Cholesterol appears to stimulate the growth of human breast cancer cells, which may explain why phytosterol-rich foods such as pumpkin seeds are associated with reduced breast cancer risk.
One in eight American women will be diagnosed with breast cancer in their lifetimes. There are a number of compounds in plant foods that may protect against breast cancer by a variety of mechanisms. I’ve talked about the benefits of broccoli, flaxseeds and soy foods, but this recent study out of Germany reported something new. Evidence for reduced breast cancer risk associated with consumption of sunflower and pumpkin seeds. Sunflower and pumpkin seeds were associated with reduced breast cancer risk, which they initially chalked up to the lignans in the seeds, something else I’ve talked about, but their lignan lead didn’t pan out. Maybe it’s the phytosterols found concentrated in seeds.
There is evidence phytosterols may be anticancer nutrients that may play a role in reducing breast cancer risk. I thought phytosterols just lowered cholesterol? What does cancer have to do with cholesterol?
Well, increasing evidence demonstrates the role that cholesterol may play in the development and progression of breast cancer. Cancer feeds on cholesterol. Transformed cells take up LDL, so-called bad cholesterol, and are capable of stimulating the growth of human breast cancer cells in a petri dish. See all these little red dots, that’s fat that the breast cancer cells are gobbling up.
The ability to accumulate fat and cholesterol may enable cancer cells to take advantage of people eating high fat and high cholesterol diets. Increased dietary cholesterol intake may result in increased breast cancer risk, and may at least partially explain the benefit of a low-fat diet on lowering human breast cancer recurrence.
Though data has been mixed, the largest study to date found a 17% increased risk in women who had cholesterol over 240, compared to women whose cholesterol was under 160, though they cannot rule out that there may be something else in cholesterol-raising foods that’s raising breast cancer risk.
Tumors suck up so much cholesterol that LDL has been considered a vehicle for targeting antitumor drugs to cancer cells. Since cancer feeds on cholesterol, maybe we could stuff some chemo into it as like a poison pill. That’s probably why people’s cholesterol levels drop so low after they get cancer—the tumor is eating it up.
In fact, patient survival may be lowest when cholesterol uptake is highest. High LDL receptor content in breast cancer tissue seems to indicate a poor prognosis, suggesting that breast tumors rich in LDL receptors may grow rapidly in the body. We’ve known about this for decades. You can tell this is an old study: back in the 80’s only 1 in 11 American women got it.
To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is just an approximation of the audio contributed by Katie Schloer.
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If cholesterol increases breast cancer risk, what about the use of cholesterol-lowering drugs? That’s the subject of my next video, Statin Cholesterol Drugs and Invasive Breast Cancer.Other foods I mentioned protective against breast cancer include:
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