Recommendations Urge Veterans to Eat A Variety of Foods
By Annette M. Boyle
MINNEAPOLIS—For 30 years, Americans have focused on reducing fat to lower their risk of diabetes and other chronic diseases. New research by the VA indicates that approach might be dead wrong.
“Low-fat diets are not the solution to the obesity epidemic in this country,” explained Hanna Bloomfield, MD, MPH, core investigator at the VA’s Center for Chronic Disease Outcomes Research and associate chief of staff for Research & Development at the Minneapolis VA Health Care System.
Instead, individuals concerned about healthy eating should focus more on other changes to their diet, Bloomfield told U.S. Medicine, adding that, “consuming more whole grains, monounsaturated fats, fruits, vegetables and legumes and avoiding refined grains and sugar are probably more important than reducing total fat intake.”
In a study recently published in the Annals of Internal Medicine, Bloomfield and her colleagues found some evidence from their review of dozens of randomized trials that “Mediterranean diets with no restriction on fat intake are associated with reductions in major clinical outcomes” including Type 2 diabetes mellitus as well as cardiovascular events and cancer.1
The study was funded by the VA’s Evidence-based Synthesis Program and Office of Quality and Performance in response to a request from VA’s National Center for Health Promotion and Disease Prevention and Primary Care Services. The VA sought to evaluate the implications of the Mediterranean diet for veteran health as a result of “the increased prevalence of obesity, diabetes and other chronic disease in the veteran population,” Bloomfield said.
About one-fourth of veterans who receive care through the VA have a diabetes diagnosis, nearly three times the rate seen in the general population, according to the VA. Those veterans also are twice as likely to develop cardiovascular disease compared to patients treated outside the VA, a study in the International Journal of Preventive Medicine found.2 Diabetes is itself a risk factor for cardiovascular disease.
The researchers characterized the Mediterranean diet as having no restriction on total fat intake and including two or more of seven additional components: high monounsaturated to saturated fat ratio, high consumption of fruits and vegetables, high intake of legumes, high consumption of whole grains and cereals, moderate red wine consumption, moderate dairy consumption and low intake of meat and meat products, along with increased consumption of fish. Foods high in monounsaturated fats include olive, peanut, sesame, sunflower and canola oil as well as avocados, seeds, nuts and nut butters.
By contrast, the typical Western diet is high in saturated fats, refined grains and sugar and artificial sweeteners with minimal intake of fruits, vegetables, fish, legumes and whole grains.
Investigators reviewed 320 articles comparing the Mediterranean diet with no fat restriction to low-fat diets published from 1990 through August 2015. Ninety papers representing 56 separate studies met the inclusion criteria and had at least 100 participants who were followed for one year or longer for mortality, diabetes, cardiovascular, hypertension and adherence outcomes. The study team also evaluated cohort studies of the same size and duration for cancer, rheumatoid arthritis and cognitive impairment outcomes.
The only study that assessed the effects of an intensive Mediterranean diet compared to a low-fat diet, PREDIMED (Prevention with Mediterranean Diet), included all of the elements of the Mediterranean diet except specific recommendations for grain and dairy consumption. Nearly 7,500 participants were divided into three groups: a low-fat control, the Mediterranean diet plus additional olive oil, and the Mediterranean diet plus extra nuts. Among those participants who did not have Type 2 diabetes at baseline, the incidence of Type 2 diabetes was 30% lower over the average 4.8 years of follow-up among those in both Mediterranean diet arms than those on the low-fat diet. There also was a 29% reduction in major cardiovascular events compared with the control group, though no overall reduction in mortality.
Overall, the evidence suggested that the Mediterranean diet with no restriction on fat intake might be associated with reduced incidence of Type 2 diabetes mellitus, cardiovascular events and breast cancer compared with any other diet but does not affect all-cause mortality, the authors concluded.
Despite these outcomes, a VA report on the study noted that the quality of available evidence for the Mediterranean diet’s effects on clinical outcomes is low or insufficient, particularly in North American and veteran populations. In addition, the VA noted that adherence to a Mediterranean diet could require significant behavioral intervention to maintain in a group accustomed to eating very differently.
Consequently, rather than recommend the Mediterranean diet, the VA encourages veterans to adopt a diet that features a variety of foods, including vegetables, fruits, and whole grains as well as nuts, fish and foods low in saturated fats.
Bloomfield supported the VA’s recommendation, saying that, as “our research showed that there is not enough evidence that the Mediterranean diet is superior to other ‘healthy diets,’ the VA, appropriately, did not make any recommendations as the institutional level.” The authors and the VA Health Services Research & Development called for additional research on the diet’s impact on both primary and secondary prevention.
VA physicians are encouraged to make dietary recommendations to their patients based on their individual situations and health status. The recent research argues that they should consider the Mediterranean diet, particularly for those who have diabetes or are at risk of developing the disease and also are overweight or obese.
Another recent study indicates that the Mediterranean Diet could help veterans lose weight, a primary recommendation for the management of diabetes. Published in the August issue of Lancet Diabetes & Endocrinology, that study used the data from the PREDIMED trial and found that the Mediterranean diet helped older individuals lose weight, even if they already had Type 2 diabetes and were overweight or obese.3
Nearly 90% of the study participants were overweight or obese at baseline and had either Type 2 diabetes, high cholesterol, high blood pressure or smoked. Over a five-year period, individuals in the Mediterranean diet plus extra olive oil group lost the most weight, two pounds, and those on the low-fat diet lost the least. Participants in the Mediterranean diet plus nuts group had the least gain in waist circumference over the study period.
- Bloomfield H, Koeller E, Greer N, MacDonald R, Kane R, Wilt TJ. Effects on Health Outcomes of a Mediterranean Diet With No Restriction on Fat Intake. Ann Intern Med. 2016;165(7):491-500.
- Assari S. Veterans and Risk of Heart Disease in the United States: A Cohort with 20 Years of Follow Up. Int J Prev Med. 2014 Jun; 5(6):703-709.
- Estruch R, Martínez-González MA, Corella D, Salas-Salvadó J, Fitó M, et al. PREDIMED Study Investigators. Effect of a high-fat Mediterranean diet on bodyweight and waist circumference: a prespecified secondary outcomes analysis of the PREDIMED randomised controlled trial. Lancet Diabetes Endocrinol. 2016 Aug;4(8):666-76.