The habit of eating late at night is linked to the development of liver disease, according to a new study. The findings have drawn attention for suggesting that when people eat — not just how much or what they eat — can affect liver health.
Researchers at Oregon Health & Science University analyzed dietary and health data from 199,155 participants in the Nurses' Health Study, the Nurses' Health Study II and the Health Professionals Follow-Up Study. The team compared participants' self-reported eating and lifestyle habits with their disease diagnoses. The median follow-up period was 16 years.
People who ate late at night had a 31% higher risk of developing metabolic dysfunction-associated steatotic liver disease than those who did not. Their risk of cirrhosis — a condition in which scar tissue builds up in the liver and impairs its function — was 28% higher. The results were similar after accounting for other factors, including age, body mass index, daily calorie intake, diabetes, alcohol consumption and physical activity.
The study defined late-night eating to include not only food consumed after midnight but also the habit of eating after dinner or past bedtime. Dr. Robert Wilechansky, a liver specialist at Oregon Health & Science University who led the study, said the liver is very closely tied to the body's circadian rhythm. He said researchers are examining whether adjusting only meal timing, without changing the composition of what people eat, can benefit health.
Circadian rhythm is a roughly 24-hour biological cycle that influences sleep and wakefulness, hormone secretion and metabolic activity. Liver function also varies according to this rhythm. The researchers explained that eating during the hours when the body is preparing for sleep can put nutrient metabolism out of step with the biological clock. Wilechansky said only some people who develop fatty liver disease progress to serious stages such as cirrhosis, but added that limiting calorie intake for several hours before going to bed may help.
The researchers stressed, however, that the study did not establish a clear causal link between late-night eating and liver disease. More evidence is needed before concluding that late-night eating causes liver disease, they said. The team is conducting follow-up clinical research to confirm the relationship, designed to determine whether changing late-night eating habits affects the prevention of liver disease. Through that work, the researchers plan to examine whether patients with fatty liver disease can slow the worsening of their condition by eating earlier.
The researchers said the study suggests that changing one's diet may not be the answer for liver health, and that simply widening the gap between the last meal of the day and bedtime may help protect the liver.
The findings were published recently in the international journal Clinical Gastroenterology and Hepatology.
