Scientists have learned about the link between eating sugary foods and breast cancer risk

Sweets are often the subject of debate about healthy eating, but their effect on cancer risk remains to be fully understood. New work has shown that not only the amount of sugar in the diet can be important, but also the products from which it comes. At the same time, fruits, despite their significant contribution to total sugar intake, did not demonstrate a similar association with the disease. About which eating habits scientists have linked to an increased risk of breast cancer, see the Izvestia article.

Sweets and the risk of disease

Researchers from Seoul National University in South Korea have studied the relationship between eating foods high in sugar and the likelihood of developing breast cancer. The results of the work are published in the European Journal of Nutrition (EJN). The analysis included data from 71,264 women aged 40 to 69 years. The participants were followed for an average of 9.2 years, during which time 713 new cases of the disease were registered.

Women who consumed more than two servings of high-sugar foods per week had a 28% higher relative risk of breast cancer compared with those who ate such foods less than once a month. The authors also found a statistically significant association between the risk of disease and the consumption of certain individual foods, in particular sweet breakfast cereals and ice cream.

However, scientists do not claim that sweets directly cause cancer. The study revealed a statistical relationship, but its results do not allow us to establish a cause-and-effect relationship.

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What products were studied

The researchers identified seven food groups with a high sugar content: sweet breakfast cereals, jam and butter, cakes and biscuits, ice cream, sweets and other sweets, carbonated drinks and traditional Korean sweet tea. When evaluating the diet, the frequency of consumption and portion size were taken into account.

The most noticeable connections were found for two categories. Women who ate ice cream more than once a week had a 26% higher relative risk of breast cancer than those who did not consume it at all. For sugary breakfast cereals, the figure was 34%: in this part of the analysis, women who ate them more than once every two months were compared with those who did not include them in the diet.

For the remaining individual categories — carbonated drinks, pastries, sweets, jam and butter, as well as traditional Korean tea — no statistically significant association with the disease was found. Therefore, the results cannot be interpreted as evidence that any sweet product has the same effect on breast cancer risk.

Why did fruits turn out to be an exception

The authors paid special attention to the sources of sugar in the diet. Fruits accounted for about 43% of the total sugar consumed by the participants, and this was the largest share among the products. However, fruit consumption was not associated with an increased risk of breast cancer. No such relationship was found for the total amount of sugar in the diet, as well as for the total intake of carbohydrates and fats.

The researchers suggested that not only the amount of sugar may matter, but also its source. Unlike many foods with added sugar, fruits contain dietary fiber, vitamins, carotenoids, and polyphenols. These components can affect metabolism and potentially mitigate some of the adverse effects of nutrition. However, such a mechanism was not directly tested as part of this work.

The authors also noted that the study failed to accurately separate added sugar from natural sugar: the database used took into account the total sugar content in products, so the assumption of differences between its sources requires further verification.

Work restrictions

The study was observational, so the association found does not prove that eating foods high in sugar causes breast cancer. In addition, the participants' diet was assessed only at the beginning of the follow-up. Over the following years, eating habits may have changed, but these changes were not taken into account in the analysis.

Scientists also did not have detailed data on the characteristics of tumors, such as their molecular subtypes and stage of the disease. Another limitation was the lack of accurate information about the menopausal status of women at the time of diagnosis: the age of the participants does not allow to determine unequivocally whether they have entered menopause.

In some groups, the connection looked more pronounced. For example, among women under the age of 50 and participants who consumed alcohol, the researchers found separate statistically significant patterns. However, such results require careful interpretation and do not mean that age or alcohol alone explain the relationship.

The authors believe that further studies with a re-evaluation of the diet, detailed information about menopausal status and tumor characteristics are needed to more accurately assess the impact of nutrition. So far, the work only suggests a possible link between the frequent consumption of certain foods with high sugar content and the risk of breast cancer in the women who participated in the study.