The Grapevine

Early Dinner Could Lower Breast, Prostate Cancer Risk

If you tend to eat your dinner later in the night and closer to bedtime, you may want to reconsider. An earlier dinner time was linked to a lower risk of breast and prostate cancer in a new study by the Barcelona Institute for Global Health (ISGlobal) in Spain.

The paper titled "Effect of mistimed eating patterns on breast and prostate cancer risk (MCC‐Spain Study)" was published in the International Journal of Cancer on July 17.

"What we know from experimental studies is that we are conditioned to function in different parts of the day," said lead author and ISGlobal researcher Manolis Kogevinas. "We — not only humans but all living organisms — have developed throughout time functioning differently in day and night."

Data on 621 cases of prostate cancer and 1,205 cases of breast cancer were examined by the research team. In addition, a control group with more than 2,000 men and women (who did not have cancer) were also taken into account in the study.

The participants provided information about their lifestyle, chronotype, meal timing, sleep habits, and more by filling out questionnaires. They also reported the extent to which they followed cancer prevention recommendations such as limiting alcohol intake and avoiding smoking.

The people who followed the recommendations were also more likely to have a longer interval between their dinner time and the time they went to bed.

Compared to those who ate after 10 p.m. or went to bed right after dinner, those who ate their last meal of the day before 9 p.m. were found to have a 20 percent lower risk of breast and prostate cancers.

If these findings are confirmed, they will have implications for cancer prevention guidelines, potentially including the timing of meals as an important factor.  The authors noted that such recommendations could be impactful in cultures, such as those of southern Europe, where people tend to eat dinner late.

But the researchers only found an association and could not identify the exact mechanism to explain it. Given that the study was based in Spain, future studies will also require a more diverse group of participants.

Findings from previous research may be relevant as they have noted how the timings of meal consumption can affect our metabolism and insulin levels.

"Population-based studies have found that people that eat late at night have higher rates of obesity and worse metabolic profiles," said Catherine Marinac, a research fellow at the Dana-Farber Cancer Institute who was not involved in the study.

"And in particular, we have found that people that have a longer nightly fasting duration, which might imply less late-night eating, have better blood sugar control and a lower risk of cancer recurrence."