Diets in Prevention and Treatment of Disease (Western Sydney University Lecture)

Diets: prevention and treatment of disease Dr Bronwen Dalziel COPYRIGHT COMMONWEALTH OF AUSTRALIA Copyright Regulations 1969 WARNING This material has been reproduced and communicated to you by or on behalf of University of Western Sydney pursuant to Part VB of the Copyright Act 1968 (the Act). The...

Diets: prevention and treatment of disease Dr Bronwen Dalziel COPYRIGHT COMMONWEALTH OF AUSTRALIA Copyright Regulations 1969 WARNING This material has been reproduced and communicated to you by or on behalf of University of Western Sydney pursuant to Part VB of the Copyright Act 1968 (the Act). The material in this communication may be subject to copyright under the Act. Any further reproduction or communication of this material by you may be the subject of copyright protection under the Act. Do not remove this notice. Learning Objectives Describe dietary management strategies for relevant medical conditions and diseases such as food allergy, insulin resistance, coeliac disease, cardiovascular disease and cancer Recognise the role of nutrition in the treatment of disease Prescription: Food as medicine 1 cup of broccoli a day Unlimited refills Foods and nutrients as well as dietary patterns interact with metabolic processes and contribute to a reduction or an increase in the risk of a number of important diseases. Metabolomics investigations focus on understating the composition of foods as well as diet-induced metabolic changes Chronic diseases such as cancer and cardiovascular disease (CVD) have many contributing factors: genetics, smoking, exercise, alcohol as well as diet. E.g. genetic variation in enzymes allow some people to experience the health benefits of brassicas (e.g. broccoli) for longer because they are slower to metabolise cancer preventing isothiocyanates Chapter 5 & 7: Nutrition in the Prevention and Treatment of Disease, fourth edition Ann M. Coulston, Carol J. Boushey, Mario G. Ferruzzi and Linda M. Delahanty, Editors Food as medicine - research Food frequency questionnaires (FFQ) preferred over food records or recall for identifying longterm diet (most likely contribution in chronic disease). Uses a list of foods and food adjustment questions FFQ captures major sources of energy and nutrients over a time-period Chapter 7: Nutrition in the Prevention and Treatment of Disease, fourth edition Ann M. Coulston, Carol J. Boushey, Mario G. Ferruzzi and Linda M. Delahanty, Editors Food as medicine - research A dietary index looks at adherence to a specific overall dietary pattern. The relationship of risk morbidity or mortality and adherence to the dietary pattern is analysed. E.g. the Mediterranean diet (from the 1960s!) is assessed with the MedDietScore. This reflects a movement towards testing dietary interventions that focus on eating patterns and not a single nutrient Chapter 7: Nutrition in the Prevention and Treatment of Disease, fourth edition Ann M. Coulston, Carol J. Boushey, Mario G. Ferruzzi and Linda M. Delahanty, Editors Food as medicine - research Be careful of cause and effect research: – Association is not cause – Alternative explanations must be considered (e.g. was it physical activity?) – Methods must be analysed (chance, poor study design, weak or strong association, biological mechanism, doseresponse relationship) – Do the results fit in the context of all available evidence – Validity of dietary intake measurements (use of biomarkers) Chapter 7: Nutrition in the Prevention and Treatment of Disease, fourth edition Ann M. Coulston, Carol J. Boushey, Mario G. Ferruzzi and Linda M. Delahanty, Editors Bioactive compounds from foods Plant compounds that exert biological activity – 2⚬ metabolite Called phytochemicals: e.g. polyphenols, carotenoids, tocochromanols and curcuminoids Chapter 15: Nutrition in the Prevention and Treatment of Disease, fourth edition Ann M. Coulston, Carol J. Boushey, Mario G. Ferruzzi and Linda M. Delahanty, Editors 🌈 🌈 🌈 🌈 🌈 🌈 Antioxidants Decrease or delay oxidative reactions Inhibit reactive oxygen species (ROS) and reactive nitrogen species (RNS) ROS target membranes, proteins, nucleic acids, carbs Endogenous enzymes have this role too Non-enzymatic components can come from diet (e.g. vitamins, flavonoids and phenolics) and can be influenced by dietary patterns and behaviours Conflicting findings on risks and benefits Chapter 16: Nutrition in the Prevention and Treatment of Disease, fourth edition Ann M. Coulston, Carol J. Boushey, Mario G. Ferruzzi and Linda M. Delahanty, Editors TREATMENT OF DISEASE Drew’s diet journey (type 1) Improved Insulin Sensitivity over standard diet High fat, low carb, no grains/legumes, dairy Paleo diet Ketogenic diet Decreased Insulin Sensitivity in muscles and liver High fat, very low carb Best Insulin Sensitivity Low fat, high carb (whole grain, fruit and veg) Whole food plant diet (vegan) Prevention of diabetes Research is needed to provide a better understanding of environmental triggers for type 1 diabetes Prevent obesity – healthy diet and BMI, 30 min exercise per day could prevent 90% of the cases of type 2 diabetes Directly target insulin resistance – dietary approaches and lifestyle interventions Chapter 30: Nutrition in the Prevention and Treatment of Disease, fourth edition Ann M. Coulston, Carol J. Boushey, Mario G. Ferruzzi and Linda M. Delahanty, Editors PREVENTION AND TREATMENT OF TYPE 2 DIABETES FIGURE 30.1: A model of relation of obesity to development of diabetes. Copyright © 2016 Elsevier Inc. All rights reserved. 14 Prevention of type 2 diabetes Finnish Diabetes Prevention Study (FDPS – 522 individuals with impaired glucose tolerance (IGT) – Control or Intervention (low fat, high fibre, exercise) – 58% reduction in incidence of type 2 diabetes after 3.2 years Diabetes Prevention Program (DPP) – 3234 ethnically diverse with IGT – Interventions: Standard treatment, standard with metformin, intensive lifestyle intervention (low fat and exercise) – Lifestyle 58% reduction in incidence, 31% reduction in metformin group after 2.8 years (true after 10 years as well) – Weight loss was the main predictor of success Chapter 30: Nutrition in the Prevention and Treatment of Disease, fourth edition Ann M. Coulston, Carol J. Boushey, Mario G. Ferruzzi and Linda M. Delahanty, Editors Dietary advice for Type 2 diabetes and gestational diabetes in Australia Glycaemic response after eating may be the most important factor. The amount and quality of carbohydrate should be considered General practice management of type 2 diabetes 2016–18 (PDF 2MB) https://www.racgp.org.au/FSDEDEV/media/documents/Clinical Resources/Guidelines/Diabetes/General-practice-management-of-type-2-diabetes_1.pdf The glycaemic index https://www.webmd.com/diabetes/treat-your-diabetes-17/video-diabetes-glycemic-index Some Low GI swaps Differences in starch structure Amylose = Low GI Amylopectin = High Gi Dietary advice for Type 2 diabetes and gestational diabetes in Australia Stick to standard Australian dietary recommendations – Eat foods proven to be beneficial to good health. These include whole fruit and vegetables, wholegrains, dairy foods, nuts, legumes, seafood, fresh meat and eggs. Limit intake of processed foods such as sugary drinks, chips, cakes, biscuits, pastries and lollies. Swap out some low GI food for high GI as part of a balance meal (Low GI does not mean eat more of that food) There is reliable evidence that lower carb eating can be safe and useful in lowering average blood glucose levels in the short term (up to 6 months). It is not safe for children, pregnancy or people with a kidney disorder. General practice management of type 2 diabetes 2016–18 (PDF 2MB) https://www.racgp.org.au/FSDEDEV/media/documents/Clinical Resources/Guidelines/Diabetes/General-practice-management-of-type-2-diabetes_1.pdf PREVENTION AND TREATMENT OF CVD Target traditional modifiable risk factors: – elevated total cholesterol (TC) – low-density lipoprotein-cholesterol (LDL-C), and hypertension – elevated triglycerides (TGs) – reduced high-density lipo- protein-cholesterol (HDL-C) New and emerging risk factors. including: – – – – – – inflammation oxidative stress the omega-3 index central blood pressure arterial stiffness postprandial derangements in metabolism or altered lipoprotein properties (e.g., particle size) All modifiable by dietary or lifestyle changes Prevention and treatment strategies Dietary recommendations Change from macronutrient targets ( whole food diet The type of nutrient used to replace fat, and the type of FA consumed markedly affects CVD risk Therefore recommended nutrient-dense foods: variety of vegetables, fruits (especially whole), grains (with at least half being whole grains) and/or low GI fat-free or low-fat dairy, oils (lower saturated fat, increased MUFA, PUFA) variety of protein foods (e.g., seafood, lean meats, eggs, legumes, nuts, seeds, and soy products) – Foods high in saturated fatty acid (SFA), trans fatty acid (TFA), added sugars, and sodium should be limited. – Alcohol should be limited – – – – – – FIGURE 27.1: Estimated percent change in the risk of CHD associated with isocaloric substitution of saturated fat. Adapted from Y. Li, et al., Saturated fats compared with unsaturated fats and sources of carbohydrates in relation to risk of coronary heart disease: a prospective cohort study, J. Am. Coll. Cardiol. 66 (14) (2015) 15381548. Copyright © 2016 Elsevier Inc. All rights reserved. 24 Protective effect of omega-3 oils (e.g. fish oil) In DART—the first RCT to investigate the effects of n-3 FA on secondary prevention of MI—men advised to consume oily fish 2-3 times per week experienced a 29% all- of FIGURE 27.3: Schema of potential dose responses and time courses for altering clinical events due toreduction the physiologicin effects EPA1DHA intake. Source: D. Mozaffarian, E.B.Rimm, Fish intake, contaminants, human health: evaluating the risks and the causeand mortality benefits, JAMA 296 (15) (2006) 18851899. 602 PART | D Cardiovascular Disease EPA = Eicosapentaenoic Acid. DHA = Docosahexaenoic Acid Copyright © 2016 Elsevier Inc. All rights reserved. 25 FIGURE 27.5: Commonalities and unique features of the DASH diet, Mediterranean-style diets, and the USDA food pattern recommended by the Dietary Guidelines for Americans 2015. Source: C.K. Richter, A.C. Skulas-Ray, P.M. Kris-Etherton, Recent findings of studies on the Mediterranean diet: what are the implications for current dietary recommendations? Endocrinol. Metab. Clin. North Am. 43 (4) (2014) 963980. Copyright © 2016 Elsevier Inc. All rights reserved. 26 NUTRITION AND COLON CANCER Prevention of colorectal cancer Evidence that diet is a modifiable environmental risk factor for colorectal cancer Proposed prevention mechanisms: fruit, vegetables and legumes (phytochemicals) – flavonoids promote apoptosis mour u t r e Canc Cell with DNA damage Progra mmed cell death Dead cell is eliminated Prevention of colorectal cancer Proposed mechanisms – Antioxidants (phytochemicals) inhibit cell damage – Modulate enzymes that act on carcinogens – Flavonoids, proanthocyanidins, isothiocyanates, and resveratrol have demonstrated antiinflammatory activity. Inflammation has been shown to promote tumour growth Prevention of colorectal cancer Of the vegetables, cruciferous (Brassica) vegetables, such as cabbage, broccoli, Brussels sprouts, and cauliflower and alliums (onion and garlic), have received the most attention for their chemopreventive properties (in animal studies). Human studies have shown inconsistent results There is convincing evidence that processed meat increases risk of colon cancer FOOD INTOLERANCES AND ALLERGY Important: Food intolerance vs allergy Food intolerance: e.g. Lactose intolerance A common example of a food intolerance Lactose intolerance At risk of calcium deficiency due to avoidance of dairy -> increased risk of osteoporosis Can normally tolerate some dairy so it should be consumed in moderate amounts – yoghurt has less lactose – Lactase supplements – Lactose reduced milk – Colonic adaptation to lactose is also encouraged Allergy – e.g. Coeliac disease The immune system reacts abnormally to gluten (a protein found in wheat, rye, barley and oats), causing small bowel damage. Normal villi Damaged villi Total avoidance of allergen is recommended -removal of gluten from diet leads to resolution of symptoms and improvement intestinal damage More than a “wheat allergy” Grains: wheat, rye, triticale, barley, wheat flour, wheat germ, wheat bran, graham flour, gluten flour, durum flour, wheat starch, bulgur, farina, semolina, couscous, spelt, kamut, einkorn, emmer, faro, orzo, atta Oats (in any form) unless uncontaminated and labelled glutenfree oats Many vegetarian meat substitutes—most contain gluten in the form texturized wheat protein, seitan, wheat gluten, bulgur wheat, wheat flour, or oats Wheat-based soy sauce, teriyaki sauce, gravies Herb tea containing roasted barley, barley malt, grain-based coffee substitutes Beer made with gluten-containing grains— “processed or treated or crafted to remove gluten.” Note: The gluten content of these products cannot be verified More than a “wheat allergy” A food label gluten-free must: – Be inherently gluten-free (raw vegetables, water, 100% juice); – Does not contain an ingredient that is a gluten containing grain such as wheat, rye, barley; – Does not contain an ingredient derived from a gluten-containing grain that has not been processed to remove gluten; – May contain an ingredient derived from a glutencontaining grain that has been processed to remove gluten (wheat starch) as long as the food does not contain more than 20 ppm gluten; – The food product contains less than 20ppm gluten.