A dietary trial with a short-term low-sucrose diet in an Italian population: effects on colorectal mucosal proliferation

Colorectal mucosal proliferation is supposed to predict colon cancer risk. We investigated whether a low-sucrose diet might reduce colorectal mucosal proliferation in a group of patients at higher risk of colorectal cancer after at least two colon adenoma resections. In a pilot phase, 14 patients [12 men and 2 women, 60.3 +/- 5 (SD) yr] were instructed to adopt a low-sucrose diet for one month. Colorectal biopsies were taken twice in the same patients, at the start and the end of the intervention period, and mucosal proliferation was measured by [3H]thymidine uptake in vitro and autoradiography. Although compliance of study participants to dietary modification was high, only a few agreed to two consecutive endoscopies; thus we carried out a randomized study, and 107 patients were assigned to a low-sucrose diet (50 treated patients: 31 men and 19 women, 59.7 +/- 7.5 yr) or instructed to continue their usual diet for one month (55 control patients: 32 men and 23 women, 59.6 +/- 7.7 yr). At the end of this period, colorectal biopsies were obtained. The results of the pilot phase and the randomized study showed that a low-sucrose diet for one-month did not affect proliferation or the distribution of proliferation activity along the crypt. The food-frequency questionnaires indicated that treated patients consumed significantly less sucrose (and fewer total calories) during the dietary modification. Urinary fructose, a measure of dietary sucrose intake, was also reduced at the end of the intervention period. In conclusion, we found no evidence that a low-sucrose diet for one month influences colorectal mucosal proliferation.

Dietary determinants of colorectal proliferation in the normal mucosa of subjects with previous colon adenomas

Dietary determinants of colorectal mucosa proliferation were studied in 69 subjects previously operated for at least two sporadic colon adenomas. Information on recent dietary habits was collected by a validated food frequency questionnaire, and proliferation was measured by [3H]thymidine incorporation in colorectal biopsies by determining the labeling index (LI) and the percentage of LI in the upper part of the crypt, two parameters that are increased in subjects at high risk of colon cancer. The LI was significantly higher in women as compared with men (P = 0.01). Diet showed several associations with colorectal mucosa proliferation: (a) subjects in the highest tertile of fish consumption had a significantly lower LI (P = 0.0013) compared with those in the lower tertiles [5.20 +/- 1.87 versus 6.80 +/- 2.18 (mean +/- SD)]; (b) subjects with a low red meat consumption had lower proliferation in the upper part of the crypt [2.38 +/- 2.10, 5.30 +/- 4.62, and 5.89 +/- 4.82 in the low, middle, and high tertile of consumption, respectively (mean +/- SD); P = 0.0093]; (c) according to estimated nutrient intakes, the LI was lower in subjects reporting a high intake of starch (P = 0.006) and higher in subjects with a low intake of beta-carotene (P = 0.002). The results show that subjects reporting a diet rich in fish, starch, and beta-carotene and low in red meat had lower colorectal mucosa proliferation and a normal pattern of proliferation along the crypt. Given the correlation between colorectal proliferative activity and colon cancer risk, such a dietary pattern might be beneficial for subjects at high risk of colon cancer.

A population-based study of inflammatory bowel disease in Florence over 15 years (1978-92)

BACKGROUND

In the group of inflammatory bowel disease (IBD), ulcerative colitis (UC) and Crohn's disease (CD) are considered to be more frequent in Western countries and in areas with a high socioeconomic development but relatively infrequent in southern Europe. Sporadic reports have indicated a lower incidence and a milder course of the disease in Mediterranean countries. Although conclusive data on this point are still lacking, recent reports suggest an increase in both incidence and prevalence rates.

METHODS

The incidence of UC and CD during the period January 1978 to December 1992 and their prevalence on 31 December 1992 were estimated in the 15-year-old population of the metropolitan area of Florence. Clinical, demographic, and follow-up information was collected for all identified IBD patients.

RESULTS

A total of 796 residents (345 females and 454 males) were newly diagnosed as having IBD during the study period. Of these 593 had UC and 203 CD. The age-standardized incidence rates, calculated for each of five 3-year consecutive periods, rose from 3.8 (in 1978-80) to 9.6 per 100,000 person-years (in 1990-92) for UC and from 1.9 (in 1978-80) to 3.4 (in 1990-92) for CD. Both trends were statistically significant. The prevalence estimated on 31 December 1992 was 121.0 and 40.0 per 100,000 inhabitants for UC and CD, respectively.

CONCLUSIONS

Our results confirm that IBD incidence rates and prevalence in this area of central Italy are currently comparable with those reported in northern Europe. These data are necessary for planning adequate health care services for IBD patients.