Nutrition: Fighting Cancer With Food (cont.)

Member: That is good to know because living in northern Wisconsin, there is a very short growing season for fresh produce.

Scroggs: The important thing is to get the fruits and vegetables in.

Member: How important are omega-3 fatty acids for someone concerned about recurrence?

Scroggs: This is a tough question because the research is not yet definite, but I can tell by the question that you've done your research. Omega-3, in a couple of studies, has shown reduced risk with prevention. But there are other studies that show there's a conflict in results where it doesn't show protection or it's neutral. So what do you do? Omega-3 is being looked at also for benefit for the immune system and it's already known that it reduces risk for heart disease. Therefore, a healthy choice would be to introduce omega-3 sources into your diet. Some examples:

  • Substituting cold-water fish for red meats.
  • Walnuts can be a decent source.
  • Sesame seeds that can be toasted and thrown on a salad can be a good source.
  • Flaxseed is also a good source of omega-3 and the flaxseed oil can be used in salad dressing.

Member: What is your opinion concerning soy intake and ER+ [estrogen-receptor positive] breast cancer?

Scroggs: My opinion is that this is the most dreaded question. You know as a healthcare provider, I am in this to help people. I get this question almost daily and the reason I dislike it is because there is no clear-cut answer. I'll do my best. Soy and the phytoestrogen genistein have been researched extensively the past 12 or so years and look very promising in prevention. The problem with an estrogen-receptor positive diagnosis is that we truly don't know if it's working as an estrogen or an anti-estrogen in your body. This is a decision that you will have to make on your own and I will try and give you some guidance. The concern comes from studies showing increased mammary tumor growth with estrogen supplementation. These are not human studies, these are mammary cell lines (breast cell lines) and in rodent studies. We don't know how taking a whole food, such as tofu or soybeans, introduced into a whole body system functions.

So what do you do? Soy has been shown to reduce risk of heart disease. There may be a role in bone protection. It's a great plant source for protein, includes all essential amino acids, has no cholesterol, is low in saturated fats, and it has other phytochemicals that have cancer-fighting properties. But with an estrogen-receptor positive diagnosis you know there's a tumor that feeds on estrogen. So we're hesitant to put something similar to estrogen, a phytoestrogen, into that picture. Will it feed the tumor? There is a proposed mechanism that it works similar to tamoxifen and blocks the receptor sites, therefore, yielding a protective factor. Some guesses, and these are guesses, are that it possibly won't hurt to have somewhere between two to five servings per week. But no one knows; it's a tough question and there's no clear answer at this time. I would refer you back to your oncologist to help with direction and guidance.

Another point might be to understand that there are phytoestrogens in other foods. Genistein is in other foods. It's in other beans, not just soybeans. It's in other plants, including apples and dates. So there's no way to 100% eliminate it from your diet. And there are other phytoestrogens in foods as well; it's just that soy has a more concentrated amount, relatively speaking.

There's also recent info looking at soy and it's protection in the Asian diet, for example, as being available through the lifecycle. With prevention and reducing risk, there is some thought that it's more appropriate to have the soy products in the diet, perhaps when breast buds are forming. And that may be where the protection comes from. We don't know if there is protection with adding soy later in life, in our 30s, 40s, or 50s, for breast cancer, specifically. But again, for prevention, there is evidence that it reduces the risk of heart disease and has a number of other positive aspects that I previously mentioned. I know I didn't answer the question; I did give a recommendation. I'm sorry there is no answer. Stay tuned!

Moderator: Thanks for joining us, members, and thanks to Sally Scroggs for being our guest.

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