Core Topic 1: Fundamentals of Human Nutrition

1. Core Topic 1: Fundamentals of Human Nutrition Macronutrients Protein

2. What is Protein? • Protein is a nutrient made up of carbon, hydrogen, oxygen and nitrogen. • The only nutrient that supplies the body with nitrogen. • Combine to create amino acids. • 23 amino acids in total • Classified as essential and non-essential amino acids. • Provides 17kj/g of energy • Located in animal and plant foods

3. Why do we need Protein? • Protein is required for: • Growth, maintenance and repair of every cell in the body • Hair, finger nails, muscles • Production of enzymes, • enzymes enable chemical reactions (digestion) • To activate the growth hormone as required • Stabilising the structure of nucleic acids, DNA & RNA • Create proteins in the blood • Haemoglobin, albumin & transferrin • Production of antibodies • to prevent diseases in the body • As a secondary source of energy when carbohydrate and fat stores are depleted.

4. Amino Acids • Essential AminoAcids must be supplied in the dietgiven the body’s inability to make them. • Non-Essential Amino Acids are synthesised by thebody. • Each Amino Acidis required to carryout the varied func-tions of protein

5. Biological Value, Complete & Incomplete Protein • The biological value is a measure of the protein’s quality • Biological value is measured by the number of essential amino acids it contains. • Protein foods that contain all essential amino acids have a High Biological Value (HBV) and are known as: • Complete Proteins: • Protein foods that are deficient in one or more of the essential amino acids have a Low Biological Value (LBV) and are known as: • Incomplete proteins.

6. Complementary Proteins • Two or more incomplete proteins can be combined to ensure each essential amino acid is consumed. • Individually they have different limiting amino acids and are of LBV, but when combined they are considered of HBV. • Nachos (corn & kidney beans) • Minestrone Soup (legumes & vegetables) • Combining two different sources of plant protein allows the amino acids to complement one another. • Particularly important for vegetarians and vegans.

7. Activity 1: What foods can be combined to create complementary protein?

8. Food Sources of Protein The proteins in animal food including meat, fish, eggs and milk are a rich source of protein. Plant foods including nuts, legumes, beans and grain contain some protein.

9. How much protein? • 17kj/g of energy • 15-25% of the total daily energy intake should come from protein. • The recommended intake of protein depends on a person’s weight and age. • The RDI is expressed as grams per kilogram of bodyweight. • Women require 0.75g of protein/kg of body weight • Men require 0.84g/kg of protein/kg of body weight • Pregnant women and men and women over 70 require 1g of protein/kg of body weight Q1. How many grams of protein will a 75kg adult male need?

10. How much protein? NRVs retrieved from Nutrition: The Inside Story

11. How much protein? • Table 1: Estimated protein requirements for athletes • Source: http://www.ausport.gov.au/ais/nutrition/factsheets/basics/protein_-_how_much

12. Excess Protein • Many Australians over-consume protein; thus, a deficiency is rare. • Waste products from protein metabolism are processed and removed by the liver and kidneys. • If protein consumption is excessive these organs are placed under additional strain. • Increased protein consumption increases the risk of dietary related disorders including obesity, heart disease and increased blood cholesterol levels. • Due to increased levels of saturated fats, which increases blood cholesterol levels, and provides many kj/g. Q. In pairs suggest 3 reasons why many Australians over consume protein.

13. Deficiency of Protein • Insufficient protein intake can lead to: • Retarded growth in children • Slow healing of wounds • Decreased levels of immunity due to insufficient antibodies. • Anaemia due to insufficient haemoglobin. • Kwashiorkor is a condition foundin developing countries where there is a deficiency in the qualityand quantity of dietary protein. • Symptoms include wasted muscles, protuberant belly, brittle hair and failureto grow, peeling skin and apathy.

14. Deficiency of Protein • When both protein and energy (kj) are in short supply , marasmus can occur. • Symptoms of Marasmus include: • Retarded growth • Extreme muscle wastage • Sunken eyes • General debility

15. Vegetarian Diets and Protein • Vegetarian diets are classified into four main types: • Vegan • Avoid eating all animal products and foods. • Lacto-Vegetarian • Avoid meat and eggs, but include dairy products • Lacto-Ovo Vegetarian • Avoid eating all animal products, but will consume milk, milk productsand eggs • Vegetarian • ‘loose’ term to describe people who do not eat animal foods

16. Concerns with Vegetarianism • Vitamin B12 and iron are concerns for a poorly balanced vegetarian diet. • To ensure essential amino acids are consumed , people need to consume complementary proteins. • Eat foods from two different food sources within the same meal. E.g. cereals with legumesor vegetables and legumes.

17. A food model for a lacto-Ovo vegetarian (Nutrition Australia 2013)

18. Extended Response • ‘Provided you get the correct amount of protein on a regular basis in your diet, it is of little consequence what food sources it is derived from.’ • Outline four main functions of protein in the diet. • Discuss the importance of careful protein selection for vegetarians and their young children. • Discuss the positive and negative aspects of being an adolescent female lacto-vegetarian . • Discuss whether animal proteins are better for us than proteins from plant products.