Risk Factors You Can Modify To Decrease Your Risk of Breast Cancer
Obesity and weight gain during adult life increases risk of postmenopausal (but not premenopausal) breast cancer because fat tissue increases estrogen levels. The adverse effect of obesity on breast cancer is strongest in women who do not use HRT. In the Nurses’ Health study, women gaining 22 pounds or more after menopause increased their risk by 18% while losing at least 22 pounds lowered their breast cancer risk by 57%.
A meta-analysis of over 40 epidemiologic studies showed that drinking 2 drinks a day may increase the risk of breast cancer by 21%. The Million Women study published in 2009 showed than drinking even 1 drink a day increases the risk of breast cancer. Each additional alcoholic drink regularly consumed per day was associated with 11 additional breast cancers per 1000 women. Even though alcohol has been previously associated with cardiac benefits, Michael Lauer MD of the US National Heart, Lung and Blood Institute editorialized that the excess cancer risk seen in this study may outweigh the benefits.
Several studies show that exercising 45 to 60 minutes daily for 5 or more days per week reduces the risk of breast cancer in postmenopausal women. One study showed regular physical activity, regardless of intensity, may reduce the risk of breast cancer in postmenopausal women.
Breast feeding has consistently been shown to lower the risk of breast cancer. A study of 47 epidemiological studies in 50,302 women with breast cancer and 96,973 women without breast cancer showed that the incidence of breast cancer was reduced by 4.3% for every 12 months of breast feeding. The protective effect is thought to be related to the delay in resumption of ovulatory cycles from breast-feeding.
Fibrocystic Breast Disease
Women diagnosed with fibrocystic breast disease (FBD) and a family history of breast cancer are at increased risk for breast cancer if a breast biopsy shows certain proliferative changes even though the pathology was benign for cancer. Symptoms of FBD may sometimes be improved with therapies including evening primrose oil, vitamin E, iodine, and diindolemethane, and avoiding caffeine.
Vitamin D Deficiency
Two 2010 meta-analysis studies showed that maintaining sufficient levels of serum vitamin D protects against breast cancer. One study showed a 41% reduction in breast cancer risk in case-control studies. The other study showed among those with the highest intake of vitamin D, the risk of breast cancer was reduced by 45% compared to those with the lowest intake of vitamin D.
Laboratory studies also support this protective action against breast cancer through several mechanisms. A 2010 review article reported that a vitamin D byproduct promotes apoptosis (programmed self-destruction) of breast cancer cells, decreases excess estrogen production and has anti- inflammatory actions.
Vitamin D is the “sunshine vitamin” and you can often get adequate levels of vitamin D by regularly receiving mid- day sun exposure in the late spring, summer, and early fall, exposing as much of the skin as possible for 20-30 minutes but being careful not to burn. Individuals with dark skin may need up to six times longer exposure time because of less ab- sorption. In winter, it’s often more challenging to get adequate levels from sun exposure alone.
For those who cannot get adequate sun exposure, vitamin D supplementation is recommended. The Canadian Cancer Society recommends a minimum of 1000 IU of vitamin D3 but much higher levels are often needed. Dr. John Cannell, Director of the Vitamin D Council suggests adults often need around 5000 IU of vitamin D3. He suggests monitoring blood 25-hydroxy Vitamin D to ensure adequate levels. Dr. Cannell also emphasizes the importance of other nutrients such as magnesium, zinc, vitamin K2, boron and a small amount of vitamin A, which improve the utilization of vita- min D.
Abnormal Estrogen Metabolism
This section may seem a little technical but do not gloss over it because it’s it is important for you to understand. Or at least come back to review it later. Anything taken into your body such as medicines or hormones produced by the body, has to be processed by the liver which is responsible for their orderly disposition. The liver is an important organ that has to break down any hormone, food, medicine or chemical you take into your body. Toxic materials are broken down into byproducts that can be easily removed from the body. The breakdown of these substances sometimes produces substances more beneficial to the body. For example, whether you’re still making estradiol or taking it, effects of estradiol occur from the estradiol itself and other effects occur through chemical reactions in the liver that produce byproducts from the processing of estradiol. The medical term for these byproducts is “downstream metabolites.”
Estradiol is broken down in the liver to various byproducts called 4-hydroxyestrone (4-byproducts) and 16-hy- droxyestrone (16-byproducts.) Excess levels are associated with a higher risk of breast cancer, ovarian cancer, and uterine cancer so we call these the “bad” estrogens. Estradiol is also converted to 2-hydroxyestrones (2-byproducts) that carry a lower risk of cancer and these are called the “good” estrogens. A small amount of the 16-byproducts is necessary to maintain strong bones. The goal is a healthy balance between these three estrogen byproducts. The 4-byproducts are the most harmful so the liver has a chemical process called methylation to neutralize these bad estrogens.
In 2006, a review article in the New England Journal of Medicine gave an extensive review of the literature supporting the role of estrogen metabolites as cancer initiators. While this may not be the only cause of these cancers, it is a risk factor that can often be modified with healthy lifestyle and supplements. There are not yet extensive randomized controlled trials showing benefit from these therapies. However, if the therapy is low-risk and possibly beneficial, why would we NOT want to consider this therapy to reduce cancer-promoting byproducts to improve the safety of estrogen therapy?
The relative amounts of “bad” estrogens can be improved with lifestyle intervention such as exercise, flaxseed, improved nutrition and the intake of cruciferous vegetables. Cruciferous vegetables include broccoli, cauliflower, cabbage, kale, and brussel sprouts. For women who may not consume adequate amounts of these vegetables, nonprescription supplements called diindolemethane (DIM) and indole-3-carbinol (I3C) contain the active protective ingredients of these vegetables.
In addition, recent studies in the cardiology literature show that when the 2-byproduct undergoes methylation, it is converted to 2-methoxyestradiol which protects against heart disease and has an anti-cancer effect. (Studies in the oncology literature are underway to study the potential use of this byproduct as an anti-cancer drug) When deficient, this beneficial byproduct can often be increased by use of supplements. Why would we NOT want to increase production of this beneficial byproduct to maximize the full benefit of estradiol therapy?
Methylation can be improved with nonprescription supplements including vitamin B12, folic acid, zinc, resveratrol, N-acetylcysteine, trimethylglycine, and S-adenosyl methionine (SAM-e). I would advise against any of the dietary supplements unless you are working with a knowledgeable professional who can monitor your levels and advise you on appropriate doses of these products. The estradiol byproducts can be measured in the urine. The test requires collecting the first morning urine made over the previous 8 hours, sending a sample of urine from that total volume and indicating the total volume. After therapy to improve estrogen metabolism has been initiated, follow-up testing is repeated in three months to assess whether there has been improvement. Thereafter testing is done on a yearly basis. With correction of estrogen metabolism, women often report reduction in breast tenderness, PMS and other menstrual related complaints. It also gives us another parameter to monitor to improve safety and enhance the full benefit of estradiol.
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The content of this blog series is for informational purposes only and is not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. This blog series may discuss nutritional products and protocols that have not been evaluated by the U.S. Food and Drug Administration. These products or the information contained on this website is not intended to diagnose, treat, cure or prevent any disease. All website content is © Copyright 2012 by Marina Johnson MD – All Rights Reserved
Excerpt from “Outliving Your Ovaries” © 2012 by Marina Johnson MD.
Dr. Johnson has no financial conflicts of interest or ties to any pharmaceutical company.
Her only objective is determining the most effective, safest therapy for patients.