DIABETES/METABOLISM RESEARCH AND REVIEWS Diabetes Metab Res Rev 2014; 30(Suppl. 1): 1–3. Published online in Wiley Online Library (wileyonlinelibrary.com) DOI: 10.1002/dmrr.2512
INTRODUCTION
Diet and diabetes: a cornerstone for therapy Paolo Pozzilli1,2* Francesco Fallucca3 1
Department of Endocrinology and Diabetes, University Campus BioMedico, Rome, Italy
2
Centre of Diabetes, St. Bartholomew’s and the London, School of Medicine, Queen Mary University, London, UK ‘In Unam Sapientiam’, University La Sapienza, Rome, Italy
3
*Correspondence to: Paolo Pozzilli, Department of Endocrinology and Diabetes, University Campus Bio-Medico, Via Alvaro del Portillo 21, 00128 Rome, Italy. E-mail: [email protected]
Received: 23 October 2013 Accepted: 18 December 2013
Copyright © 2013 John Wiley & Sons, Ltd.
Summary An appropriate diet represents the cornerstone for diabetes therapy. Diets that differ in their carbohydrate, lipid and protein content are used but the evidence of their effects on the long term is missing. Several confounding factors and compliance to diet render difficult the evaluation of the ‘best diet’ for diabetes. On a short run, however, useful indications can be obtained regarding the effective diets capable to optimize metabolic control in type 2 diabetes. Copyright © 2013 John Wiley & Sons, Ltd. Keywords
diabetes; diet; diabetes prevention
There is now unequivocal evidence that type 2 diabetes can be prevented or even delayed by a well-structured diet and increased physical activity, generally resulting in weight loss. Some of the major trials like the US Diabetes Prevention Programme, a 27-centre randomized clinical trial reported a 58% reduction in the incidence of diabetes in individuals with impaired glucose tolerance when treated with the lifestyle intervention compared with the metformin [1]. The look AHEAD (Action for Health in Diabetes), conducted in 16 canters in the USA, is the first large clinical trial to compare an intensive weight loss intervention with a support and educational group in overweight or obese adults with type 2 diabetes. At 1 year, participants achieved an average loss of 8.6% of initial body weight and a 21% improvement in cardiovascular fitness, attributable to the higher physical activity goal. The more intense dietary intervention, which included not only calorie and fat restriction but also structured meal plans, each of which has previously been associated with successful weight loss and maintenance [2]. The Da Qing study compared diet, exercise and diet plus exercise with a no-treatment control group and found that all three lifestyle approaches reduced the risk of developing diabetes by 31–46% [3]. More recently, the Finnish Diabetes Prevention Study showed that a lifestyle intervention designed to produce weight loss associated with physical activity reduced the risk of diabetes by 58% in overweight subjects with impaired glucose tolerance (IGT) [4]. Furthermore, the Prevención con Dieta Mediterránea, a multicentre trial that included type 2 diabetes patients and individuals with major risk factors but no overt diabetes, demonstrated that an energy-unrestricted Mediterranean diets supplemented with extra-virgin olive oil and or nuts intervention resulted in an absolute risk reduction of approximately three major cardiovascular events per 1000 person-years and a relative risk reduction of approximately 30% [5]. The dietary recommendations in type 2 diabetes adults commonly include low fat and high unrefined carbohydrate, which take around 25–30% of caloric intake from fat and around 50% of the total caloric intake from unrefined carbohydrate, or low glycaemic index diets that include food with a low
2
P. Pozzilli and F. Fallucca
glycaemic index (pasta products, oats, beans and some fruits and vegetables) and so-called ‘functional foods’ macro-nutrients and micro-nutrients with an adequate content of fibre, usually in combination with weight reducing advice [6]. The vegetarian, normo-caloric macrobiotic Ma-Pi 2 diet has shown benefit in adults with type 2 diabetes, significantly improving the metabolic control and reducing the cardiovascular risk. The nutritional characteristics of the diet meet the functional requirements, being rich in natural fibres, complex carbohydrates, whole grains and whole grain products, fruits, vegetables and legumes, fermented products, sea salt and green tea, without animal protein or fat (including milk and dairy products) and no simple sugars [7]. A recent systematic review and meta-analysis of prospective studies assessed the effect of dietary patterns (based on consumption of cooked and raw vegetables, fruit, fish and olive oil, including legumes, grains, nuts and fish) on prevention of type 2 diabetes concluding that, overall, the adherence to healthy dietary pattern was associated with a significant reduction of the risk of developing type 2 diabetes [8]. Particularly, two studies have evaluated the role of the Mediterranean diet in diabetes prevention concluding that the adherence to the diet had an 83% lower risk of diabetes [9] and a 35% lower risk of new diabetes [10]. More recently, the fundamental role of gut microbes ‘gut microbiota’ and their interaction with the ingested food has been underlined (the well-known biochemical macronutrient – carbohydrate, lipids and proteins – and the role of non-digestible fibres) [11–13]. The new concept of ‘probiotic’ and ‘prebiotic’ in the meal and its function [14] appears to be pivotal in the redefinition of diet, leading to the assumption that food may act as a ‘hormone’ [15]. It is likely that the ideal diet for type 2 diabetes should be designed not only on the basis of its biochemical features and of calories of single elements but also taking into account the gut microbiota and the food like hormone actions [15]. To date, the socio-economic impact of obesity that in the USA occurs among population groups with the highest poverty rates and the least education may be mediated, in part, by the low cost of energy-dense food because diets based on refined grains, added sugars and added fats
are more affordable than the recommended diets based on lean meats, fish, fresh vegetables and fruit. To encourage the choices of prepared and prepackaged foods, also called food poor in nutrients, a major contribution consists in taste and convenience of added sugars or/and fat [16]. Dietary habits differ between and within European populations as a cultural consequence, and the choice of diet in population subgroups is strongly related to the socio-economic status. It is well known that individuals, with a low income and unhealthy habits like smoking and sedentary, have been reported to consume more lipids with a higher intake of saturated fatty acids and refined sugar. Education has been reported to be the strongest and most consistent indicator in assessing socio-economic differentials when it comes to healthy dietary practice. There is also a gender difference in food choices reported in many studies, where a large sample of young adults from 23 countries established that there is a 22% of gender difference in fat choices, 23% of fibre choices and 7% of fruit, but none of the gender difference in salt [17]. Along the years, researchers have proposed many types of diet in different approaches based on either lowcarbohydrate high-protein diets that determine a more weight loss than conventional high-carbohydrate low-fat diets over a short-term (3–6 months). On the long term (12 months), very-high-carbohydrate and very low-fat vegetarian diets were more effective than a conventional high-carbohydrate low-fat diet. Overall, participants in weight loss programmes revert to their usually macronutrient intakes over time but may nonetheless be able to maintain weight loss [6,8]. It may extremely be useful to assess whether type 2 diabetes responds better in the long term to diets than to a specific macronutrient composition. In conclusion, this supplement of the journal offers to the readers a critical evaluation of the current diets for the treatment of type 2 diabetes and suggests new avenues to pursue in search for the optimal dietetic management of this disease.
Conflicts of interest The authors have no conflicts of interest to declare.
References 1. Diabetes Prevention Program Research Group, Knowler WC, Fowler SE, et al. 10-year follow-up of diabetes incidence and weight loss in the Diabetes Prevention Program Outcomes Study. Lancet 2009; 374: 1677–1686. Copyright © 2013 John Wiley & Sons, Ltd.
2. Reduction in weight and cardiovascular disease risk factors in individuals with type 2 diabetes: one-year results of the look AHEAD trial. Look AHEAD research group. Diabetes Care 2007; 30: 1374–1383.
3. Pan XR, Li GW, Hu YH, et al. Effects of diet and exercise in preventing NIDDM in people with impaired glucose tolerance: the Da Qing IGT and Diabetes Study. Diabetes Care 1997; 20: 537–544. Diabetes Metab Res Rev 2014; 30(Suppl 1): 1–3. DOI: 10.1002/dmrr
3
Diet and Diabetes 4. Tuomilehto JLJ, Eriksson JG, Valle TT, et al. Prevention of type 2 diabetes mellitus by changes in lifestyle among subjects with impaired glucose tolerance. N Engl J Med 2001; 344: 1343–1392. 5. Estruch R, Ros E, Salas-Salvadó J, et al. Primary prevention of cardiovascular disease with a Mediterranean diet. N Engl J Med 2013; 368: 1279–1290. 6. 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; 97: 505–516. 7. Fallucca F, Porrata C, Monaco G, Bufacchi A, Pianesi M. Ma-Pi macrobiotic diet intervention during 21 days in adult with type 2 diabetes mellitus. Minerva Endocrinol 2012; 37(suppl. 4): 116. 8. Esposito K, Kastorini C-M, Panagiotakos DB, Giugliano D. Prevention of type 2
Copyright © 2013 John Wiley & Sons, Ltd.
diabetes by dietary patterns: a systematic review of prospective studies and meta-analysis. Metab Syndr Relat Disord 2010; 8: 471–476. 9. Martinez-Gonzalez MA, de la FuenteArrillaga C, Nunez- Cordoba JM, et al. Adherence to Mediterranean diet and risk of developing diabetes: a prospective cohort study. BMJ 2008; 336: 1348–1351. 10. Mozaffarian D, Marfisi RM, Levantesi G, et al. Incidence of new-onset diabetes and impaired fasting glucose in patients with recent myocardial infarction and the effect of clinical and lifestyle risk factors. Lancet 2007; 370: 667–675. 11. Cani PD, Amar J, Iglesias MA, et al. Metabolic endotoxemia initiates obesity and insulin resistance. Diabetes 2007; 56: 1761–1772.
12. Wu X, Ma C, Han L, et al. Molecular characterization of the faecal microbiota in patients with type 2 diabetes. Curr Microbiol 2010; 61(1): 69–78. 13. Biagi E, Candela M, Turroni S, et al. Ageing and gut microbes: perspectives for health maintenance and longevity. Pharmachol Res 2013; 69(1): 11–20. 14. Roberfroid D, Gibson DR, Hoyles L, et al. Prebiotic effects: metabolic and health benefits. Br J Nutr 2010; Suppl 2: S1–S63. 15. Ryan KK, Seeley RJ. Food as hormone. Science 2013; 339: 918–919. 16. Drewnowski A. Obesity and the food environment: dietary energy density and diet costs. Am J Prev Med 2004; 27: 154–162. 17. Wardle J, Haase AM, Steptoe A, Nillapun M, Jonwutiwes K, Bellisie F. Gender differences in food choice: the contribution of health beliefs and dieting. Ann Behav Med 2004; 27: 107–116.
Diabetes Metab Res Rev 2014; 30(Suppl 1): 1–3. DOI: 10.1002/dmrr
INTRODUCTION
Diet and diabetes: a cornerstone for therapy Paolo Pozzilli1,2* Francesco Fallucca3 1
Department of Endocrinology and Diabetes, University Campus BioMedico, Rome, Italy
2
Centre of Diabetes, St. Bartholomew’s and the London, School of Medicine, Queen Mary University, London, UK ‘In Unam Sapientiam’, University La Sapienza, Rome, Italy
3
*Correspondence to: Paolo Pozzilli, Department of Endocrinology and Diabetes, University Campus Bio-Medico, Via Alvaro del Portillo 21, 00128 Rome, Italy. E-mail: [email protected]
Received: 23 October 2013 Accepted: 18 December 2013
Copyright © 2013 John Wiley & Sons, Ltd.
Summary An appropriate diet represents the cornerstone for diabetes therapy. Diets that differ in their carbohydrate, lipid and protein content are used but the evidence of their effects on the long term is missing. Several confounding factors and compliance to diet render difficult the evaluation of the ‘best diet’ for diabetes. On a short run, however, useful indications can be obtained regarding the effective diets capable to optimize metabolic control in type 2 diabetes. Copyright © 2013 John Wiley & Sons, Ltd. Keywords
diabetes; diet; diabetes prevention
There is now unequivocal evidence that type 2 diabetes can be prevented or even delayed by a well-structured diet and increased physical activity, generally resulting in weight loss. Some of the major trials like the US Diabetes Prevention Programme, a 27-centre randomized clinical trial reported a 58% reduction in the incidence of diabetes in individuals with impaired glucose tolerance when treated with the lifestyle intervention compared with the metformin [1]. The look AHEAD (Action for Health in Diabetes), conducted in 16 canters in the USA, is the first large clinical trial to compare an intensive weight loss intervention with a support and educational group in overweight or obese adults with type 2 diabetes. At 1 year, participants achieved an average loss of 8.6% of initial body weight and a 21% improvement in cardiovascular fitness, attributable to the higher physical activity goal. The more intense dietary intervention, which included not only calorie and fat restriction but also structured meal plans, each of which has previously been associated with successful weight loss and maintenance [2]. The Da Qing study compared diet, exercise and diet plus exercise with a no-treatment control group and found that all three lifestyle approaches reduced the risk of developing diabetes by 31–46% [3]. More recently, the Finnish Diabetes Prevention Study showed that a lifestyle intervention designed to produce weight loss associated with physical activity reduced the risk of diabetes by 58% in overweight subjects with impaired glucose tolerance (IGT) [4]. Furthermore, the Prevención con Dieta Mediterránea, a multicentre trial that included type 2 diabetes patients and individuals with major risk factors but no overt diabetes, demonstrated that an energy-unrestricted Mediterranean diets supplemented with extra-virgin olive oil and or nuts intervention resulted in an absolute risk reduction of approximately three major cardiovascular events per 1000 person-years and a relative risk reduction of approximately 30% [5]. The dietary recommendations in type 2 diabetes adults commonly include low fat and high unrefined carbohydrate, which take around 25–30% of caloric intake from fat and around 50% of the total caloric intake from unrefined carbohydrate, or low glycaemic index diets that include food with a low
2
P. Pozzilli and F. Fallucca
glycaemic index (pasta products, oats, beans and some fruits and vegetables) and so-called ‘functional foods’ macro-nutrients and micro-nutrients with an adequate content of fibre, usually in combination with weight reducing advice [6]. The vegetarian, normo-caloric macrobiotic Ma-Pi 2 diet has shown benefit in adults with type 2 diabetes, significantly improving the metabolic control and reducing the cardiovascular risk. The nutritional characteristics of the diet meet the functional requirements, being rich in natural fibres, complex carbohydrates, whole grains and whole grain products, fruits, vegetables and legumes, fermented products, sea salt and green tea, without animal protein or fat (including milk and dairy products) and no simple sugars [7]. A recent systematic review and meta-analysis of prospective studies assessed the effect of dietary patterns (based on consumption of cooked and raw vegetables, fruit, fish and olive oil, including legumes, grains, nuts and fish) on prevention of type 2 diabetes concluding that, overall, the adherence to healthy dietary pattern was associated with a significant reduction of the risk of developing type 2 diabetes [8]. Particularly, two studies have evaluated the role of the Mediterranean diet in diabetes prevention concluding that the adherence to the diet had an 83% lower risk of diabetes [9] and a 35% lower risk of new diabetes [10]. More recently, the fundamental role of gut microbes ‘gut microbiota’ and their interaction with the ingested food has been underlined (the well-known biochemical macronutrient – carbohydrate, lipids and proteins – and the role of non-digestible fibres) [11–13]. The new concept of ‘probiotic’ and ‘prebiotic’ in the meal and its function [14] appears to be pivotal in the redefinition of diet, leading to the assumption that food may act as a ‘hormone’ [15]. It is likely that the ideal diet for type 2 diabetes should be designed not only on the basis of its biochemical features and of calories of single elements but also taking into account the gut microbiota and the food like hormone actions [15]. To date, the socio-economic impact of obesity that in the USA occurs among population groups with the highest poverty rates and the least education may be mediated, in part, by the low cost of energy-dense food because diets based on refined grains, added sugars and added fats
are more affordable than the recommended diets based on lean meats, fish, fresh vegetables and fruit. To encourage the choices of prepared and prepackaged foods, also called food poor in nutrients, a major contribution consists in taste and convenience of added sugars or/and fat [16]. Dietary habits differ between and within European populations as a cultural consequence, and the choice of diet in population subgroups is strongly related to the socio-economic status. It is well known that individuals, with a low income and unhealthy habits like smoking and sedentary, have been reported to consume more lipids with a higher intake of saturated fatty acids and refined sugar. Education has been reported to be the strongest and most consistent indicator in assessing socio-economic differentials when it comes to healthy dietary practice. There is also a gender difference in food choices reported in many studies, where a large sample of young adults from 23 countries established that there is a 22% of gender difference in fat choices, 23% of fibre choices and 7% of fruit, but none of the gender difference in salt [17]. Along the years, researchers have proposed many types of diet in different approaches based on either lowcarbohydrate high-protein diets that determine a more weight loss than conventional high-carbohydrate low-fat diets over a short-term (3–6 months). On the long term (12 months), very-high-carbohydrate and very low-fat vegetarian diets were more effective than a conventional high-carbohydrate low-fat diet. Overall, participants in weight loss programmes revert to their usually macronutrient intakes over time but may nonetheless be able to maintain weight loss [6,8]. It may extremely be useful to assess whether type 2 diabetes responds better in the long term to diets than to a specific macronutrient composition. In conclusion, this supplement of the journal offers to the readers a critical evaluation of the current diets for the treatment of type 2 diabetes and suggests new avenues to pursue in search for the optimal dietetic management of this disease.
Conflicts of interest The authors have no conflicts of interest to declare.
References 1. Diabetes Prevention Program Research Group, Knowler WC, Fowler SE, et al. 10-year follow-up of diabetes incidence and weight loss in the Diabetes Prevention Program Outcomes Study. Lancet 2009; 374: 1677–1686. Copyright © 2013 John Wiley & Sons, Ltd.
2. Reduction in weight and cardiovascular disease risk factors in individuals with type 2 diabetes: one-year results of the look AHEAD trial. Look AHEAD research group. Diabetes Care 2007; 30: 1374–1383.
3. Pan XR, Li GW, Hu YH, et al. Effects of diet and exercise in preventing NIDDM in people with impaired glucose tolerance: the Da Qing IGT and Diabetes Study. Diabetes Care 1997; 20: 537–544. Diabetes Metab Res Rev 2014; 30(Suppl 1): 1–3. DOI: 10.1002/dmrr
3
Diet and Diabetes 4. Tuomilehto JLJ, Eriksson JG, Valle TT, et al. Prevention of type 2 diabetes mellitus by changes in lifestyle among subjects with impaired glucose tolerance. N Engl J Med 2001; 344: 1343–1392. 5. Estruch R, Ros E, Salas-Salvadó J, et al. Primary prevention of cardiovascular disease with a Mediterranean diet. N Engl J Med 2013; 368: 1279–1290. 6. 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; 97: 505–516. 7. Fallucca F, Porrata C, Monaco G, Bufacchi A, Pianesi M. Ma-Pi macrobiotic diet intervention during 21 days in adult with type 2 diabetes mellitus. Minerva Endocrinol 2012; 37(suppl. 4): 116. 8. Esposito K, Kastorini C-M, Panagiotakos DB, Giugliano D. Prevention of type 2
Copyright © 2013 John Wiley & Sons, Ltd.
diabetes by dietary patterns: a systematic review of prospective studies and meta-analysis. Metab Syndr Relat Disord 2010; 8: 471–476. 9. Martinez-Gonzalez MA, de la FuenteArrillaga C, Nunez- Cordoba JM, et al. Adherence to Mediterranean diet and risk of developing diabetes: a prospective cohort study. BMJ 2008; 336: 1348–1351. 10. Mozaffarian D, Marfisi RM, Levantesi G, et al. Incidence of new-onset diabetes and impaired fasting glucose in patients with recent myocardial infarction and the effect of clinical and lifestyle risk factors. Lancet 2007; 370: 667–675. 11. Cani PD, Amar J, Iglesias MA, et al. Metabolic endotoxemia initiates obesity and insulin resistance. Diabetes 2007; 56: 1761–1772.
12. Wu X, Ma C, Han L, et al. Molecular characterization of the faecal microbiota in patients with type 2 diabetes. Curr Microbiol 2010; 61(1): 69–78. 13. Biagi E, Candela M, Turroni S, et al. Ageing and gut microbes: perspectives for health maintenance and longevity. Pharmachol Res 2013; 69(1): 11–20. 14. Roberfroid D, Gibson DR, Hoyles L, et al. Prebiotic effects: metabolic and health benefits. Br J Nutr 2010; Suppl 2: S1–S63. 15. Ryan KK, Seeley RJ. Food as hormone. Science 2013; 339: 918–919. 16. Drewnowski A. Obesity and the food environment: dietary energy density and diet costs. Am J Prev Med 2004; 27: 154–162. 17. Wardle J, Haase AM, Steptoe A, Nillapun M, Jonwutiwes K, Bellisie F. Gender differences in food choice: the contribution of health beliefs and dieting. Ann Behav Med 2004; 27: 107–116.
Diabetes Metab Res Rev 2014; 30(Suppl 1): 1–3. DOI: 10.1002/dmrr
