title: Dietary lipid intake influences the level of cholesterol bound to haemoglobin in human erythrocytes.
abstract: BACKGROUND
  Blood cholesterol levels are affected by diet and in particular by the type of fat intake. We originally showed that a significant but variable amount of cholesterol is firmly bound to haemoglobin (Hb) yielding the Hb-lipid adduct (Hb-Ch) in erythrocytes isolated from normo-lipidemic males.
  
  
  OBJECTIVE
  To establish whether dietary lipids affect the level of Hb-Ch in human erythrocytes.
  
  
  METHODS
  Seventy-four healthy free-living adults were separated according to their serum cholesterol levels into two groups: normo-cholesterolemic (LDL cholesterol <3.4 mmol/l and total cholesterol <5.2 mmol/l) (NC) and hyper-cholesterolemic (LDL cholesterol >or=3.4 mmol/l) (HC). Habitual dietary information was used to classify subjects in both study groups into sub-groups of low-fat (<or=30% total energy as fat) and high-fat consumers (>30% total energy as fat). The NC low-fat consumers were placed on a high-lipid (high-fat and high-cholesterol) diet whereas the HC subjects with high-fat intake were assigned to a low-lipid (low-fat and low-cholesterol) diet. Both types of dietary intervention were allowed to continue for 6 weeks. The main variable under scrutiny was the Hb-Ch concentration.
  
  
  RESULTS
  In both study groups low-fat intake subjects had low levels of Hb-Ch (approx. 0.35 mmol/l RBC) compared with high-fat intake subjects (approx. 0.60 mmol/l RBC), and serum cholesterol was not correlated with Hb-Ch. The two dietary interventions produced substantial changes in the Hb-Ch level that paralleled variation in the serum cholesterol concentration. A high-lipid diet (35% fat, 15% saturated; 580 mg cholesterol) increased Hb-Ch (by approximately 47%, P<0.001) in subjects with low Hb-Ch at onset, whereas a low-lipid diet (28% fat, 9% saturated; 280 mg cholesterol) decreased Hb-Ch (by approximately 40%, P<0.001) in subjects with high Hb-Ch at onset.
  
  
  CONCLUSIONS
  High consumption of dietary lipids, including saturated fat and cholesterol, has an important influence on the level of Hb-Ch in human erythrocytes.
authors.affiliation: Faculty of Chemistry, University of Belgrade, Studentski trg 16, P.O. Box 158, 11000 Belgrade, Serbia. mnikolic@chem.bg.ac.yu
authors.forename: Milan
authors.initials: M
authors.lastname: Nikolic
authors.forename: Danijela
authors.initials: D
authors.lastname: Ristic Medic
authors.forename: Dragana
authors.initials: D
authors.lastname: Stanic
authors.forename: Marija
authors.initials: M
authors.lastname: Postic
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Arsic
authors.forename: Vesna
authors.initials: V
authors.lastname: Niketic
mesh_terms: D000328:Adult; D002784:Cholesterol / Q000097:blood / Q000378:metabolism*; D008076:Cholesterol, HDL / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D018752:Diet, Fat-Restricted; D004041:Dietary Fats / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004912:Erythrocytes / Q000737:chemistry* / Q000378:metabolism; D005260:Female; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D006937:Hypercholesterolemia / Q000097:blood* / Q000178:diet therapy; D008297:Male
chemical_list: D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D004041:Dietary Fats; D006454:Hemoglobins; D002784:Cholesterol