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  • A healthy diet: some surprising facts

A HEALTHY DIET.

Most people think that they can remain free of coronary disease and thrombosis by avoiding "bad" items in the diet. Many processed foods contain substances that are toxic (poisonous). Read the label and do not buy anything containing preservatives, flavouring, flavour enhancers etc, i.e., anything that is not natural food. Beware of low fat products which are often adulterated with such chemicals, even if advertised as “low fat” or “healthy”. Most of the “bad” things in diet are from processed food and fast food. Many of these products are adulterated with artificially hydrogenated fat – the worst kind of fat you can eat. Avoid packaged, processed meats. Packaged chicken is often infected and contain antibiotics. As much as possible, eat grass fed, free range meat, free range chicken and eggs and fruit and vegetables locally grown in season. Organic foods which have been packaged and derived from distant sources may not be as good as local free range produce. When it comes to natural fresh food, there is no evidence that particular diets offer benefit, because they cannot be tested in double blind trials, as can drugs.

This means that neither the patient, nor the doctors know who is taking the active drug and who is taking an exactly similar looking and tasting dummy (placebo). This kind of trial is not possible with diets.

There are three main nutritional components in food - protein, fat (lipid) and carbohydrate. A long time ago, it was recognised that the traditional eskimo diet was associated with almost total freedom from arterial disease. The main component of this diet was fish oil and seal blubber, i.e. fat. Since the descendants of these people have adopted the typical North American (partly fast food) diet, coronary disease has appeared amongst them. It is curious, in view of this seeming clear cut advantage of a high fat diet, that the most popular diet nowadays is a low fat diet!

It appears that this popularity arises from the association known for several decades between arterial disease and blood cholesterol. Presumably, it was then thought that, as cholesterol is a fat, and fatty deposits are found in the "bad" parts of diseased arteries (lipid rich plaques), one should avoid eating fat as much as possible, in order to reduce blood cholesterol. The importance of lowering cholesterol seemed to be confirmed by the undoubted fact that lipid lowering drugs called statins, reduce arterial disease and prolong life of sufferers. The benefits of these drugs have been proven by double blind trial, but not the supposed benefits of low fat diet. It is now apparent that statins have a beneficial effect even when the cholesterol is low. There are also many patients with coronary disease that have normal cholesterol.

Obviously, the issue is much more complicated than was thought at first. More risk factors for the development of coronary disease that are just as strong as cholesterol, eg insulin resistance and homocysteine. It should also be remembered that cholesterol in the diet is not taken into the body as such. It is broken down into fatty acids. The body then makes (synthesises) its own cholesterol and this biochemical process is subject to complex controls. This is a very different situation to the dietary considerations relevant to insulin resistance and homocysteine. Glucose, which is the main dietary problem in insulin resistance, is absorbed directly into the blood from the food. Protein is broken down in the gut to amino acid, one of which is methionine, the immediate precursor of homocysteine; the homocysteine concentration in the blood is directly associated with the amount of methionine in the food. There would therefore appear to be a much stronger case for trying to control glucose and homocysteine by dietary modification than in trying to control cholesterol by that means.

One must also consider the evil consequence of low fat diets, which are that they contain large quantities of carbohydrates which break down into glucose in the gut. This would appear to be the reason for the modern epidemic of obesity, hypertension and adult type diabetes (type 2 diabetes mellitus) - the insulin resistance triad. It has been known for a very long time that the best treatment for this kind of diabetes is a low carbohydrate diet. Therefore, it is logical to apply the same treatment to all forms of insulin resistance and glucose intolerance, a condition that is very common. This approach has been much championed by Atkins, whose dietary recommendations are becoming popular. There may be some details of his recommendations that are not well substantiated, but he certainly puts forward many good published scientific articles that are compatible with the idea that a low carbohydrate diet is beneficial, eg by reducing weight and lowering blood cholesterol. It will be interesting to see in the future whether the popularity of this diet is associated with reduced coronary disease.

What can we recommend, in view of the absence of proof for benefit of any of these diets? We think that common sense should indicate that natural fresh food is likely to be healthier than processed food, fast food and junk food. There are lipids, which are now accepted to be probably beneficial. Seal blubber is not readily available, but it can neutralise activated platelets, ie it helps prevent thrombosis. Other lipids now recommended are Omega 3 fish oil and olive oil. As low-fat preparations are high in carbohydrate and do not appear to satisfy appetite, these foods should probably be avoided. Also, in view of the common presence of insulin resistance, it would seem sensible to avoid those foods containing carbohydrate that release the most glucose, e.g., bread, pizza, pasta, potatoes (crisps, chips), cakes, confectionary, cereals, and others according to Atkins’ tables. Similar considerations apply to drinks, eg sugary fruit drinks and beer. Whether one goes to the length of substituting sucrolose for ordinary sugar (sucalose) depends on the magnitude of the need to reduce weight. There seems to be no good reason to avoid natural fatty food, eg meat, fish, butter, eggs, cheese, olive oil, which appear to satisfy appetite more than carbohydrate. As far as protein is concerned, possibly lean meat should be restricted (not completely avoided) to reduce the amount of methionine. There seems to be good reason to favour fatty meat over lean meat from this point of view. Fresh fruit and vegetables are known to be an important source of the essential vitamin folic acid.

One must also remember that there are no general rules; each patient will require individual dietary modification depending on their condition, eg patients with failing kidneys need a low protein diet. For Mr and Mrs Average, if there are such persons, you could try:

Breakfast: Pure fruit juice. Bacon and egg. Tea or coffee.

Lunch: Meat, fish, egg or cheese with salad and real mayonnaise. Water.

Dinner: Fresh meat or fish with leafy green vegetable and parsnip, turnip or carrot. Blueberries, strawberries or raspberries and cream (no sugar). A glass of wine.

This kind of food is enjoyable to eat as well as, hopefully, healthy. We can however, offer no guarantees, because scientific proof of benefit of any diet is lacking.

Healthy fat in the diet is now thought to be beneficial in the elderly.