Night shift work has long been associated with disruption of circadian rhythms and an increased risk of cardiovascular disease. However, an important question has remained unresolved: can dietary habits help mitigate this elevated risk? A recent large-scale prospective study led by Professor Diana A. Nôga from Uppsala University, published in the European Journal of Epidemiology, analyzed data from more than 220,000 participants in the UK Biobank. The findings suggest that dietary patterns—particularly higher dietary fiber intake—may significantly reduce the additional coronary heart disease risk associated with night shift work. This long-term study provides valuable insights for millions of shift workers worldwide and highlights the potential role of nutrition as a practical strategy to support cardiovascular health.
Background: Night Shift Work and Cardiovascular Risk
Across the globe, approximately 5% of workers in the European Union and more than five million people in the United States work regular night shifts. The medical community has long recognized that persistent disruption of circadian rhythms can gradually increase the risk of coronary heart disease. However, a key question has remained unanswered: Is it possible to build a protective barrier for the heart through everyday dietary choices among night shift workers?
Recently, a research team led by Professor Diana A. Nôga at Uppsala University published a landmark study in the European Journal of Epidemiology. The findings offer encouraging insights for hundreds of millions of night shift workers worldwide. The study suggests that adjusting dietary patterns—particularly by increasing dietary fiber intake—may help offset the additional cardiovascular risks associated with night shift work.
Study Design: Large-Scale Data and Long-Term Follow-Up
The study utilized data from the UK Biobank, one of the world’s largest biomedical databases. A total of 222,801 employed adults were included in the analysis (53.8% female; mean age 52.6 years). Participants were categorized into three groups according to their work schedules:
- Day workers (83.6%)
- Occasional shift workers or those rarely working night shifts (13.1%)
- Regular night shift workers (3.3%)
Researchers collected detailed dietary information through standardized questionnaires, focusing on two key indicators:
- Daily dietary fiber intake (measured in grams)
- Meat consumption habits (whether individuals intentionally avoided meat)
Participants were followed for a median of 12.6 years, during which 12,265 cases of coronary heart disease (CHD) were recorded, including both fatal and nonfatal events such as myocardial infarction and angina.
To minimize bias, the analysis rigorously adjusted for more than ten potential confounding factors, including age, sex, ethnicity, education level, smoking, alcohol consumption, body weight, physical activity, and pre-existing health conditions. Multiple sensitivity analyses were also conducted to confirm the robustness of the findings, demonstrating the study’s methodological rigor and reliability.
Key Findings: How Diet May Help Protect the Heart
1. Regular Night Shift Work Is Associated with Higher Heart Risk
After comprehensive adjustment for confounding variables, regular night shift workers showed a 10% higher risk of coronary heart disease compared with day workers (HR = 1.10, 95% CI 1.01–1.20).
In contrast, individuals who worked night shifts only occasionally did not show a statistically significant increase in risk. This finding suggests that the frequency and regularity of night shifts are critical factors, with long-term and consistent night work posing the greatest concern.
2. Diet Alone Demonstrates Clear Cardiovascular Benefits
The study also found that dietary patterns independently influence coronary heart disease risk.
- Dietary Fiber: Each additional 1 gram of daily fiber intake was associated with an average 0.6% reduction in coronary heart disease risk (HR = 0.994). Although the reduction appears modest, cumulative increases in fiber intake may produce meaningful health benefits over time.
- Meat Consumption: Compared with individuals who regularly consumed meat, those who intentionally avoided meat experienced a 10.4% lower risk of coronary heart disease (HR = 0.896). Importantly, this protective association was observed across all work patterns and was not dependent on night shift status.
3. A Breakthrough Insight: Fiber Intake May Neutralize Night Shift Risk
One of the most notable findings of the study was the significant interaction between dietary fiber intake and work schedule. This means that the cardiovascular risk associated with night shift work is not fixed, but may change depending on dietary fiber consumption.
Through predictive modeling, the researchers identified two key thresholds:
- Occasional night shift workers: When daily fiber intake reached 15 grams, coronary heart disease risk became comparable to that of day workers.
- Regular night shift workers: When daily fiber intake reached 19 grams, the excess cardiovascular risk was largely neutralized.
What does 19 grams of fiber look like in everyday foods?
Approximately:
- 100 g oats (~10 g fiber)
- 150 g broccoli (~4 g fiber)
- 1 apple with skin (~4 g fiber)
- A small handful of almonds (~2 g fiber)
In practice, this can be achieved by choosing whole grains, legumes, dark-colored vegetables, and fruits with edible skins, all of which are rich sources of dietary fiber.
Practical Dietary Suggestions for Night Shift Workers
Based on these research findings, the following practical dietary recommendations may help support cardiovascular health among individuals who work night shifts.
Prioritize Adequate Fiber Intake
- Replace refined grains with oatmeal, whole-wheat bread, or mixed-grain porridge at breakfast.
- Aim for half a plate of vegetables at lunch and dinner, particularly high-fiber options such as broccoli, spinach, and mushrooms.
- Choose fruits with skins, such as apples, pears, and berries, as snacks.
- Include a small handful of nuts as a healthy snack option.
- Plan 2–3 meals per week featuring legumes, such as soybeans, black beans, or chickpeas.
Make Smarter Choices About Meat
- Reduce the frequency of red meat (pork, beef, lamb) and processed meats such as sausages and bacon.
- Prioritize fish and poultry, and select healthier cooking methods such as steaming or boiling rather than frying.
- Avoiding meat does not necessarily mean adopting a fully vegetarian diet—the key lies in maintaining a balanced intake in both quality and quantity.
Important Considerations
Individual differences should always be taken into account.
- Individuals with gastrointestinal conditions—such as irritable bowel syndrome or inflammatory bowel disease—should increase fiber intake gradually and consult a healthcare professional or dietitian if needed.
- Dietary improvements should be viewed as a supportive strategy rather than a complete solution. Regular health check-ups, smoking cessation, moderate alcohol consumption, and regular physical activity remain essential components of cardiovascular health management.
Conclusion
The significance of this research is not to suggest that night shift work becomes harmless. Instead, it highlights an encouraging message: individual lifestyle choices—particularly dietary habits—can influence health outcomes even in challenging work conditions.
Cardiovascular health is a long-term endeavor, and dietary adjustments represent one important component of that effort. When work schedules are difficult to change, starting with small steps—such as adding an extra serving of vegetables or replacing refined grains with whole grains—may provide meaningful benefits over time.
These small yet consistent choices may become a gentle but powerful “night shift allowance” for protecting the heart.