Core Topic 1: Fundamentals of Human Nutrition http://www.nrv.gov.au/disease/macronutrient.htm

Overview of Topic 1 1.1 Humans need essential nutrients for good health: Investigate why humans must include essential nutrients in their diet. Analyse how macronutrients and micronutrients function and their relationship to optimal wellbeing. Investigate the relevance of Acceptable Macronutrient Distribution Ranges (AMDR) and develop skills to compare percentage requirements. Understand and investigate how foods can be combined to improve their nutritional status.

Macronutrients - Carbohydrates Found in plants and created through the process of photosynthesis. When plants use energy from the sun to combine CO2 and water from the environment to form carbohydrate. Carbohydrates are made up of Carbon, Hydrogen and Oxygen; thus, carbohydrates are abbreviated as CHO.

Why do we need Carbohydrates? The body requires carbohydrates to: Provide the body with heat and fuel to perform daily activities (1g = 16kj) Provide dietary fibre to stimulate the digestive system The regulation of protein and fat use by the body

Carbohydrate Classification Carbohydrates Monosaccharide Disaccharide Polysaccharide The term ‘saccharide’ refers to sugar. Therefore, the classification of each carbohydrates depends on the total amount of sugar units.

Monosaccharide Simple sugars There are three forms of monosaccharides: Glucose Most carbohydrates are converted to glucose by the digestive system Easily absorbed and used for energy The body’s preferred source of fuel Sources include ripe fruits, some vegetables and honey Fructose (fruit sugar) sources include fruit and honey Galactose formed during the digestion of lactose (milk sugar)

Disaccharide Disaccharides contain two monosaccharide units. Disaccharides include: Sucrose (glucose + fructose) Found in cane sugar, fruits and some vegetables Lactose (glucose + galactose) Found in dairy products Maltose (2 molecules of glucose) Found in germinating grain crops

Investigation Skills Name the graph. Interpret the findings The sugar content of various foods. Name the graph. Interpret the findings

Polysaccharide Monosaccharides can be joined together in long chains called polysaccharides. Polysaccharides include: Starch Found in cereals including wheat, rice and corn, cereal products including rice and pasta and vegetables including potato and peas. Glycogen Stored in the liver and muscles Can be converted back to glucose

Polysaccharides Pectin (soluble) Found in seeds, pith and peel of fruits and vegetables. Digested by intestinal bacteria. Attracts water and turns to gel during digestion May help reduce cholesterol Allows nutrients to be released more slowly Contributes to a feeling of satiety

Polysaccharides Cellulose (dietary fibre – insoluble) Forms in the cell walls of plants Partly digested Adds bulk to the stool Appears to help foods pass quickly through the stomach and intestines Contributes to a feeling of satiety

How much Carbohydrate? 1g of carbohydrate yields 16kj of energy. 45-65% of the total daily energy intake should be from Carbohydrates. For example if the total energy intake is 8,000kj, then 3,600-5,200kj should derive from carbohydrates.

Carbohydrate Deficiency and Excess Symptoms of deficiency Symptoms of excess Fatigue Inability to exercise (no glycogen) Headaches Fainting Lack of vitamins and minerals Low dietary fibre intake – constipation Protein depletion Dental caries (decay or cavity) build up of plaque, which sticks to acids in our mouth. The acid eats away at the outermost layer of the tooth called the enamel. Weight gain – increase in adipose tissue The brain and energy system can only use glucose for energy. Without glucose headaches, fainting and inability to exercise may result. Excess glucose is converted to glycogen, which is stored in the liver and muscles. Any glycogen remaining is placed in adipose tissue (body fat) Glycogen is necessary for exercise. When insufficient carbohydrate and lipids are consumed, the body converts protein into glucose. A carbohydrate deficiency will deplete protein stores. The body will convert muscle tissue into glucose to provide energy.

Dietary Fibre Fibre is grouped into two types: Indigestible Insoluble Digestible Soluble Fibre is grouped into two types: Soluble – digested by intestinal bacteria legumes, oats, barley and fruits Insoluble –partly digested Vegetables, grains, cereals and seeds

Why is Fibre Important? Fibre is important in the diet because it: Slows down initial digestion for nutrients to be released into the body slowly; thus, the absorption of vitamins and minerals is maximised. Helps produce soft, bulky stools, which are easy to expel from body. Provides a feeling of fullness in the stomach – thus reduces obesity. Increases the transit time of stools through intestines; thus, prevents constipation, diverticular disease, bowel cancer, haemorrhoids and potentially varicose veins. Slow digestion important for diabetics, as it helps regulate blood sugar levels.

What is the graph depicting? Depicting the fibre content of different foods. Name the graph. Interpret the results.

Why is Fibre Important? Fibre is important in the diet because it: Slows down initial digestion for nutrients to be released into the body slowly; thus, the absorption of vitamins and minerals is maximised. Helps produce soft, bulky stools, which are easy to expel from body. Provides a feeling of fullness in the stomach – thus reduces obesity. Increases the transit time of stools through intestines; thus, prevents constipation, diverticular disease, bowel cancer, haemorrhoids and potentially varicose veins. Slow digestion important for diabetics, as it helps regulate blood sugar levels.

The Glycaemic Index (GI) ‘The speed at which a carbohydrate food breaks down into glucose has been studied and the foods have been ranked.’ (Queensland Government 2011) The amount and type of sugar in a food will impact a food’s GI.

Glycaemic Index (GI) Milk Weet Bix French fries Low = < 55% Intermediate = 55-69% High > 70% Milk Weet Bix French fries Yoghurt Brown Rice White bread Nuts Soft drinks Jelly Beans Beans Brown rice Water melon Pasta Sucrose Rice crackers

Glycaemic index (GI) Low GI diets: help diabetics control glucose tolerance can reduce total cholesterol and triglyceride levels, increase HDL, reduce blood clotting and risk of CVD are more filling and can aid wait control

Structure of a Extended Response Question Usually written in three of four parts. Ensure you address each dot point. This section must be written in continuous prose. NO DOT POINTS ! Definitions should be given where possible. Give yourself time to structure your response. Use relevant explanations and examples to support your response.

Extended Response Question Polysaccharides are better for us than monosaccharides and disaccharides. Define monosaccharides, disaccharides and polysaccharides. Discuss the significance of polysaccharides for human beings. Outline concerns if a person does not consume sufficient Polysaccharides. Outline dietary strategies to boost one’s intake of polysaccharides.