Nutrition and wellness units PDF

Preview

Summary

Summary of FSHN1030 units 1, 2 & 3 - nutrition and wellness units...

Description

UNIT 2 Nutrition and wellness Read this A definition that is widely used in nutrition textbooks states that nutrition is “the science of food, the nutrients and the substances therein, their action, interaction, and balance in relation to health and disease, and the process by which the organism ingests, absorbs, transports, utilizes, and excretes food substances”. ('The Council on Food and Nutrition of the American Medical Association' at https://www.emedicinehealth.com/nutrition_and_diet/article_em.htm#nutrition_guidelin es_overview) On the other hand, “diet” simply refers to all the food and drink we consume. Our diet provides all the nutrients and other substances required by the body to grow and maintain our health and prevent disease. Nutrition is the science that links diet to health and disease. The WHO defines “Nutrition as the intake of food, considered in relation to the body’s dietary needs. Good nutrition – an adequate, well balanced diet combined with regular physical activity – is a cornerstone of good health. Poor nutrition can lead to reduced immunity, increased susceptibility to disease, impaired physical and mental development, and reduced productivity.” A healthy diet has variety, balance and moderation. ● ● ● ● ● ● ● ● ● ● ● ● ●

Gives you energy and vitality. Allows you to grow and develop to your potential, physically, intellectually and physiologically Helps you stay at a weight that is right for you Boosts your immune system Prevents serious illnesses such as heart disease, stroke, certain cancers, mature-age onset diabetes (Type II), anaemia and gall bladder disease Delays the effects of ageing Builds strong dense bones – prevent osteoporosis Improves your capacity to exercise and stay fit and your sports performance Keeps you active and fit into old age Protects your teeth and keep your gums healthy Enhances your ability to concentrate Possibly enhances your mood For women: helps to have healthy pregnancies and healthy babies

The Australian Dietary Guidelines were developed by the National Health and Medical Research Council (NHMRC) and are based upon current scientific research. The latest guidelines were released in 2013. There are 5 guidelines: ● ● ●

To achieve and maintain a healthy weight, be physically active and choose amount of nutritious food and drinks to meet your energy needs Enjoy a wide variety of nutritious foods from the five food groups daily and drink plenty of water Limit intake of foods containing saturated fat, added salt, added sugars and alcohol

● ●

Encourage, support and promote breastfeeding Care for your food; prepare and store it safely

The 5 food groups are: ● ● ● ● ●

Vegetables and legumes/beans Fruit Grain (cereal foods), mostly wholegrain and/or high fibre cereal varieties Lean meat and poultry, fish, eggs, tofu, nuts and seeds and legumes/beans Milk, yoghurt, cheese and/or alternatives, mostly reduced fat

Note that the guidelines are now displayed as the “healthy eating plate” rather than a “pyramid”. The plate shows the proportions of the five foods groups to be consumed each day. Also note that legumes/beans appear in two of the five food groups. Consequences of an unbalanced diet: Dietary imbalance

Possible resulting health problem

Intake of too many kilojoules in relation to physical activity

Overweight, obesity, type 2 diabetes,

High intake of saturated fat

Heart disease, stroke, peripheral vascular disease

High intake of sugar

Dental cavities

heart disease, breast cancer

Insufficient fluoride High salt intake

High blood pressure, stroke, stomach cancer

Low fibre intake

Constipation, haemorrhoids, diverticular disease, bowel cancer

Excess alcohol

Cirrhosis of the liver, high blood pressure, cancers of the mouth, throat, oesophagus, stomach, bowel, liver, breast

Insufficient fruit and vegetable intakes

Heart disease, cancers of lung, breast, prostate, bowel bladder, impaired night vision

Low calcium intake

Osteoporosis, cancer of the bowel

Low iron intake

Anaemia

Standard serve sizes do not change – but different individuals will require a different number of serves per day. Food group

Standard Serve Weight (g) or Energy (kJ)

Standard Serve Examples

Vegetables and legumes/beans

75 g or

½ cup cooked carrots

100 – 350 kJ

1 medium tomato 1 cup raw salad vegetables

Fruit

150 g or 350 kJ

1 medium banana; 2 small apricots; 1 cup diced fruit

Grain (cereal) foods,

500 kJ

1 slice (40g) bread; ½ cup cooked pasta; ¼ cup muesli; 3 (35g) crispbreads

Lean meat, poultry, fish, eggs, tofu, nuts, seeds, legumes/beans

500 – 600 kJ

65g cooked lean meat (90-100g raw); 2 (120g) large eggs; 30g nuts or peanut butter

Milk, yoghurt, cheese and/or alternatives, mostly reduced fat

500 – 600 kJ

1 cup (250ml) milk; 2 slices (40g) hard cheese; ¾ cup yoghurt; ½ cup ricotta cheese

mostly wholegrain / high fibre

The recommended number of serves of each food group for adults depends on: ○ ○ ○ ○

age gender whether pregnant or breastfeeding physical activity level

Males have higher food intakes than females. Older people require less than younger people (except for milk products). Nutritional needs are higher in pregnancy and when breastfeeding.

Sample daily food patterns are on page 41 of this document. It’s a long read – worth reading the entire document if you have time; if not a skim read will suffice but look carefully at page 41: https://www.eatforhealth.gov.au/sites/default/files/files/the_guidelines/n55a_australian _dietary_guidelines_summary_book.pdf Discretionary choices are “extra” foods that can form part of an individual’s diet. The amount of these foods should be limited.

A healthy diet provides: •

just enough energy to meet your energy needs (energy expenditure) and to maintain a healthy body weight

•

sufficient nutrients to prevent nutritional deficiencies

•

some nutrients and other substances in quantities that decrease the risk of diet-related chronic diseases

Nutrients are chemical substances obtained from food that are vital for the growth, performance and maintenance of a healthy body throughout life. Nutrients ● ● ● ● ●

Are essential for health – our bodies can’t make them Provide energy Provide building blocks Maintain body cells Regulate body processes

Note that: Energy is not a nutrient and alcohol is not a nutrient. Nutrients are divided into 2 main categories – macronutrients and micronutrients. Macronutrients are needed in large quantities (such as grams) and are typically large molecules. Micronutrients are required in smaller quantities (milligrams or micrograms) and are typically smaller molecules. These two categories can be further divided into the 6 categories of nutrients. Macronutrients – carbohydrates, fats and proteins

Micronutrients – vitamins, minerals and water Nutrients can also be divided into three functional groups: •

Provide energy and building blocks (proteins, most carbohydrates, most lipids (fats))

•

Promote growth, development and maintenance (proteins, lipids, some vitamins, some minerals, water) ●

Regulate body processes (proteins, some lipids, some vitamins, some minerals, water)

Do this ● ● ● ● ●

●

Have a read of this website https://www.eatforhealth.gov.au/guidelines/aboutaustralian-dietary-guidelines Look at all the separate publications here – https://www.eatforhealth.gov.au/guidelines Name some nutrition advice that has changed in your lifetime that you are aware of. Being able to read food labels is important. Read this link https://www.healthdirect.gov.au/how-to-read-food-labels Quick experiment – you’ll need a box of breakfast cereal, 2 identical bowls, a set of kitchen scales and/or kitchen measuring cups. Pour out the amount of breakfast cereal that you would normally serve yourself into the first bowl. Look at the nutrition panel to see the recommended serving size. Determine your serving size (it may be in cups or grams depending on the box of cereal that you have). How does your serve compare to the recommended serve? Now pour the recommended amount into the second bowl and compare it visually to the amount you would normally serve yourself. Take a photo of both bowls and upload your comparison photos onto the UONLINE page for this course. Have a look at the nutrition panels of five food products in your house and examine the recommended serving sizes. How do they compare to the amount you’d normally eat?

Think about this (these will be discussed during our class “chat sessions”) ● ● ● ●

Why are there so many separate publications in the government guidelines? Is the plate image better than a pyramid? Why do males have a higher energy requirement than females (except females who are pregnant or breastfeeding)? Are these Healthy Eating Guidelines easy to access and are they being adhered to? Why do you think this?

Extra resources https://theconversation.com/exaggerated-portions-alongside-real-nutrition-claims-on-cereal-boxesmay-mislead-consumers-new-study-101269 http://www.nutritionaustralia.org/national/resource/healthy-eating-pyramid (the pyramid is still in use here – their ‘additional messages’ are worth reading)

https://www.heartfoundation.org.au/healthy-eating

Unit 3 The Energy Nutrients and Wellness Read this Energy is not a nutrient – but it is released from food via chemical reactions during digestion. The macronutrients (carbohydrates, proteins and fats) are also known as the energy nutrients since they contribute energy to the body. Alcohol also contributes energy to the body – but it is not a nutrient as it does not provide any nutrition, hence it is often referred to as “empty calories”. The metric unit of energy is Joules (the old measure was calories). 1000 joules (J) = 1 kilojoule (kJ) Calories are more confusing. 1 kilocalorie = 1000 calories = 1 Calorie (note the capitalisation). 1 Calorie = 4.18 kJ Energy in each macronutrient and alcohol: Nutrient

kcal/g

kJ/g

Carbohydrate

4

17

Protein

4

17

Fat

9

37

(Alcohol)

(7)

(29)

Carbohydrates are chemical compounds made up of carbon, hydrogen and oxygen atoms. They can be divided into 2 categories – complex carbohydrates (such as starches) and simple carbohydrates (sugars). Carbohydrates are broken down during digestion to glucose which is the body’s (especially the brain’s) main source of fuel. Examples include: bread, rice, pasta, potatoes and sugar.

There are 6 simple carbohydrates: Monosaccharides (“mono” meaning one sugar unit) ○ ○ ○

Glucose (Blood Sugar) Fructose (Fruit and Honey Sugar) Galactose (Part of Milk Sugar)

Disaccharides (“di” meaning two sugar units, formed by the combination of 2 monosaccharides) ○ ○ ○

Sucrose (Table Sugar) Lactose (Milk Sugar) Maltose (Malt Sugar, used in brewing)

The important disaccharides in nutrition are sucrose, lactose and maltose. All contain glucose. ● ● ● ●

Sucrose (Glucose + Fructose) – Table Sugar Lactose (Glucose + Galactose) – Milk Sugar Maltose (Glucose + Glucose) – Malt Sugar Once digested into monosaccharides and absorbed, the fructose and galactose are converted to glucose by the liver.

Complex carbohydrates are also known as polysaccharides. Poly is Greek for “many” since they contain many monosaccharide units joined together. Glycogen, starch and dietary fibre are the three most important complex carbohydrates in nutrition. Glycogen is a storage molecule found in the muscles and liver. Starch usually consists of around 3000 glucose molecules joined together and is a good energy source for the body. Dietary fibre is indigestible plant material. It can be divided into insoluble (such as cellulose) and soluble fibre (such as the fibre found in fruit, vegetables, gums, and psyllium). Proteins are chemical compounds made up of carbon, hydrogen, oxygen and nitrogen atoms. Some sulfur is also found in proteins. Examples of proteins include: meat, fish, eggs, milk and nuts. Protein accounts for around 17% of body weight. Proteins are made of units called amino acids. There are 20 amino acids and 9 are considered “essential”. This means that they cannot be manufactured by the body and must come via diet.

Essential AA

Nonessential AA

Histidine

Alanine

Isoleucine

Arginine

Leucine

Asparagine

Lysine

Aspartic Acid

Methionine

Cysteine

Phenylalanine

Glutamic acid

Threonine

Glutamine

Tryptophan

Glycine

Valine

Proline

Serine

Tyrosine

Proteins containing all essential amino acids in the correct proportions for use by the body are known as complete proteins or “high quality” proteins. Complete proteins are only found in animal proteins (meat, milk, eggs), soy and quinoa. Incomplete (or “low quality”) protein is deficient (i.e. it may be present but in low amounts) in at least one essential amino acid. By eating a variety of foods, a full complement of amino acids can be attained through the diet. Plant protein can be of low quality – even staple foods are deficient: •

Wheat in lysine

•

Rice in threonine

•

Corn in tryptophan

•

Legumes in methionine, cysteine, tryptophan

Therefore, this is an important issue in vegetarian diets, especially vegans, who do not eat milk and eggs. Some animal proteins are also incomplete, e.g. gelatine – an incomplete animal protein no tryptophan at all and low in isoleucine, threonine and methionine. Protein has varied roles in the body including - regulating body processes (hormones, neurotransmitters and enzymes), promoting growth and development (muscles and other tissues), fighting infections (antibodies), transporting nutrients (haemoglobin carries oxygen to cells), fluid balance (albumins and globulins in blood), acid-base balance (protein buffers) - rather than being used for energy. Using protein as an energy source places a large stress on the liver and kidneys and is generally avoided by the body unless there is limited supply of carbohydrates. Most individuals eating a standard Western diet consume more protein than is required each day. The amount of protein needed each day is 0.8 g of protein / kg of healthy body weight for an average person. Excess protein is stored in the body as fat. Individuals who undertake regular vigorous exercise have higher protein requirements (1.5 – 2 g / kg). Pregnant and breastfeeding women also have higher protein requirements. Scientifically, fats are known as lipids. They are chemical compounds made up of carbon, hydrogen, oxygen and nitrogen atoms. Many fats are known as triglycerides and consist of a glycerol unit and 3 fatty acids. There are two essential fatty acids – these must be consumed in the diet. They are linoleic acid (“omega-6”) and linolenic acid (“omega-3”). The balance between the omega-3 and 6 compounds is important for conditions involving inflammation like arthritis. The ratio should between 5:1 and 10:1. Age

Adequate Intake (AI)

Linoleic acid

a-linolenic acid

(ω-6)

Total fish LC ω-3 (DHA+EPA+DPA)

(ω-3) Boys and girls 1-3 yr

5 g/day

0.5 g/day

40 mg/day

4-8 yr

8 g/day

0.8 g/day

55 mg/day

9-13 yr

10 g/day

1.0 g/day

70 mg/day

14-18 yr

12 g/day

1.2 g/day

125 mg/day

9-13 yr

8 g/day

0.8 g/day

70 mg/day

14-18 yr

8 g/day

0.8 g/day

85 mg/day

Men

13 g/day

1.3 g/day

160 mg/day

Women

8 g/day

0.8 g/day

90 mg/day

Boys

Girls

Adults 19+ yr

These are needed for immune function, vision, and for the production of hormone-like compounds and are a structural component of cell membranes. The hormone-like compounds made from the essential fatty acids are important for regulating blood pressure, body temperature, pain, childbirth, clotting, stomach secretions, the immune system defence against infections and allergic and inflammatory reactions. Triglycerides are the main form of energy storage in the body. If a lipid is a solid at room temperature, it is called a fat and if it is a liquid at room temperature, it is called an oil. Triglyceride properties differ due to differences in the length of the fatty acids (more or less atoms in the chain) and due to the type of chemical bonding (single or double carbon bonds). If a lipid has double bonds in its chains, it is called “unsaturated”. If it has one double bond, it is called “monounsaturated” (such as olive oil and avocado oil) and if it has multiple double bonds then it is called “polyunsaturated” (such as sunflower oil, safflower oil, canola oil and linseed oil). These all tend to be liquids at room temperature (i.e. oils). If a lipid has single bonds in its chains then it is known as a saturated fat and tends to be solid and room temperature. Animal fats are high in saturated fat, as are palm oil and coconut oil. Trans fatty acids have a slightly different chemical structure to most fatty acids (which are known as cis fatty acids). Due to this structure, they are treated differently by the body and can raise blood cholesterol, like saturated fatty acids. Trans fatty acids occur naturally in low levels but are found in much higher concentrations in manufactured fats and oils, such as margarines, shortening and many commercially prepared baked goods.

They are often labelled as “hydrogenated oils”. Cholesterol is also a lipid. It is an essential component of cell membranes (with phospholipids – allows fat soluble compounds in and out). ● ● ● ● ● ● ● ● ● ● ● ●

Produced by the liver Found only in animal products Forms important hormones (oestrogen, testosterone, vitamin D) Precursor to bile acids (made by liver – emulsifiers) Aids with transport of lipids/triglycerides in the bloodstream Sources of cholesterol: foods of animal origin only We obtain one third of our cholesterol from the diet, unless you are a complete vegetarian (vegan), The rest (two thirds) we make ourselves, therefore cholesterol is not an essential nutrient 40-60% of dietary cholesterol is absorbed Plant sterols (phytosterols) – in plant foods and margarine (e.g. ProActive) reduce body’s absorption of cholesterol and lower blood cholesterol Saturated fatty acids and trans monounsaturated fatty acids raise blood cholesterol Polyunsaturated and cis monounsaturated fatty acids decrease blood cholesterol

The “Standard Adult” dietary requirement is 8700 kJ per day. This is defined by our government law in the Food Standards for Australia and New Zealand (FSANZ) Code 1.1.1 Nutrient

Quantity per day

kJ

% of total kJ

(calculated)

Energy

8700