Can eating high protein foods cause HER2 breast cancer?

Decker

Since HER2 breast cancer is a result of an over-amplification of HER2 proteins, is there a potential link between eating high protein foods (e.g. meat, eggs, milk, whey protein powder etc.) and causing HER2 breast cancer?

December11

When I was first diagnosed, I did a lot of reading. The only thing I remember being associated with HER2 was a high fat diet, but I don't remember reading anything about protein.

ShetlandPony

No. Proteins are large biomolecules that perform all sorts of functions in our bodies. I mean, they’re everywhere. So even though Her2 is a protein and food has other proteins, there is no connection. That said, some high-protein foods, for example beef and soy protein isolate, are in that group of generally not-so-healthy foods that people might choose to minimize in their diet. There are other high-protein foods that are really good for us, such as walnuts and salmon.

Here is a resource I like:

https://foodforbreastcancer.com/articles/breast-cancer-diet-for-her2%2b-patients-and-survivors

P.S. Don’t blame yourself, Decker. And trying to figure out WHY can drive you crazy.

BlueGirlRedState

I don't think that protein is like sugar, where cancer feeds on it, so reducing added sugar is a healthy choice. When I asked about soy, phytoestrogens, and ER+ cancer, the advice that soy as food is fine (beans, tofu, tempeh), but to stay away from adding soy protein to meals.

sbelizabeth

My son was in medical school when I was diagnosed. We talked about what caused my BC. He said "mom, there is no smoking gun."

WC3

Decker:

One of the definitions of protein is "any of a class of nitrogenous organic compounds that consist of large molecules composed of one or more long chains of amino acids and are an essential part of all living organisms, especially as structural components of body tissues such as muscle, hair, collagen, etc., and as enzymes and antibodies."

An analogy would be the things you would find in a hardware store...doors, windows, light fixtures, switches.

The HER2 protein is fashioned in to a type of switch called a HER2 receptor, that, when flipped "on", causes a chain of events which ultimately results in cell proliferation.

When you consume proteins, they are broken down in to amino acids which are then used to construct the proteins necessary for your body to function.

Many types of cells have HER2 receptors. Though many of us seem largely unaffected when our HER2 receptors are inhibited by Herceptin and Perjeta, they likely serve some vital function in our healthy cells at some point in our lives.

HER2 amplified cancer cells have too many HER2 receptors, among other things. I've read around 2 million, while normal cells have about 20.

Low protein diets...at least diets low in animal proteins (and maybe also low in soy?) are associated with lower rates of cancer. However, it's not feasible to stop HER2 positive cancer by completely starving yourself of protein because it would be like trying to stop a hypothetical cancer that is driven by oxygen by holding your breath. You would die from holding your breath because your other cells also need oxygen. Also, humans have the ability to synthesize some amino acids from certain plant based foods, which your body will form in to proteins. As an interesting aside, cats cannot do this. They are obligate carnivores and must eat meat.

There is some evidence to suggest though that the source of the protein you consume matters with respect to risk of developing cancer. For example, protein from animal sources raises blood serum levels of insulin like growth factor 1 (IGF-1), high levels of which has been associated with an increased risk of certain cancers, while protein from plant sources, with perhaps the exception of soy, has not been found to do this as far as I know.

But I'm not a dietician or nutritionist. If you are interested in learning more about these things, I recommend consulting with a dietician or nutritionist at your local cancer center.