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Previous human studies found associations between high sugar intake and breast cancer risk. This study looked at the direct effect of sugar on breast cancer growth and metastasis in mice. While researchers observed that sugar increased tumor growth and metastasis, more work needs to be done to see if this finding is relevant in humans. It is important to remember, the overall health benefits of limiting sugar intake remain undisputed.
How sugar may drive breast tumor growth and metastasis in a mouse model of breast cancer.
This is an early step in understanding how high sugar intake might affect breast cancer growth and development.
This study was done in well-established mouse models of breast cancer in which researchers knew that about half of the mice would develop breast cancer in the course of the experiment. While these types of early laboratory studies in mice are important for scientists trying to understand how cancer develops and spreads, they are not directly applicable to humans. It is important to remember that while the researchers tried to match the sugar levels the mice received to those found in Westernized diets, the rest of the mouse diet was not comparable to an average person’s diet.
The dangers of consuming excessive amounts of sugar are well established—the American Heart Association recommends that men and women consume no more than 37.5g and 25g of sugar, respectively. While this study does not conclusively show that sugar should be avoided or that excess sugar causes breast cancer to occur or spread, the overall health benefits of limiting sugar intake remain undisputed.
Previous studies in humans have found associations between high sugar intake and breast cancer risk, including a recent study that found that increased consumption of sugar-sweetened beverages is a contributor to worldwide obesity, heart disease, and cancer. However, no study has directly studied whether a high-sugar diet can cause breast cancer to grow and/or affect breast cancer metastasis.
In January 2016, Yan Jiang and colleagues at the University of Texas MD Anderson Cancer Center published a paper in the journal Cancer Research looked at breast cancer development, growth, and metastasis in mice with various amounts of table sugar in their diets. This is the first study to look at a direct effect of consuming sugar and breast cancer development using mouse models of breast cancer.
Whether sugar consumption led to breast tumor growth and metastasis in mouse models of breast cancer.
This study used two well-established mouse models of breast cancer. The first is a model in which 50% of the mice are known to develop tumors after six months under normal conditions. The second is a model in which breast cancer metastasizes to the mouse lung.
Compared to mice than did not consume sugar, mice that did consume sugar:
While this is the first study to look directly at the effect of sugar on tumor growth, more work is needed to determine whether the same effect occurs in humans. It is important to note that close to half of the mice in the study would have developed tumors after six months regardless of the amount of sugar they ate. While they were fed an amount of sugar that is equivalent to a Westernized diet, other nutrients in their diet were not the same as in a Westernized human diet.
This study suggests that sugar may play a role in breast tumor growth and metastasis. It does not, however, implicate sugar or a particular amount of sugar as a cause of breast cancer. It is important to remember that this is early research in mice and more work needs to be done to understand this effect in humans. Although limiting sugar consumption is recommended for overall health, the data from this study does not provide enough evidence for people to stop consuming sugar entirely to reduce their risk of breast cancer development, growth, or metastasis.
Aside from the results of this study, everybody should limit sugar consumption, as recommended by the American Heart Association; your own personal or family health history may dictate that you follow more specific health guidelines. If you are concerned with how your diet affects your cancer or cancer risk, please discuss your options with your health care provider.
Jiang Y, Pan Y, Rhea PR, et al. “A Sucrose-Enriched Diet Promotes Tumorigenesis in Mammary Gland in Part Through the 12-Lipoxygenase Pathway.” Cancer Research (2016); 76(1): p. 24-28.
Miller PE, McKinnon RA, Krebs-Smith SM, et al. “Sugar-sweetened beverage consumption in the U.S.: novel assessment methodology.” American Journal of Preventive Medicine (2013); 45: p. 416–21.