- Email: [email protected]
Tu-W28:2 Low-carbohydrate or low-fat, high-carbohydrate diets for treatment of obesity: Which option to select?
Tu-W28
176
Tues&ty, June 20, 2006: Workshop Nutritional approaches: the global picture
mechanistic based dietary recommendations. This potential could and needs to be developed within the context of nutritional genomics that in conjunction with systems biology may provide the tools to achieve the holy grail of dietary prevention and therapy of CVD. This approach will break with the traditional public health approach of "'one size fits all.'" Results: The current evidence based on a few candidate genes involved in lipid metabolism (i.e., APOA1, APOA5, APOE, LIPC) [1] has begun to identify subgroups of individuals who benefit more from a low fat diet, whereas others appear to benefit more from a high monounsaturated or polyunsaturated fat (PUFA) diets. Of interest is the increasing evidence showing that when it comes to cardiovascular health, n-6 and n-3 families of PUFAs interact very different with genetic variants to modulate cardiovascular risk factors. Thus, while some subgroups of individuals may be at higher risk from high consumption of PUFA n-6, others may benefit from increased consumption of PUFA n-3. Moreover, given the emerging epidemic of obesity, it is important to understand the effect of obesity in triggering the associations between genetic variants and cardiovascular risk factors (i.e., APOE, APOA5) [2] and the role of genetic variants predisposing to obesity and response to dietary treatments (i.e., PLIN). Conclusions: The continuous progress in Nutrigenomics will allow us in the future to identify those persons for whom diet plays no major role in their risk of CVD as well as those persons who may benefit from specific gene-based dietary advice. References [1] Corella D, Ordovas JM. Single Nucleotide Polymorphisms that Influence Lipid Metabolism: Interaction with Dietary Factors. Annu Rev Nutr. 2005;25:341-90. [2] Elosua R, Ordovas JM, Cupples LA, Lai CQ, Demissie S, Fox CS, Polak JR Wolf PA, D'Agostino RA, O'Donnell CJ. Variability at the APOA5 locus is associated with carotid atherosclerosis with a modifying effect of obesity: the Framingham Heart Study. J Lipid Res. 2006 Feb 11. [3] Corella D, Qi L, Sorli JV, Godoy D, Portoles O, Coltell O, Greenberg AS, Ordovas JM. Obese subjects carrying the 11482G>A polymorphism at the perilipin locus are resistant to weight loss after dietary energy restriction. J Clin Endocrinol Metab. 2005;90:5121-6. Funding: Supported by NIH/NHLBI grant no. HL54776 and contracts 53K06-5-10 and 58-1950-9-001 and 58-3148-2-083 from the USDA and Grant PI04/2239, ISCIL Spain.
I Tu-W28:2 I L O W - C A R B O H Y D R A T E
O R LOW-FAT, HIGH-CARBOHYDRATE DIETS FOR TREATMENT OF OBESITY: W H I C H O P T I O N T O S E L E C T ?
Other diets, such as The Zone, Montignac, and the South Beach Diet, are less carbohydrate restrictive, but might produce a weight loss through a high protein content (30-50% energy), in combination with restrictive dietary choices and low glycemic index foods [3]. There seems to be good evidence to support the hypothesis that increasing the protein content of the diet from 15% up to 20-30% may increase the satiating effect of the diet, and induce a spontaneous weight loss without adverse effects. Higher=fat diets with normal proteb~ contents: Large prospective studies, e.g. "'The Nurses Health Study", suggest that current dietary recommendations are not optimal for the prevention of diet-related diseases such as obesity, type 2 diabetes, cardiovascular disease and cancer. They suggest that optimal recommendations should include more whole-grain products with low glycemic index, more vegetable oils, nuts, beans, poultry and fish, and this has resulted in the "'Inverted Food Pyramid" by Walter Willett. This pyramid also suggests reducing the amount of refined and high-glycemic index products, including bread, potatoes and maize, in the diet, and less dairy and red meat is suggested. This diet, preferably with 40% of energy from fat and more than > 2 0 % of energy from mono-unsaturated fat (MUFA), is regarded as optimal and these scientists do not expect this to lead to weight gain. However, it is generally agreed that dietary recommendations should be based on large, long-term, randomised, dietary intervention studies, and such axe currently being conducted. References [1] Skov AR, Toubro S, R~nn B, Holm L, Astrup A. Randomized trial on protein versus carbohydrate in ad libitum fat reduced diet for the treatment of obesity. Int J Obes 1999;23:528-536. [2] Howard BV, Manson JE, Stefanick ML, Beresford SA, Frank G, Jones B, Rodabough RL Snetselaax L, Thomson C, Tinker L, Vitolins M, Prentice R. Low-fat dietary pattern and weight change over 7 years: the Women's Health Initiative Dietary Modification Trial. JAMA 2006;295:39-49. [3] Due A, Toubro S, Skov AR, Astrup A. Effect of normal-fat diets, either medium or high in proteim on body weight in overweight subjects: a randomised 1-year trial. Int J Obes 2004;28:1283-90. Funding: Not applicable
I Tu-W28:3
I
I THE EFFECTS OF AN 8-YEAR LOW-FAT DIETARY PATTERN ON CARDIOVASCULAR DISEASE (CVD)
i
B.V. Howard 1, L. Van Horn 2, J. Hsia 3, J.E. Manson 3, M.L. Stefanick 4 , S. Wassertheil-Smoller 5 , S.A.A. Beresford 6, R.L. Prentice 7 . 1MedStar
Studies, The Royal Veterinaty & Agricultural Universi~, Frederiksberg, Denmark
Researeh bzstitute, Hyattsville, MD, USA." 2NorthwestetTt Universi~, Chicago, IL, USA." 2George Washington Universi~, Washington, DC, USA." Brtgham & Women's Hospital, Chestnut Hill, MA, USA." 4Stanford Universi~, San Jose, CA, USA." 5Albert Einstein College of Medicine, Bronx, NY, USA: 6Fred Hutchbtson Cancer Researeh Center; Seattle, WA, USA: 7Fred Hutchbtson Cancer Researeh Center; Seattle, WA, USA
The recommended diet for prevention of weight gain, obesity, and the metabolic syndrome (MS) is low-fat, and fibre-rich, rich in low-energy density carbohydrates (fruit, vegetables, and whole grain products), and low in energy-containing drinks. The reduction of the total fat content of ad libitum diets has been shown to produce weight loss in the short term [1], and over a period as long as 7 years [2]. The fat-reduced diet in combination with physical activity has been shown to reduce all risk factors for cardiovascular disease in obese subjects, and to reduce the incidence of type 2 diabetes. The combination of reduction of dietary fat and energy, and more physical activity, has been shown to reduce the incidence of diabetes by 58% in two major trials. In the latter study 53% of participants had MS at baseline. The incidence of MS was reduced by 41% in the lifestyle group and by 17% in the metformin group compared with placebo. High protein diets - either high or low in fat: The Atkins diet and other low-carbohydrate diets have become extremely popular worldwide. They claim to be very effective in promoting weight loss without energy restriction. The dietary principle is ad libitum high-protein and fat foods, and restriction of carbohydrate to less than 30 g per day. Recent randomised trials show that such low-carbohydrate diets do indeed induce weight loss and improve cardiovascular risk factors in the short term. Much of the weight loss may be loss of glycogen and water, but it is likely that the high satiating power of protein in combination with the ketogenic effect of the low carbohydrate content can reduce spontaneous caloric intake and produce weight loss. While beneficial improvements in blood lipids and insulin sensitivity axe seen as long as weight loss occur, an adverse effect on LDL-cholesterol and other cardiovascular risk factors is likely during weight stability, because of the high intake of saturated fat. Adverse effects such as headache, muscle cramps, and diaxrhoea axe reported more frequently on low-caxbohydrate than on low-fat diets.
Objective: Epidemiologic studies and some short-term trials have linked diet with CVD, but no long-term prevention/intervention studies are available. The Women's Health Initiative randomized controlled Dietary Modification Trial evaluated whether diet intervention to lower total fat and increase vegetables, fruits, and grains, intended to reduce cancer, would also reduce risk of CVD in post-menopausal women. Methods: 48,835 post-menopausal women aged 50-79 years were recruited from 40 Clinical Centers throughout the United States and randomly assigned to dietary modification intervention (40%) or comparison group (60%) for 8.1 years. The intensive behavioral modification program aimed to motivate and support large reductions in total fat and to increase servings of vegetables, fruits, and grains. Group sessions, self-monitoring techniques, and other tailored and targeted strategies were applied. Results: Intervention group participants significantly reduced their percent energy from fat by 11% at Year 1 and 8.1% at Year 6. Saturated, polyunsaturated, and trans fats decreased by 2.9%, 1.5%, and 0.6%, respectively, and vegetables/fruits and fiber servings increased by 1.1 serving and 0.5 g/day, respectively. Weight decreased by 1.3 kg, LDL cholesterol by 3.5 mg/dL, and H O M A by 0.4 units. The diet had no significant effects on incidence of coronary heart disease (CHD) (HR 0.97; CI 0.90-1.06), stroke (HR 1.02; CI 0.90-1.15), or CVD (HR 0.98; CI 0.92-1.05). Excluding individuals with CVD at baseline (3.4%), the HR (CI) for CHD was 0.94 (0.86-1.02). There were greater reductions in CHD among those in the intervention group who reached the lowest levels of saturated fat compared to those in the control group (HR 0.82; CI 0.67-99) and trans fat (HR 0.84; CI 0.69-1.02) and highest levels of vegetables/fruits (HR 0.89, CI 0.74 = 1.06). C o n d u s i o n s : Over a mean of 8.1 years this dietary intervention, which focused on total fat reduction but did not specify type of fat, did not significantly
A. Astrup. Department of Human Nutrition, The Centre for Advanced Food
XIV bztentational Symposium on Atherosclerosis, Rome, Italy, June 18-22, 2006
176
Tues&ty, June 20, 2006: Workshop Nutritional approaches: the global picture
mechanistic based dietary recommendations. This potential could and needs to be developed within the context of nutritional genomics that in conjunction with systems biology may provide the tools to achieve the holy grail of dietary prevention and therapy of CVD. This approach will break with the traditional public health approach of "'one size fits all.'" Results: The current evidence based on a few candidate genes involved in lipid metabolism (i.e., APOA1, APOA5, APOE, LIPC) [1] has begun to identify subgroups of individuals who benefit more from a low fat diet, whereas others appear to benefit more from a high monounsaturated or polyunsaturated fat (PUFA) diets. Of interest is the increasing evidence showing that when it comes to cardiovascular health, n-6 and n-3 families of PUFAs interact very different with genetic variants to modulate cardiovascular risk factors. Thus, while some subgroups of individuals may be at higher risk from high consumption of PUFA n-6, others may benefit from increased consumption of PUFA n-3. Moreover, given the emerging epidemic of obesity, it is important to understand the effect of obesity in triggering the associations between genetic variants and cardiovascular risk factors (i.e., APOE, APOA5) [2] and the role of genetic variants predisposing to obesity and response to dietary treatments (i.e., PLIN). Conclusions: The continuous progress in Nutrigenomics will allow us in the future to identify those persons for whom diet plays no major role in their risk of CVD as well as those persons who may benefit from specific gene-based dietary advice. References [1] Corella D, Ordovas JM. Single Nucleotide Polymorphisms that Influence Lipid Metabolism: Interaction with Dietary Factors. Annu Rev Nutr. 2005;25:341-90. [2] Elosua R, Ordovas JM, Cupples LA, Lai CQ, Demissie S, Fox CS, Polak JR Wolf PA, D'Agostino RA, O'Donnell CJ. Variability at the APOA5 locus is associated with carotid atherosclerosis with a modifying effect of obesity: the Framingham Heart Study. J Lipid Res. 2006 Feb 11. [3] Corella D, Qi L, Sorli JV, Godoy D, Portoles O, Coltell O, Greenberg AS, Ordovas JM. Obese subjects carrying the 11482G>A polymorphism at the perilipin locus are resistant to weight loss after dietary energy restriction. J Clin Endocrinol Metab. 2005;90:5121-6. Funding: Supported by NIH/NHLBI grant no. HL54776 and contracts 53K06-5-10 and 58-1950-9-001 and 58-3148-2-083 from the USDA and Grant PI04/2239, ISCIL Spain.
I Tu-W28:2 I L O W - C A R B O H Y D R A T E
O R LOW-FAT, HIGH-CARBOHYDRATE DIETS FOR TREATMENT OF OBESITY: W H I C H O P T I O N T O S E L E C T ?
Other diets, such as The Zone, Montignac, and the South Beach Diet, are less carbohydrate restrictive, but might produce a weight loss through a high protein content (30-50% energy), in combination with restrictive dietary choices and low glycemic index foods [3]. There seems to be good evidence to support the hypothesis that increasing the protein content of the diet from 15% up to 20-30% may increase the satiating effect of the diet, and induce a spontaneous weight loss without adverse effects. Higher=fat diets with normal proteb~ contents: Large prospective studies, e.g. "'The Nurses Health Study", suggest that current dietary recommendations are not optimal for the prevention of diet-related diseases such as obesity, type 2 diabetes, cardiovascular disease and cancer. They suggest that optimal recommendations should include more whole-grain products with low glycemic index, more vegetable oils, nuts, beans, poultry and fish, and this has resulted in the "'Inverted Food Pyramid" by Walter Willett. This pyramid also suggests reducing the amount of refined and high-glycemic index products, including bread, potatoes and maize, in the diet, and less dairy and red meat is suggested. This diet, preferably with 40% of energy from fat and more than > 2 0 % of energy from mono-unsaturated fat (MUFA), is regarded as optimal and these scientists do not expect this to lead to weight gain. However, it is generally agreed that dietary recommendations should be based on large, long-term, randomised, dietary intervention studies, and such axe currently being conducted. References [1] Skov AR, Toubro S, R~nn B, Holm L, Astrup A. Randomized trial on protein versus carbohydrate in ad libitum fat reduced diet for the treatment of obesity. Int J Obes 1999;23:528-536. [2] Howard BV, Manson JE, Stefanick ML, Beresford SA, Frank G, Jones B, Rodabough RL Snetselaax L, Thomson C, Tinker L, Vitolins M, Prentice R. Low-fat dietary pattern and weight change over 7 years: the Women's Health Initiative Dietary Modification Trial. JAMA 2006;295:39-49. [3] Due A, Toubro S, Skov AR, Astrup A. Effect of normal-fat diets, either medium or high in proteim on body weight in overweight subjects: a randomised 1-year trial. Int J Obes 2004;28:1283-90. Funding: Not applicable
I Tu-W28:3
I
I THE EFFECTS OF AN 8-YEAR LOW-FAT DIETARY PATTERN ON CARDIOVASCULAR DISEASE (CVD)
i
B.V. Howard 1, L. Van Horn 2, J. Hsia 3, J.E. Manson 3, M.L. Stefanick 4 , S. Wassertheil-Smoller 5 , S.A.A. Beresford 6, R.L. Prentice 7 . 1MedStar
Studies, The Royal Veterinaty & Agricultural Universi~, Frederiksberg, Denmark
Researeh bzstitute, Hyattsville, MD, USA." 2NorthwestetTt Universi~, Chicago, IL, USA." 2George Washington Universi~, Washington, DC, USA." Brtgham & Women's Hospital, Chestnut Hill, MA, USA." 4Stanford Universi~, San Jose, CA, USA." 5Albert Einstein College of Medicine, Bronx, NY, USA: 6Fred Hutchbtson Cancer Researeh Center; Seattle, WA, USA: 7Fred Hutchbtson Cancer Researeh Center; Seattle, WA, USA
The recommended diet for prevention of weight gain, obesity, and the metabolic syndrome (MS) is low-fat, and fibre-rich, rich in low-energy density carbohydrates (fruit, vegetables, and whole grain products), and low in energy-containing drinks. The reduction of the total fat content of ad libitum diets has been shown to produce weight loss in the short term [1], and over a period as long as 7 years [2]. The fat-reduced diet in combination with physical activity has been shown to reduce all risk factors for cardiovascular disease in obese subjects, and to reduce the incidence of type 2 diabetes. The combination of reduction of dietary fat and energy, and more physical activity, has been shown to reduce the incidence of diabetes by 58% in two major trials. In the latter study 53% of participants had MS at baseline. The incidence of MS was reduced by 41% in the lifestyle group and by 17% in the metformin group compared with placebo. High protein diets - either high or low in fat: The Atkins diet and other low-carbohydrate diets have become extremely popular worldwide. They claim to be very effective in promoting weight loss without energy restriction. The dietary principle is ad libitum high-protein and fat foods, and restriction of carbohydrate to less than 30 g per day. Recent randomised trials show that such low-carbohydrate diets do indeed induce weight loss and improve cardiovascular risk factors in the short term. Much of the weight loss may be loss of glycogen and water, but it is likely that the high satiating power of protein in combination with the ketogenic effect of the low carbohydrate content can reduce spontaneous caloric intake and produce weight loss. While beneficial improvements in blood lipids and insulin sensitivity axe seen as long as weight loss occur, an adverse effect on LDL-cholesterol and other cardiovascular risk factors is likely during weight stability, because of the high intake of saturated fat. Adverse effects such as headache, muscle cramps, and diaxrhoea axe reported more frequently on low-caxbohydrate than on low-fat diets.
Objective: Epidemiologic studies and some short-term trials have linked diet with CVD, but no long-term prevention/intervention studies are available. The Women's Health Initiative randomized controlled Dietary Modification Trial evaluated whether diet intervention to lower total fat and increase vegetables, fruits, and grains, intended to reduce cancer, would also reduce risk of CVD in post-menopausal women. Methods: 48,835 post-menopausal women aged 50-79 years were recruited from 40 Clinical Centers throughout the United States and randomly assigned to dietary modification intervention (40%) or comparison group (60%) for 8.1 years. The intensive behavioral modification program aimed to motivate and support large reductions in total fat and to increase servings of vegetables, fruits, and grains. Group sessions, self-monitoring techniques, and other tailored and targeted strategies were applied. Results: Intervention group participants significantly reduced their percent energy from fat by 11% at Year 1 and 8.1% at Year 6. Saturated, polyunsaturated, and trans fats decreased by 2.9%, 1.5%, and 0.6%, respectively, and vegetables/fruits and fiber servings increased by 1.1 serving and 0.5 g/day, respectively. Weight decreased by 1.3 kg, LDL cholesterol by 3.5 mg/dL, and H O M A by 0.4 units. The diet had no significant effects on incidence of coronary heart disease (CHD) (HR 0.97; CI 0.90-1.06), stroke (HR 1.02; CI 0.90-1.15), or CVD (HR 0.98; CI 0.92-1.05). Excluding individuals with CVD at baseline (3.4%), the HR (CI) for CHD was 0.94 (0.86-1.02). There were greater reductions in CHD among those in the intervention group who reached the lowest levels of saturated fat compared to those in the control group (HR 0.82; CI 0.67-99) and trans fat (HR 0.84; CI 0.69-1.02) and highest levels of vegetables/fruits (HR 0.89, CI 0.74 = 1.06). C o n d u s i o n s : Over a mean of 8.1 years this dietary intervention, which focused on total fat reduction but did not specify type of fat, did not significantly
A. Astrup. Department of Human Nutrition, The Centre for Advanced Food
XIV bztentational Symposium on Atherosclerosis, Rome, Italy, June 18-22, 2006