M. Fields et Cg. Lewis, Cholesterol-lowering nature of unsaturated fat in rats may be due to its inability to increase hepatic iron, METABOLISM, 48(2), 1999, pp. 200-204
The present investigation was conducted to determine whether the cholestero
l-raising properties of saturated fat and cholesterol-lowering properties o
f unsaturated fat are associated with levels of hepatic iron. The magnitude
of hepatic iron retention was manipulated by feeding rats diets that were
either copper-deficient or -adequate, iron-adequate or -supplemented, and c
ontained either beef tallow or corn oil. Weanling male Sprague-Dawley rats
were randomly divided into eight dietary groups according to the type of di
etary fat (beef tallow or corn oil) and level of dietary copper (0.74 or 6.
9 mu g Cu/g diet) or iron (44.4 or 86.7 mu g Fe/g diet). Beef tallow and co
pper deficiency alone increased hepatic iron levels, which in turn were ass
ociated with increased plasma cholesterol. When the three dietary factors w
ere combined, ie, iron, beef tallow, and copper deficiency, they induced th
e highest magnitude of hepatic iron retention, which in turn was associated
with the highest concentration of plasma cholesterol, In contrast, when he
patic iron retention was not increased, such as by feeding a diet containin
g corn oil or by consumption of a copper-adequate diet, plasma cholesterol
was not elevated. Based on these data, it is suggested that nutrients that
have the ability to increase hepatic iron have the potential to increase pl
asma cholesterol. Copyright (C) 1999 by W.B. Saunders Company.