Interaction between cholesterol and glucose metabolism during dietary carbohydrate modification in subjects with the metabolic syndrome.
BACKGROUND
Carbohydrate modification based on rye bread and pasta enhances early insulin secretion in subjects with the metabolic syndrome.


OBJECTIVE
Because the actions of insulin and cholesterol metabolism are interrelated, the question is raised of whether it is possible to alter cholesterol metabolism by means of dietary carbohydrate modification.


METHODS
We investigated the 12-wk effects of dietary carbohydrate modification on cholesterol synthesis and absorption by measuring the ratios of surrogate markers of precursor (cholestenol, desmosterol, and lathosterol) and absorption (cholestanol and plant sterols) sterols to cholesterol and their association to glucose metabolism in 74 subjects with the metabolic syndrome. The subjects were randomly assigned to diets with rye bread and pasta (RPa) or oat, wheat bread, and potato (OWPo) as the main carbohydrate source (34% and 37% of energy intake, respectively).


RESULTS
During the study, serum cholesterol concentrations remained unchanged. Cholesterol synthesis was lower (6-10% for cholestenol and lathosterol; P < 0.05) and absorption higher (9%; P < 0.05 for sitosterol) with the OWPo diet than at baseline. With the RPa diet, cholesterol absorption was lower and synthesis higher than with the OWPo diet. The increment in the glucose area under the curve with the RPa diet was positively related to baseline cholesterol synthesis (eg, lathosterol; r = 0.480, P < 0.05) and negatively to absorption (for cholestanol; r = -0.520, P < 0.05). In the combined group, the changes in the cholestanol ratio and the insulinogenic index were interrelated (r = -0.464, P < 0.001).


CONCLUSIONS
Carbohydrate modifications had dissimilar effects on cholesterol metabolism. Consumption of RPa, as compared with OWPo, may be clinically more favorable because it seems to inhibit the absorption of cholesterol, a factor crucial in the development of arterial atherosclerosis.
Hallikainen
Maarit
M
Department of Clinical Nutrition, University of Kuopio, Kuopio, Finland. maarit.hallikainen@uku.fi
Toppinen
Leena
L
Mykkänen
Hannu
H
Agren
Jyrki J
JJ
Laaksonen
David E
DE
Miettinen
Tatu A
TA
Niskanen
Leo
L
Poutanen
Kaisa S
KS
Gylling
Helena
H
D000328:Adult; D000368:Aged; D019540:Area Under Curve; D018554:Avena; D001786:Blood Glucose / Q000378:metabolism*; D002784:Cholesterol / Q000096:biosynthesis* / Q000378:metabolism; D003897:Desmosterol; D004040:Dietary Carbohydrates / Q000008:administration & dosage* / Q000145:classification / Q000378:metabolism; D005260:Female; D038321:Glycemic Index; D006801:Humans; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D007408:Intestinal Absorption; D008297:Male; D024821:Metabolic Syndrome / Q000178:diet therapy / Q000378:metabolism*; D008875:Middle Aged; D012434:Secale; D011198:Solanum tuberosum; D014908:Triticum
D001786:Blood Glucose; D004040:Dietary Carbohydrates; D007328:Insulin; D003897:Desmosterol; C001521:lathosterol; D002784:Cholesterol