Implementation of a 4-y, high-fiber, high-fruit-and-vegetable, low-fat dietary intervention: results of dietary changes in the Polyp Prevention Trial.
BACKGROUND
The Polyp Prevention Trial (PPT) was a multicenter randomized clinical trial designed to determine the effects of a high-fiber (4.30 g/MJ), high-fruit-and-vegetable (0.84 servings/MJ), low-fat (20% of energy from fat) diet on the recurrence of adenomatous polyps in the large bowel.


OBJECTIVE
Our goal was to determine whether the PPT intervention plan could effect change in 3 dietary goals and to examine the intervention's effect on the intake of other food groups and nutrients.


METHODS
Participants with large-bowel adenomatous polyps diagnosed in the past 6 mo were randomly assigned to either the intervention (n = 1037) or the control (n = 1042) group and remained in the trial for 4 y. Three dietary assessment instruments were used to measure dietary change: food-frequency questionnaires (in 100% of the sample), 4-d food records (in a 20% random cohort), and 24-h dietary recalls (in a 10% random sample).


RESULTS
Intervention participants made and sustained significant changes in all PPT goals as measured by the dietary assessment instruments; the control participants' intakes remained essentially the same throughout the trial. The absolute differences between the intervention and control groups over the 4-y period were 9.7% of energy from fat (95% CI: 9.0%, 10.3%), 1.65 g dietary fiber/MJ (95% CI: 1.53, 1.74), and 0.27 servings of fruit and vegetables/MJ (95% CI: 0.25, 0.29). Intervention participants also reported significant changes in the intake of other nutrients and food groups. The intervention group also had significantly higher serum carotenoid concentrations and lower body weights than did the control group.


CONCLUSIONS
Motivated, free-living individuals, given appropriate support, can make and sustain major dietary changes over a 4-y period.
Lanza
E
E
National Cancer Institute, Bethesda, MD, USA. el33t@nih.gov
Schatzkin
A
A
Daston
C
C
Corle
D
D
Freedman
L
L
Ballard-Barbash
R
R
Caan
B
B
Lance
P
P
Marshall
J
J
Iber
F
F
Shike
M
M
Weissfeld
J
J
Slattery
M
M
Paskett
E
E
Mateski
D
D
Albert
P
P
D018256:Adenomatous Polyps / Q000178:diet therapy / Q000517:prevention & control*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003111:Colonic Polyps / Q000178:diet therapy / Q000517:prevention & control*; D015930:Diet Records; D018752:Diet, Fat-Restricted; D004041:Dietary Fats / Q000008:administration & dosage* / Q000009:adverse effects; D004043:Dietary Fiber / Q000008:administration & dosage*; D002149:Energy Intake; D005247:Feeding Behavior; D005260:Female; D005638:Fruit; D015438:Health Behavior; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D011939:Mental Recall; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D015596:Nutrition Assessment; D052756:Nutritional Sciences / Q000193:education; D011795:Surveys and Questionnaires; D014675:Vegetables
D004041:Dietary Fats; D004043:Dietary Fiber