title: Plasma triacylglycerol and HDL cholesterol concentrations confirm self-reported changes in carbohydrate and fat intakes in women in a diet intervention trial.
abstract: Diet intervention trials are currently testing whether reduced fat intake can reduce the risk and progression of breast cancer. Energy from dietary fat is generally replaced by energy from carbohydrate in these studies, and altering the proportion of energy from dietary carbohydrate and fat has been shown to affect plasma lipid concentrations in controlled feeding studies. The purpose of this study was to examine the effect of increased carbohydrate and reduced fat intakes on plasma lipids in a randomized, controlled trial that is testing the effect of diet modification on risk for recurrence and survival in women previously treated for breast cancer. Plasma concentrations of lipids and related factors were measured at enrollment and 1-y follow-up in 393 women enrolled in the trial. Dietary goals for the intervention group focused on an increase in vegetable, fruit and fiber intakes, and reduced fat intake. Women assigned to the intervention group significantly reduced fat intake (from 28.1 to 21.0% of energy), and significantly increased intakes of carbohydrate (from 56.9 to 65.3% of energy) and fiber (from 21.0 to 29.6 g/d) (P < 0.05). Body weight did not change significantly in either study group. A small but significant increase in fasting plasma triacylglycerol concentration, and decreases in HDL cholesterol and apoprotein-A1 concentrations, were observed in the intervention group (P < 0.05) but not in the comparison group. Changes in total cholesterol, LDL cholesterol, apoprotein-B, lipoprotein (a), and insulin concentrations, and in the LDL cholesterol/HDL cholesterol ratio, were not observed in either group. The lipid responses that were observed in this study provide biological evidence that validates the self-reported change in dietary intakes of fat and carbohydrate in response to the intervention efforts. The degree of change in these lipid concentrations was small and does not suggest increased cardiovascular disease risk.
authors.affiliation: Department of Family and Preventive Medicine, Reproductive Medicine, and Medicine, University of California, San Diego, CA, USA. clrock@ucsd.edu
authors.forename: Cheryl L
authors.initials: CL
authors.lastname: Rock
authors.forename: Shirley W
authors.initials: SW
authors.lastname: Flatt
authors.forename: Cynthia A
authors.initials: CA
authors.lastname: Thomson
authors.forename: Marcia L
authors.initials: ML
authors.lastname: Stefanick
authors.forename: Vicky A
authors.initials: VA
authors.lastname: Newman
authors.forename: Lovell
authors.initials: L
authors.lastname: Jones
authors.forename: Loki
authors.initials: L
authors.lastname: Natarajan
authors.forename: John P
authors.initials: JP
authors.lastname: Pierce
authors.forename: R Jeffrey
authors.initials: RJ
authors.lastname: Chang
authors.forename: Joseph L
authors.initials: JL
authors.lastname: Witztum
mesh_terms: D016588:Anticarcinogenic Agents / Q000627:therapeutic use; D015992:Body Mass Index; D001943:Breast Neoplasms / Q000473:pathology / Q000517:prevention & control*; D008076:Cholesterol, HDL / Q000097:blood*; D004034:Diet Surveys; D004040:Dietary Carbohydrates / Q000008:administration & dosage / Q000627:therapeutic use*; D004041:Dietary Fats / Q000008:administration & dosage / Q000627:therapeutic use*; D002149:Energy Intake; D015444:Exercise; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood*; D011939:Mental Recall; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000517:prevention & control*; D013629:Tamoxifen / Q000627:therapeutic use; D014280:Triglycerides / Q000097:blood*
chemical_list: D016588:Anticarcinogenic Agents; D008076:Cholesterol, HDL; D004040:Dietary Carbohydrates; D004041:Dietary Fats; D007328:Insulin; D014280:Triglycerides; D013629:Tamoxifen