As a functional medicine nutritionist for over a decade, I have had the opportunity to explore several questions about diet and lifestyle, including:
• Does the quality of our diet matter, or is the essence of healthy eating just about calories?
• Are all lifestyle interventions created equal?
• What is the role of personalization in health care?
Last week, these questions came to mind again after reading a study published in the New England Journal of Medicine (1) claiming that intensive lifestyle intervention did not help to reduce cardiovascular risks in overweight individuals with Type 2 diabetes any better than the control group that received social support and education related to diabetes. In a follow-up editorial by Gerstein (2), it was suggested that "these findings may mean that lifestyle interventions do not effectively reduce the rate of cardiovascular events in patients with Type 2 diabetes."
At first, I was a bit surprised to see this conclusion. After all, how can anyone argue with the therapeutic impact of lifestyle -- the basics of healthy eating and increased physical activity -- for the reduction of chronic disease? One study published in the same journal in 2002 by Knowler et al. (3) used essentially the same lifestyle regimen, albeit in non-diabetics and looking at different endpoints, and cited this finding after the 2.8-year study duration:
"Lifestyle changes and treatment with metformin both reduced the incidence of diabetes in persons at high risk. The lifestyle intervention was more effective than metformin."
When it comes to cardiovascular disease, Dr. Dean Ornish has published extensively in this area, indicating that lifestyle intervention not only prevents, but leads to regression of cardiovascular disease (4). These are just two examples, but the literature is replete in articles to suggest the efficacy of lifestyle for an array of chronic diseases.
Moreover, a meta-analysis of different dietary approaches for the management of Type 2 diabetes in 20 randomized clinical trials was published months ago in the American Journal of Clinical Nutrition (5) and concluded:
Low-carbohydrate, low-GI, Mediterranean, and high-protein diets are effective in improving various markers of cardiovascular risk in people with diabetes and should be considered in the overall strategy of diabetes management.
Knowing the breadth of research on the benefits of lifestyle medicine, it was difficult for me to digest the results of the current study without looking deeper into the actual lifestyle intervention that was used. After all, in the best sense, lifestyle medicine is more than the generalities of eat healthy and get exercise. There is much room for interpretation in those two pivotal recommendations -- for example, what is "healthy" eating exactly and how much and what type of exercise is best? In my experience, I believe that effective lifestyle intervention consists of a personalized approach to each individual patient to meet their genetic composition and environmental inputs.
In this particular study, the lifestyle intervention was designed to produce and maintain weight loss and increase fitness. Subjects were augmented with weight loss medication, if needed, in order to meet the weight loss goal. As part of the protocol, a fixed-calorie, controlled-macronutrient diet, with fat at less than 30 percent of calories and less than 10 percent of calories from saturated fat, was prescribed. Subjects were provided with a commercially-available liquid meal replacement and bars to enhance compliance.
I immediately asked myself: What was the quality of the nutrients that were provided in the average diet of the study participants? In my experience, it is challenging to obtain a high-nutrient density diet from consuming commercial liquid meal replacements. Furthermore, in my functional medicine view, health is not just about the calories and percentage of energy from macronutrients, such as in the case of adhering to a low-fat diet, but about the dietary signals we are relaying to our DNA through complex, therapeutic food constituents like the vast array of thousands of phytonutrients, complete protein, anti-inflammatory omega-3 fatty acids, insoluble and soluble fiber, vitamins, and minerals. In 2008, Dr. Jeffrey Bland and I published an article in Nutrition Reviews (6) detailing the role of nutrients, particularly phytonutrients, in important cellular cascades that control pathways related to metabolism and insulin sensitivity. Dr. Dave Jacobs at the University of Minnesota also refers to promoting the intake of a variety of nutrient dense foods. He proposed the idea of "food synergy," which is that the whole of food is more than any particular part (7).
Thus, with all the evidence in favor of looking at food constituents as signaling agents to the cell that determine its epigenetic outcome, can we continue to carry the view of nutrition that a healthy diet is distilled into simply focusing on eating a low-fat diet? There have been numerous studies to suggest that the Mediterranean diet, a diet not necessarily low in fat, but high in good quality fat, may have benefit for the prevention and improvement in biomarkers associated with chronic conditions, including cardiovascular disease (8, 12, 14, 15) and Type 2 diabetes (5, 9, 10, 11, 12, 13).
Therefore, when I read a study such as this one, I can't help but question, "What is lifestyle intervention?" and "What should it be?" I remain an advocate of treating patients in a personalized manner with integrative therapies within a functional medicine paradigm that helps them to get well. In the 21st century, it would seem that it is time to move beyond generalized dietary and lifestyle prescriptions and into the realm of utilizing functional biomarkers, point-of-care diagnostics, and virtual health care providers to give patients what they deserve -- quality lifestyle intervention with specific nutrient-dense foods, quality dietary supplements, tailored physical activity regimens and mind-body medicine techniques to address each person's unique physiology and psychology, otherwise known as personalized lifestyle medicine. Improved outcomes will result from this approach and the use of technology available to best assess moment-to-moment changes in health.
For more on the definition of personalized lifestyle medicine, see the recent article published by Bland and myself: http://www.hindawi.com/journals/tswj/2013/129841/. For more information on personalized lifestyle medicine, please visit www.plminstitute.org.
1. The Look AHEAD Research Group. Cardiovascular Effects of Intensive Lifestyle Intervention in Type 2 Diabetes. N Engl J Med. 2013 Jun 24. [Epub ahead of print]
2. Gerstein HC. Do Lifestyle Changes Reduce Serious Outcomes in Diabetes? N Engl J Med. 2013 Jun 24. [Epub ahead of print]
3. Knowler WC, Barrett-Connor E, Fowler SE, Hamman RF, Lachin JM, Walker EA, Nathan DM; Diabetes Prevention Program Research Group. Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. N Engl J Med. 2002 Feb 7;346(6):393-403.
4. Ornish D, Scherwitz LW, Billings JH, Brown SE, Gould KL, Merritt TA, Sparler S, Armstrong WT, Ports TA, Kirkeeide RL, Hogeboom C, Brand RJ. Intensive lifestyle changes for reversal of coronary heart disease. JAMA. 1998 Dec 16;280(23):2001-7.
5. Ajala O, English P, Pinkney J. Systematic review and meta-analysis of different dietary approaches to the management of type 2 diabetes. Am J Clin Nutr. 2013 Mar;97(3):505-16. doi: 10.3945/ajcn.112.042457. Epub 2013 Jan 30.
6. Minich DM, Bland JS. Dietary management of the metabolic syndrome beyond macronutrients. Nutr Rev. 2008 Aug;66(8):429-44. doi: 10.1111/j.1753-4887.2008.00075.x.
7. Jacobs DR, Tapsell LC. Food synergy: the key to a healthy diet. Proc Nutr Soc. 2013 May;72(2):200-6. doi: 10.1017/S0029665112003011. Epub 2013 Jan 14.
8. Estruch R, Ros E, Salas-Salvadó J, Covas MI, Corella D, Arós F, Gómez-Gracia E, Ruiz-Gutiérrez V, Fiol M, Lapetra J, Lamuela-Raventos RM, Serra-Majem L, Pintó X, Basora J, Muñoz MA, Sorlí JV, Martínez JA, Martínez-González MA; PREDIMED Study Investigators. Primary prevention of cardiovascular disease with a Mediterranean diet. N Engl J Med. 2013 Apr 4;368(14):1279-90. doi: 10.1056/NEJMoa1200303. Epub 2013 Feb 25.
9. InterAct Consortium, Romaguera D, Guevara M, Norat T, Langenberg C, Forouhi NG, Sharp S, Slimani N, Schulze MB, Buijsse B, Buckland G, Molina-Montes E, Sánchez MJ, Moreno-Iribas MC, Bendinelli B, Grioni S, van der Schouw YT, Arriola L, Beulens JW, Boeing H, Clavel-Chapelon F, Cottet V, Crowe FL, de Lauzon-Guillan B, Franks PW, Gonzalez C, Hallmans G, Kaaks R, Key TJ, Khaw K, Nilsson P, Overvad K, Palla L, Palli D, Panico S, Quirós JR, Rolandsson O, Romieu I, Sacerdote C, Spijkerman AM, Teucher B, Tjonneland A, Tormo MJ, Tumino R, van der AD, Feskens EJ, Riboli E, Wareham NJ. Mediterranean diet and type 2 diabetes risk in the European Prospective Investigation into Cancer and Nutrition (EPIC) study: the InterAct project. Diabetes Care. 2011 Sep;34(9):1913-8. doi: 10.2337/dc11-0891. Epub 2011 Jul 25.
10. Hodge AM, English DR, Itsiopoulos C, O'Dea K, Giles GG. Does a Mediterranean diet reduce the mortality risk associated with diabetes: evidence from the Melbourne Collaborative Cohort Study. Nutr Metab Cardiovasc Dis. 2011 Sep;21(9):733-9. doi: 10.1016/j.numecd.2010.10.014. Epub 2010 Dec 30.
11. Itsiopoulos C, Brazionis L, Kaimakamis M, Cameron M, Best JD, O'Dea K, Rowley K. Can the Mediterranean diet lower HbA1c in type 2 diabetes? Results from a randomized cross-over study. Nutr Metab Cardiovasc Dis. 2011 Sep;21(9):740-7. doi: 10.1016/j.numecd.2010.03.005. Epub 2010 Jul 31.
12. Elhayany A, Lustman A, Abel R, Attal-Singer J, Vinker S. A low carbohydrate Mediterranean diet improves cardiovascular risk factors and diabetes control among overweight patients with type 2 diabetes mellitus: a 1-year prospective randomized intervention study. Diabetes Obes Metab. 2010 Mar;12(3):204-9. doi: 10.1111/j.1463-1326.2009.01151.x.
13. 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 Mar 15;57(11):1299-313. doi: 10.1016/j.jacc.2010.09.073.
14. Panagiotakos D, Sitara M, Pitsavos C, Stefanadis C. Estimating the 10-year risk of cardiovascular disease and its economic consequences, by the level of adherence to the Mediterranean diet: the ATTICA study. J Med Food. 2007 Jun;10(2):239-43.
15. Estruch R, Martínez-González MA, Corella D, Salas-Salvadó J, Ruiz-Gutiérrez V, Covas MI, Fiol M, Gómez-Gracia E, López-Sabater MC, Vinyoles E, Arós F, Conde M, Lahoz C, Lapetra J, Sáez G, Ros E; PREDIMED Study Investigators. Effects of a Mediterranean-style diet on cardiovascular risk factors: a randomized trial. Ann Intern Med. 2006 Jul 4;145(1):1-11.
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