Are High-Sugar Diets Linked with Breast Cancer?

Are High-Sugar Diets Linked with Breast Cancer?

Sugar – there are lots of reasons to purge it from your diet. For one, sugar is a big fat zero when it comes to nutritional value. Each teaspoon has 16 calories and a little over 4 grams of carbs – but that’s about it – no vitamins or minerals to speak of.

Many people are consuming more sugar than they think they are. Staying away from the sugar bowl isn’t enough. Sugar “hides” in many packaged foods in surprisingly large amounts. Recent research has already linked diets high in sugar with a greater risk for heart disease. Now, a new study uncovers a possible link between diets high in sugar and a greater risk for breast cancer.

 Does a High-Sugar Diet Increase Breast Cancer Risk?

A new study carried out by the Canadian Cancer Society raises fresh concerns about diets high in sugar. Researchers asked a group of 1555 women, half post-menopausal and half pre-menopausal, to complete a questionnaire about their dietary habits, including how much sugar they consumed on a regular basis. After tabulating the results, they noted a link between sugar consumption and increased breast density in pre and post-menopausal women. Women who ate more sugary treats and sipped more sugar-sweetened beverages had higher breast densities, on average than women who limited sweets in their diet.

Why does breast density matter? A number of studies show a link between breast density, as determined by mammography, and a greater risk for breast cancer. In one study, women in their 40s and 50s with the highest breast density had a six-times increased risk of breast cancer compared to women with the lowest breast densities

Increased breast density not only makes it harder to see breast cancer on a mammogram – it’s an independent risk factor for breast cancer. Some doctors now recommend that women who have very dense breasts be screened for breast cancer more frequently or with a different method like breast MRI. Breast density normally goes down after menopause as estrogen levels drop and glandular tissue turns to fatty breast tissue. Breast density may be a marker for higher estrogen levels. Estrogen fuels the growth of certain forms of breast cancer.

How Might a High-Sugar Diet Increase Breast Cancer Risk?

What’s the link between sugar and breast cancer? The answer may lie with the effect sugar has on insulin. When you eat sugary foods or sugar-sweetened drinks, it causes a rapid rise in blood sugar. Your pancreas responds by producing more insulin. When you do this on a regular basis, you have higher insulin levels in your bloodstream. Elevated insulin levels boost the production of a growth factor by your liver called IGF-1. IGF-1 is very good at stimulating the growth of tissues – including breast tissue. In fact, studies have linked higher levels of IGF-1 with pre-menopausal breast cancer. In animal studies, insulin itself promotes the growth of a number of tumor types including colon and prostate tumors. Insulin, along with IGF-1, fuels the growth of cancer cells.

The other way high-sugar diets contribute to cancer is related to their effects on body weight. Eat a diet high in sugar and processed carbs and your risk for obesity is higher. Obesity is a risk factor for a number of cancers in women including cancer of the uterus, breast cancer, and colon cancer. According to the American Cancer Society, one in three cancers is related to excess body weight, lack of exercise and poor nutrition. Lifestyle matters!

Be Smart – Cut Back on Sugar

How much sugar should you be consuming? The American Heart Association recommends that women restrict their sugar intake to less than 6 teaspoons a day. To put that in perspective, the average 12-ounce soft drink contains about 9 teaspoons of sugar. Where most people get dinged is with “hidden” sugars in foods.

It’s no surprise that doughnuts, cookies and ice cream are full of sugar. What’s more surprising is marinara and pasta sauce can have as much as 2 teaspoons of sugar per serving and breakfast cereals as much as 5 teaspoons in each serving. Beware of hidden sugar in salad dressings, ketchup and condiments too. Salsa is usually lower in sugar than ketchup and is a good substitute for high-sugar ketchup. Some yogurt brands have as much as 5 teaspoons of sugar.

The focus of this article is sugar, but high-glycemic carbohydrates like white flour, processed foods, and white rice are rapidly broken down into simple sugars and cause a rapid rise in insulin. Stick with high-fiber carbohydrate sources like moderate amounts of whole grains and whole fruit and plenty of non-starchy vegetables.

Here’s the good news. If you slowly cut back on sugar, the amount you add to your tea and coffee and the number of sweet “treats” you eat, your taste buds will adapt and become more sensitive to the taste of sweet. As a result, you won’t crave the same level of sweetness. Give it a try!

The Bottom Line?

Sugar may be bad for your heart – and for your breasts by increasing breast density. To lower your risk for breast cancer, enjoy more whole foods like fruits and vegetables and exercise regularly. A number of studies show regular exercise lowers breast cancer risk. Also, when you get your next mammogram, ask how dense your breasts are. If they’re very dense, you may benefit from a different screening method like breast MRI.



JAMA Internal Medicine. “Added Sugar Intake and Cardiovascular Diseases Mortality Among US Adults”

JNCI J Natl Cancer Inst (1995) 87 (9): 670-675. doi: 10.1093/jnci/87.9.670.

WebMD. “Breast-Density Changes May Be Tied to Cancer Risk”

Science Daily. “High Insulin Levels Raise Risk Of Breast Cancer In Postmenopausal Women”

Medscape.com. “The Pathway from Diabetes and Obesity to Cancer, on the Route to Targeted Therapy”

American Cancer Society. “Does Body Weight Affect Cancer Risk?”


Related Articles By Cathe:

Why are Processed Foods So Hard to Give Up?

Metabolic Health May Be More Important Than Body Weight for Breast Cancer Risk

Short, Intense Exercise May Reduce Your Risk of Breast Cancer

Exercise and Breast Health: Can Exercise Keep Your Breasts Healthy?

Exercise and Breast Cancer Prevention: Does It Matter What Age You Begin Working Out?

Why Women Crave Sugary Foods More Than Men


Hi, I'm Cathe

I want to help you get in the best shape of your life and stay healthy with my workout videos, DVDs and Free Weekly Newsletter. Here are several ways you can watch and work out to my exercise videos and purchase my fitness products:

Get Your Free Weekly Cathe Friedrich Newsletter

Get free weekly tips on Fitness, Health, Weight Loss and Nutrition delivered directly to your email inbox. Plus get Special Cathe Product Offers and learn about What’s New at Cathe Dot Com.

Enter your email address below to start receiving my free weekly updates. Don’t worry…I guarantee 100% privacy. Your information will not be shared and you can easily unsubscribe whenever you like. Our Privacy Policy