Published on August 15, 2022
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The link between obesity and cancer risk is clear. Research shows that being overweight and having obesity are linked with a higher risk of getting 13 kinds of cancer:
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Being overweight or obese doesn’t mean that someone will definitely get cancer, but it does mean that they are more likely to get cancer than if they kept a healthy weight.
“The problem with excessive visceral fat is that it affects certain processes in your body. This includes how your body manages hormones, like insulin and estrogen. All of this can lead to an increased cancer risk by affecting how and when cells divide and die.”~ Karen Basen-Engquist, Ph.D., professor in Behavioral Science at MD Anderson Cancer Center.
“The problem with excessive visceral fat is that it affects certain processes in your body. This includes how your body manages hormones, like insulin and estrogen. All of this can lead to an increased cancer risk by affecting how and when cells divide and die.”
~ Karen Basen-Engquist, Ph.D., professor in Behavioral Science at MD Anderson Cancer Center.
Obesity affects the risk of cancer and recurrence in several ways.
Sex hormones, such as estrogen and progesterone, are known to increase risk of breast cancer. Premenopausal women produce most of their estrogen through their ovaries. When they become postmenopausal, they stop producing estrogen via their ovaries, but continue to produce it in their fat tissue — where androgens (male hormones), made primarily in the adrenal glands, are converted to estrogen. As a result, the more body fat a woman has, the higher her estrogen level. Estrogen fuels tumor growth. More specifically, as relates to breast cancer, high levels of post-menopausal estrogen can stimulate abnormal breast cell growth, which leads to more rapid development of estrogen-positive breast cancers.
Among many women with breast cancer, the standard of care is to use drugs that block or inhibit estrogen activity, such as tamoxifen or aromatase inhibitors. However, the effectiveness of these drugs may be compromised by the higher estrogen levels in women with higher body fat. (This is a major factor as to why obese women who have had breast cancer are at the highest risk for recurrence.)
As relates to ovarian cancer, although the exact cause of ovarian cancer is not known, one of the risk factors is thought to be obesity. The link? Estrogen is, as I stated earlier, made in body fat . . . and the more fat cells a woman has, the more estrogen she produces. In pre-menopausal women, each month progesterone is also produced to enable the lining of the womb to be shed during the menstrual cycle. However, after menopause, when estrogen production by the ovaries drops dramatically, it continues to be produced in fat tissue. Therefore, women in menopause and who have excess body fat continue to produce high levels of estrogen, and these act on the womb lining — but without the regulating effects of progesterone. It’s this that’s the link to ovarian cancer.
When it comes to estrogen, men are NOT off the hook! Men also must concern themselves with estrogen because, again, visceral fat produces estrogen. Obesity increases a man’s risk of developing prostate (and colon) cancer, and the fatter the man, the more aggressive the cancer.
Insulin is the hormone that regulates blood sugar. Inflammation caused by obesity can keep the body from properly responding to insulin. This is called insulin resistance. When the body doesn’t respond to insulin correctly, it produces more insulin to make up for that.
The increase in insulin due to insulin resistance triggers an increase in the number of cells produced, which can lead to cancer.
Increased insulin also affects how hormones like estrogen are controlled. More insulin can lead to more available estrogen, which increases cancer risk.
The number one cause of insulin related issues is diabetes, and obesity is a known risk factor for diabetes.
Visceral fat cells are large, and there are a lot of them. This excess fat doesn’t have much room for oxygen. And that low-oxygen environment triggers inflammation.
Inflammation is the body’s natural response to injury and disease. For example, when you get a deep cut, the area around the cut becomes red and painful to touch. This minor inflammation around the wounded area helps repair the damaged tissue and aids with the healing process.
Having your organs marinated in visceral fat 24/7 is inflammatory (to say the least!) to those organs, and long-term inflammation caused by excess visceral fat damages your body and increases your risk for cancer.
Being obese is like having a factory in your body polluting you with cancer-causing chemicals every day.
“Next to smoking, keeping oneself at a healthy weight is the most important thing an individual can do to reduce their cancer risk.”~ Taraneh Soleymani, M.D., obesity medicine specialist, Penn State Health Medical Group, Middletown, PA
“Next to smoking, keeping oneself at a healthy weight is the most important thing an individual can do to reduce their cancer risk.”
~ Taraneh Soleymani, M.D., obesity medicine specialist, Penn State Health Medical Group, Middletown, PA
If you’re overweight or obese, heed the warning of how excess fat is linked to cancer, especially if you’ve been fortunate to have thus far survived one bout already. Remember: obesity gives you the greatest risk of recurrence.
The bottom line for everyone is that being obese or overweight hurts the body’s ability to work well. Maintaining a healthy weight is essential for reducing your risk for cancer.
P.S. Are you wondering which cancer has the most relationship with obesity? Breast cancer after menopause is the most common obesity-associated cancer among women. Colorectal cancer is the most common obesity-associated cancer among men.