Body mass index (BMI) is a popularly used measure of body fat percentage we carry.

Lately, however, we’ve discovered that BMI is not the most accurate way to measure just how much of our weight can be attributed to body fat.

And when body fat is associated with a deadly cancer, this really matters…

What is hormone-positive breast cancer?

Contrary to what you may think, there’s more than one type of breast cancer.

Estrogen receptor-positive (ER-positive) breast cancer, also called hormone-positive breast cancer, means there are specific estrogen receptors on the tumor cells.

When estrogen binds with these receptors, it stimulates the cancer cells to grow and reproduce. Therefore, one of the main goals of therapy or intervention with hormone-positive cancer is to reduce hormonal stimulation as much as possible.

Why weight matters for post-menopausal women

Estrogen is made by the ovaries during the years before menopause, but it’s also made in fat cells where enzymes convert other hormones to estrogens. After menopause, fat is the primary source of estrogen production in the body.

So of course, maintaining a healthy weight is a prime way for post-menopausal women to reduce their risk for this type of breast cancer.

But more than weight, the amount of excess fat a woman is carrying is of primary importance in determining her risk for this cancer.

Traditionally, body mass index (BMI) has been the way body fat has been measured.

But now we’re finding that it’s not the most accurate way.

BMI underestimates ER+ breast cancer

BMI does not account for age, sex, or ethnicity. So a team of Spanish researchers used another validated measure of body fat that does account for these factors, known as CUN-BAE.

Both BMI and CUN-BAE numbers were obtained for 1033 white post-menopausal women with breast cancer, as well as for 1143 who were cancer-free but matched for age and sex.

Using BMI, they found an estimated 19.9 percent of breast cancer cases to be hormone-positive, but using the alternative measurement, about 41.9 percent were determined to be hormone-positive.

“Our findings suggest that the population impact could be underestimated when using traditional BMI estimates, and that more accurate measures of body fat, such as CUN-BAE, should be considered when estimating the cancer burden attributable to obesity in postmenopausal breast cancer.”

The team also noted that, when planning effective strategies to prevent breast cancer, this difference is crucial.

Lose weight to reduce risk for ER+ breast cancer

If you’re a woman who is beyond menopause, the best way to help prevent estrogen receptor-positive breast cancer, other than maintaining a healthy weight, is to control cholesterol.

Research has shown that byproducts of cholesterol can bind to estrogen receptors and promote the growth of ER+ tumors.

Following a healthy low-fat diet can help you do both…

Whole grain fiber foods, like barley, oats, and brown rice are great at lowering cholesterol. A high-fiber diet promotes the binding of both cholesterol and estrogen in the colon, which reduces reabsorption.

In fact, a Swedish study found that fiber intake from fruit and cereal may play a role in reducing breast cancer risk in postmenopausal women, particularly.

But cutting down on dairy fat and saturated fats is also a must.

Other foods can help tame estrogen and guard against cancer as well, including:

Manuka honey. Researchsuggests that this medicinal honey could be developed into a natural supplement or even a standalone treatment for ER-positive breast cancer, especially for patients who experience resistance to the commonly used therapies.

Cruciferous vegetables like broccoli and kale contain diindolylmethane (DIM), a compound that promotes the healthy metabolism of estrogen.

Green tea. Green tea contains powerful polyphenols that have proven to play a role in resisting a variety of cancers — liver, breast, prostate, lung and skin cancers, among others.

Don’t forget to exercise. Combining aerobics and strength training gets you the most cancer protection from both cancer incidence and mortality.

Sources:

Around 40% of postmenopausal hormone positive breast cancers linked to excess body fat — Eureka Alert

Burden of postmenopausal breast cancer attributable to excess body weight: comparative study of body mass index and CUN-BAE in MCC-Spain study — Journal of Epidemiology and Community Health