Each food we eat is a chemical kaleidoscope of many different nutrients varying slightly from any other food. Even within the one type, there can be variations. A tomato, vine-ripened, can contain more vitamin C than one brought to maturity in a glasshouse. Orange juice left open to the effects of the air, will lose some of the same vitamin.

Around fifty essential nutrients have been identified in food, and while the body is able to synthesise and metabolise these elements, they must initially be consumed in order for the body to begin to make use of them.

How we choose to mix and match these foods has been the source of much pleasure and pain, experiment and error, throughout history.

PROTEIN

A combination of amino acids, should account for about 12% of our total daily kilojoules. It is needed to create, maintain and renew body cells. Protein also helps form enzymes, antibodies and blood components. Children and adolescents need a higher proportion of protein to their body weight than adults, and pregnant and lactating women, and people recovering from burns and accidents need more protein than an average adult.

CARBOHYDRATES,

which should account for 55-60% of daily kilojoules, are the body's most important nutrient and provide bulk and fuel. Only 15% of carbohydrate should come from simple sugars, with the remainder being from starchy cereals, vegetables and pulses. Carbohydrate is broken down during digestion into components that are absorbed as glucose by the blood stream. Most carbohydrate which is not used for energy is converted to fat, although a small amount is stored as glycogen in the liver and muscles.

I'VE NEVER MET A CARBOHYDRATE I DIDN'T LIKE...

... so goes the caption on a greeting card, but for many people its not a very funny line, especially if they are fighting obesity. Perhaps the best news to come out of modern nutritional research is that carbohydrates are now considered better for you than at any time in the past few decades.

Recent nutritional research has found that fat, not sugar, and definitely not carbohydrates in general, is the problem factor in many diseases such as heart disease, colon cancer, breast cancer, obesity. In addition many unrefined carbohydrates contain fibre that is now thought to be actively helpful in assisting the body to rid itself of the debris left by fat.

Carbohydrate has some winning points in its favour:

• they are found in some of the more attractive foods - bread and grains, fruit and vegetables, potatoes - and can be prepared in a multitude of interesting ways, sparing us boredom.

• the fibre they contain adds bulk to our diet, helping us to feel more satisfied more quickly and for a lower kilojoule cost. This bulk is also healthy for our bowels and is thought to help prevent diseases such as diverticulitis and irritable bowel syndrome, as well as cancer.

• the bulkiness and often the effort we must use to eat carbohydrate foods means we will eat less and so they contribute less kilojoules than fat. A teaspoon of butter or oil contains 150kJ, as many as 2 rounded teaspoons of sugar, or (a better choice) 1/2 a thick slice of wholemeal bread, or a small orange.

• most carbohydrate-rich foods (apart from highly refined ones such as sugar) contain many other nutrients as well, and a varied diet will almost automatically ensure that we have all we need nutritionally.

Perhaps the greatest change in recent nutritional thought has been the revision of diabetic diets to include carbohydrates in greater quantity. Here again, fats have been found to be more of a problem than carbohydrate, even sugar, and the fibre contained in many foods especially grains, pulses and fruits and vegetables, better controls blood glucose and insulin levels and has allowed more flexibility in diabetic diets and better management of the condition

FATS,

which should make up no more than 30% of our total daily kilojoules, are the most concentrated source of kilojoules - double that of carbohydrates or protein. Depending on their chemical structure they may be termed saturated, polyunsaturated or monounsaturated. The less saturated oils, including those containing essential fatty acids such as those present in fish oils, have been found to provide better protection against heart disease.

CHOLESTEROL

WHAT IT IS

A white waxy substance natural in the human body and the body's requirements can be naturally produced by the liver. Fats in the diet, unsaturated as well as saturated, affect cholesterol levels even more than the cholesterol we consume.

WHERE IT IS

Excess cholesterol can build up in arteries causing atherosclerosis that in turn heightens the risk of stroke, heart attack, blindness, kidney failure, impotence and normal circulation of the blood. Cholesterol in food is only  found in food from an animal origin, never from plants.

WHY IT IS

Cholesterol is essential for life and is part of all cells.

AND WHEN IT IS – OK

A blood cholesterol reading of 4.2-5.4mmol/litre is considered average. Below this is considered low risk, above is high or very high, depending on the reading.

HOW TO MODERATE CHOLESTEROL IN YOUR DIET

Monitor your total fat intake from all sources, not just animal products - 20-30% of total calories is thought to be a safer intake than the national average of 40%. Where possible use monosaturated fats such as canola or olive oils, avocados, seeds or nuts, and oily fish. Limit cholesterol to around 300mg daily.
Maintain healthy weight.
Exercise regularly.
Consume the recommended amount of fibre, preferably from a variety of sources.
Drink plenty of water.

LOWER FAT EATING

In recent years, with the increased interest in and concern about our health, the eating public have been bombarded with a new language. The scientific jargon used to describe the fats we eat and their effect on our body, rather than enlighten us, has often just confused us more, resulting in some strange misunderstandings. We have all seen avocados with 'Cholesterol Free' stickers on them. Are they different to their un-stickered mates in the fruit market? Of course not. All avocadoes, because they are from a plant origin are free of cholesterol. Yet some fruits or vegetables have saturated fat, some are unsaturated and still others are monosaturated. Confused? It's no wonder. Let's try to demystify the vocabulary.

DEFINITION OF TERMS

Saturated fats are fats that are solid at room temperature and generally come from an animal source. Here we have  butter, lard, suet and dripping. Be careful though. Cream is saturated, but because it also contains milk (read the label – it may be 35%, 40% or even 48% fat) it remains liquid. Coconut oil is interesting, as even though it is from a plant source, it still hardens at room temperature e.g. copha. Palm oil, widely used in the manufacture of confectionery, cakes and biscuits is also saturated.

Monosaturated fats are preferable because they help the body to deal with cholesterol obtained from other foods. Three of the most importantly commonly available monosaturated  oils are those found in avocados, canola and olives. Tests and research carried out on people from Mediterranean countries, for instance point to the fact that the use of monosaturated oils actually reduces the amount of cholesterol in the blood. It is believed that the increased HDL's are able to clean excess cholesterol from the blood vessels and keep the body at a healthy equilibrium.

Polyunsaturated fats are found in most nut, seed and vegetable oils. Traditionally they have been used either in combination or with dairy foods to make margarine and cooking oils.  It was originally believed that this would be a preferable and healthier alternative to butter and other saturated fats, but recent studies now suggest that this was often a misguided belief. The very process necessary to make margarine – that of beating the oil – actually saturated it. We can see how saturated margarine is by its relative firmness at room temperature.

Cholesterol is a fatty substance made in the body by all animals, including humans and is essential to the health of the body. The problem comes when our intake overtakes our needs.  The first and most visible effect is that we will become obese and our bodies may then convert fat into blood cholesterol. It is then likely that deposits will form in our arteries, building up over a period of time like clogged drains. Eating large amounts of cholesterol will not raise our blood cholesterol levels if we are healthy, but because we are consuming more energy (kilojoules) than our body needs, we may put on weight. Cholesterol can also be raised by the consumption of cholesterol-free saturated fats.

There are five types of cholesterol present in the body, the most important being HDL's and LDL's. Current medical opinion believes that the ratio of these two is more important than cholesterol levels.

• LDL stands for low-density lipo-protein cholesterol and is believed to be the factor that correlates with heart disease and fatty build-ups on artery walls.

• HDL stands for high-density lipo-protein cholesterol, believed to actually aid the body is clearing excess cholesterol from the arteries.

WHICH FATS AND WHY AND WHEN?

Fats and oils provide more kilojoules gram for gram than any other food. Simple arithmetic immediately shows us that while we may be getting a terrific energy package, the nutritional backup is out of balance. Fats and oils do contain vitamins A and D, but other foods also provide vitamin A, and sunlight helps us make our own  vitamin D.
Oils are 100% fat, but butter and margarine, because they contain milk or water are around 80% fat. For example, when substituting oil for butter use approximately 1/3 - 1/5 less.
People in many affluent Western cultures find that over 50% of their energy intake is supplied by fats. This is very high and can cause the exclusion of other more important foods from the diet. Fats give a sense of satisfaction – they fill us up ­– and may cause us to eat less of other bulkier, more nutrient-rich foods. Nutritionists and physicians are suggesting that no more than 30% of energy should be supplied by fat and that 15-20% may be even more beneficial.

STRATEGIES FOR SUBSTITUTING FATS IN THE DIET

Spreads:

Look for the lowest fat spread you enjoy and use it. Butter and margarine have 4g of fat in every teaspoon. Light cream cheese has .8g. Natural yoghurt, jam, tomato sauce and chutney have even less. Avocado is a high fat fruit but its monosaturated benefits make it worth considering – half a medium one (135g) has 20g fat or equal to 5 teaspoons of butter, but without the cholesterol.

Frying:

Oil is 100% fat, but you can reduce the amount you use or omit it entirely by using non-stick pans. Cook with half water-half oil to retain some of the flavour and  browning, crisping effects of oil, but to halve the amount of fat. As the food cooks the liquid evaporates and the remaining oil continues to fry the food. You could substitute wine or fruit juice for water for a different flavour, or poach food entirely in liquid. If frying in oil, cook at the correct temperature so that the food does not soak up excess oil and when cooked, drain thoroughly on kitchen paper or paper towels. Olive or canola oils, because they are monosaturated, are preferable to saturated ones.

Food preparation:

Trim fat from all meat, skin chicken and fish, (although the Omega 3 fatty acids in most fish are beneficial).  Be aware of the fat that is present within meat as well as around the cuts. Well-marbled meat may be superior in flavour but it is heavier in cholesterol. Ask for lean cuts.

Shopping:

Manufacturers are becoming more aware of consumer's needs and preferences. It is now possible to buy reduced fat cheese in the block, or sliced and grated. There are low-fat yoghurts, sour cream, ricotta and cream cheese and many processed meats and bakery items that bear the label 'Fat Reduced' or others such as '95% fat-free'. Check carefully. Some may be as misleading as the 'Cholesterol Free' avocado stickers. Some foods may be 95% fat free in any case, but because of the relatively large amount needed to make up a serving, you are bound to consume a large amount of fat grams.

LOW FAT SAUCES

It is so easy to add many grams of fat (and of course hundreds of kilojoules) with sauces. Here are a few that won't break the daily fat budget:

• No-fat mayonnaise or dressings - look for them in the supermarket
• Tomato sauce
• Chutneys
• Chopped herbs mixed with skim yoghurt
• Onions 'sauteed' in water or low-fat stock, then pureed
• Cooked and pureed carrots or pumpkin, seasoned with herbs or curryCooked apple, pureed and seasoned with lemon juice and cinnamon
• Pureed mango or pawpaw with coriander
• Salsas made by combining fresh fruit, onion, herbs and seasoning
• Skim ricotta or cottage cheese pureed with herbs and cooked vegetable or fruits
• Mashed avocado and yoghurt, seasoned with chilli and coriander
• Watercress pureed with a little consomme or juice
• V8 juice thickened with cornflour.

Vitamins are only needed in small amounts and are called micronutrients. There are thirteen known vitamins, and they are vitally important to regulate metabolism and chemical reactions in the body and assist in the use of other nutrients.

Vitamin A

• also called retinol in animal foods and beta-carotene in plant sources
• useful for maintaining good vision and normal growth and development
• found in bright orange and dark green vegetables and fruits, liver, fish liver oils, butter, margarine, egg yolk

Vitamin B1

• also called Thiamin
• useful for metabolising carbohydrates and regulating the heart and nervous system
• found in wholegrain products, yeast and yeast spreads, milk

Vitamin B2

• also called Riboflavine
• useful for assisting metabolic function and growth
• found in milk, meat, eggs, grains and cereal products, and yeastVitamin B3also called Niacin
• useful for regulating the nervous system, gastrointestinal tracts and skin and manufacture of fatty acids
• found in meat and poultry, bread and cereals, and yeast

Vitamin B5 (sometimes called B3)

• also called Pantothenic acid
• useful for metabolising carbohydrates, fats and proteins and formation of certain hormones, and for regeneration of tissue.
• found in meat, vegetables, rice, and bran

Vitamin B6

• also called Pyridoxine
• useful for metabolising fat and protein, energy production and brain and nervous system health, and helps in the formation of red blood cells
• found in meat, liver, poultry, fish, bread and cereals, legumes, eggs, avocados and bananas

Vitamin B12

• also called Cyanocobalamin
• useful for the production of red blood cells, the health of the nervous system, and interacts with folic acid
• found in all animal sources such as meat, fish, milk, cheese, eggs and fermented foods such as mis

Folate

• also called folic acid and folatin
• A B-group vitamin necessary for cell growth and division and the metabolism of protein. Works with B12 for the formation of red blood cells
• found in liver, kidneys, eggs, wholegrain cereals, green leafy vegetables, corn, nuts, legumes, yeast, oranges, bananas and avocados.

Vitamin C

• also called Ascorbic acid

• useful for keeping bones, teeth and blood vessels healthy, aids in the absorption of iron, growth and repair of tissue, and as a ‘free-radical’ scavenger, helping the body to detoxify and resist diseases

• found in all fruits and vegetables, especially citrus, parsley, capsicums, blackcurrants

Vitamin D

• also called Calciferol
• useful for assisting the body to use calcium and phosphorous to ensure strong teeth and bones
• found in fatty fish, margarine, foils and egg yolk and formed by the body when exposed to sunlight

Vitamin E

• also called Tocopherol
• useful as an antioxidant, protects essential fatty acids and promotes health of red blood cells, muscle and tissues, and acts as a ‘free radical scavenger’ helping the body to detoxify and resist diseases
• found in polyunsaturated seed oils, wheatgerm, egg yolk, tuna, avocados, asparagus and broccoli

Vitamin H

• also called Biotin
• useful for metabolising carbohydrates, fats and protein
• found in egg yolk, beef liver and yeast

Vitamin K

• (no other name as it refers to group of compounds)
• useful for blood clotting
• found in green leafy vegetables and liver, and is also produced in the intestine. Lactobacillus, found in yoghurt, helps to facilitate this production.

Vitamin P

• also called Rutin
• useful for blood vessel stability
• found in buckwheat

Minerals:

Minerals occur in minute amounts in food, yet without them we would not survive. They regulate water balance, nerve responses, chemical reactions, and muscle contraction. At least 17 trace minerals have been identified and each has a different specific and vital use in the body.

Calcium

• useful for the health of bones and teeth, cell maintenance and correct nerve and muscle function
• found in dairy foods, seeds and nuts, canned fish with bones, meat, cereals, legumes and green leafy vegetables

Chromium

• useful for the regulation of blood sugar
• found in brewer’s yeast, kiwi fruit, meats, liver, oysters cereals, yeast and egg yolk

Iodine

• useful for enabling the thyroid to manufacture regulatory hormones essential to the metabolic rate of the body
• found in seafood, meat, milk, cheese, and cerealIron
• useful for forming haemoglobin, essential for oxygenation of the blood.
• found in lean meat, liver, kidneys, chicken, fish, green leafy vegetables and legumes

Magnesium

• useful for normal muscle contraction and nerve transmission, and energy release of food components
• found in seafood, nuts, meats, cereals, and legumes

Phosphorus

• useful for partnering calcium to form bones and teeth, and helps B vitamins function
• found in all natural unprocessed foods

Potassium

• useful for working with sodium to regulate heart muscle contraction, and nerve impulse transmission, as well as regulating fluid balance, blood pressure and volume.
• found in all natural unprocessed foods, especially bananas, milk, orange juice, dried fruits, meat, peanut butter and potatoes

Selenium

• useful as an antioxidant, interacting with vitamin E
• found in meats, seafoods and cereals

Sodium

• useful for working with potassium to regulate heart muscle contraction, and nerve impulse transmission, and regulating fluid balance, blood pressure and volume.
• found in all natural processed foods which have a good balance of sodium to other nutrients. Difficulties arise in cooked or processed foods where sodium has been added

Zinc

• useful for formation of insulin, cell health, and production of protein.
• found in muscle meats, organ meats, beans, nuts, cereals, eggs, oysters

Water:

Water is the most important of all nutrients and is essential to replace fluid lost from the body each day due to normal processes, maintaining a normal temperature, transporting wastes for elimination, and aiding metabolism.

Dietary Fibre is found only in foods of a plant origin and is generally not broken down by enzymes in the small intestine. Some fibre is partially broken down in the large intestine and used for energy, and soluble fibre, such as that found in barley, oats and legumes, and some fruits, is believed to be helpful in regulating cholesterol in the blood and controlling blood sugar levels.

FIBRE FACTS

Once there was wheat bran, and those that thought they should struggled down a couple of tablespoons each morning on their cereal. This done they wondered why they didn't always have the result they expected.

Then came other brans - oat, barley, rice - with added claims. These would help prevent heart disease, whisk out our cholesterol and keep us regular as well! And with that came CONFUSION. Just what fibre do we need? How much? How often? Why?

To simplify:

• Fibre is only found in plant foods.

• It is indigestible.

• It helps intestinal health, bowel regularity, benefits diabetes and blood cholesterol levels, assists weight control, and is thought to help prevent colon cancer.

• We each should eat 30-40 grams a day.

• There are two types of fibre - soluble and insoluble and we need a combination of them.

• We can increase our fibre intake by:

• Eating a high-fibre breakfast (wholemeal toast, fresh fruit, nuts, whole grain cereal or added bran cereal)

• Eat wholemeal bread or crispbreads

• Increase the amount of fruit and vegetables eaten and use the skins and seeds when possible

• Enrich home cooked cakes, biscuits, pastries, desserts, rissoles and meat loaf recipes, casseroles and soups with whole flour or oats, nuts, seeds or bran

• Choose snacks like fruit (fresh or dried), nuts or seeds, fresh vegetables, wholegrain crispbreads or popcorn.