J
John Sankey
Guest
Found the following. Until data is available it seems sensible to count
a gram of squalene as a gram of cholesterol for olive oil but not for
any other food.
-----------
Effects of trace components of dietary fat on cholesterol metabolism:
Phytosterols, oxysterols, and squalene
Nutrition Reviews, Nov 2002 by Ostlund, Richard E Jr, Racette, Susan B,
Stenson, William F
....
Similar to the situation in animal cells, squalene is usually only a minor
component of the nonsaponifiable materials of plants. It is estimated that the
average consumption of squalene in foodstuffs is only 28 mg/ day, a small
proportion of the cholesterol production rate of 1114 mg/day. However, dietary
squalene can vary remarkably and olive oil is a stark exception to the rule that
plant levels are generally low. Olive oil contains 200 to 700 mg squalene/100 g
oil. 7- to 300-fold more than other vegetable oils and up to 5000-fold more than
some vegetable foods . The efficiency of gastrointestinal squalene absorption
has been estimated at 42% in animals and 86% in humans, and dietary squalene
is found in postprandial lipoprotein fractions. Once absorbed, squalene
appears to be quantitatively converted to cholesterol. Some dietary squalene
is converted to cholesterol within the intestinal epithelium and may thereby
influence cholesterol absorption. The effect of long-term squalene feeding in
humans has not been investigated adequately. In a small study using purified
squalene (1 g/day) added to margarine, LDL cholesterol increased 17%, apo B
increased 14%, and fecal neutral sterols increased 9%. The incorporation of
labeled water into cholesterol was reported to be significantly lower after
olive oil consumption compared with other vegetable oils. This result would be
expected as compensation for increased unmeasured cholesterol synthesis from
unlabeled exogenous squalene. In a large study that used an undefined dietary
supplement containing squalene (presumably an extract of shark liver), there was
a 14% reduction in LDL cholesterol compared with placebo. It is unclear
whether the effect was due to squalene itself or to other components. Commercial
squalene supplements are often less than 50% pure.
Squalene content is potentially important in the interpretation of studies
involving olive oil administration. Based on the above data it is possible that
individuals consuming 50 g olive oil per day might have a squalene intake of 350
mg, an amount that could easily affect cholesterol metabolism because it is
would be equivalent to 350 mg of cholesterol, assuming similar efficiency of
absorption. Olive oil elevates serum cholesterol and LDL cholesterol relative to
other vegetable oils in controlled diet studies. However, it is not known
whether squalene is the active agent. Whether cholesterol derived from absorbed
squalene has effects similar to absorbed cholesterol is also not known. Because
many studies of monounsaturates were conducted with olive oil as the test
material, it would be important to define further the role of its squalene
component.
....
a gram of squalene as a gram of cholesterol for olive oil but not for
any other food.
-----------
Effects of trace components of dietary fat on cholesterol metabolism:
Phytosterols, oxysterols, and squalene
Nutrition Reviews, Nov 2002 by Ostlund, Richard E Jr, Racette, Susan B,
Stenson, William F
....
Similar to the situation in animal cells, squalene is usually only a minor
component of the nonsaponifiable materials of plants. It is estimated that the
average consumption of squalene in foodstuffs is only 28 mg/ day, a small
proportion of the cholesterol production rate of 1114 mg/day. However, dietary
squalene can vary remarkably and olive oil is a stark exception to the rule that
plant levels are generally low. Olive oil contains 200 to 700 mg squalene/100 g
oil. 7- to 300-fold more than other vegetable oils and up to 5000-fold more than
some vegetable foods . The efficiency of gastrointestinal squalene absorption
has been estimated at 42% in animals and 86% in humans, and dietary squalene
is found in postprandial lipoprotein fractions. Once absorbed, squalene
appears to be quantitatively converted to cholesterol. Some dietary squalene
is converted to cholesterol within the intestinal epithelium and may thereby
influence cholesterol absorption. The effect of long-term squalene feeding in
humans has not been investigated adequately. In a small study using purified
squalene (1 g/day) added to margarine, LDL cholesterol increased 17%, apo B
increased 14%, and fecal neutral sterols increased 9%. The incorporation of
labeled water into cholesterol was reported to be significantly lower after
olive oil consumption compared with other vegetable oils. This result would be
expected as compensation for increased unmeasured cholesterol synthesis from
unlabeled exogenous squalene. In a large study that used an undefined dietary
supplement containing squalene (presumably an extract of shark liver), there was
a 14% reduction in LDL cholesterol compared with placebo. It is unclear
whether the effect was due to squalene itself or to other components. Commercial
squalene supplements are often less than 50% pure.
Squalene content is potentially important in the interpretation of studies
involving olive oil administration. Based on the above data it is possible that
individuals consuming 50 g olive oil per day might have a squalene intake of 350
mg, an amount that could easily affect cholesterol metabolism because it is
would be equivalent to 350 mg of cholesterol, assuming similar efficiency of
absorption. Olive oil elevates serum cholesterol and LDL cholesterol relative to
other vegetable oils in controlled diet studies. However, it is not known
whether squalene is the active agent. Whether cholesterol derived from absorbed
squalene has effects similar to absorbed cholesterol is also not known. Because
many studies of monounsaturates were conducted with olive oil as the test
material, it would be important to define further the role of its squalene
component.
....