Consuming at least 20% of daily calories from fast food correlated with an increased risk for nonalcoholic fatty liver disease, with more damaging effects among individuals with underlying metabolic comorbidities.
“Fast food consumption has been linked to diabetes and obesity, but there is very little clinical or population-based data on how eating fast foods impact the risk of fatty liver, which is a diet-sensitive liver disease that can lead to cirrhosis and liver cancer,” Ani Kardashian, MD, assistant professor of gastrointestinal and liver disease at the University of Southern California Keck School of Medicine, told Healio.
Using data from the National Health and Nutrition Examination Survey from 2017 to 2018, Kardashian and colleagues analyzed 3,954 adults, aged 20 years and older, to investigate the effect of fast food intake on the risk for liver steatosis.
Researchers quantified liver fat, measured with vibration-controlled transient elastography, using controlled attenuation parameter (CAP dB/m) as a continuous and categorical variable with two validated cutoffs (CAP 263 dB/m and CAP 285 dB/m).
According to study results published in Clinical Gastroenterology and Hepatology, 52% of adults consumed fast food and 29% derived at least 20% of their daily calories from fast food. After multivariable adjustment, this level of fast food intake was “significantly associated” with greater steatosis (OR = 1.45; 95% CI, 1.23-1.73 for the CAP 263 dB/m cutoff).
“Eating one-fifth of total daily calories from fast food is associated with higher amounts of fat in the liver,” Kardashian said. “While the effects are modest in the general population (4 dB/m higher CAP score), the effects were significantly more deleterious in people who have underlying diabetes or obesity.”
Consuming at least 20% of daily calories from fast food was associated with an 11-unit higher adjusted CAP among obese adults (301 dB/m; 95% CI, 294-308 vs. 290 dB/m; 95% CI, 283-297) compared with a two-unit lower CAP among nonobese adults (238 dB/m; 95% CI, 234-243 vs. 240 dB/m; 95% CI, 236-245).
In addition, researchers reported a 16-unit higher adjusted CAP among adults with diabetes (297 dB/m; 95% CI, 289-306 if consuming 20% fast food vs. 281 dB/m; 95% CI, 273-289 if consuming < 20%) compared with a three-unit higher CAP among nondiabetic adults (263 dB/m; 95% CI, 259-266 if consuming 20% fast food vs. 260 dB/m; 95% CI, 256-264 if consuming < 20%).
“We also found that if fast food were eliminated, one in six cases of fatty liver could be
prevented among people with diabetes and obesity,” Kardashian added.
Using the continuous CAP cutoff ( 263 dB/m), researchers reported the population attributable risk for fast food was 17% among adults with obesity (95% CI, 8-26) and diabetes (95% CI, –1 to 33).
“Additional research is needed to understand the impact of social determinants of health and food insecurity on fast food consumption in people with chronic diseases,” Kardashian told Healio. “We also need to design, implement and research healthy food interventions for people with metabolic conditions who are at high risk of developing fatty liver.”
She continued, “These findings are particularly important for people who have diabetes or obesity, who should be counseled that if they consume fast food on a regular basis, their risk of severe fatty liver increases significantly. At a policy level, public health efforts are needed to improve access to affordable, healthy and nutritious food options across the U.S.”