Re: Level of Oxidized Cholesterol in Various Foods


A newer report with levels of oxidized cholesterol:


It has been estimated that approximately 1% of the cholesterol
consumed in a mixed Western diet is oxidized cholesterol (van de
Bovenkamp et al., 1988). Dietary sources of oxysterols are cholesterol-
rich foods, such as dairy, processed eggs, and meat products.
Cholesterol containing foods, when subjected to high temperatures
during manufacture and/or processing may form variable amounts of
oxysterols, depending on the analytical method applied for their
identification, as was discussed above. The most commonly detected
oxysterols in foods are the major products of cholesterol oxidation: 7
a-hydroxycholesterol, 7 ß-hydroxycholesterol, a-epoxycholesterol, ß-
epoxycholesterol, and 7-ketocholesterol, which can be found in amounts
ranging from nano gr to mg/gr of sample (Sander et al., 1989;
Paniangvait, et al., 1995).

Eggs and egg-derived products
Foods that are naturally characterized by high cholesterol content are
major sources of oxysterols when processed, such as eggs and egg-
derived products. An average egg contains 200-220 mg cholesterol,
which is about twice the cholesterol content of butter and freeze-
dried meat products, and about 5-10 times more cholesterol than is
found in most dairy products. Dried whole egg or dried egg yolk, but
not fresh egg yolk, are significant sources of oxysterols when used in
the manufacture of convenience foods (Missler et al., 1985; Galobart
et al., 2002). Oxysterol content of eggs (dehydrated, dried) are in
the range of 0.05-1.50 ug/g, and for egg-yolk (dehydrated or dried)
amounts are 15-120 ug/g (Morgan & Armstrong, 1992). Irradiation
applied to the control of Salmonella considerably increases the amount
of oxysterols in egg yolk powder from 10 ug/g to 470 ug/g on average
(Du & Ahn, 2000).

Dairy products
Several dairy products and milk powder are reported to contain
oxidized cholesterol after processing (Dionisi et al., 1998). The
oxysterols found in these products are the same as those in processed
eggs. However, fresh milk contains 0 or only trace amounts of
cholesterol oxides, which means that processing (e.g high temperature)
is the main source of oxysterols (Angulo et al., 1997). Other milk-
derived products such as cheeses, yogurt, and evaporated milk, contain
very low amounts of cholesterol oxides. The oxysterol content of milk
powder is in the range 1.0-2.5 ug/g. Dehydrated cheese has 8-15 ug/g;
skimmed milk powder, 0.01-0.1 ug/g; and whole milk powder, 0.2-0.8 ug/
g (Paniangvait et al., 1995). The amount of oxysterols present in
these products depends on the processing temperature and the length of
the storage period (Nourooz-Zadeh & Appelqvist, 1988).

Meat and meat-derived products
The mean lipid content of lean meat is 10%, wet weight basis, of which
triglycerides and phospholipids are major components and cholesterol
is a lesser component, ranging from 50 to 89 mg. The main source of
oxysterols in meats (from bovine, poultry and porcine origin) is heat
processing, mainly over-heating. Fresh meat and fresh meat products
contain 0 or trace amounts of cholesterol oxides. Oxysterols contained
in cooked meat range from 180-1900 ug/g (Paniangvait et al., 1995).

Other food products
It has been proposed that frying in animal/vegetable oils is an major
source of oxysterol in the Western diet. The primary target are French
fried potatoes, which together to other deep-fried foods cooked in
animal/vegetable fat are considered the main source of oxysterols in
the U.S. and Latin America. The oxysterol content of potatoes fried in
tallow or vegetable/animal oil may be in the range of 1.4 mg/g to 16.7
mg/g, depending on the origin and/or the animal fat content of the
frying oil (Paniangvait et al., 1995).