Why is Obesity Linked to Breast Cancer?

GENE CHANGES CAUSE CANCER, resulting in a loss of normal controls on cell growth, division, and spread. We know that being overweight or obese can increase the chances of getting post-menopausal breast cancer, but why?

Researchers from Bergen (Norway) may have some answers: They recently discovered that lipids (more on this substance in a moment) associated with obesity make cancer cells more aggressive.

Let me back up a bit. A lipid is an organic compound that doesn’t dissolve in water. Examples include oils, fats, waxes, hormones, and certain parts of membranes of living cells. Lipids store energy and are chemical messengers.

Breast cancer basics

Breast cancer is the most common cancer among women and is a leading cause of cancer-related death. Risk factors include non-modifiable ones such as age, female sex, and inherited genetics.

Potentially modifiable breast cancer risk factors include tobacco use, alcohol consumption, number of full-term pregnancies, and post-menopausal obesity. Let’s look at the last of these, excessive weight after menopause.

Women who are obese after menopause have an up to 1.12-times higher risk of developing breast cancer driven by so-called female hormones such as estrogen.

Moreover, analyses of collections of studies show obesity is associated with worse breast cancer survivability; the cancer is more likely to metastasize or spread to distant body sites.

Altered neighborhood around the cancer cells

In our lives, our surroundings can influence our behavior. The same phenomenon occurs when it comes to breast cancer that occurs after menopause.

The Norwegian researchers discovered this:

A changed environment surrounding an abnormal cell, associated with a change from normal body weight to overweight or obese, induces the cancer cell to adapt. The result? Malignant cells form a mass or tumor.

Here’s where things get curious: Study author Nis Halberg explains that these findings mean that “even in the absence of new gene mutations, obesity increases the risk that tumors will form.” He puts this in context: Obesity is the cause of about 500 000 new cancer cases annually — a number that will likely grow as obesity rates continue to rise.

Epigenetic change and cancer

I will end with a brief look at epigenetics. The United States Centers for Disease Control and Prevention offers this definition:

Epigenetics is the study of how your behaviors and environment can cause changes that affect the way your genes work. Unlike genetic changes, epigenetic changes are reversible and do not change your DNA sequence, but they can change how your body reads a DNA sequence.

One common form of epigenetic change is known as DNA methylation. DNA methylation involves attaching small chemical (methyl) groups — each methyl group has one carbon atom and three hydrogen atoms — to DNA building blocks.

When methyl groups are attached to a gene, that gene becomes silent, making no proteins. Lifestyle can cause epigenetic changes. I will continue to focus on my four pillars of health:

• Rest (adequate sleep)
• Diet
• Mindfulness
• Movement

Thank you for joining me today.