardiovascular disease and debated what constituted proof of a causal link between dietary fat and heart disease. Individual macronutrients and bioactive compounds in food, such as cholesterol, were the focus of research exploring diet's relation to the health status of populations.In this context, the American Heart Association (AHA) Ad Hoc Committee on Dietary Fat and Atherosclerosis issued the first dietary guidelines for the prevention of cardiovascular disease in 1957. The guidelines were brief and tentatively worded, reflecting controversy over the hypothesized link between dietary fat and heart disease. Obese people or those with a personal or family history of heart disease were urged to control their weight, reduce dietary fat to 25 to 35% of total energy intake, and substitute polyunsaturated fats for animal fats. The guidelines thus focused on macronutrients, specifically fats. Committed to reducing heart disease, the AHA revised its guidelines throughout the 1960s. By 1968, people of all ages were urged to limit dietary cholesterol as well and to adhere to principles of good nutrition.When the AHA issued its first “heart healthy” cookbook, in 1973, it was a latecomer. Cookbooks catering to heart health first appeared in the 1950s, offering recipes for limiting caloric intake and reducing dietary fat and cholesterol. The first cookbook to promote the hypothesized relationship between diet and heart health was probably that of physician Helen Gofman, The Low Fat Low Cholesterol Diet (1951). Gofman's husband, the medical physicist and lipidologist John Gofman, also wrote a cookbook, Dietary Prevention and Treatment of Heart Disease (1958), examining the relationship of dietary carbohydrates to dietary fat in atherogenesis. There were many others, but the most popular were two cookbooks by Keys and his biochemist wife, Margaret, Eat Well and Stay Well (1959) and How to Eat Well and Stay Well the Mediterranean Way (1975). These interpreted “diet” in the classic Greek sense, as a “way of life,” and advocated moderate exercise in addition to “heart-healthy eating” that was grounded largely in Italian and Greek cuisine. Cookbooks, with their focus on dietary pattern, allowed Keys to explore the irreducible elements of a healthy diet, something he and others struggled to do in the laboratory. As food-policy expert Marion Nestle has observed, there is striking similarity between Keys's 1959 recommendations and those in recent editions of the Dietary Guidelines for Americans from the U.S. Department of Agriculture (USDA) and the Department of Health and Human Services.4Since 1980, these guidelines, revised every 5 years, have set dietary standards for an increasingly obese and diabetic American public. In part, they reflect an ongoing dance between evidence-based dietary advice and the food-industry lobby. In part, they reflect a stable dietary foundation for avoiding degenerative diseases: eat more fruits, vegetables, and nuts; limit red meat and dairy; consume more fish and poultry; curtail salt and sugar; use olive and other vegetable oils; and substitute whole grains for refined ones. This advice should sound familiar, yet because the 2010 guidelines often use difficult-to-translate macronutrient language and fill more than 95 pages, they have become less accessible to the public. And the USDA nutritional icon “MyPyramid” (2005) and its replacement, “MyPlate” (2011), intended to distill cumbersome dietary advice, have been criticized for being too simple, misleading, or excessively influenced by the food industry.5In 2010, the United Nations Educational, Scientific, and Cultural Organization (UNESCO) placed the Mediterranean diet on its Intangible Cultural Heritage list, a sort of endangered-species list of treasured elements of cultures, valuable both in their native lands and globally. The PREDIMED results reinforce the Mediterranean diet's value for health internationally, suggesting a dietary template that may be of particular value as chronic disease becomes a global issue.1
Sofi F ,Abbate R ,Gensini GF ,Casini A . Accruing evidence on benefits of adherence to the Mediterranean diet on health: an updated systematic review and meta-analysis. Am J Clin Nutr 2010;92:1189-1196
12Allbaugh LG. Crete — a case study of an underdeveloped area. Princeton, NJ: Princeton University Press, 1953.34Nestle M . Mediterranean diets -- historical and research overview. Am J Clin Nutr 1995;61:Suppl:1313S-1320S
Web of Science | Medline5Datz T. Harvard serves up its own `plate': Healthy Eating Plate shows shortcomings in government's MyPlate. Harvard Gazette. September 24, 2011 (http://news.harvard.edu/gazette/story/2011/09/harvard-serves-up-its-own-plate/).
Limiting “Sugary Drinks” to Reduce Obesity — Who Decides?
Wendy K. Mariner, J.D., M.P.H., and George J. Annas, J.D., M.P.H.
Interview with Prof. Wendy Mariner on New York City's invalidated Portion Cap Rule and other efforts to regulate public health. (10:21)When a judge struck down the New York City Board of Health's partial ban on selling “sugary drinks” in containers of more than 16 fluid ounces, the reaction was swift. The Portion Cap Rule was widely viewed as a signature accomplishment of Mayor Michael Bloomberg's third term as the “public health mayor,” and he vowed to appeal, saying, “I've got to defend my children, and yours, and do what's right to save lives. Obesity kills.”1 But the question before the judge was not about the health risks posed by obesity or even the relationship between obesity and access to large cups of sugary drinks; it was whether the city's Board of Health (part of the New York City Department of Health and Mental Hygiene) had the legal authority to restrict the serving size of such drinks.Written in the mayor's office, the Portion Cap Rule was adopted by the board on an 8-to-0 vote with one abstention in September 2012 and was almost immediately challenged in court. Judge Milton A. Tingling heard the case and wrote a 36-page opinion striking down the rule.2 There was no dispute that obesity is a serious problem; the only issue considered by the judge was whether the board has the power to adopt the rule. The substance of the rule is that “A food service establishment may not sell, offer, or provide a sugary drink in a cup or container that is able to contain more than 16 fluid ounces.” A “sugary drink” is defined as a nonalcoholic drink that is “sweetened by the manufacturer or establishment with sugar or another caloric sweetener; has greater than 25 calories per 8 fluid ounces of beverage; and does not contain more than 50 percent of milk . . . by volume.”Legislatures make policy, and administrative agencies carry out the policy made by the legislature. The New York City Board of Health is an administrative agency, which can do only what it is authorized to do by legislation. The threshold question was whether the board exceeded its authority “and impermissibly trespassed on legislative jurisdiction.”2 The judge relied heavily on a 1987 case involving a successful challenge to the state Public Health Council's anti–indoor-smoking rules.3 In that case, the Court of Appeals (the highest court in New York State) examined “the difficult-to-define line between administrative rule-making and legislative policy-making.” Four “coalescing circumstances” persuaded the Court of Appeals that the state administrative agency had crossed the line in that case. The 1987 rules prohibited smoking in a “wide variety of indoor areas that are open to the public” but expressly excluded many venues, including restaurants with fewer than 50 seats, conventions, trade shows, bars, and hotel rooms. The Court of Appeals determined that those rules were based more on economic and social concerns than on public health matters, were written on a “clean slate” rather than simply filling in regulatory gaps left to the agency by the legislature, involved a matter on which the legislature had repeatedly tried and failed to reach agreement, and were developed without the exercise of any special public health expertise.3Judge Tingling found the indoor-smoking decision to be a controlling precedent in the Portion Cap Rule case. He examined the “coalescing circumstances” to determine whether New York City's board had exceeded its administrative authority. Tingling found first that, like the indoor-smoking rule, the regulation was “laden with exceptions based on economic and political concerns,” which are outside the Board of Health's purview. Next, he concluded that the powers granted to the health department by the New York City Charter (from its origin in 1730 through more than a dozen amendments to date) did not grant the board “the authority to limit or ban a legal item under the guise of `controlling chronic disease.'”2 Third, the judge found that that city's legislature, the New York City Council, had not passed any laws addressing the subject matter. The judge's bottom line is that the health department violated the separation-of-powers doctrine by exceeding its authority as an administrative agency and acting like a legislature. Accepting the city's arguments would, the judge concluded, “create an administrative Leviathan” that would give the Board of Health “authority to define, create, mandate and enforce [rules] limited only by its own imagination.”2The judge also adopted a separate basis for striking down the Portion Cap Rule, determining that it was arbitrary and capricious because it does not apply to “all food establishments in the City, it excludes other beverages that have significantly higher concentrations of sugar sweeteners . . . on suspect grounds,” and it has many loopholes — for instance, it imposes no limitations on refills, which defeats its purpose.2The rule and the opinion raise several issues. First, the city's health department has taken other actions without direct authorization by the city council that could now be challenged. For example, in 2005, the Board of Health required laboratories to report to the department the names, dates of birth, addresses, physicians, and blood-sugar levels of people with type 2 diabetes — without patient consent.4Second, the judge's conclusion that the legislative branch is the proper branch to make public health policy is correct. Both the New York City Council and the New York State legislature have the authority to regulate the sale of soda in large containers and to grant this authority to the city or state health department. Should either legislative body do so, it is much less likely that a court would overturn the Portion Cap Rule as arbitrary and capricious. On the other hand, the rule has been widely ridiculed, which makes its enactment by elected officials highly unlikely. Jon Stewart probably expressed a widespread public sentiment when he joked that he loved the rule because “it combines the draconian government overreach people love with the probable lack of results they expect.”Third, there are reasonable alternatives to the Portion Cap Rule, such as higher taxes on all sales of sodas. Higher prices often discourage consumption, as has been the case with cigarettes. Such taxes tend to be regressive, however, with disproportionate effects on lower-income people, who in this case could not afford to buy fancy bottled water or juice drinks. That may be one reason why some New York communities oppose such taxes.Some alternatives, however, are not reasonable — in particular, the current proposals to shame people who are overweight.5 Such shaming amounts to treating a health risk, whose development may be involuntary, as a moral failure. Any public policy entailing overt discrimination based on physical appearance is simply wrong. People who are obese know it; making them feel worse about themselves encourages bullying, another public health problem, and helps no one.Perhaps the most important lesson is old news: economics often drives health policy. New York City's efforts to reduce obesity grew with its desire to control its health care costs for its residents, a disproportionate share of whom are obese or have diabetes. Meanwhile, large corporations continue to use their influence and money to derail public health measures that could reduce their profits. Although the general public shares the goals of public health, many people remain skeptical of government's choice of means for achieving those goals. Agencies that overstep their bounds or adopt rules that are intrusive or just plain silly invite backlash, which can make effective public health regulation impossible. They make fools of themselves and heroes of the opponents of public health.1 Grynbaum MM. Court halts ban on large sodas in New York City. New York Times. March 12, 2013:A1.2 New York Statewide Coalition of Hispanic Chambers of Commerce v. New York City Dept. of Health and Mental Hygiene, No. 653584/12 (N.Y. Sup. Ct., N.Y. Cty., Mar. 11, 2013).3 Boreali v. Axelrod, 71 N.Y.2d 1, 517 N.E.2d 1350 (1987).4Mariner WK . Medicine and public health: crossing legal boundaries. J Health Care Law Policy 2007;10:121-1515Callahan D . Obesity: chasing an elusive epidemic. Hastings Cent Rep 2013;43:34-40
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