Women’s Health Update

by Tori Hudson, ND

Research News

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Ponder

Soy and Breast Cancer Prognosis: Continued Clarity

Data from the Women’s Healthy Eating and Living (WHEL) were used to examine the effect of soy intake on breast cancer prognosis in 3088 breast cancer survivors. These women were early-stage breast cancer patients who were followed for an average of 7.3 years. Soy isoflavone intakes were measured after the diagnosis with a food frequency questionnaire. The association between soy intake and breast cancer recurrence and/or death was then tracked. As soy isoflavone intake increased, the risk of death decreased. Women at the highest levels of soy isoflavone intake (> 16.3 mg isoflavones/day) had a 54% reduction in risk of death.

Comment

: This is the third epidemiologic study to report no adverse effects of soy foods on the prognosis of breast cancer. Soy foods, which contain isoflavones, a phytoestrogen, shows both antiestrogenic and estrogenlike properties. The confusion and controversy has been that many studies have shown that isoflavones may protect against an initial breast cancer, but in a very few laboratory studies, certain isoflavone components of soy have been able to enhance the proliferation of breast cancer cells in select doses, and have been able to both promote and inhibit mammary tumor growth in rats.

However, in 2009, some clarity began to emerge for breast cancer patients. In breast cancer survivors, one study in Asian women (the Shanghai Breast Cancer Survival Study) and anoother in US women (the Life after Cancer Epidemiology study), suggest that soy-containing foods do not negatively affect breast cancer prognosis, do not counteract the effect of the breast cancer drug tamoxifen, and may in fact provide potential benefits in decreasing risk of recurrence or death from breast cancer.

The current study has explored this issue further, by examining data from a randomized controlled trial: the WHEL study. The results of this study, and the two previous in 2009, should give practitioners and women alike great reassurance as to the safety of soy consumption for women with who have/have had a diagnosis of breast cancer. We no longer need to advise against soy consumption for breast cancer survivors. This is great news, given all the potential health benefits of soy for bone health, cardiovascular health, and as a part of a whole-food and healthful diet.

Caan B, Natarajan L, Parker B, et al. Soy food consumption and breast cancer prognosis. Cancer Epidemiol Biomarkers Prev. 2011;20(5):854–858.

Red Wine As an Aromatase Inhibitor:

Would It Be a Good Idea?

For this pilot study, premenopausal women with regular ovulatory cycles for 12 months with a body mass index between 18.5 and 30, no alcohol abuse, and normal serum liver function tests were recruited. Participants were randomly assigned to either red wine or white wine during the first study cycle and the other wine for the second cycle, consuming 8 ounces of the wine daily for 3 weeks. These 36 women were instructed not to drink any other alcohol or grape products during the research period. Blood was collected in the early follicular phase and the midluteal phase at baseline and during each wine phase, with a washout period between.

Red wine consumption was associated with a significantly higher free testosterone and lower sex hormone binding globulin (SHBG) compared with white wine consumption. A nonstatistically significant trend toward lower levels was seen in total estradiol levels with the red wine compared with white wine. There was also a nonstatistically significant higher FSH level with red wine while LH was significantly different. According to the authors, these results of a higher free testosterone, lower SHBG, and higher LH suggest an aromatase-inhibiting effect of red wine.

Comment

: Numerous epidemiologic studies have reported an increased risk of breast cancer associated with wine, beer, and liquor consumption. In the Million Women Study, a study of over 1 million middle-aged women in the UK, even moderate alcohol consumption was associated with an increased risk. The average amount of alcohol consumed by women in developed countries is 6.0 g/day, equivalent to about half a unit/drink of alcohol per day. The relative risk of breast cancer was 1.32 for an intake of 35 to 44 g per day and 1.46 if 45 or more g per day of alcohol. That turned out to be an increase of 7.1% relative risk of breast cancer for each additional 10 g per day of alcohol (for each additional glass). If this relationship is causal, then these results suggest that approximately 4% of breast cancers in developed countries are due to alcohol.

The aromatase inhibitor (AI) class of drugs are used mainly to manage estrogen–receptor positive breast cancers in postmenopausal women. AIs work by preventing the conversion of androstenedione and testosterone into estrogen and, by doing so, lead to increases in serum testosterone and decreases in estradiol, estrone, and SHBG. AIs are found not only in red wine, but in grapes, grape juice, grape seed extract, and some mushrooms. White wine apparently does not contain AIs.

The benefit/risk balance of alcohol for women is complicated. Yes, there can be benefits in up to a certain amount of alcohol consumption, particularly cardiovascular. However, the amount to gain optimal benefit may exceed the amount that does harm, particularly in the realm of cancers of the larynx, oral cavity, pharynx, and esophagus. Statistically significant increases in risk also exist for cancers of the breast, stomach, colon, rectum, liver, and ovaries.

In summary, it appears that the majority of epidemiologic studies do provide scientific evidence for a positive association between breast cancer risk and alcohol consumption. Less than 1 drink per day is unlikely to significantly affect breast cancer risk – unless you are have or have had breast cancer, in which case less than 3 drinks per week may be the threshold to not increase your risk of recurrence, according to a recent study. Regular alcohol at 1 or 2 drinks per day may contribute to a modest increase in breast cancer risk. My view is that we know many ways to reduce our risk of cardiovascular disease, but few ways to lower our risk of breast cancer. Alcohol intake is one of those lifestyle factors that we can modify in order to reduce our risk.

Shufelt C, Merz CN, Yang Y, et al. Red versus white wine as a nutritional aromatase inhibitor in premenopausal women. J Women’s Health. Epub 2011;doi:10.1089/jwh.2011.3001.

Dr. Tori Hudson graduated from the National College of Naturopathic Medicine (NCNM) in 1984 and has served the college in many capacities over the last 25 years. She is currently a clinical professor at NCNM and Bastyr University; has been in practice for over 28 years; and is the medical director of the clinic A Woman’s Time in Portland, OR, and director of research and development for Vitanica, a supplement company for women. She is also a nationally recognized author, speaker, educator, researcher, and clinician.