Some nutrients have been linked to chronic disease.
Nutrients in excess:Saturated fats are often referred to as 'bad fats' as they are known to contribute to plaque formation in the arteries and the prevalence of cardiovascular diseases.
Sodium (salt) helps to regulate blood pressure. An over consumption of sodium may contribute to the incidence of high blood pressure in sensitive individuals.
Energy: Excess energy in any form will lead to overweight. However foods high in added sugar and fats are the easiest to over-consume.
Under consumption of nutrients:Fibre from wholegrain sources has shown to decrease the risk of cardiovascular disease, type 2 diabetes and colon cancer.
Carbohydrates: Carbohydrates consist of ‘simple’ sugars (monosaccharides and disaccharides) and starches (polysaccharides or ‘complex’ carbohydrates). Once eaten, carbohydrates are broken down to glucose and used for energy by the body. This group of foods (bread, rice, pasta, grains, some vegetables, legumes, milk and fruit) are good sources of nutrients as well as energy.
A note on GI: many people ask about it. Simply put, it is the Glycemic Index (a value/number) given to indicate how quickly the glucose formed when we eat CHOs, is absorbed into the bloodstream. A high GI means CHOs are quickly digested and absorbed; a low GI means CHOs are digested and absorbed at a slower rate. This has an effect on the release of insulin which is important in the management of diabetes (especially type 2 diabetes). The GI is useful for comparing foods within a food group, e.g. white bread vs. wholegrain bread. However, relying solely on GI to determine the type of foods to eat can be misleading, e.g. chocolate, which is high in fat and sugar has a low GI.
Sugar: It is important to monitor the amount of added sugar in foods such as refined cereals. Naturally occurring sugars in foods are not a problem (e.g. lactose in milk or fructose in fruit). However, when sugars are extracted from their natural source they are devoid of nutrients and in excess replace other valuable nutrients in the diet and provide excess kilojoules.
Fibre: Is a part of plants, such as fruits, vegetables, unrefined grains and cereals, legumes, nuts, and seeds, that cannot be digested using the normal digestive enzymes in the stomach and small intestine. Fibre (especially soluble fibre) is broken down by bacteria in the large intestine. The by-products of this process are important for healthy gut function. Fibre has many other beneficial properties such as promoting a feeling of fullness after eating, slowing down the absorption of glucose, and hindering the absorption of cholesterol from food. The refining of wheat, rice, pasta, etc. removes fibre. When fruits and vegetables are peeled or the skin is removed, a lot of the fibre (and other nutrients) are also removed.
Lipids is the term used to describe fats and oils. By definition, fats are solid at room temperature and oils are liquid at room temperature. However, lipids are generally referred to as fats.
Most lipids we eat can be classified as saturated or unsaturated. All fats and oils contain a mixture of saturated and unsaturated fats. They are classified according to the dominant type of fat.
The saturated fats generally come from animal sources and are often referred to as 'bad fats' because of the negative effect they have on cardiovascular (heart) health. Unsaturated fats generally come from plant sources and are referred to as 'good fats' because of their positive effects on cardiovascular health. However, all types of fat are a rich source of energy (calories or kilojoules) and too much of either type of fat can lead to us becoming overweight.
The unsaturated fats can further be classified as monounsaturated or polyunsaturated fats. Polyunsaturated fats are classified as omega-3 or omega-6 fats.
This flowchart shows the relationships between the fats. In this course we will only concentrate on saturated and unsaturated.
A note on trans-fats: They are formed when liquid vegetable oils are ‘hydrogenated’ to form solid substances such as margarine, fat for deep-frying or shortening for baking. Trans fats act like saturated fats and are worse for heart health. They are found in pies, cakes, doughnuts, biscuits etc. They are also naturally present in milk and meat. Trans fats from milk and meat products may not have the same negative effects as other trans fats. Food Standards Australia New Zealand (FSANZ), the government body responsible for food safety, monitors the levels of trans fats in food in Australia and is working with health organisations such as the Heart Foundation and The Dietitians Association of Australia to reduce the level of trans fat in the food supply. If a claim for fat is made on the label, the level of trans fat must be included in the NIP.
Participant Activity: What foods contain mostly saturated or unsaturated fats?Go to page 7 in your (participant’s) workbook and do the exercise on saturated and unsaturated fats. Tick one or the other. There is no point in differentiating between the unsaturated types. If asked, explain it is the chemical structure that is different, but most of the unsaturated fats are considered healthy.
There may be some surprises in this table. For instance, some plant sources are classified as saturated and game meats are classified as unsaturated. Re-emphasise that fats are classified as being saturated or unsaturated according to which fat is present in the largest amount.
Saturated:full-fat dairy (butter, cheese, cream, milk), fatty meats, lard, palm oil (often referred to as vegetable oil and found in commercial foods), coconut cream/milk.
Unsaturated:oils (all but coconut and palm e.g. olive, canola, grape seed, sunflower, safflower, peanut, macadamia, etc.), margarines made from oils, lean meats, nuts and seeds, avocados.
Note: be aware of oils made from nuts or seeds – check your school policy regarding nuts. High grade oils are unlikely to cause a reaction, but it is impossible to tell from the label if the oil is high grade.
Omega 3: an important fat found in fatty fish and nuts. Essential for brain function and needed by most cells, hence the need to eat fish 2-3 times per week.
Reference: Participant‘s Workbook p.7 / Trainer’s Manual p.12
Sodium: Salt is a combination of the minerals sodium and chloride. The terms sodium and salt are often used interchangeably. It is important to monitor the sodium content of food in children and adolescents so they don’t get used to eating very salty foods, as eating patterns are developed during childhood. High levels of sodium in food and drinks have been linked to an increased excretion of calcium (via the kidneys). Calcium is important to bone strength and children cannot afford to lose calcium, as it helps protect them against osteoporosis later in life. High intakes of sodium may also increase the risk of high blood pressure in adulthood in sensitive individuals (2013 Australian Dietary Guidelines).
Calcium is important for healthy bones and teeth. You may have heard the term 'peak bone mass' . This refers to the greatest amount of bone that you have in your lifetime. Peak bone mass is achieved somewhere between the ages of 16 and 30. Because most bone is formed in childhood and adolescence, calcium is an important nutrient for children. Low calcium intakes have been associated with low bone mass, which often results in bone fractures later in life (osteoporosis).
The recommended dietary intake (RDI)1 for school children aged 9 -18 years is 1000mg - 1300mg of calcium a day. The most recent National Children’s Nutrition and Physical Activity Survey identified calcium as a nutrient at risk, especially in older children. Older children (9-16 years) were least likely to meet the estimated average requirements (EAR)2 of 800mg – 1050 mg of calcium daily (Dept of Health and Ageing 2008). In the 12-13 year old age group almost 70% of all children did not meet the EAR; this figure rises to almost 90% if we look at girls aged 12-13 years in isolation.
Dairy products are the best source of calcium in the diet. Other sources of calcium may include fortified soy products (milk, yoghurts) and fish with bones (salmon, sardines). Almonds are often cited as an alternative source of calcium. However, eating the amounts required to gain an equivalent ‘serve size’ of calcium compared to a fortified soy drink would require the consumption of in excess of 3000kJs. (1 cup low-fat calcium fortified soy ~ 500kJs)
1 RDI - The average daily dietary intake level that is sufficient to meet the nutrient requirements of nearly all (97–98 per cent) healthy individuals in a particular life stage and gender group
2 EAR - A daily nutrient level estimated to meet the requirements of half the healthy individuals in a particular life stage and gender group (NHMRC 2006)