Previous studies indicate that, like the rest of the body, the liver follows a 24-hour internal clock, or circadian rhythm. Meal timing is believed to be a cue that keeps the liver in phase with the 24-hour day. Researchers recently conducted a study to determine if the risk of NAFLD is related not just to what, but also to when and how often a person eats.
“Modern society has seen a growing number of people working nights or staying up much later than before, which often upsets ‘normal’ sleeping and eating patterns,” states James Philip G. Esteban, MD, fellow, Gastroenterology and Hepatology; Medical College of Wisconsin; and lead investigator in the study. “We are just beginning to explore if these changes have potentially harmful effects on our health. For instance, previous research has hinted that shift work may increase the risk for diabetes and obesity. In our study, we asked if specific meal timing patterns affect the risk of NAFLD.”
Dr. Esteban’s team analyzed data from 9,015 adults who participated in the third National Health and Nutrition Examination Survey (NHANES III) conducted throughout the United States in 1988-1994. Survey participants underwent gallbladder ultrasound to evaluate the severity of fatty liver and were also asked about specific food intake from the last 24 hours. Only adults without hepatitis B or C infection, significant alcohol consumption and intake of medications potentially toxic to the liver were included in the analysis.
A day was arbitrarily divided into four intervals to roughly correspond to morning (4am-10am), midday (10am-4pm), evening (4pm-10pm), and late night (10pm-4am) meals. Within each interval, the researchers looked to see if skipping meals, specific meal time and relative caloric intake affect the severity of fatty liver and the presence of significant liver fibrosis or scarring. Also, the researchers adjusted their calculations to take into consideration variations in age, sex, ethnicities, cigarette and alcohol use, and total caloric intake.
The study showed that dividing the day’s calories into more meals per day was associated with lower odds of having fatty liver and significant fibrosis – the odds decreased by 10 percent for every additional meal. Odds of fatty liver may also be reduced 14 to 21 percent by consuming a greater percentage of the day’s calories in the morning.
On the other hand, skipping morning and mid-day meals as well as having a late night/early morning meals are potentially harmful. Participants who did not have any meals from 4am to 10am and 10am to 4pm had 20 percent and 73 percent higher odds of fatty liver, respectively. When compared to participants who had a meal at 10pm, participants with a meal between midnight and 4am had 65 percent higher odds of significant fibrosis.
“Our study suggests that the chances of developing NAFLD may be reduced by simple modifications to the way that we eat and time our meals, and adherence to a few ‘rules of thumb,’ such as not skipping daytime meals and avoidance of late night meals,” says Dr. Esteban. “However, we would like to point out that the data only reflects associations, and additional research is needed to establish whether there are more definitive or potentially causative connections.”