Heart Disease

Heart disease accounts for about half of all deaths in America today and the figures are rising throughout the Western world. But there are many kinds of heart diseases, with different causes, and we are concerned here only with one kind of heart disease, coronary heart disease. A brief review of the kinds of heart diseases should be helpful.

Congenital heart disease is the kind you are born with. The heart or its attached great blood vessels develop abnormally and the result is a mechanically defective pump; there are mistakes in "plumbing". Despite great publicity because of spectacular successes in correcting the "hole-in-the-heart" by surgery, congenital heart disease is not common. It is a small part of our total heart problem. Grossly deficient diets during pregnancy may increase the frequency of abnormalities in the offspring of animals, but there is no evidence that human congenital heart disease can be attributed to the diet of the mother. And, of course, the diet of the patient with such a condition cannot change the defective architecture of the heart.

Heart disease caused by syphilis used to be fairly common but it is becoming extremely rare in most of the so-called "richly developed" countries. The conquest of syphilis by antibiotics will soon make this kind of heart disease only a historical curiosity. The diet plays no role in producing syphilitic heart disease; the villain is the infecting spirochete, Treponema pallidum.

Rheumatic fever heart disease, which deforms the valves of the heart, is generally believed to be a special kind of reaction to a streptococcal infection. This explains the high hopes for control by prevention and early treatment of streptococcal infections, particularly "strep throats", with penicillin and other antibiotics. The frequency of rheumatic fever, and of new cases of the heart disease it produces, is clearly diminishing, though it still accounts for too many deaths. Surgery can repair the deformed heart valves in some cases. There is no good evidence that the diet is important in the production or prevention of the disease.

Hypertension can produce heart disease by constantly overstraining the heart, and this, next to coronary heart disease, is the most common and fatal kind of heart disease in many countries. It causes a significant number of deaths. In hypertension the arteries of the body are constricted so that only by pumping at a higher pressure can the heart maintain adequate blood flow. The heart muscle tends to grow larger and stronger, just like any other muscle when it is forced to exercise a great deal, but eventually even this compensation may be insufficient. The constant high blood pressure also damages the arteries, particularly in the kidneys, and kidney failure is not uncommonly a complication or even the main cause of disability and death. Finally, high blood pressure can literally "burst" the blood vessels so hypertensive patients are prone to haemorrhages in the brain and elsewhere.

Sometimes the cause of hypertension can be found in the kidneys or in an overgrowth of a part of the adrenal gland, but the cause of most cases of hypertension is unknown. Obesity is believed to favour its development. Some experts suspect that a high intake of salt in the diet may be involved also, but even if so it would not seem to be a direct and first cause. Whether dietary moderation in the use of salt and avoidance of obesity can do much to prevent hypertension is unknown. But good sense suggests that such simple dietary precautions would be wise.

High blood pressure in the lungs or any impediment to blood flow through the lungs causes excessive work for the right side of the heart. This is different from general hypertension where the strain is on the left side of the heart, the side which pumps blood to the body as a whole. The result may be the heart disease called "cor pulmonale". Fortunately, cor pulmonale is not common. There is no indication that a dietary factor is involved as a cause or in the clinical status of the patient.

Finally we come to coronary heart disease, the condition produced by interference with the blood flow in the arteries that supply the heart muscle itself. According to the latest vital statistics, this one cause accounts for some three-fourths of all heart deaths in the United States and is killing Americans at a rate of almost half a million a year. Table 1 shows the vital statistics for several countries in the year 1955. The toll in America is far more than that of all cancers and other tumours. In England and Wales the numbers dying from coronary heart disease are equal to those dying from cancer and in Scotland there are many more. In Great Britain as a whole the coronary death rate is many times greater than the far more highly publicized number of deaths from road accidents. Moreover, it is not true, as sometimes imagined, that coronary heart disease is mainly a problem for the aged. For example, in the United States, coronary heart disease is officially blamed for 26 per cent of all deaths of white males under the age of 65. In England and Wales the corresponding figure is reported as 23 per cent. The situation is less alarming in some countries but it should be remembered that most of the coronary heart disease is concentrated in a limited social and Deaths per 100,000 of each sex, ages 45-64, inclusive. Data from the United NationsCentrale di Statistica, Rome.

Country	Year			Austria .. ..	1956	1,441	817	73	14	388	282	266	91
Australia' .. ..	1955	1,346	790	25	5	230	212	470	160
Canada .. ..	1956	1,241	745	18	8	251	248	485	154
Denmark .. ..	1955	984	714	9	5	269	289	255	81
England and Wales	1955	1,354	768	40	9	359	262	345	107
Finland .. ..	1956	1,627	779	109	34	368	230	479	126
Italy .. ..	1955	1,172	719	65	14	272	211	188	100
Japan .. ..	1955	1,412	953	129	60	285	229	94	74
Netherlands ..	1955	950	630	14	5	285	245	219	77
New Zealand ..	1955	1,158	753	27	12	203	243	419	126
Norway .. ..	1955	895	566	29	11	237	236	218	62
Scotland .. ..	1956	1,575	932	42	7	392	290	487	182
Sweden .. ..	1955	936	681	23	8	203	239	246	89
Switzerland ..	1955	1,195	764	37	15	318	253	225	103
U.S.A. .. ..	1955	1,534	838	27	6	283	256	582	182
Union of S. Africa2	1951	1,683	1,039	52	20	290	241	518	180

economic class and for people in this select group the burden - and the threat - is far from negligible. Among such countries we may count Italy, Spain, Portugal, Argentina and Greece.

Worse still, in contrast with our other health problems, coronary heart disease seems to be increasing, even when we allow for the changing age of the population. But in this black picture there is a growing belief that we can, if we will, reverse the trend. From studies on populations all over the world, and other researches, we believe that coronary heart disease should be preventable and that dietary adjustment offers a real hope.