Influence of mental stress and circadian cycle on postprandial lipemia.
BACKGROUND
Mental stress produces alterations in serum lipids and lipoproteins.


OBJECTIVE
The objective was to assess the effect of mental stress during the day and night on postprandial lipoproteins.


METHODS
Fourteen healthy subjects aged 26.6 +/- 5.0 y were given randomly the same meal either at night (0100) or during the day (1300), with or without (control session) a mental stress challenge. The meal contained 40% of estimated daily energy needs. The mental task was performed on a computer and consisted of a task of choice reaction. Blood samples were drawn at baseline and hourly for 7 h after the meal.


RESULTS
Urinary epinephrine concentrations were higher (P < 0.012) during the mental task than during the control sessions. Repeated-measures analysis of variance showed that mean postprandial triacylglycerol concentrations were significantly higher (P < 0.02) and total cholesterol (P < 0.0001) and HDL-cholesterol concentrations were significantly lower (P < 0.0001) at night than during the day. The mean postprandial VLDL-triacylglycerol concentration was significantly higher (P < 0.04) during the mental task than during the control sessions. Similarly, the VLDL-cholesterol response, calculated as the area under the postprandial curve, was significantly greater (P < 0.02) during the mental task than during the control sessions. There was no interaction between mental stress and nyctohemeral cycle on postprandial lipoprotein responses, suggesting that both indexes act independently on postprandial lipid metabolism.


CONCLUSIONS
Mental stress is associated with increased concentrations of postprandial triacylglycerol-rich lipoprotein fractions. Therefore, postprandial hyperlipidemia is one possible mechanism contributing to the higher risk of ischemic heart disease in stressed people.
Le Fur
C
C
CERESTE, Service de Nutrition, and Service de Pharmacologie Hospitalière, CHR et U de Lille, Lille, France.
Romon
M
M
Lebel
P
P
Devos
P
P
Lancry
A
A
Guédon-Moreau
L
L
Fruchart
J C
JC
Dallongeville
J
J
D000328:Adult; D000704:Analysis of Variance; D002784:Cholesterol / Q000097:blood*; D002940:Circadian Rhythm; D004435:Eating; D006801:Humans; D008055:Lipids / Q000097:blood; D008297:Male; D012016:Reference Values; D013315:Stress, Psychological; D013997:Time Factors; D014280:Triglycerides / Q000097:blood*
D008055:Lipids; D014280:Triglycerides; D002784:Cholesterol