Nutrition: Obesity PDF NMT200 Case 1

NUTRITION: OBESITY Dr. Adam Gratton NMT200 MSc ND September 11, 2023 LECTURE COMPETENCIES Describe the nature and classification of carbohydrates Explain the importance and function of carbohydrates LECTURE COMPETENCIES Gain a comprehensive understanding of the dietary factors that...

NUTRITION: OBESITY Dr. Adam Gratton NMT200 MSc ND September 11, 2023 LECTURE COMPETENCIES Describe the nature and classification of carbohydrates Explain the importance and function of carbohydrates LECTURE COMPETENCIES Gain a comprehensive understanding of the dietary factors that can influence the development and progression of non-alcoholic fatty liver disease (NAFLD). Familiarize yourself with the nutritional interventions and strategies that can be employed to manage NAFLD effectively. Develop the ability to recommend and educate patients about the dietary and lifestyle modifications necessary for the management of NAFLD Acquire knowledge about the role of excess caloric intake, added sugars, and high-fructose corn syrup in NAFLD, and understand how to advise patients on reducing their consumption of these factors. RESOURCES Required readings posted on Moodle Sources will change from case to case INTRODUCTION Non-Alcoholic Fatty Liver Disease (NAFLD or NFLD) is ultimately a disorder of dysregulated fuel storage May progress through several stages leading to cirrhosis or hepatocellular carcinoma Once liver inflammation and liver damage begin a diagnosis of Non- Alcoholic Steatohepatitis (NASH) is made Most patients will present with early stages of NFLD INTRODUCTION Many of the risk factors for insulin resistance also apply to NAFLD Given how much obesity and sedentary lifestyles increase the risk of NAFLD diet and lifestyle counselling are foundational interventions BACKGROUND: CARBOHYDRATES Three monosaccharides: - Glucose - Fructose - Galactose Physiologically important disaccharides: - Sucrose (glucose + fructose) - Lactose (glucose + galactose) - Maltose (glucose + glucose) GLUCOSE The common body fuel for oxidation and found in blood and tissue fluids and metabolized in most body tissues Most complex carbohydrates are digested into units of glucose or converted to glucose for fuel Dietary sources are extensive GALACTOSE Not found as a monosaccharide in foods but rather bound to glucose to form the disaccharide lactose Converted to glucose in the liver to be used as fuel through a reversible process Glucose converted to galactose during lactation Galactose is a common constituent in glycolipids and glycoproteins Dietary sources include anything with lactose (dairy foods, etc.) FRUCTOSE The sweetest of simple sugars Converted to glucose in the liver and intestine Transport and metabolism of fructose does not require insulin Only a few tissues have the capacity to metabolize it (liver, intestine, kidney, adipose and muscle tissue) FRUCTOSE Since so few tissues can metabolize it directly, the vast majority is metabolized in the liver Usually ends up replacing liver glycogen or being used in the synthesis of triglycerides FRUCTOSE The majority of ingested fructose is passively absorbed by GLUT5 transporters High fructose diets can amplify absorption by upregulating additional transport mechanisms FRUCTOSE Processing of fructose in the liver is not controlled by hormone or allosteric mechanisms (there is no rate- limiting step like there is with glycolysis) Metabolic changes do not act as feedback inhibitors as they do with glycolysis Excess metabolites (like pyruvate) enter various other pathways such as fatty acid synthesis and cholesterol FRUCTOSE: DIETARY SOURCES Naturally found in fruit and some vegetables, honey, agave nectar/syrup High-fructose corn syrup (HFCS) - Sugar-sweetened beverages - Processed foods - “Added” sugar COMPLEX CARBOHYDRATES Polysaccharides – longer chains of glucose units Oligosaccharides – smaller chains of 3 – 10 glucose units Physiologically relevant polysaccharides: - Starch is the storage form of carbohydrates in plants - Glycogen is the storage form of carbohydrates in animals Not all polysaccharides can be digested which we refer to as dietary fiber THERAPEUTICS NUTRITIONAL OPTIONS FOR NAFLD PREVENTION General recommendations that prevent obesity also prevent NAFLD Examples? THERAPEUTIC CONSIDERATIONS Avoiding additional damage to the liver - Avoiding/abstaining from alcohol consumption - Mindful of other therapeutics that can harm the liver Recognizing other risk factors or conditions - NAFLD is often found in patients with other conditions like diabetes, obesity, hypertension, etc. THERAPEUTIC CONSIDERATIONS At a very basic level - Avoiding excess sugar/carbohydrate consumption, especially fructose - Reducing saturated/trans fat intake - Opting for lean proteins and increasing vegetable consumption - EXERCISE THERAPEUTIC CONSIDERATIONS What is the best diet for preventing and treating NAFLD? A lot of evidence points to the Mediterranean diet as being the best for both prevention and treatment Depending on other comorbidities (poorly managed diabetes, for example) a general low-concentrated carbohydrate diet may also be advisable SAMPLE QUESTION Which of the following is the storage form of glucose in plants? A. Lactose B. Sucrose C. Glycogen D. Starch SAMPLE QUESTION Which of the following dietary recommendations is consistent with the Mediterranean diet? A. Three servings or more of red meat per week B. Three or more servings of legumes per week C. One daily serving of white wine D. Less than four tablespoons of olive oil per week