STUDY CASTS DOUBT ON THE HYPOTHESIS THAT LOWFAT DIETS CAN REDUCE THE RISK OF COLORECTAL CANCER, BREAST CANCER AND CARDIOVASCULAR DISEASE IN POSTMENOPAUSAL WOMEN

The Women's Health Initiative Dietary Modification Trial is a randomized controlled trial with 48,835 postmenopausal female participants.  The women were recruited from 40 clinical centers throughout the United States.  The baseline mean characteristics for both the intervention and the control group were 37.8% of calories from fat, 12.7% of calories from saturated fat, about 16.5% of calories from protein, 45.6% of calories from carbohydrates, and 3.6 daily servings of fruits and vegetables.  The intervention was designed to promote a reduction of total fat intake to 20% of calories while increasing fruit and vegetable servings to five per day and grain servings to six per day.  Though adherence was greater at the beginning of the trial, at the end of year 6, the intervention group reported an 8.2% lower mean total fat intake and a 2.9% lower mean saturated fat intake than the control group, which was consuming 37.0% of calories from total fat and 12.4% of calories from saturated fat.  Both groups reported reduced caloric intake from a mean of about 1790/day for both groups to 1431/day for the intervention group and 1546/day for the control group. 

The February 2006 issue of the Journal of the American Medical Association reported the results of this dietary modification as related to specific diseases in three separate articles. The study shows that a lowfat diet may not reduce the risk of colorectal cancer, breast cancer and cardiovascular disease in postmenopausal women. 

Low-Fat Dietary Pattern and Risk of Cardiovascular Disease, pp. 655-666

• After a mean of 8.1 years of follow up, the incidences of total, fatal, or nonfatal stroke were not influenced by the dietary interventions. 

• At year 3, the dietary intervention had no statistically significant effects on levels of triglycerides or HDL-C; ratio of total cholesterol to HDL-C, levels of non-HDL-C, lipoprotein, glucose, or insulin; or insulin resistance.  In the latter 3 factors, there were trends toward improvement.

• After 3 years, LDL-C reduced more in the intervention group (9.7mg/dL vs. 6.2 mg/dL). This reduction was similar to the change predicted using current equations based on differences in fatty acid intakes.

• Compared with those in the control group, a trend (not s.s.) was observed toward reduction of CHD risk among those in the intervention group who reached the lowest levels of saturated fat (<6.1% of energy), trans fat (<1.1% of energy) or the highest intakes of vegetables and fruits (>/= 6.5 servings/d).

Citation:
Low-Fat Dietary Pattern and Risk of Cardiovascular Disease. Howard BV and others. The Journal of the American Medical Association.2006 Feb 8;295(6):655-66.

To read the abstract, go to
Low-Fat Dietary Pattern and Risk of Cardiovascular Disease

Low-Fat Dietary Pattern and Risk of Colorectal Cancer, pp. 643-654

• As of March 31, 2005, there was a 0.13% incidence rate of colorectal cancer in the intervention group and a 0.12% incidence rate in the control group, similar to national statistics for women in this age range.

• There was no evidence of reduced risk for any category of colorectal cancer outcome associated with the intervention.

• There were no effects noted relative to energy intake, percentage of energy from fat and/or saturated fat, or dietary fiber.

• There were no effects noted relative to servings of vegetables and fruits, of red meat, or of grains or folate intake.

• The authors noted that despite the significant dietary changes, the hazard ratio for the intervention group was actually in the direction of an increased risk.

Citation:
Low-Fat Dietary Pattern and Risk of Colorectal Cancer. Beresford SAA and others. The Journal of the American Medical Association.2006 Feb 8;295(6):643-54.

To read the abstract, go to
Low-Fat Dietary Pattern and Risk of Colorectal Cancer

Low-Fat Dietary Pattern and Risk of Invasive Breast Cancer, pp. 629-642

• After approximately 8 years of follow-up, breast cancer incidence was 9% lower for women in the dietary intervention group compared with women in the contol group.  This difference was not statistically significant and the authors suggest that chance may provide the explanation for the slightly lower rates in the intervention group.

• Women in the intervention group with a higher baseline percentage of energy from fat showed greater evidence for reduced breast cancer risk. This indicates that women with diets very high in fat may reduce risk by following a lowfat diet plan.

Citation:
Low-Fat Dietary Pattern and Risk of Invasive Breast Cancer. Prentice RL and others. The Journal of the American Medical Association.2006 Feb 8;295(6):629-42 .

To read the abstract, go to
Low-Fat Dietary Pattern and Risk of Invasive Breast Cancer

To those of you who ordered a free School Wellness Tool Kit, it will be shipped in early March.  If you haven't ordered and you're interested in becoming involved in the wellness program in your school, you may order a kit by e-mailing FREE SCHOOL WELLNESS TOOL KIT. Please give us your UPS delivery address and phone number (for UPS purposes).  Be sure to put "School Wellness Tool Kit" in the subject line. 

NEWSLETTER TOOLS

      Funded by Cattlemen's Beef Board         Managed by National Cattlemen's Beef Association