A large new study published in the European Journal of Epidemiology suggests that people who work night shifts face a higher risk of coronary heart disease (CHD) than daytime workers - but diet, particularly fiber intake, may play an important role in reducing that risk.

Night shift work is common in essential professions such as healthcare, emergency response, and law enforcement. However, working overnight disrupts the body’s natural sleep–wake cycle, limiting the restorative benefits of sleep and placing strain on the cardiovascular system.

Previous research has already linked shift work to higher rates of cardiovascular disease, prompting organizations like the American Heart Association to emphasize lifestyle factors that support heart health.

To better understand how diet influences this risk, researchers analyzed data from 222,801 adults with an average age of about 53. Participants were grouped into daytime workers, shift workers with few or no night shifts, and regular night shift workers.

Their dietary habits were assessed through questionnaires, and cardiovascular events were tracked over a median follow-up period of 12.6 years.

The findings revealed that night shift workers had about a 10 percent higher risk of developing coronary heart disease compared with daytime workers. Those who worked shifts but rarely at night did not show a significantly higher risk after accounting for lifestyle and demographic factors.

Dietary fiber emerged as a key factor. Shift workers who consumed lower amounts of fiber had a higher risk of CHD than daytime workers. However, as fiber intake increased, this risk gap narrowed significantly. Researchers estimated that night shift workers would need about 19 grams of fiber per day to bring their CHD risk in line with daytime workers, while those with occasional night work required about 15 grams daily.

The study also found that avoiding red and processed meat was associated with a roughly 10 percent lower risk of coronary heart disease overall. However, unlike fiber intake, this benefit did not differ across work schedules, suggesting meat avoidance provides similar cardiovascular protection regardless of whether a person works nights or days.

Researchers cautioned that the study shows associations rather than direct cause-and-effect relationships. Dietary habits were measured only once at the beginning of the study, and other lifestyle factors - such as eating patterns during night shifts - may also influence outcomes. Additionally, high fiber intake may not be appropriate for everyone, particularly individuals with certain medical conditions.

The authors emphasized that while dietary fiber appears beneficial, it should not be viewed as a substitute for other heart-protective behaviors, including regular physical activity, adequate sleep, and avoiding smoking.

Future research with more diverse populations and longer follow-up periods will be needed to confirm these findings and better understand how diet can help protect the cardiovascular health of shift workers.