Scientific studies have suggested that overweight and obese women are at a higher risk of breast cancer, especially after menopause. Compared to their counterparts who maintain a healthy weight, they may also be at increased risk of developing secondary cancers.
However, the relationship between obesity and breast cancer is complicated. Will losing weight help, or is it too late once you gain weight? Does a fluctuating weight have an overall effect? How can our weight protect against breast cancer? These are some questions we aim to answer in this article.
What is obesity?
In Singapore, obese or overweight women are defined as having a BMI (body mass index) over 22.9. These values are corrected for the Asian population, who physically differ from their western counterparts. More importantly, obesity is defined as abnormal or excessive fat accumulation that endangers health. Hence, some exceptionally muscular individuals with a BMI over 22.9 are thus not unhealthy.
How does obesity cause breast cancer?
Obesity is strongly associated with an increased risk of several types of cancer, including breast cancer. An estimated 55% of all cancers in women occur in those who are overweight or obese. However, is there a direct cause-and-effect chain between obesity and breast cancer?
The answer is yes, for certain kinds of breast cancer. Cancer is essentially an accumulation of mutated cells, which grow invasive and harmful. Obesity plays a part in encouraging these mutations through various mechanisms, such as hormones and inflammation. All fat cells produce estrogen, and excessive fat cells translate to excessive estrogen. Additional estrogen then causes hormone-receptor-positive (HER-positive) breast cancers to develop and grow
I already have breast cancer. Will obesity affect me?
Unfortunately, women with invasive breast cancer have a statistically significant increased risk for second cancers associated with increasing BMI. The association was strongest for a diagnosis of ER-positive second breast cancer.
What can I do? Is it too late?
Many women are conflicted by the volume of data concerning obesity and breast cancer. Some studies suggest that extra fat in the waist carries more risk than around the hips and thighs. Other studies suggest women with excess weight since childhood are exempt from increased cancer risks. This overwhelming information overload can sometimes leave us paralysed, unable to take action and quell our worries.
Take a deep breath
There are small steps we can take right now to make a difference. Regardless of your weight now, avoiding additional weight gain is vital. Any additional fat cells incite a new biological imbalance and, undoubtedly, increase breast cancer risk.
To maintain your current weight, aim for a caloric balance. Every day, we gain calories through the food and drink we consume. We also burn calories from our resting metabolism and any other activities. With a healthy diet and regular physical exercise, we can avoid additional weight gain. It’s best to start small – short walks every other evening, choosing healthier food options some days. Slowly build up your healthy lifestyle, and keep at it consistently.
While the goal is to maintain the current weight, some may find that these small changes even allow weight loss. While this impact on breast cancer risk is still uncertain, it will improve your overall health.
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