John_Yudkin_-_Pure_White_and_Deadly_revised_1986_OCR

Pure, White and Deadly
deaths in Britain very closely followed the rise in the consumption
of sugar. In South Africa, it was shown that the black population
had little coronary disease while the white and the Indian populations
had as much as the white populations in America, Western
Europe and Australasia. It seems, however, that the situation is
changing in South Africa: heart disease is beginning to occur also in
the black population. These facts fit the figures for consumption of
sugar, which has been high for a long time among the whites and
Indians, was low amongst the black population until some 20 or so
years ago, but is now, with increasing affluence, rising rapidly.
In Israel, A. M. Cohen of Jerusalem found that recently arrived
immigrants from the Yemen had very little coronary disease, though
it was common among Yemenis who had immigrated twenty or so
yeai:s earlier. The diet in the Yemen had been quite high in animal
fat and butter but low in sugar; when the immigrants arrived in
Israel they began to adopt the usual high-sugar diet of the country.
The Masai and the Samburu are two tribes in East Africa that
live very largely on milk and meat, and thus have a very high consumption
of animal fat. There is, however, very little heart disease
among them. You might say that this is because they are physically
very active. Another possibility is that they have a different sort of
metabolism from that of other people, and recent work suggests that
this is actually the case for the Masai. It seems that they have a more
efficient way of dealing with animal fat without being subjected to
a rise in the level of blood cholesterol. It is not clear, however,
whether this is some genetic characteristic of the Masai or whether
they have become so good at metabolizing fats because they have
been coping with large quantities all their lives.
But what is often left out of these discussions is that both the
Masai and the Samburu eat virtually no sugar.
Asian immigrants in Britain have a significantly higher mortality
from coronary disease than do the native British - some 20 per cent
higher in men and nearly 30 per cent higher in women. Yet a recent
study has shown that the total intake of fat is abnost the same in
both communities, while the intake of saturated fat is lower and of
polyunsaturated fat higher among the Asians. Thus, their ratio of
polyunsaturated to saturated fat in the diet (the P:S ratio) is 0'85,
compared with 0'28 for the native British. The high ratio in the
Asian diet fulfils the recommendation of those who advocate
changes in dietary fat in order to prevent coronary disease. It is
clear then that the higher coronary mortality in Asians is not to be
88
Coronary thrombosis, the modern epidemic
explained by differences in their fat intake. What was not measured
in this study was the consumption of sugar by the Asians, but other
investigations have shown that they in fact eat more sugar than do
the rest of the British population. As we shall see later (p. 108), this
is also relevant to the high prevalence of diabetes among Asians in
Britain.
Let me quote only one other special study, made in St Helena.
Coronary disease is quite common in that island. This is not because
the inhabitants eat a lot of fat; they eat less than the Americans or
the British. It is not because they are physically inactive; St Helena
is extremely hilly and there is very little mechanical transport. It is
not because they smoke a lot; cigarette consumption is much lower
than it is in most Western countries. There is only one reasonable
cause of the high incidence of coronary disease: the average sugar
consumption in St Helena is around 100 pounds per person a year.
In summary one can say that in most of the affluent populations
I have considered, the prevalence of coronary disease is associated
with the consumption of sugar. Since sugar consumption is, however,
only one of a number of indices of wealth, the same sort of
association exists with fat consumption, cigarette smoking, motor
car ownership, and so on. At this point it would be equally justifiable
to look at anyone of these factors as being a possible cause of coronary
disease.
You can also put this rather differently by considering the
relationship between any two of the factors I have mentioned. If you
look at how much fat and sugar is eaten in different countries you
find that they tend to be very similar for anyone country; on the
whole, both are low in poor countries, moderate in moderately well
off countries, and high in wealthy countries. So anything that is
related to one is likely to be related to the other. You can now say,
if you wish, that fat is a cause of coronary disease, and the association
between sugar and the disease is accidental because fat and sugar
are related. Or you can put it the other way round and say that sugar
is a cause of coronary disease and it is the association with fat that
is accidental.
When I arrived at this point it seemed to me that the next step
was to look at the sugar consumption of individual people with and
without coronary disease. For averages can be misleading; it is one
thing to show that there is more coronary disease in countries where
on average more sugar is eaten and quite another to show that, in