In a recent study published in The Journal of Clinical Nutrition, researchers delved into the connection between the consumption of highly processed foods (referred to as UPF) and the health of the liver.
The Significance of Liver Health
The liver plays a pivotal role in processes such as detoxification, metabolism, and immunity. Hepatic conditions, ranging from less severe and reversible ailments like non-alcoholic fatty liver disease (NAFLD) to potentially life-threatening ones such as liver cirrhosis and malignancies, pose substantial challenges to healthcare systems and are a global health concern. While previous research has linked UPF consumption to conditions like diabetes and obesity, data regarding the impact of UPF on liver health is scarce.
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Study Objectives and Methodology
In this recent prospective cohort study, the researchers set out to examine whether increased consumption of UPF could raise the risk of liver conditions such as NAFLD, hepatic cirrhosis or fibrosis, severe liver diseases, and hepatic malignancies, while also affecting various serological markers related to liver health.
Sample and Data Collection
The study encompassed 173,889 participants from the United Kingdom Biobank (UKB), all aged between 40 and 69, who were recruited between 2006 and 2010. These individuals lived within 25 miles of 22,106 centers across Scotland, Wales, and England, as identified through the National Health Service (NHS) registers. To evaluate UPF consumption, the researchers used the NOVA classification and one-day dietary recalls.
They calculated portion sizes, energy content, and nutrient composition of food items using the 2002 UK McCance and Widdowson’s Composition of Foods, sixth edition guidelines.
Key Biomarkers Analyzed
The researchers identified liver outcomes by referring to the International Classification of Diseases, tenth revision (ICD-10) codes from mortality registries, hospital records, and cancer registries.
The serological biomarkers assessed included C-reactive protein (CRP), alkaline phosphatase (ALP), alanine transaminase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), triglycerides, glucose, glycated hemoglobin (HbA1c), platelet counts, total protein, total bilirubin, and albumin.
To establish the connection between UPF consumption and liver health, the researchers employed Cox proportional hazard modeling. They adjusted for lifestyle factors like smoking status, alcohol intake, and physical activity, as well as demographic factors (age, ethnicity, sex, body mass index (BMI), Townsend deprivation index), diabetes, total calorie intake, and aspirin usage.
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Furthermore, multivariate logistic regression modeling was used to explore the links between UPF intake and hepatic biomarkers. Sensitivity analyses were conducted to ensure the robustness of the findings.
Study Results and Sensitivity Analyses
Out of a total of 210,964 individuals who underwent dietary assessments during the follow-up period, 18,078 individuals who reported unusual nutritional intake on certain days, 14,674 individuals with a history of cancer, 1,079 individuals with liver cirrhosis at the start of the study, and 417 individuals with extreme calorie intake were excluded.
Additionally, 409 participants who were lost to follow-up or diagnosed with hepatic conditions or malignancies before dietary evaluation, as well as 2,418 individuals with missing covariate data, were also excluded. Consequently, the primary analyses included 173,889 individuals, and the biomarker analyses included 137,173 individuals after excluding 36,716 individuals with missing data.
During the nine-year median follow-up, 350 cases of liver cirrhosis or fibrosis, 1,108 cases of NAFLD, 550 cases of severe hepatic illness, and 134 cases of hepatic malignancy were reported.
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Key Findings and Implications
The study revealed that increased UPF consumption was associated with heightened risks of non-alcoholic fatty liver disease (HR for the fourth quartile (Q4) versus the first quartile (Q1), 1.4), liver cirrhosis or fibrosis (HR 1.2), and severe hepatic illness (HR 1.5), but did not increase the risk of hepatic malignancies (HR 1.0). Elevated UPF consumption was significantly linked to increased levels of ALP, CRP, AST, GGT, triglycerides, and decreased levels of cholesterol.
The analysis based on the absolute weight of UPF consumption revealed that beverages (25%), dairy products (15%), and bread and pastries (15%) were the primary contributors. Individuals with higher UPF intake tended to be younger, non-white, physically inactive, diabetic, and either non-drinkers or occasional alcohol consumers with a higher BMI. Sensitivity analyses yielded consistent results, affirming the robustness of the findings.
When examining cirrhosis type, increased UPF consumption significantly increased the risk of both compensated and decompensated cirrhosis, with HR for Q4 versus Q1 at 1.3 for both.
The Concluding Verdict
Based on these findings, it is evident that UPF consumption can elevate the risks of conditions like NAFLD, hepatic cirrhosis or fibrosis, and severe hepatic diseases, while also impacting various serological biomarkers related to liver health. Therefore, reducing the consumption of UPF is crucial to enhance liver well-being.
The study suggests that UPF may harm liver health by increasing oxidative stress, inflammation, microbial imbalances, and insulin resistance due to its high content of saturated fats, energy density, salt, added sugars, and additives, while lacking fiber and essential vitamins.