I have been a bit disturbed after reading the New Dietary Guidelines which
linked heightened LDL levels to increased dietery cholesterol intake. The
following favourable paper in fact indicated higher LDL levels, but
maintenance of the LDL/HDL ratio was observed (ie, higher HDL's).

Marilyn

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_ui
ds=12074253&dopt=Abstract

Pre-menopausal women, classified as hypo- or hyperresponders, do not alter
their LDL/HDL ratio following a high dietary cholesterol challenge.

Herron KL, Vega-Lopez S, Conde K, Ramjiganesh T, Roy S, Shachter NS,
Fernandez ML.

Department of Nutritional Sciences, University of Connecticut, Storrs 06269,
USA. [log in to unmask]

BACKGROUND: Cholesterol is the dietary component that has elicited the most
public interest in conjunction with coronary heart disease. However, the
impact of excess dietary cholesterol intake on plasma cholesterol levels
cannot be accurately predicted; therefore, its role in disease progression
is not straightforward. Individual response variation can be due to factors
such as ethnicity, hormonal status, obesity and genetic predisposition.
OBJECTIVE: The purpose of this study was to evaluate the differences that
occur within the plasma compartment of normolipidemic pre-menopausal women,
classified based on their response to a high dietary cholesterol challenge.
DESIGN: We recruited 51 pre-menopausal women (29 Caucasian and 22 of
Hispanic origin) aged 18 to 49 years with initial plasma cholesterol
concentrations ranging from 3.62 to 5.17 mmol/L. Using a cross-over research
design, women were randomly allocated to an egg (640 mg additional dietary
cholesterol per day) or placebo group (0 mg additional dietary cholesterol
per day) initially, and the two 30 day periods were separated by a
three-week washout. RESULTS: An initial evaluation of the ethnicity effects
revealed elevations in both plasma LDL-C (p < 0.0001) and HDL-C (p < 0.001)
concentrations in both Hispanics and Caucasians during the high dietary
cholesterol period. However, these increases were not accompanied by a
change in the LDL/HDL ratio. Subjects were then classified as hypo- (< 0.05
mmol/L increase in total plasma cholesterol per each additional 100 mg of
dietary cholesterol consumed per day) or hyper-responders (> or =0.06 mmol/L
increase in total blood cholesterol per each additional 100 mg of dietary
cholesterol consumed per day), based on their reaction to the additional
dietary cholesterol provided. Hypo-responders did not experience an increase
in LDL-C or HDL-C during the egg period, while both lipoproteins were
elevated in hyper-responders. However, the LDL/HDL ratio, an important
parameter of coronary heart disease risk, was maintained for all subjects
during the egg period independent of response. Furthermore, hyper-responders
had higher concentrations of apo C-III (p < 0.001), apo B (p < 0.001) and
cholesterol ester transfer protein (CETP) (p < 0.05) during this period.
CONCLUSION: These data revealed that excess dietary cholesterol does not
increase the risk of developing an atherogenic lipoprotein profile in
pre-menopausal women, regardless of their response classification. Although
the addition of 640 mg of cholesterol to the diet did result in an increase
in plasma cholesterol in hyperresponders, the LDL/HDL ratio was maintained.
This result, accompanied by increases in CETP activity, leads to the
speculation that hyper-responders may process the excess cholesterol in the
plasma compartment through an enhancement of the reverse cholesterol
transport pathway. With this mechanism identified, further measurement of
additional parameters is needed to verify this conclusion.

PMID: 12074253 [PubMed - in process]