Healthy plant foods can half the risk of NAFLD

Non-alcoholic liver disease (NAFLD) is fast becoming one of the major non-communicable diseases affecting 30% of the US(1) and almost a quarter (24%) of the European population(2). And without any approved drug interventions, lifestyle and particularly dietary intervention is of key focus. See our full report.

The authors set out to investigate the role of plant-based dietary patterns and the quality of the plant foods consumed with the incidence and risk of NAFLD in US American adults.

Method

Data from 3,900 participants of the large National Health and Nutrition Examination Survey (NHANES) was used.

To assess NAFLD transient elastography (TE) was used which detects and grades hepatic steatosis.

To assess the diet for degree of plant-food inclusion as well as quality of the overall diet, 24-hour dietary recalls were scored using the overall plant-based diet (PDI), the healthful PDI (hPDI) and the unhealthful PDI (uPDI) index – with total scores ranging from 18 to 90.

• PDI: positive points allocated to all plant foods (irrespective of quality) and negative points for animal foods. Higher scores indicate a diet higher in all plant foods.

• hPDI : positive points are only allocated to healthy plant foods whilst unhealthy plant foods as well as animal foods are scored negatively. The higher the score, the more healthful plant-foods and fewer unhealthy plant foods and animal foods included in the diet.

• uPDI : the opposite scoring system to PDI and hPDI. Positive points are allocated to unhealthy plant foods and animal foods whilst healthy plant foods are scored negatively. A higher score indicates a diet that is high in unhealthy plant foods.

Results were adjusted to take into account other confounding factors such as age, sex, energy intake, education, presence of diabetes, degree of physical activity and body mass index (BMI)

Results

Prevalence of NAFLD in this cohort with an average age of 49.2 years, was exceptionally high at 42.5%.

Individuals with high overall PDI scores were also high consumers of sweetened soft beverages.

Compared to participants with high uPDI scores, those with higher overall PDI and hPDI scores had lower BMI, were older, more likely to be females with higher education and income and non-smokers.

PDI score and NAFLD

When adjusting for BMI (a significant NAFLD associated factor) only those with a higher hPDI score were associated with a 50% reduced odds ratio (OR) of NAFLD (comparing extreme tertiles OR = 0.50, 95% CI 0.35, 0.72, p trend < 0.001). No statistically significant correlations were noted for either overall PDI or uPDI scores.

Without adjusting for BMI, uPDI scores were positively associated with NAFLD, whilst overall PDI scores had no association.

In summary

The study confirms the growing prevalence of NAFLD in normal healthy adults and how healthful plant-based dietary patterns are critical to reverse the situation. The study also emphasises that quality rather than quantity of plant foods is the key driver to reducing NAFLD incidence. This finding concurs with previous studies and highlights the importance to accommodate for the quality and not just the quantity of plant-foods when undertaking research to assess the health implications of plant-based diets.

Save article as PDF

Save article as PDF