Eating dinner earlier could reduce cancer risk

Uncovering simple lifestyle interventions that may reduce cancer risk is a major focus of medical research. Most recently, the timing of our evening meal has come under scrutiny.

According to a study that was conducted at the Barcelona Institute for Global Health in Spain, eating your final meal of the day too late can increase the risk of developing cancer.

The relationship between food and cancer has been investigated a great deal.

For instance, regularly eating fresh vegetables has been shown to reduce cancer risk.

Conversely, regularly eating red meat increases the risk of certain cancers.

Over the years, there have also been a number of studies looking at the links between obesity and cancer. However, the impact of when food is eaten has been much less studied.

A recent study investigated potential links between meal timing and two common types of cancer: prostate cancer and breast cancer.

These cancers are also known to be linked with night-shift work and disruption to the biological clock, which infers that they might be sensitive to the timing of lifestyle factors, too.

Meal times and cancer risk

In all, the scientists had access to data from 621 men with prostate cancer and 1,205 women with breast cancer. As controls, they also included 872 males and 1,321 females without cancer.

Participants' lifestyles were assessed, including information about their meal times and sleeping habits. They also defined their chronotype — that is, whether they are a morning or an evening person.

Their findings, which are published in the International Journal of Cancer, make surprising reading.

People who ate their evening meal before 9:00 p.m. or at least 2 hours before going to bed had around 20 percent less risk of breast or prostate cancer than those who ate after 10:00 p.m. or went to bed soon after eating.

"Our study concludes that adherence to diurnal eating patterns is associated with a lower risk of cancer. [The findings] highlight the importance of assessing circadian rhythms in studies on diet and cancer."

Lead study author Manolis Kogevinas

Implications and further work

There will need to be follow-up work to confirm these startling conclusions, but if these results are replicated, they could have an impact on official guidelines — which do not currently take into account the timing of meals.

We already know that disrupting circadian rhythms influences tumor growth, and that meal timing impacts circadian rhythms.

As researcher Dora Romaguera explains, previous animal studies have shown that the timing of food intake has "profound implications for food metabolism and health."

However, unraveling the precise interactions between these factors is likely to take a great deal of unpicking.

Eventually, this insight could have far-reaching consequences, as Kogevinas explains, "The impact could be especially important in cultures such as those of southern Europe, where people have [dinner] late."

The results are striking, but Romaguera is cautiously optimistic, saying, "Further research in humans is needed in order to understand the reasons behind these findings, but everything seems to indicate that the timing of sleep affects our capacity to metabolize food."