Ironically, saturated fats found mainly in meat may not be linked to heart disease at all. One review of the literature on saturated fat failed to show any link between it and heart disease (BMJ, 1996; 313: 84-90). The review cited three studies in the last 20 years which show no link between meat eating and cholesterol and heart disease. In fact, the link between meat eating and heart disease is made in only one major paper (BMJ, 1996; 313: 1258). Lowering fat intake and cholesterol does not, in any case, appear to make that much difference to total plasma cholesterol concentrations (JAMA, 1982; 284: 1465-77).
A number of studies suggest vitamins may have a more protective effect. Of these, magnesium shows the greatest promise. Deficiency in magnesium has been long been thought to increase kidney damage and as a result can cause hypertension and thus heart trouble (J Exp Med, 1957; 106: 767-76; Am J Clin Nutri, 1959; 7: 13-22; Lancet, 1980; ii: 720-2). More recent studies have shown that the mean daily intake of magnesium in men who later experienced heart disease is around 12 per cent less than in those who did not (Br Heart J, 1988; 59: 201-6).
Intravenous infusion of magnesium salts, if given soon after a heart attack, has been shown in a randomized, double blind placebo controlled trial to be comparable to that of more aggressive thrombolysis or antiplatelet therapy (Lancet, 1992; 339: 1553-8) with no long lasting side effects.
Some practitioners continue to argue that magnesium is less effective than standard treatments, usually quoting the ISIS-4 trial. However, in this leg of the large clinical trial investigating stroke and heart attack treatments, 7.64 per cent of patients receiving magnesium died compared to 7.24 per cent in the standard treatment group (Lancet, 1995; 345: 669-85), showing that magnesium is at least as effective as orthodox treatments.
Why, then, are these less aggressive measures not put into practice? Diagnosing and treating heart problems can be complicated. GPs routinely refer patients with suspected heart trouble directly to a specialist, even when this is not clinically justified (JAMA, 1996; 276: 481-5). One survey found that GPs attitudes to the prevention of coronary heart disease by health promotion was that it was "tedious, dull and boring". (Soc Health Illness, 1994; 16: 372-93). Doctors were unhappy with the uncertainties entailed in identifying risk factors, ambivalent about the effectiveness of changes in behaviour and concerned that their actions were a moral intrusion into their patient's lives.
Specialists have a greater faith in the drugs and technology at their disposal (N Eng J Med, 1994; 331: 1136-42). It can be difficult for doctors to believe that in some cases doing nothing may be the best course of action. Equally, it is sometimes difficult for patients who have suffered a heart attack to believe that what needs to be done needs to be done by them and not to them.
!APat Thomas