Detailed data to support this viewpoint have emerged from an analysis of the past 25 years' research on cholesterol. A review in the British Medical Journal of 41 research studies showed that a diet that lowers the blood cholesterol by 10 per cent will have little or no effect on the risk of a heart attack for two years or so, but that after five years the reduction in risk becomes substantial.
The benefits to health are, however, crucially dependent on age. Someone aged 35 who sticks with a cholesterol-lowering diet for five years cuts his or her risk of having a heart attack by 50 per cent. At the age of 50 the decrease in risk is 40 per cent. It is 30 per cent at the of 60 and only 20 per cent at the age of 70-75. Beyond that, who knows? Very little research has been done on really old people.
The message is plain: the earlier in adult life the diet is modified to lower cholesterol (by cutting down on the intake of dairy and animal fats) the greater the benefits.
Might a cholesterol-lowering diet do the elderly any harm? Sceptics who have questioned the whole campaign to change the foods we eat have drawn attention to the fact that people with very low blood cholesterol have increased death rates from cancer - and suicide. Recent careful analysis of the data has shown, however, that it is usually the disease that lowers the cholesterol not the low cholesterol that causes the disease.
Further, studies of men with jobs show no link between low cholesterol and cancer; the association is confined to studies of whole populations which include the unemployed and people in poor health. Several types of cancer have now been shown to lower the cholesterol level, often before they cause any symptoms. People with depression, too, have low cholesterol levels and this is the explanation for the link with suicide.
So if the elderly are likely to derive neither much benefit nor any harm from a low fat diet, are there any ways in which they can improve their health? That depends on how good their health is already. Without doubt, stopping smoking will help people with coronary heart disease, poor circulation in their legs, stomach ulcers and a good many other conditions. Losing weight will help the breathless and people with arthritic hips and knees. People who have become dependent on alcohol or tranquillisers will need specialist help to wean them off. But we should remember that research on the elderly has mostly been on the sick elderly. Those fit men and women who come from families in which everyone lives to be 90 have, presumably, bred out any faulty genes for heart disease, stroke or dementia and doctors are ill advised to give such healthy people any advice, no matter how well intentioned.-Reuse content