Does a Diet High in Sugar Increase the Risk of Cancer?

Does a Diet High in Sugar Increase the Risk of Cancer?

(Last Updated On: April 13, 2019)

can a diet high in sugar increase your risk of cancer

Cancer isn’t a diagnosis most of us want to get. Even the word evokes fear and anxiety. Thankfully, cancer is curable in some cases, and even when it can’t be cured, it can be controlled. Still, it’s always better to prevent it than to deal with the disease after the fact.

Studies show that genetics play a role in some cases of cancer, but lifestyle is still a powerful force for prevention. In fact, studies show that at least 40% of cancer is preventable through lifestyle.

The lifestyle habits that help prevent cancer are fairly basic but not always easy to adhere to consistently. According to the Centers for Disease Control and Prevention, these are factors that may lower your risk of cancer:

·       Not smoking & avoiding second-hand smoke

·       Minimizing alcohol use

·       Meeting the guidelines for physical activity

·       Staying a healthy body weight

·       Protecting skin from ultraviolet light (skin cancer)

These factors almost certainly play a role in who develops cancer and who doesn’t. However, diet and exercise are important too. One dietary component that’s come under scrutiny recently is sugar.

Sugar and Cancer Risk

Sugar is in almost every packaged food and beverage you encounter these days. It’s not always obvious as sugar goes under a variety of names on a nutrition label. Experts are quick to blame the obesity epidemic on an increase in the consumption of sugar and refined carbohydrates. Some studies also suggest that a diet high in sugar is a contributor to heart disease – but what about cancer?

You may have seen literature stating that sugar fuels the growth of cancer. In fact, a study found that over half of mice that ate a diet high in sugar developed breast cancer. But, mice aren’t humans and breast cancer are only one type of cancer. So, we can’t necessarily extrapolate from mice to humans or to all cancers.

At the very least, there is an indirect link between sugar and cancer. Obesity is a risk factor for at least 13 forms of cancer. If you believe the empty calories in sugar contribute to obesity, then sugar is a roundabout contributor to the risk of developing cancer.

Obesity may increase cancer risk in several ways. For one, obesity, especially abdominal obesity, is linked with low-grade inflammation. Fat cells are prodigious producers of inflammatory chemicals called cytokines. Over time, inflammation can damage cells and tissues and spark mutations in a cell’s genetic material that boost the risk of malignancy. We also know that women who are obese frequently have higher levels of the sex hormone estrogen. Higher levels of estrogen are linked with certain types of cancer, including breast cancer, cancer of the uterus, and ovarian cancer.

Finally, carrying too much body fat increases the activity of certain growth factors, particularly IGF-1. High levels of IGF-1 fuel the growth of some types of cancer, including pre-menopausal breast cancer, colon cancer, cancer of the uterus, prostate cancer, colon cancer, and malignancy of the kidney.

Insulin Resistance, Sugar, and Cancer

Other studies point to a link between insulin resistance and cancer. Insulin resistance is where cells don’t respond as easily to insulin’s signals to open the gates of cells to let glucose in. As a result, the pancreas produces more and more insulin to try to get cells to respond and this leads to high levels of insulin in the bloodstream. Studies show that insulin itself promotes the growth of malignant cells. For example, a study found that insulin turns on an enzyme called ACAT1 that helps colon cancer cells grow faster. Insulin is a growth promoter for a number of types of cancer cells. In fact, people who have type 2 diabetes, a condition marked by insulin resistance, have a higher risk of developing cancer.

Curb Your Sugar Intake

At the very least, we know that sugar is a source of empty calories. It contains no nutrients or other elements your body needs. When you eat a diet high in sugar, you displace other more nutritious elements from your diet. Sugary foods cause a rapid rise in blood sugar and lead to a greater release of insulin. As mentioned, insulin creates an environment that allows malignant cells to grow more easily. Plus, it promotes fat storage and blocks the breakdown of stored fat. So, the impact of sugar on the risk of malignancy may be direct, indirect or both. Sounds like a good reason to reduce the amount of sugar in your diet, right? Refined carbohydrates have a similar effect as sugar. So, jettison them from your diet too!

The Bottom Line

It’s likely that sugar and refined carbs directly or indirectly contribute to insulin resistance and obesity and these are health issues that increase the risk of cancer. But, some foods may also be protective against certain types of malignancies. For example, fruits and vegetables are rich in phytochemicals that help curb inflammation, a risk factor for cancer. Other dietary components that may offer some protection against cancer include some spices, nuts, legumes, tea, and olive oil. However, more research is needed.

Your best bet is to reduce or eliminate sugar & refined carbs from your diet and replace them with whole, unrefined foods. Of course, that’s always a good practice! Whole foods contain nutrients and phytonutrients in the right proportions without the additives you find in so many packaged foods. Diet matters when it comes to lowering your risk of cancer. So, take advantage of the factors you have control over – and eat right.


References: “More than 4 in 10 Cancer Are Preventable”

Centers for Disease Control and Prevention. “Cancer Prevention and Control”

Medical News Today. “Sugar and cancer: A surprise connection or 50-year cover-up?”

Science Daily. “Scientists reveal the relationship between sugar, cancer”

National Cancer Institute. “Obesity and Cancer”

Lipids Health Dis. 2018; 17: 122.

The New England Journal of Medicine. “Body Fatness and Cancer — Viewpoint of the IARC Working Group”

Diabetes Spectr. 2014 Nov; 27(4): 276–280.


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Working Out May Lower Your Risk of Developing 13 Types of Cancer

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