Soy Protein and Breast Cancer Risk Reduction

The University of Texas System (UT)

Status and phase: Completed; Phase 2

Conditions: Breast Cancer

Treatments: Dietary Supplement: cow's milk; Dietary Supplement: soy milk

Study type: Interventional

Funder types: Other; Other U.S. Federal agency; NIH

Identifiers

NCT00204477

Army's HSRRB log no. A-10926 (Other Identifier)

DAMD17-01-1-0417 (Other Grant/Funding Number)

1UL1RR029876-01 (U.S. NIH Grant/Contract)

02-422

UTMB GCRC 533 (Other Identifier)

M01RR000073 (U.S. NIH Grant/Contract)

Details and patient eligibility

About

Soy consumption has been associated with reduced risk for developing breast cancer. Ovarian hormones and breast density are considered breast cancer risk markers. We propose to test the hypothesis that consumption of soy protein reduces ovarian steroid hormones and results in a corresponding reduction in breast density comparing to casein protein.

Full description

The aims will be tested by conducting a randomized, double-blind study, with two arms and 100 women in each arm. Premenopausal women will be recruited and randomly allocated to take one of two different dietary supplements daily for 2 years. The two test diets soy protein drink and caseinate protein drink. Multiple blood, urine, and breast fluid samples will be obtained before and during the dietary intervention period and analyzed for ovarian hormones. At baseline and after the intervention period, breast density, and bone density will be assessed by radiological techniques at baseline and 1 yr and 2 yr after protein drink supplementation. The efficacy of the dietary intervention will be determined by comparing mean changes of ovarian steroids, and density of the breast and bone tissues over the 2 year dietary intervention period in the two diet groups with adjustment for baseline values and individual patient characteristics of interest. We predict that 2 years of soya dietary supplements will reduce breast density, which will be explained by individual hormonal changes.

Enrollment: 321 patients

Sex: Female

Ages: 30 to 40 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• healthy premenopausal women
• 30 to 40 years old
• normal mammograms
• regular menstrual cycles

Exclusion criteria

• abnormal mammograms
• first degree relatives with breast cancer
• pregnant or lactating
• peri- or post-menopause
• breast augmentation, reduction, and lifting
• on oral contraceptive medications or exogenous hormones
• medically prescribed diets
• allergic reaction to soy or cow's milk

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Quadruple Blind

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321 participants in 2 patient groups, including a placebo group

Soy milk

Active Comparator group

Description:

Subjects will consume two soy milk drinks from the content of 2 sachets (40 g isoflavone-free soy protein and 600 mg calcium) in place of a small meal, five days per week. Each sachet will contain 20 g soy protein and 300 mg calcium. Content of sachets will be mixed with \~1.6 liter of water for ingestion.

Treatment:

Dietary Supplement: soy milk

Cow's milk

Placebo Comparator group

Description:

Subjects will consume two cow's milk drinks from the content of 2 sachets (40 g cow's milk protein, casein, and 600 mg calcium) in place of a small meal, five days per week. Each sachet will contain 20 g cow's milk protein and 300 mg calcium. Content of sachets will be mixed with \~1.6 liter of water for ingestion. Casein is free of ovarian hormones.

Treatment:

Dietary Supplement: cow's milk