Both lipid and protein intakes stimulate increased generation of reactive oxygen species by polymorphonuclear leukocytes and mononuclear cells.
BACKGROUND
It was recently shown that glucose challenge leads to increased generation of reactive oxygen species (ROS) by polymorphonuclear leukocytes (PMNs) and mononuclear cells (MNCs).


OBJECTIVE
To further elucidate the relation between nutrition and ROS generation, we investigated the effect of lipid and protein challenges on ROS generation by leukocytes.


METHODS
After having fasted overnight, one group of healthy subjects consumed a carbohydrate- and protein-free cream preparation (1257 kJ) and another group of healthy subjects consumed an equienergetic pure preparation of casein. Sequential blood samples were obtained after the intake of cream and casein. ROS were measured by chemiluminescence after stimulation by N-formyl-methionyl-leucinyl-phenylalanine. Lipid peroxidation was measured as thiobarbituric acid-reactive substances (TBARS) and alpha-tocopherol was measured by HPLC.


RESULTS
ROS generation by MNCs and PMNs increased significantly 1, 2, and 3 h after cream intake and 1 h after protein intake. Cholesterol concentrations did not change significantly, whereas triacylglycerol concentrations increased significantly 2 h after cream intake. Total TBARS concentrations increased 1 h after cream intake and remained elevated 3 h after intake, but the increase was not significant when corrected for changes in triacylglycerol. After casein intake, total cholesterol, triacylglycerol, and TBARS concentrations did not change significantly. alpha-Tocopherol concentrations did not change significantly after either cream or casein intake.


CONCLUSIONS
Both fat and protein intakes stimulate ROS generation. The increase in ROS generation lasted 3 h after cream intake and 1 h after protein intake. Cream intake also caused a significant and prolonged increase in lipid peroxidation. These data are important because increased ROS generation and lipid peroxidation are key events in atherogenesis.
Mohanty
Priya
P
Division of Endocrinology, Diabetes and Metabolism, State University of New York at Buffalo, USA.
Ghanim
Husam
H
Hamouda
Wael
W
Aljada
Ahmad
A
Garg
Rajesh
R
Dandona
Paresh
P
D000368:Aged; D001786:Blood Glucose / Q000187:drug effects; D002851:Chromatography, High Pressure Liquid; D003611:Dairy Products; D004041:Dietary Fats / Q000494:pharmacology*; D004044:Dietary Proteins / Q000494:pharmacology*; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood; D007963:Leukocytes, Mononuclear / Q000187:drug effects* / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects*; D008297:Male; D008875:Middle Aged; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism; D014810:Vitamin E / Q000097:blood
D001786:Blood Glucose; D004041:Dietary Fats; D004044:Dietary Proteins; D007328:Insulin; D017382:Reactive Oxygen Species; D017392:Thiobarbituric Acid Reactive Substances; D014810:Vitamin E