What does breast cancer do with cholesterol? Here are some of the potential mechanisms by which cholesterol boosts breast cancer growth. Cholesterol is what our body makes estrogen out of, it’s packaged into LDL, which we saw appeared to increase proliferation of breast cancer cells, decrease patient survival, and it’s a major component of lipid rafts.
Compared with their normal counterparts, cancer cells have higher levels of cholesterol-rich lipid rafts in their plasma membrane, which may be important for cancer cell survival, as well as serve in human cancer development in terms of tumor migration and invasion.
Elevated levels of cholesterol-rich lipid rafts have been found in breast cancer cells, and the thought is that reducing blood cholesterol levels may disrupt lipid raft formation and thereby inhibit breast cancer development. This suggests cholesterol targeting may be used as a cancer therapy.
Controlled laboratory experiments have shown that phytosterols in seeds and nuts at dietary relevant levels appear to inhibit the growth of several types of tumor cells including breast cancer cells, both estrogen-receptor negative and estrogen-receptor positive cancer.
The therapeutic implications are that plant-based diets rich in phytosterols may offer protection against the development of breast cancer. Of course you can’t make a lot of money on pumpkin seeds, so researchers looked to cholesterol-lowering statin drugs.
However, evaluating the safety of statin therapy for women is particularly difficult. Little research has explicitly proceeded from a gender-based perspective. Some petri dish work looked promising, but population studies have shown mixed results. Some studies showed that women on statins had decreased breast cancer risk, some showed increased risk, and most showed no association. But these were all relatively short-term studies. So-called “long-term” statin use was defined as mostly just three to five years. Breast cancer can take decades to grow. The one study that looked at ten or more years of statin use only included 62 cases. Given the increase in statin use over the past few decades, and the fact that they’re commonly prescribed to be taken every day for the rest of people’s lives, the studies published to date have had limited ability to evaluate the impact of long durations of use. And we better figure this out. About one in four women over 45 in this country are on these drugs. But that was the only data we had, until now.
Thousands of breast cancer cases included, and long term statin users—women taking statins for ten years or more, had more than double the risk of both types of breast cancer: invasive ductal carcinoma and invasive lobular carcinoma.
Now, the number one killer of women is heart disease, not breast cancer, so we still need to bring down cholesterol levels. But might there be a way to get the benefits without the risks. Plant-based diets have been shown to lower LDL-cholesterol by over 30%, within just a couple weeks, equivalent to most of the standard cholesterol lowering statin drugs without potential side effects such as increased breast cancer risk.
If you missed the “prequel” video you might be confused about the role cholesterol plays in breast cancer risk. Watch Cholesterol Feeds Breast Cancer Cells.
Though as drugs go, statins are remarkably safe, they can present rare but serious side effects in both men and women: Statin Muscle Toxicity.
How can we lower cholesterol without drugs? It’s Purely a Question of Diet. We can lower our cholesterol by lowering our intake of three things: Trans Fat, Saturated Fat, and Cholesterol: Tolerable Upper Intake of Zero. Where are trans fats found? Trans Fat In Meat And Dairy. Where is cholesterol found? Predominantly eggs: Eggs and Cholesterol: Patently False and Misleading Claims. There are also some foods adept at lowering cholesterol levels:
Michael Greger, M.D.About Michael Greger M.D.Michael Greger, M.D., is a physician, author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous “meat defamation” trial. Currently Dr. Greger proudly serves as the Director of Public Health and Animal Agriculture at the Humane Society of the United States.