Scientist from Jimei University and Fujian Aonong Biological Science and Technology Group Co., Ltd in China note that all organisms store energy as fat, and, just as we see in humans, a high fat diet can lead to excessive storage of fat and liver damage.
“Therefore, studying the regulation of fat storage in fish can contribute to our understanding of human metabolic disorders,” they wrote in Antioxidants.
The new study indicated that supplementing a high fat diet with hydroxytyrosol led to significant improvements in measures of both liver health and mitochondrial function.
Interest in nutritional and dietary ways to improve mitochondrial function has increased over the past decade.
It is already known that the function of mitochondria declines with age, while aging is a known risk factor for several common age-related and neurodegenerative disorders. This led to the proposition that secondary mitochondrial dysfunction may lead to degenerative diseases.
“Emerging evidence suggests that mitochondrial dysfunction mediates the pathogenesis for non-alcoholic fatty liver disease (NAFLD),” added the China-based researchers.
The new study used spotted seabass (Lateolabrax maculatus) juveniles that were randomly divided into one of four groups: A normal fat diet with or without supplemental hydroxytyrosol (200 mg/kg) or a high-fat diet with or without supplemental hydroxytyrosol.
After eight weeks of intervention, the researchers reported that the high fat diet-fed fish did indeed display higher levels of fat deposition in the liver and had increased levels of oxidative stress. However, both of these were ameliorated when hydroxytyrosol was added to the diet.
The data also revealed that the high-fat diet was associated with disruptions to the mitochondria, while hydroxytyrosol again helped to relieve these detrimental changes.
Additional study in zebrafish showed that hydroxytyrosol may exert its benefits by activtating PINK1-mediated mitophagy. Mitophagy is the mitochondrial quality control mechanism that removes damaged and redundant mitochondria (for more on mitophagy, please see “Mitophagy: An Emerging Role in Aging and Age-Associated Diseases” by Chen et al, Front. Cell Dev. Biol., 2020)
“This result confirmed the suppression of the level of mitophagy by [fatty acid] treatment and its improvement with [hydroxytyrosol] application,” wrote the China-based scientists.
“Moreover, our findings revealed the similarity of the mitophagy process in fish and humans, as macroautophagy is the main type of mitophagy in humans.”
2022, 11(5), 893; doi: 10.3390/antiox11050893
“Hydroxytyrosol Promotes the Mitochondrial Function through Activating Mitophagy”
Authors: Y. Dong et al.