Alan Barclay. Low carbohydrate diets and diabetes. BSc(Nutrition); Grad Dip Dietetics; PhD

Transcription

1 Low carbohydrate diets and diabetes Alan Barclay BSc(Nutrition); Grad Dip Dietetics; PhD Alan Barclay 2015 Australia other countries. All rights reserved

2 The Headlines

3

4 The facts

5 Carbohydrate definitions

6 What are carbohydrates 1? Class (Polymerisation) Sub-Group Components Sugars (1-2) Oligosaccharides (3-9) Polysaccharides (>9) Monosaccharides Disaccharides Polyols Malto-oligosaccharides Other oligosaccharides Starch Non-starch polysaccharides Glucose, galactose, fructose Sucrose, lactose, maltose Erythritol, Glycerol, Lactitol, Maltitol, Mannitol, Sorbitol, Xylitol Maltodextrins Raffinose, stachyose, fructooligosaccharides Amylose, amylopectin, modified starches Cellulose, hemicellulose, pectins, hydrocolloids glucose starch 1. Carbohydrates in human nutrition FAO Food and Nutrition Paper 66.

7 Carbohydrates are an essential nutrient 2,3 Primarily an energy source for our bodies: the preferred fuel for our brains and nervous systems, and for our exercising muscles Structural (within cells) Genetic (RNA and DNA) Function of certain proteins (glycoproteins) Adds taste, texture and colour to our foods and drinks. 2. Mann and Truswell Wahlqvist, 1988.

8 Glycemic index (GI) compares equal quantities of available carbohydrate in foods is a measure of their effect on blood glucose levels in 10+ healthy people over a 2 hr period is a percentage ISO

9 Glycemic Index (GI): Ranking Individual food portion 4 : Low 55 or less Moderate High 70+ Whole day 5 : Low 45 or less Moderate High Australian Standard. Glycemic Index of Foods AS Standards Australia Brand-Miller, Nutrition & Dietetics 2009; 66:

10 Glycemic load (GL) Definitions a function of a food s glycemic index and its total available carbohydrate content and defined as: Glycemic Load = GI (%) x Carbohydrate (g) Using an apple as an example: GI value = 38%; Carbohydrate per serve =15 g GL = 0.38 x 15 = 6 The GL of a typical apple is 6

11 Glycemic Load (GL): Ranking Individual food portion 6 : Low 0-10 Moderate High 20+ Whole day 7 : Low < 100 g 8,700 kj/d diet 6. Brand-Miller JC, Holt SHA, and Petocz P. Glycemic load values:2002. Am J Clin Nutr. 2003; 77 (1): Livesey et al, AJCN

12 Glycemic Load Glycemic Load = GI (%) x Carbohydrate (g) 1 unit of GL ~ 1 g of glucose The higher the GL, the greater the elevation in blood glucose and insulin levels 8. You can lower the GL of your foods, meals and diet, by: Eating less carbohydrate Lowering the GI of the carbohydrate you eat Both 8. Foster-Powell K, et al. Am J Clin Nutr. 2003; 76 (1): 5-56.

13 Definition of low high carbohydrate diets 9 Very low-carbohydrate ketogenic diet: g/d or less than 10% of a 8,400 kj diet Low carbohydrate diet: <130 g/d or <26% of energy from a 8,400 kj diet Moderate Carbohydrate Diet: g/d, or 26-45% of energy from a 8,400 kj diet High Carbohydrate Diet: > 230g/d or 45% of energy from a 8,400 kj diet 9. Feinman et al. Nutrition

14 What is the minimum carbohydrate requirement?

15 Minimum carbohydrate requirement 10 Adult brains require 140 g of glucose per day Red blood cells require 40 g of glucose per day Therefore minimum requirement is 180 g glucose / day However, gluconeogenesis (lactic acid, amino acids and glycerol) can supply ~130 g glucose per day So absolute minimum is 50 g glucose per day However, judgement can be impaired and fetus may be affected in short-medium term Long-term ( 2 years) effects not known 10. Mann and Truswell. Essentials of Human Nutrition. 2003

16 What do the evidence based guidelines say?

17 Guidelines for people with diabetes

18 Goals of nutritional management of diabetes 11 1.) Achieve and maintain blood glucose levels, lipid and lipoprotein profiles and blood pressure levels in the normal range or as close to normal as is safely possible 2.) Prevent, or at least slow, the rate of development of the chronic complications of diabetes by modifying nutrient intake and lifestyle 3.) Address individual nutrition needs, taking into account personal and cultural preferences and willingness to change 4.) Maintain the pleasure of eating by only limiting food choices when indicated by scientific evidence 11. Evert et al. Diabetes Care, 2013.

19 Carbohydrate recommendations Evert et al. Diabetes Care. 2013

20 11. Evert et al. Diabetes Care Fat recommendations 11

21 Protein recommendations Evert et al. Diabetes Care. 2013

22 11. Evert et al. Diabetes Care Dietary Patterns 11

23 Macronutrient mix 11,12 US and Canadian Diabetes Associations, 2013 Evidence suggests that there is not an ideal percentage of calories from carbohydrate, protein, and fat for all people with diabetes (B); therefore, macronutrient distribution should be based on individualized assessment of current eating patterns, preferences, and metabolic goals. The ideal macronutrient distribution for the management of diabetes may need to be individualized based on individual preferences and perceived palatability, as several studies suggest that wide variations can be effective 11. Evert. Diab Care. 2013; 12. Dworatzek et al. Can Jour Diab, 2013

24 Is one pattern better than another? Systematic review and meta-analysis of 20 RCTs of 7 different dietary patterns following 3,073 people for 6 months 13 Low-CHO, low-gi, Mediterranean, and high protein diets all effective in HbA1c by % points Dietary behaviors and choices are often personal, and it is usually more realistic for a dietary modification to be individualized rather than to use a one-size-fits-all approach for each person. 13. Ajala et al,. AJCN, 2013.

25 What about the recent CSIRO study 14? 6 months RCT; 115 adults with T2DM; 9 dietetic visits 14% (57 g) of energy carbohydrate vs 53% (205 g) 24.7 g of fibre vs 31.1g Saturated : unsaturated fat ratio 0.23 vs 0.48 No difference in weight, BMI, waist, FM, FFM No difference in fasting glucose, HbA1c, BP, TC, LDL Maximum glucose, glucose range, MAGE and other measures of glucose variability improved on very low CHO diet HDL and TG improved on very low CHO diet 14. Tay, et al. Diabetes Care. 2014

26 What about vegetarian diets? Systematic review and meta-analysis of 6 RCTs including 255 people followed for an average of 24 weeks (range 4-74 weeks) 15 ~10% of energy from fat, 15% protein, 75% carbohydrate Consumption of vegetarian diets was associated with a significant reduction in HbA1c 0.39 % points 15. Yokoyama Y, et al. Cardiovasc Diagn Ther. 2014

27 What about studies in people with Type 1 diabetes 16? 4 week RCT; 10 adults with T1DM 39% (221 g) of energy carbohydrate vs 70% (363 g) 11 g of fibre vs 72 g Saturated : unsaturated fat ratio 0.46 vs 0.24 No difference in weight, fasting glucose or HbA1c Carbohydrate disposal per unit of insulin, and basal insulin decreased on the high carb, high fibre diet Total and HDL cholesterol decreased on the high carb, high fibre diet 16. Anderson et al. AJCN. 1991

28 Why are we able to be flexible in our carbohydrate recommendations?

29 Both amount and type of carbohydrate affect BGLs The total amount of carbohydrate ingested (whether in a single food or as part of a meal) accounts for 57 65% of the variability in blood glucose response. The type (GI) of carbohydrate explains a similar amount (60%) of the variance. Together (GL), the amount and the type of carbohydrate accounted for 90% of the total variability in blood glucose response 17, Wolever TM and Bolognesi C. J Nutr 1996;126: Wolever TM and Bolognesi C. J Nutr 1996;126:

30 Carb-counting and glycated hemoglobin 19 6 RCT s. 667 participants Carb counting meta analysis Model Study name Statistics for each study Std diff in means and 95% CI Std diff Standard Lower Upper in means error Variance limit limit Z-Value p-value Trento Scavone DAFNE Laurenzi Gilbertson Kalergis Fixed Random Fav ours Carb count Fav ours Control HbA1c changes In adults using carbohydrate counting, there was a -0.4% improvement in HbA1c (p = 0.048) 19. Bell, Barclay, Petocz, Colagiuri, Brand-Miller. Lancet Diabetes Endocrinol

31 GI and BGLs in children with type 1 20 Randomised cross-over trial, 20 Australian children aged 7-17 yrs. High GI (84) diet Low GI (48) diet 20. Ryan et al. Diabetes Care ;31(8):

32 GI and glycated hemoglobin RCT s. 402 participants Significantly less hypos (difference of -0.8 episodes per patient per month, P < 0.01). 21. Thomas and Elliot. The Cochrane Collaboration, 2009.

33 GL is the most important predictor of insulin response healthy young people consuming 121 types of single foods (study 1) and 13 mixed meals (study 2): For foods: GL was a more powerful predictor of insulin response than GI or available carbohydrate - explaining 59%, 55% and 49%, respectively (P=0.005). For mixed meals: GL was the only predictor of postprandial insulin response, explaining 46% (P = 0.01) of the variation. Carbohydrate content alone predicted the insulin responses to single foods (P<0.001) but not to mixed meals. 22. BAO et al. AJCN. 2011;93:1-13

34 23. Bao et al. AJCN ; 89: Food Insulin Index 23

35 Are we eating too much carbohydrate?

36 Macronutrient consumption in Australia /2 24,25 National representative surveys of Australians: 14,000+ in 1995 and 12,000+ in 2011/2 24. ABS. National Nutrition Survey. Com of Aust, 1998; 25 ABS. Australian survey. Com of Aust,

37 People with diabetes in Australia 26 People with diabetes Mean % energy Energy (kj) 8,350 Protein (g) 97* 19.7 Fat (g) Saturated fat (g) Poly fat (g) 14 Mono fat (g) 27 Total carbohydrate (g) Starch (g) 102 Sugars (g) Alcohol (g) Fibre (g) 29 GI 55 GL Barclay et al. BJN. 2006; 96, *1.67 times Australia RDI

38 Too many carbs, or wrong type? We already eat a moderate carbohydrate diet: 45 % of kjs = 230 g a day for average weight stable Australian adult in 1995 NNS 43.5% of kjs = 222 g a day in NHS We do eat the wrong type 27, 9 Average daily GI 55 and GL 132 Aim for GI ~ 45 and GL <100 Lower the populations GL by GI not carbs? 27. Barclay, Petocz, Flood, Brand-Miller, AJCN. 2008;87: Livesey et al, AJCN, 2013

39 Recommendations into practice

40 Healthy eating principles Choose the healthiest option within each food group or category Key nutrients to consider: Energy (kjs) < 2,200 kj per serve for mains < 600 kj per serve for snacks Saturated fat (g) < 28% of total fat Carbohydrate (g) < 60 g per serve for mains < 30 g per serve for snacks Fibre > 4 g per serve GI 55

41 Use the swap it, don t stop it approach to choose the right type of carbohydrate Simply swap low GI carbs for high GI carbs within each food group or category This principle will lower the dietary GL

42 Sample meal plan for overweight adult with type 2 diabetes Breakfast Lunch Dinner 45g Traditional muesli 2 x toast 1 1/3 Cup Spaghetti 1/2 cup milk ( fat) + Canola margarine Bolognaise Sauce 1 x toast 210 g NAS Baked + 2 cups salad + Canola margarine Beans + vinaigrette Morning Tea Afternoon Tea Supper Fruit biscuits (2 small) 200 ml yoghurt Fruit (eg, 1 sml Apple) (NNS)

43 Nutrient analysis of sample meal plan Comparison to key recommended intakes: Protein = 64 g (0.76g/kg or 19% of energy) Total Fat = 27 g (18 % of energy) Saturated Fat = 6 g (4% of energy) Carbohydrate = 200 g (56% of energy) Fibre = 30 g (5g/1000kJ) GI = 45 (~45 / day) GL = 90 (<100 / day) Sodium = 1,137 mg ( )

44 Sample Cantonese menu plan modified

45 Nutrient analysis of Cantonese menu plan

46 Sample Greek menu plan - modified

47 Nutrient analysis of Greek menu plan

48 Sample South Indian menu plan

49 Nutrient analysis of South Indian menu plan

50 Summary Healthy eating is an important part of diabetes management The amount and type of carbohydrate consumed are the strongest predictors of an individuals BGLs On average, Australians do not consume high carbohydrate diets, and there is evidence that people with diabetes consume less, but the GL is too high Help people to maintain the pleasure of eating by only limiting food choices when indicated by strong scientific evidence The amount and type of carbohydrate consumed should be influenced by the individuals cultural background and personal food preferences

51 Declaration of interests I am a Board member and consultant to the GI Foundation. I am a co-author of the Diabetes and Pre-diabetes Handbook / Managing Type 2 Diabetes and The Ultimate Guide to Sugars and Sweeteners.

52 Further information Alan Barclay +61 (0) (0)