title: Maximal response to a plasma cholesterol-lowering diet is achieved within two weeks.
abstract: OBJECTIVE
  Replacing saturated fat with polyunsaturated fat reduces plasma cholesterol concentrations; however, it has not been well documented how rapidly the decline occurs nor how long is required to reach the maximum cholesterol-lowering effect. The aim of the present study was to determine the time course of change in plasma cholesterol concentrations when participants adopt a lipid-lowering diet.
  
  
  RESULTS
  Participants (n = 19) were asked to follow for 19 days a diet high in saturated fat and then crossed over--without washout--for 19 days to a diet high in n-6 polyunsaturated fat. Participants were asked to maintain a total fat intake of 30-33% of total energy on both diets. Energy and nutrient intakes were assessed by self-reported food records covering 3 days. Plasma total cholesterol concentrations were measured on days 0, 1, 2, 5, 8, 12, and 19 of the n-6 polyunsaturated fat rich diet. Mean (95% CI) plasma total cholesterol concentration declined from 5.10 mmol/L (4.77, 5.46) at day 0 to 4.25 mmol/L (3.83, 4.67) on day 12 and remained unchanged at 4.23 mmol/L (3.85, 4.61) on day 19. A statistically significant decrease in plasma cholesterol concentration was achieved on day 2 of the intervention; by day 5, 59% (0.51 mmol/L) of the maximum reduction (0.87 mmol/L) had been reached.
  
  
  CONCLUSIONS
  Adopting a lipid lowering diet initiates an immediate decline in plasma cholesterol concentration, the full effect of which is achieved within two weeks.
authors.affiliation: Department of Human Nutrition, University of Otago, PO Box 56, Dunedin, New Zealand.
authors.forename: L
authors.initials: L
authors.lastname: Hodson
authors.forename: C M
authors.initials: CM
authors.lastname: Skeaff
authors.forename: J E
authors.initials: JE
authors.lastname: McKenzie
mesh_terms: D000328:Adult; D002784:Cholesterol / Q000097:blood*; D018592:Cross-Over Studies; D015930:Diet Records; D018752:Diet, Fat-Restricted; D004041:Dietary Fats / Q000008:administration & dosage* / Q000378:metabolism; D004042:Dietary Fats, Unsaturated / Q000008:administration & dosage* / Q000378:metabolism; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated / Q000008:administration & dosage / Q000378:metabolism; D005260:Female; D006801:Humans; D006937:Hypercholesterolemia / Q000178:diet therapy*; D008297:Male; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D004041:Dietary Fats; D004042:Dietary Fats, Unsaturated; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated; D002784:Cholesterol