Health Concern: FAT?

The term "fat" includes fats from meat, fish, poultry, and dairy products as well as vegetable oils and the nuts, seeds, and grains from which they have been extracted. There are two basic kinds of fats—saturated, occurring mostly in animal foods (although some vegetable fats such as the kind that coconut contains fall into this category too), and unsaturated, in the form of vegetable oils such as safflower, corn, and sunflower, and in seeds and nuts. Fish tends to contain more unsaturated than saturated fats, meat more saturated than unsaturated.

Whether saturated or unsaturated, all the fats you eat rapidly form a film around blood cells and platelets, creating a kind of sludge which causes them to stick together. This clumping significantly interferes with circulation by clogging blood vessels and even temporarily closing down small capillaries. As a result, your cells do not receive all the oxygen and nutrients they need to function efficiently. They only run at about 80 percent capacity. This interferes with cell metabolism as well as with the efficient elimination of cellular and tissue wastes.

The chemical structure of an unsaturated fatty acid differs from its saturated brother in that at least two of the carbon atoms in its formula are free. This means that they have no hydrogen atoms attached to them, as the molecule of a saturated fatty acid does. It was long thought that while saturated fats were bad for you, unsaturated fats were good. For unsaturated fats have been shown to reduce cholesterol levels in the blood, and therefore were believed to be helpful in preventing arteriosclerosis and coronary heart disease. That is the reason we have been encouraged in the last thirty years or so to include plenty of polyunsaturates in our diet by switching from butter to margarine and vegetable oils. The catch is that although unsaturates do this, like all fats they still raise triglyceride levels (another factor linked with coronary heart disease) and they also create the same clumping as the saturated fats do, which leads to tissue anoxia.

Women have also lately been encouraged by poorly informed writers to include lots of polyunsaturates in their diet for their beauty's sake. Unsaturated fatty acids are an important constituent of skin and muscle tissue and so it was thought, quite wrongly, that we need more of them. For what we have not been told is that the chemical structure of unsaturated fats with their free carbon atoms makes them extremely unstable compounds, and that when an unsaturated fat is exposed even to the smallest trace of a catalytic agent it begins a process of autooxidation which results in the fat molecule's breaking down to produce what are known as free radicals.

Free radicals are highly reactive particles which, if left unchecked in the presence of oxygen molecules, will form toxic peroxides. These peroxides can damage and destroy cells. They have also been implicated as a primary cause of the aging process itself. When a cell, or the genetic material of a cell, is destroyed by free radicals, the result is something known as a lipofuscin pigment granule—often referred to by biochemists as a "clinker." With age, ever more cells are damaged or destroyed as tissue degenerates, leading to increase in the number of these pigment granules. This is something you want to avoid in every way you can if you don't want to look and be old before your time.

To some extent, the presence of sufficient amounts of an antioxidant such as vitamin E in the system may prevent this from happening, because it minimizes the damage done by free radical chain reactions by breaking the chain. Vitamin E, like other antioxidants, helps block the oxidation that turns fatty acids into harmful peroxides. The more unsaturated fatty acids in your diet, the greater will be your need for the vitamin.

An interesting dietary survey that was done at the University of California at Irvine looked at over 1,000 patients and examined the degree of wrinkling and crow's-feet, frown lines, and other indications of skin degeneration such as damage to the collagen and elastin fibers and the irregular pigmentation characteristic of old skin. The subjects ranged in age from seventeen to eighty-one and 76 percent of them were women. Cadvan Griffiths, M.D., the professor of surgery who carried out the study, discovered that there is an undeniable link between marked clinical signs of aging and the intake of unsaturated fats in one's diet. Those who regularly and frequently included polyunsaturated fats and oils in their diet had marked signs of premature aging. Some looked as much as twenty years older than they were. Very few of those who had made no special effort to eat more polyunsaturates showed any clinical signs of premature aging. Evidence is also accumulating that links free radical reactions to the etiology of cancer, senility, atherosclerosis and hypertension—all of them disorders generally associated with aging. This is all the more reason to limit the amount of every kind of fat you eat to no more than you actually need.

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.

Dieting Factors that Affect Hypertension

There is some evidence that an increase of potassium, calcium and magnesium in the diet may help to lower blood pressure. But a great deal of research still has to be done into this subject and it is too soon to recommend that people take mineral supplements for the control of hypertension. Similarly, although it is thought that omega-3 and omega-6 polyunsaturated fatty acids may decrease blood pressure, further research is needed before recommendations can be made.

Alcohol as a risk factor

Excessive alcohol consumption - defined as more than two drinks daily - is linked to both high blood pressure and high cholesterol levels. HDL (cholesterol) levels tend to increase with an increase in alcohol intake, but the risks associated with a moderate alcohol intake (1-2 beers or 2 glasses of wine or 2 tots of whisky or brandy per day) appear to be no higher than those of abstainers; however, heavy drinkers have increased levels of most of the coronary risk factors.

Interestingly, results of the CORIS (Coronary Risk Factor) Study - which involved men as well as women - showed that blood pressure and cholesterol levels tended to be slightly lower in light drinkers than in both heavy drinkers and in those who don't drink at all. A moderate alcohol intake therefore seems to be associated with lower blood pressure levels and also appears to protect the individual from cardiovascular risk and mortality. However, the serious medical and social problems associated with alcoholism should discourage any increase in alcohol consumption.

Breaking new ground

As research into the causes of heart disease continues, additional factors come to light which appear to be relevant in the prevention of CHD. Sometimes, however, it can take years before a suspected link is proved scientifically.

The fat/fibre connection

Recent studies on the role of dietary fibre in lipid (fat) metabolism have shown that fibre can have a positive effect by interfering with the body's absorption of fat. It has also been proved that dietary fibre - and especially water-soluble fibre, which is found in dried legumes, oats, oat bran, apples and oranges - has a cholesterol-lowering effect. It is not yet clear what precise mechanism is involved. Because of its obvious benefits in this and other areas, we should all increase our intake of dietary fibre to at least 20-30 g a day. This can be achieved by eating unrefined cereals, more wholewheat bread, fruit and vegetables and by substituting dried legumes (such as beans or lentils) for animal protein at least once per week. An additional benefit of a high fibre diet is that it is also high in complex carbohydrates - a good substitute for fat in the diet.

The vitamin controversy

The role of vitamins in the prevention and treatment of coronary heart disease is controversial and much research is still being done in this area. It has been suggested - but not proved conclusively - that ascorbic acid (vitamin C) and vitamin E may have a protective effect in the early stages of atherosclerosis (blockage of the arteries). Niacin (one of the B-complex vitamins) is often combined with cholesterol- lowering drugs used to treat high blood cholesterol levels. However, there is not sufficient proof as yet to suggest that vitaminsupplementation will lower anyone's risk of developing coronary heart disease.

Cholesterol-lowering Eating Plan

The Heart Foundation has given the following guidelines for achieving the goals of the Prudent Dietand maintaining low blood cholesterol levels:

• Eat less fat and substitute unsaturated for saturated fats. One of the major goals of a cholesterol-lowering eatingplan is to eat less total fat, not only because this is an effective way to reduce the amount of saturated fat in your diet, but also because it helps to decrease your total daily kilojoule intake.
• Cut down on foods of animal origin. Dietary cholesterol found in these foods raises blood cholesterol levels significantly.
• Eat more complex carbohydrates, especially those rich in fibre. Good sources include wholewheat bread, brown rice, pasta, cereals, dried peas and beans, fruit and vegetables. (Fibre - especially the water- soluble type found in oats, oatbran, some fruit and legumes - may even help to reduce blood cholesterol levels.)
• Avoid being overweight. To achieve or maintain your ideal body weight, your kilojoule intake should not exceed the number of kilojoules your body needs.
• Use less salt (sodium). A high sodium intake may cause high blood pressure. Cut down on the salt you use at the table and in the preparation of food. Be aware of the 'hidden' salt in commercial foods.
• Limit your alcohol intake. A moderate intake is regarded as two drinks (2 glasses of wine, 2 x 25 ml tots of spirits or 1-2 beers) per day. If you are overweight, avoid alcohol entirely.

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.

What are the choices?

First let's look at the choices open to you, which also happen to reflect three different 'schools of thought' on the subject of diet and cancer:

The first choice is to carry on as before, on the grounds that there is still controversy over the extent to which diet is involved in cancer development, that the changes you would have to make are huge and unacceptable, that success is not guaranteed and that in any case there is a large element of individual susceptibility.

Next, there is the stance of the 'activists' who believe that the evidence available is very convincing, that major changes are needed and that they can be put into practice. If you take this approach, you will find a good deal of support in the marketplace, since food products with a low energy or fat content and/or which are high in fibre are becoming more readily available.

Many in this activist group take the holistic approach to avoiding disease, in other words, they believe that we should improve our diets so as to protect ourselves against all diet-related 'killers', not only cancer. Sir Richard Doll, a well-known British medical statistician, expressed this attitude in his 1982 Harveian Oration in London on 'Prospects for Prevention', when he urged:

'...whether the object is to avoid cancer, coronary heart disease, hypertension, diabetes, diverticulitis, duodenal ulcer or constipation ... the type of diet least likely to cause disease is one that provides a high proportion of calories in whole grain cereals, vegetables and fruit; provides most of its animal protein in fish and poultry; limits the intake of fats and if oils are to be used, gives preference to liquid vegetable oils; includes very little dairy produce, eggs and refined sugar; and is sufficiently restricted in amounts not to cause obesity'.

The third group recognizes the truth of the evidence put forward and accepts that dietary changes are required. But their view is that what is needed is simply to eat less and to practice moderation, even to the extent of cutting out alcohol and rich foods. This was the attitude taken by Hippocrates, Galen, Moses Maimonides and numerous other great physician-philosophers of the past.

The bottom line

Firstly, in spite of what might be regarded as a pessimistic tone to this chapter, it must be emphasised that what has been given here is an overview. The results of research may certainly give the experts good cause to be pessimistic - but remember that they deal in statistics. As in so many areas of life, if you as an individual are motivated enough to make the necessary changes, you can make the difference - to yourself and possibly to your family. In fact, considering the wealth of information now available, the prospect of taking individual avoiding action has never been better!

A diet which supplies 25% of energy from fat, and which contains 30g of fibre on a daily basis can certainly be formulated and could, with determined effort, become your personal norm. To do this you will probably have to eat far more of cereal products (which include whole grain breads, unrefined rice and breakfast cereals) and increase your vegetable and fruit intake considerably. You may also have to combat conservatism, inertia and lack of conviction and get used to a 'less palatable' diet - at least until you begin to enjoy foods that are closer to the way nature intended them to be!

It is important to realise that our eating habits are just that - habits - which we have learned and are capable of 'unlearning' if necessary. We don't come into the world craving over-refined breads, fried foods or creamy desserts; our tastes are developed from an early age in our own homes (which is why parents have a particularly important responsibility to guide the development of those tastes). A child who is regularly given white bread sandwiches and sweets for school lunches will probably always regard wholewheat bread and fresh fruit as hard work - yet getting into the habit of eating these and other unrefined foods will undoubtedly put him or her on a healthier nutritional path for life.

In conclusion, the take-home anti-cancer message could be reduced to simply this:

'Stop smoking; eat moderately; eat plenty of plant foods; and seek medical help early'.

Points to ponder

• Recently, there have been major reductions in the occurrence of a number of common diseases, including strokes and coronary heart disease. The full reasons are not known. Hence, it is conceivable that decreases could occur in some cancers, again for reasons not altogether understood. For example, there has already been a major fall in stomach cancer and in some childhood cancers.
• Individuals differ tremendously in their susceptibility to diseases. Obviously, if a parent had colon cancer, or a mother or sister had breast cancer, then the chances of getting such cancers are increased. However, because of differences in the ways people respond to cancer-producing substances, protection against the disease may not require too much avoiding action by a section of the community. This means that even partial reduction in the risk factors mentioned could put some people in a less vulnerable position.
• The dietary and non-dietary measures for the avoidance of cancer are exactly the same as those urged for the avoidance of coronary heart disease and other important diseases. So by following a low fat, high fibre diet you will in any case be protecting yourself against other 'killer' diseases.
• The field of alternative medicine may well produce some useful guidelines for fighting cancer in the future. Already the question is being asked: Are there 'non-orthodox' methods to prevent cancer, or to treat it, or even to cure it? Some interesting recommendations have been made, for example in the diets put forward by Kelley, by Gerson and by Forbes. These diets are largely or wholly vegetarian, with much of the plant food being eaten raw. There are encouraging case- histories which record the arrest and even regression of tumours, but none of the programmes described have been subjected to any form of controlled trial. At present enormous amounts of money are spent on trials in the treatment of various diseases, especially coronary heart disease. Perhaps some money should be devoted to investigating cases of possible 'alternative' cures for cancer. Even the validation of a small number of individual cases would be of great value, bearing in mind the formidable nature of the disease.