Saturated fat does not cause stroke
Dr. He and colleagues found that the intake of saturated fat not was
associated with the incidence of stroke (1). They missed to mention the
following when they discussed their results.
Are the coronary arteries more sensitive to high levels of serum
cholesterol than the arteries of the brain? This is indicated by the fact
that coronary heart disease (CHD) is strongly correlated with high plasma
cholesterol (2) and that stroke is not (3). New ultrasound research
indicates that echolucent carotid plaques are associated with higher risk
for future ischaemic stroke (4). These plaques are associated with reduced
levels of HDL, but not with elevated levels of LDL. Saturated fat increase
HDL. This might explain why saturated fat is not correlated with stroke.
Ecological studies suggest that stroke and CHD have some quite
different risk factors (5). For example there are more strokes in Asia
than in Western Europe and Northern America, while the quite opposite is
the case for CHD. We also see that the incidences of stroke are low in
Great Britain and Scandinavia compared to many countries in the
Mediterranean area. In the case of CHD the opposite is observed.
My last point is that animal fat rich foods like whole milk, also
contains plenty of beneficial vitamins and minerals. In a large
prospective cohort study, high daily whole milk consumption was strongly
correlated with reduced risk for CHD (6). It is also noteworthy that the
stroke incidence in Japan has declined sharply, as the consumption of
foods high in saturated fat has increased (7). Is this correlation causal?
We don’t know, but animal studies have shown that milk fat-rich diet can
reduce the incidence of cerebrovascular disease in stroke-prone
spontaneously hypertensive rats without a significant fall in blood
pressure (8). This indicates that one can not judge how healthy a food
stuff is, only on the basis of its content of saturated fat.
The differences in epidemiology between CHD and stroke is very
interesting, and deserves more attention.
1. He K, Merchant A, Rimm EB, et al. Dietary fat intake and risk of
stroke in male US healthcare professionals: 14 year prospective cohort
study. BMJ 2003;327:777-782.
2. Lloyd-Jones DM, Wilson PW, Larson MG, Leip E, Beiser A, D'Agostino
RB et al. Lifetime risk of coronary heart disease by cholesterol levels at
selected ages. Arch Intern Med. 2003; 163: 1966-72.
3. Prospective Studies Collaboration. Cholesterol, diastolic blood
pressure, and stroke: 13,000 strokes in 450,000 people in 45 prospective
cohorts. Lancet 1995;346: 1647-53.
4. Nordestgaard BG, Gronholdt ML, Sillesen H. Echolucent rupture-
prone plaques. Curr Opin
Lipidol. 2003;14: 505-12.
5. Seely S. Similarities and differences between the epidemiology and
possible dietary causes of coronary arterial disease and strokes. Int J
Cardiol. 1989; 25:333-8.
6. Ness AR, Smith GD, Hart C. Milk, coronary heart disease and
mortality. J Epidemiol Community Health; 2001: 379-82.
7. Shimamoto T, Iso H, Iida M, Komachi Y. Epidemiology of
cerebrovascular disease: stroke epidemic in Japan. Epidemiol. 1996; 6: 43-
8. Ikeda K, Mochizuki S, Nara Y, Horie R, Yamori Y.Effect of milk
protein and fat intake on blood pressure and the incidence of
cerebrovascular diseases in stroke-prone spontaneously hypertensive rats
(SHRSP).J Nutr Sci Vitaminol (Tokyo). 1987; 33: 31-6.
Competing interests: No competing interests