Health Concern: FAT? continue...

How much Fat do you Need?

Very little. Just about any food you can think of contains some fat, and when your diet is made up of at least 75 percent vegetables, fruits, and grains with a few nuts and seeds but without added oils, fats, cheese, or butter, as in the Lifestyle Diet, about 15 percent of your calories will be in the form of fat anyway. This is all you need. The body is capable of making its own fatty acids from the foods you eat with the exception of linoleic acid, and the mere three grams you need per day is more than supplied by eating a couple of tablespoons of sunflower seeds or one small dish of oatmeal. Even leafy green vegetables such as kale or spinach contain about 10 percent of their calories in fat. It is hard to be fat-deficient. Studies of people put on very low-fat diets, even when as little as .7 percent of their calories are taken in the form of fat as linoleic acid, have shown no adverse physical or psychological effects.

Even official bodies have recently begun to recognize the need to reduce dietary fats for the sake of preserving health. The U.S. Senate's Select Committee on Nutrition and Human Needs recommended in its report "Dietary Goals for the United States" a reduction of fat intake from the present 45 to 30 percent as well as a decrease in sugar consumption to 15 percent of total calories and a corresponding increase in the consumption of complex carbohydrates—the fruits, vegetables, and grains that are the foundation of the Lifestyle Diet. For long-term health and beauty, you should make an even greater reduction so that only about 15 percent of your daily calories are taken in fat.

This is in line with the Pritikin and other low-fat, low-protein diets which have recently caused great interest in both the medical profession and the general public. Pritikin recommends a diet of 80 percent complex carbohydrates, 10 percent protein and 10 percent fat. Although a radical departure from the traditional British, European, and American dietary habits, regimens like the Pritikin diet can not only substantially reduce cholesterol and triglyceride levels, high blood pressure, and high blood sugar, but can also lead to an automatic weight loss and leave people feeling and looking years younger. Such a low protein, low fat diet can also literally beautify a woman both physically and psychically.

At first such a change takes a bit of getting used to, but soon it becomes second nature and the increased vitality, slimness, and good looks it brings you in a few weeks help make it an easy way to eat permanently.

When these are broken down slowly throughout the day, they provide the pancreas with a steady flow of glucose at a rate of about two calories a minute. When you eat something sweetened with refined sugar, the glucose poured into the system (say 100 calories or more all at once) suddenly soars. So does the production of pancreatic insulin in reaction to the insult. When this insult occurs repeatedly, as it does in the usual Western diet, with its average of two pounds of sugar per person per week, the blood sugar levels become depressed, then soar, then become depressed over and over again by a pancreas made trigger happy. In many people this leads to hypoglycemia or low blood sugar, with its corresponding fatigue and mental and emotional symptoms. It can also result in diabetes and in the development of allergic reactions to foods and to petrochemicals, which have recently been linked with diverse mental disorders as well as many acute and chronic forms of illness.

Repeated eating of sugar and products containing it can also result in deficiencies in the B-complex vitamins and an imbalance in certain important minerals. And just in case you are reassuring yourself that you, after all, only eat raw sugar, you should know that one sugar is just about as bad as another. Raw sugar does contain some of the natural vitamins, minerals, and fiber that are found in the sugar beets or sugarcane from which the sugar has been taken but raw, brown, and turbinado sugars are all still highly concentrated simple sugars which create the same metabolic problems as white sugar. As such, they are potential disease-makers. The Lifestyle Diet excludes every form of refined sugar—from chocolate to jams to packaged breakfast cereals with their hidden sweetness. It does allow a little honey for sweetening muesli (two tablespoonfuls a day) plus one tablespoonful of blackstrap molasses if you want it for its nutritional value.

The GI of food: How low should you go?

Just as all kilojoules are not equal, so all carbohydrates are not equal. Extensive and in-depth clinical trials and studies over the past decade or so have brought about what has become known as The Glucose Revolution, which also happens to be the title of a world best-selling book by Australians Professor Jennie Brand-Miller, Kay Foster-Powel and Dr Anthony Leeds.

Carbohydrates always used to be regarded as the main reason for obesity. Regrettably that theory has remained stuck in the minds of many people in the medical profession and slimming industry and to this day many dieters are following low-carbohydrate diets - much to their detriment, as you know.

Well, here is what every dieter should know about starch: forget all that tripe you were taught and start eating your starches, but eat them wisely. Eat mainly starches with a low GI (Glycaernic Index).

The GI of food indicates the way it scores according to its effect on your blood sugar levels. Carbohydrate foods that are rapidly converted to glucose during the digestive process and therefore rapidly increase your blood sugar (glycogen) levels, have high GI values. Carbohydrates that break down slowly, naturally release their glucose into the bloodstream at a slower rate, therefore raising blood sugar levels at a slower rate. At the school we call this the 'carbo speedometer'. Of all foods, refined sugar (sucrose) and glucose have the highest GI, namely 100. All other foods are rated on a scale from 0 to 100 according to their effect on the blood sugar levels, or to put it plainly, the rate at which they drip into your bloodstream.

Much has been said about the incredible weight-loss benefits of the so-called Mediterranean diet. The popular belief is that it works so well because of the good fats found mainly in the olives and the oily fish prescribed in this diet. Yes, that is true. However, the other main reason for its success seems to have been overlooked. In fact, it is probably the most important reason why it is such an effective, healthy and delicious diet - it also offers loads of (and mainly) low GI starches. That includes beans, pulses and pasta to name but a few, Paradoxically, the one flaw in this diet is the fat: too much of the 'good' fat can make you as fat as bad fat does. And on this diet you are allowed to consume far too much of that lovely good fat! Just think of those tables groaning with tappas and antipasti.

That diet aside, following a low GI eating plan will, in my opinion, be the very best you can do for your weight loss efforts, mainly because of the way in which you are able to manipulate and control your blood sugar levels and consequent insulin production.

The main benefits of low CI foods

• They cause a gradual rise and fall in blood sugar levels, thereby causing lower insulin levels, which makes it easier for fat to be burnt and less likely to be stored.
• They assist in lowering blood fats.
• They are more bulky and are therefore more satisfying.
• They reduce the risk of diabetes and heart disease.

Can sugar change your behaviour?

Hypoglycaemia - believed by some to be the cause of behavioural changes such as hyperactivity - has become one of the buzzwords of the past few years. Unfortunately, much of what is believed about it is not based on scientific fact. Firstly, it is not a disease but a condition in which the level of sugar (in this case, glucose) in the blood is below normal. It can occur as a symptom of organic disorders such as diabetes, or as a result of shock or anxiety.

Hypoglycaemia can also occur if for some reason the body loses its ability to maintain blood sugar at a constant level. In this case, eating sugar can result in a rapid rise, then a dramatic drop in blood sugar, with the accompanying symptoms (headaches, weakness, fatigue and dizziness). This condition (known as reactive hypoglycaemia) is very rare. It is difficult to diagnose, partly because the symptoms are so varied and could result from any number of other causes, including anxiety. However, it may well be that some individuals are particularly sensitive to a drop in blood sugar levels after consumption of a sugar load which triggers off the production of just a little too much insulin. Treatment for those who genuinely suffer from this disorder includes cutting out sugar and eating several small, balanced meals a day.

Some people believe that hypoglycaemia is a relatively common disorder and that it is responsible for behavioural changes that occur after eating sugar, such as hyperactivity and even criminal behaviour. In the USA, this theory gained such popularity that the defence used in a certain murder trial was that the defendant had eaten sugar- containing confectionery and was therefore not responsible for his actions! Prison diets were also changed so as to exclude all forms of sugar. Subsequently, however, controlled scientific experiments have failed to show a link between sugar consumption and hyperactivity - some studies have even shown sugar to have a calming effect!

Overweight and Cholesterol intake in your diet

The effect of dietary cholesterol on cholesterol levels in the blood is less crucial and more variable among individuals than the effects of saturated fat - nevertheless, it plays an important contributory role and this is why the recommended limit for cholesterol consumption has been set at 300 mg per day. Of course, the average person has no means of measuring the amount of cholesterol in various foods, but what you can do is identify those which are rich sources and ensure that you eat them in moderation only (see below).

Foods high in cholesterol

Beef, butter, chicken, turkey, duck, cream, all full-cream dairy products, fish, lamb , mutton, pork, tongue

Foods very high in cholesterol

Brains, caviar, egg yolks, giblets, kidneys, liver, prawns, shrimps

These foods are also high in saturated fat and should be eaten only occasionally. (Saturated fats raise blood cholesterol levels far more than does dietary cholesterol in animal foods.)

Overweight and heart disease

The role of obesity or overweight as an independent risk factor for CHD has not been clearly established, but what is known is that it is associated with risk factors such as raised LDL (`bad') cholesterol and total blood cholesterol, lower HDL (`good') cholesterol, hypertension(high blood pressure) and diabetes mellitus. Hypertension is much more common in overweight people; moreover, when weight is reduced and then maintained at a lower level, blood pressure tends to drop as well - if the weight goes up again, so does the blood pressure. There is a particularly strong link between obesity and hypertension in children and for this reason, it is important that children and adolescents do not gain excess weight - in fact, maintaining an ideal body weight should be a goal for the population in general.

Obesity also seems to be a significant, independent predictor of coronary heart disease, especially in women. Although women generally have lower blood cholesterol levels than men, these tend to rise after the menopause. Smoking also seems to be on the increase in women and this can be an important contributory factor. It has been shown that if you are overweight, a cigarette smoker and you take oral contraceptives, your risk of having a heart attack increases significantly.

In summary, the maintenance of ideal body weight by means of a combined diet and exercise programme makes good sense because of the relationship between obesity and an increased risk of heart disease. Also, for a large number of people who suffer from hypertension, weight control can be an effective way of treating the problem and may prevent the necessity for drug treatment.

Must Know: Facts about fat in Your Diet

Although the effect of the total amount of fat in the diet on blood cholesterol levels has been well documented, the most important effectrelates to the type of fat.

Saturated fats have a profound hypercholesterolemic effect (in other words, they increase blood cholesterol levels significantly) and simultaneously increase concentrations of LDL or 'bad' cholesterol. Sources: Saturated fatty acids are found in both animal and plant products, but animal products (such as butter, cheese, full-cream milk, cream, ice-cream, beef, pork and lamb) are the major source of saturated fat in the average South African diet. Similarly, hard or brick margarine (the product packaged in a wrapper) is high in saturated fat; soft of 'tub' margarine is the healthier alternative, since it is low in this type of fat and higher in polyunsaturated fats. Using a polyunsaturated fat will also help to improve your P:S ratio (see below). Coconut oil, cocoa butter, palm oil and palm kernel oil are common 'saturated' vegetable fats which are generally found in many commercially baked goods such as biscuits, also in non-dairy creamers, cake mixes and chocolates. Read labels carefully if youwant to avoid these products.

Mono-unsaturated fats were previously thought to be 'neutral' intheir action on blood cholesterol levels, but recent studies suggest that these fatty acids may play a useful role in the dietary prevention of CHD, since they appear to have most of the benefits of polyunsaturated fatty acids.

Sources: Olive oil, avocado pears and nuts are rich sources of monounsaturated fat.

Polyunsaturated fats lower blood cholesterol levels as well as the concentraton of LDL cholesterol.

Sources: Sunflower oil, tub margarine.

There are two classes of polyunsaturated fatty acids, namely omega-3 and omega-6, which have a variety of functions in the body. Omega-3 fatty acids are found in some vegetable oils and, in particular, in fatty fish. Eicosapentanoic acid (EPA) - a fatty acid which falls into thissub-class - is derived from fish and is highly concentrated in fish oils. Research suggests that this fatty acid may play a beneficial role in a diversity of biological processes including arthritis, eczema and even cancer. However, the role of omega-3 fatty acids - and specifically EPA - in the treatment of hypertension and raised serum cholesterollevels remains controversial.

It seems from studies done so far that fish and fish oil supplements may lower triglyceride levels, reduce clot formation, decrease blood viscosity (or thickness) and lower blood pressure levels. However, the optimal doses of these fatty acids have not been established and until answers to these questions are known, the widespreadsupplementation of omega-3 fatty acids is not recommended. It is a better idea to substitute fish, especially fatty fish (such as salmon, galjoen, snoek, pilchards and tuna) as a source of protein in two or three meals a week, thus consuming a whole spectrum of nutrients and not just a single fatty acid fraction.

The P:S ratio

The ratio of polyunsaturated to saturated fatty acids in a diet is known as the P:S ratio. The typical South African diet has a P:S ratio of 0.5:1.0 (in other words, twice as much saturated as polyunsaturated fat). However, the eating plan recommended for the prevention of CHD suggests a ratio of at least 1:1 (or an equal quantity of both), which for most of us means restricting our saturated fat intake and replacing it, where practical, with polyunsaturated fat such as fish or sunflower oil. Most of the comparisons between the effects of saturated and polyunsaturated fat have indicated that gram for gram, the blood cholesterol-raising effect of saturated fat is up to two times greater than the cholesterol-lowering effect of polyunsaturated fat.

Many studies have shown that so-called 'intervention trials' aimed at lowering raised blood cholesterol levels, reduce the CHD risk and slow the progress of arterial damage. These studies provide strong support for recommendations for a considerable overall decrease in dietary fat by the general public, from the present 35-38°/o to 30% of total kilojoule intake, and a decrease in saturated fat to 10% of total kilojoule intake.

Hints from Dietary recommendations to see how important is diet?

How important is diet?

There is a lot of international and local evidence to suggest that diethas a significant effect on many of the risk factors associated with coronary heart disease. As already discussed above, the most important of these - as regards both the cause and the treatment of CHD - is hypercholesterolaemia or a high blood cholesterol level.

The second important risk factor which is obviously linked to diet is overweight - or its exaggerated form, obesity - which in turninfluences both blood cholesterol and blood pressure levels. Tocomplicate matters, overweight sometimes develops when another risk factor such as cigarette smoking is stopped. Finally, the third riskfactor - hypertension or high blood pressure - is greatly affected by dietary sodium (salt) and possibly potassium consumption.

In view of all the above and because of increased concern about the high incidence of coronary heart disease in this country, SouthAfricans are being urged to change their eating habits significantly or face the fact that they could become part of the statistics.

Dietary recommendations

• Total fat intake should not exceed 30% of total daily kilojoule intake.
• Intake of saturated fatty acids should be no more than 10% of daily energy intake.
• Intake of poly-unsaturated fatty acids should not exceed 10%. * Intake of trans fatty acids should be limited.
• Cholesterol intake should not exceed 300 mg per day.
• In cases of under-nutrition, relevant and affordable protein sources
  should not be limited for the sake of limiting cholesterol intake.
• Salt intake should be limited to 3 g of sodium per day (which amounts to 7,5 g or 1¹/₂ teaspoonful of salt per day or 1 teaspoon plus that which is present in foods.
• Fibre intake should be kept at 20-30g per day in the form of fresh,unrefined foods.
• The maximum daily intake of alcohol should be 2-3 tots (10-20 g).
• Ideal weight must be maintained through adequate physical exercise and controlled food intake.

Hypertension - the 'silent' killer

Apart from being one of the three major risk factors for CHD, high blood pressure is also the single most important risk factor for cerebrovascular disease (strokes). Hypertension affects one in five people in South Africa - yet many are unaware that they suffer from it until a routine medical check-up reveals the problem.

The specific causes of 95% of hypertension cases are unknown, although it is clear that certain dietary factors are important contributors. These include obesity, stress and excessive intakes of sodium (salt) and alcohol. The danger of high blood pressure is that it adds to the workload of the heart and arteries and accelerates atherosclerosis (blocking of the arteries), causing structural changes in the arteries - the higher the pressure, the greater the amount of damage done.

The salt/hypertension link

Evidence that there is an important link between a high salt intake and hypertension is sometimes described as 'circumstantial', but it is nevertheless very significant. While it may be impossible to prove that sodium is a direct cause of the condition, the incriminating evidence seems sufficient to recommend a general reduction in the consumption of salt.

Sodium is an unnecessary supplement to our diet - many foods have a natural sodium content which is quite sufficient for our needs - but we acquire the taste for added salt simply because it is given to us from an early age and it becomes a habit to pour it onto our food. The average South African consumes 10-15 g of salt a day, which is well above the recommended amount of 7,5 g. This includes salt which has been added to processed foods, in home cooking and at the table.

Although many people have normal blood pressure levels in spite of a high sodium intake, the recommendation is that since a low intake has no ill effects - while too much salt clearly raises the blood pressure levels of a large number of people - it makes sense to be on the safe side and either throw out the salt cellar or at least restrict its use considerably.

How fibre affects the body continue...

Appendicitis

Appendicitis is inflammation of the appendix, the small blind-ended tube at the beginning of the large bowel. Although the underlying causes of appendicitis are not clearly understood, there is evidence that regular intake of fibre may prevent the development of the disease.

Hiatus hernia, varicose veins and piles

Many doctors believe that abdominal straining due to constipation encourages the development of conditions such as hiatus hernia (where the top of the stomach is pushed upwards, out of the abdomen and into the thoracic cavity), varicose veins and haemorrhoids (piles). It is often necessary to have surgical treatment for these conditions. Treating constipation with high fibre diets and, as a result, avoiding straining, may prevent these problems and may even reduce the need for more drastic treatment in some cases.

Coronary heart disease (CHD)

Coronary heart disease is the most common cause of death in affluent Western countries (see page 151). A large number of factors influence the development of the disease, of which raised blood cholesterol levels, high blood pressure and hypercoagulability (the tendency of the blood to clot too easily) are probably the most important.

Researchers believe that high-fibre, low fat diets protect against CHD by lowering blood cholesterol and probably also by decreasing blood pressure and the clotting ability of blood. It is especially the water soluble or gel-forming dietary fibres - found in oats, legumes and some fruit and vegetables - which help to lower cholesterol levels. While it should be borne in mind that diet is but one of the many factors which influence the development of CHD, it is also one of the controllable ones.

Diabetes mellitus

There are two forms of diabetes mellitus, a disease characterised by the excretion of glucose (sugar) in the urine (see What is diabetes? on page 175). Both forms are today treated with a high carbohydrate, high fibre, low fat diet. Fibre in the diet normalizes the body's response to dietary carbohydrate (glucose tolerance). A regular high intake of dietary fibre also improves insulin function by increasing the sensitivity of muscle and fat cells to the hormone.

Gallstones

The body manufactures these crystalline substances when the amount of cholesterol in the bile is so high that the bile salts cannot keep it in solution. The stones may block bile ducts between the liver and gall bladder or between the gall bladder and small intestine, resulting in severe pain and even jaundice. As in the case of other diseases of affluence, a number of factors may contribute to the development of gallstones. It has however been shown that high fibre intakes stimulate the production of those bile salts which keep cholesterol in solution, thus decreasing the risk of gallstone formation. Populations who follow high fibre diets have a significantly lower risk of the disease than those on the average refined Western diet.

To what degree is fibre involved?

Although research has proved that dietary fibre has a positive effect on body functions in general, the degree to which it is involved in the risk and development of the above diseases is still unclear. Studies are hampered by the fact that a variety of causes play some role and also because high-fibre diets differ in more than one respect from low-fibre ones. For example, they usually have a lower fat content - especially saturated fatty acids from food of animal origin - and are higher in vitamins and minerals. These factors could add to the beneficial effects seen in people who eat a high-fibre diet.

What is diabetes?

Diabetes is a disorder in which the pancreas cannot produce enough insulin, a hormone which prevents blood sugar levels from rising too high, or in which the insulin that has been produced does not function properly. It does this by helping body cells to take up glucose - either to metabolise to energy or to store as glycogen or fat.

If an individual manufactures too little insulin, there are two possible forms of treatment: The young, more severely affected diabetic can only survive if given daily injections of insulin for the rest of his or her life. However, if diabetes develops at a later age, treatment with pills is usually effective. These pills are not insulin; they are essentially compounds which give the pancreas the necessary stimulus to produce more insulin to cope with the carbohydrate (sugars and starches) which the individual eats. Because sugar causes a dramatic rise in blood sugar levels, diabetics should obviously avoid it in their diets; indeed, they should avoid all unnecessary food in general if they are overweight, as not only is the insulin requirement related to food intake, but excess weight has an aggravating effect on the condition. Obese diabetics who develop the disease in later life can often be treated by diet alone.

A low fat, high fibre intake - which 'dilutes' the contents of the digestive tract - slows down the passage of glucose into the blood stream and hence the elevation of the blood sugar is less dramatic.

Drugs that cause increased excretion of nutrients

Diuretics are frequently taken to correct oedema (water retention) which results from a medical disorder. While they are successful in reducing the excess water level in the body, they also result in the excretion of larger amounts of potassium and magnesium. Patients being treated on a regular basis with thiazide diuretics should therefore increase their intake of foods which are high in potassium such as bananas, orange juice and potatoes.

Alcohol as a drug

Alcohol is regarded as both a drug and a food, since it supplies 29 kilojoules per gram. Because it has mood-altering effects and interferes with the absorption, metabolism and excretion of certain drugs and nutrients, it should possibly be treated with more respect than is usually the case. The reason why the effects of alcohol are felt so swiftly is that it takes a direct route into the system, traveling via the stomach to the small intestine, from where it is quickly absorbed into the blood. A small amount evaporates through the breath and perspiration, but most of it has to be processed by the liver before it isexcreted from the body via the urine.

A regular, excessive alcohol intake decreases the absorption of folic acid, thiamin, vitamin B6, vitamin B12, magnesium, zinc and other trace minerals. High alcohol consumption also tends to go hand in hand with a general decrease in food intake. Alcohol is used as a base in many over-the-counter medications and, ironically, some addicts find all-night chemists a useful secondbest after closing time at the pub!

When combined with the use of other drugs, alcohol can cause serious complications. This is because alcohol itself is a powerful drug and generally speaking, when two or more drugs are taken at the same time they often have a different (and more pronounced) effect than either produces on its own. In addition, if they both act on the same system in the body, their combined effect is often more powerful than might be expected. For example:

• In combination with barbiturates: Both alcohol and phenobarbital (a barbiturate) are depressants. When taken together, even at very low doses, these drugs may increase central nervous system depression and can be fatal.
• In combination with aspirin: Alcohol tends to irritate the stomach lining; when taken in combination with aspirin, which is also an irritant, it can cause internal bleeding.

Other medication: When alcohol is consumed with some antidepressants (ie monoamine-oxidase inhibitors) it may increase blood pressure to a dangerous level. Alcohol combined with antialcohol (Antabuse), antidiabetic and many other medications can lead to abdominal cramps, flushing and vomiting.

Drugs in disguise

Many of us know people who imbibe tea made with loquat leaves for their diabetes, or swear by certain home-brewed herbal mixtures for a multitude of ills. It would certainly be unrealistic to assume that drugs come only in the form of pills or potions created in a laboratory - the early use of the poppy for its narcotic effects is well known - but there are considerable advantages to obtaining one's medication from a pharmacist and not from the garden. These include the fact that the quantity of a compound can be controlled in a pill but not in a leaf, the question of year-round availability and, not least, the convenience.

Some foods are well-known for their adverse drug effects. Liquorice, for example, contains a compound which can cause raised blood pressure if eaten in quantity by people sensitive to this particular substance. Another interesting example (although not of local relevance) is a type of broad bean known as a lava bean' which has a drug-like effect in certain people. Some members of the population in Mediterranean countries have a metabolic defect which causes jaundice, blood in the urine and other symptoms if they eat this variety of bean.