Metabolic dysfunction-associated steatotic liver disease (MASLD), previously known as non-alcoholic fatty liver disease (NAFLD), is the most common liver disease worldwide. It has an estimated global prevalence of 38% in adults, and is projected to reach 55% by 2040.
The link between adherence to a Mediterranean dietary pattern and a lower risk of MASLD is well recognised in scientific literature, although there remains a paucity of evidence regarding the associations in older adults.
To elucidate the effect of the Mediterranean diet and UPF intake on the risk of MASLD specifically in older adults, researchers in Australia performed a post-hoc analysis based on data from two previous studies.
Namely the ASPirin in Reducing Events in the Elderly (ASPREE) randomised trial and the ASPREE Longitudinal Study of Older Persons (ALSOP) cohort study, these research involved 16,703 Australians aged 70 years or older.
The Mediterranean diet is characterised by a high intake of olive oil, fruits, vegetables, nuts, wholegrains, legumes, and oily fish, and limited consumption of red and processed meat.
UPFs are classified as packaged foods that have undergone industrial processing with additives, such as biscuits, pastries, breakfast cereals, flavoured yoghurts, pre-made meals, muesli bars, protein powders, factory-made breads, and soft drinks.
The findings showed that both a higher intake of the Mediterranean diet and a lower intake of UPFs were associated with a decreased risk of MASLD.
On the other hand, high UPF intake was associated with an increased risk of MASLD.
Notably, it was found that individuals who had higher adherence to the Mediterranean diet — even with a concurrent high UPF intake — had a decreased risk of MASLD, compared to a lower Mediterranean diet intake.
Furthermore, higher Mediterranean diet intake was also associated with lower triglycerides, lower BMI, and a lower waist circumference in older adults.
“Our study has demonstrated that people who had greater adherence to the Mediterranean diet were at a significantly lower risk of having MASLD. When adjusted for age, sex and variables known to be associated with MASLD, such as diabetes, hypertension, and chronic kidney disease, this finding remained consistent.
“These results contribute valuable knowledge to the existing literature through both providing initial data for future prospective studies, as well as supporting public health dietary recommendations for older persons,” the researchers wrote.
Importance of overall diet quality
In middle-aged people, MASLD can lead to a significant increase in morbidity and premature mortality via increased rates of cardiovascular disease (CVD) as well as the progression of liver disease to cirrhosis and the development of liver cancer.
While the link between MASLD, mortality, and CVD is not as clear in older persons, there are known older person-specific associations, including frailty and persistent physical disability.
Several studies have also demonstrated the heightened risk of developing MASLD, type 2 diabetes and metabolic syndrome with increasing UPF intake.
The association between UPF and MASLD is explained by an overall poor diet quality, in addition to high saturated fat and refined grain intake.
“Our novel finding of the Mediterranean diet’s protective effect even with high consumption of UPFs highlights the importance of overall dietary quality and the context in which foods are consumed, rather than individual nutrients being considered in isolation.”
There are various phytochemicals, known for their anti-inflammatory and antioxidant properties, found in foods that may influence the development of steatosis (fat accumulation in liver cells) and ameliorate dyslipidaemia (abnormal lipid levels in the bloodstream).
These include isoflavones in legumes, polyphenols in extra virgin olive oil, and other bioactive compounds available in many of the plant-based foods commonly consumed in the Mediterranean diet.
“Similarly, the Mediterranean diet may have beneficial effects on the gut microbiome, which is potentially causative or protective for the development of MASLD. This is an area that warrants further research, as does evaluating whether particular classes of UPFs are at a greater risk of being associated with MASLD,” the researchers concluded.
Source: Nutrients
https://doi.org/10.3390/nu17091415
“Associations Between MASLD, Ultra-Processed Food and a Mediterranean Dietary Pattern in Older Adults”
Authors: Isabella Commins, et al