Health effect of vegetable-based diet: lettuce consumption improves cholesterol metabolism and antioxidant status in the rat.
OBJECTIVE
It is often assumed that fruits and vegetables contribute to protect against degenerative pathologies such as cardiovascular diseases. Besides epidemiological observations, scientific evidences for their mechanism of action are scarce. In the present study, we investigated the mean term and post-prandial effects of lettuce ingestion on lipid metabolism and antioxidant protection in the rat.


RESULTS
Feeding rats a 20% lettuce diet for 3 weeks resulted in a decrease cholesterol LDL/HDL ratio and a marked decrease of liver cholesterol levels (-41%). Concurrently, fecal total steroid excretion increased (+44%) and apparent absorption of dietary cholesterol was significantly depressed (-37%) by the lettuce diet. Lettuce diet also displayed an improvement of vitamin E/TG ratio in plasma and limited lipid peroxidation in heart as evidenced by TBARS. In post-prandial experiment, lettuce intake significantly increased both ascorbic acid and alpha-tocopherol plasma levels which contribute to improve plasma antioxidant capacity within 2 h of consumption. Other lipid-soluble antioxidants (lutein and vitamin E) may also improve the plasma antioxidant capacity.


CONCLUSIONS
Lettuce consumption increases the total cholesterol end-products excretion and improves antioxidant status due to the richness in antioxidants (vitamins C, E and carotenoids). In our model, lettuce clearly shows a beneficial effect on lipid metabolism and on tissue oxidation. Therefore regular consumption of lettuce should contribute to improve protection against cardiovascular diseases.
Nicolle
Catherine
C
Vilmorin, Clause & Cie, Chappes, France. cnicolle@clermont.inra.fr
Cardinault
Nicolas
N
Gueux
Elyett
E
Jaffrelo
Lydia
L
Rock
Edmond
E
Mazur
Andrzej
A
Amouroux
Pierre
P
Rémésy
Christian
C
D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D001205:Ascorbic Acid / Q000097:blood / Q000378:metabolism; D002318:Cardiovascular Diseases / Q000517:prevention & control; D002338:Carotenoids / Q000097:blood / Q000378:metabolism; D002784:Cholesterol / Q000097:blood / Q000378:metabolism*; D008076:Cholesterol, HDL / Q000378:metabolism; D008078:Cholesterol, LDL / Q000378:metabolism; D004032:Diet; D005243:Feces / Q000737:chemistry; D018545:Lactuca; D015227:Lipid Peroxidation; D008099:Liver / Q000737:chemistry / Q000378:metabolism*; D008297:Male; D019518:Postprandial Period; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis; D014810:Vitamin E / Q000097:blood / Q000378:metabolism
D000975:Antioxidants; D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D017392:Thiobarbituric Acid Reactive Substances; D014810:Vitamin E; D002338:Carotenoids; D002784:Cholesterol; D001205:Ascorbic Acid