1. Introduction
In recent years, the olive oil industry has become a focal point for researchers because of the health-promoting properties of its byproducts. The Mediterranean diet, renowned for its cardiovascular and neuroprotective benefits, places olive oil in its heart. However, it is not just an oil with health potential. By-products from the olive oil extraction process, once seen as mere waste, are now recognized as rich sources of bioactive compounds including polyphenols. These compounds have drawn attention for their potential role in preventing Alzheimer’s disease (AD), a neurodegenerative disorder that affects millions of people globally. In the article Olive Oil Industry By-Products as a Novel Source of Biophenols with a Promising Role in Alzheimer Disease Prevention, we explored the neuroprotective effects of olive-derived polyphenols, particularly their antioxidant, anti-inflammatory, and cognitive benefits. This review highlights the critical role that these bioactive compounds may play in mitigating AD pathology, which is a pressing concern as global cases of AD are expected to rise sharply by 2050.
2. Olive Oil By-Products: An Untapped Resource
The production of olive oil, particularly in Mediterranean countries, generates substantial quantities of by-products such as olive leaves, pomace, and wastewater. Historically, these by-products have been treated as waste, posing environmental challenges. However, they also contain a plethora of phenolic compounds, including hydroxytyrosol and oleuropein, which are known for their potent antioxidant and anti-inflammatory properties. These compounds are especially relevant for AD prevention, as oxidative stress and neuroinflammation are key contributors to AD progression.
3. The Mediterranean Diet and Alzheimer’s Disease
Adherence to the Mediterranean diet has been linked to a lower incidence of cognitive decline and neurodegenerative diseases. Olive oil, the cornerstone of this diet, is rich in polyphenols that help prevent oxidative stress and reduce inflammation, both of which are implicated in AD. This study builds on this foundation by focusing on the phenolic compounds found in olive oil byproducts, which may offer an even more potent protective effect against AD. This study highlights the potential of using these compounds in nutraceuticals and functional foods as part of a preventive strategy.
Figure. In vitro studies on olive-derived polyphenols: mechanisms of action in Alzheimer’s disease prevention. OLE: oleuropein aglycone; HT: hydroxytyrosol; SH-SY5Y: SH-SY5Y cells; ROS: reactive oxygen species; Aβ1–42: amyloid beta 1–42; AChE: acetylcholinesterase; BChE: butyrylcholinesterase; BACE-1: beta-site APP-cleaving enzyme 1. Leri et al. (2021) [252] https://www.mdpi.com/1422-0067/22/13/7225, accessed on 8 October 2024. Maiuolo et al. (2023) [253] https://www.mdpi.com/1422-0067/24/17/13461, accessed on 8 October 2024.
4. Polyphenols in AD Prevention: Mechanisms of Action
The phenolic compounds in olive oil by-products function through multiple mechanisms that offer neuroprotection. These compounds reduce oxidative stress by scavenging free radicals, which are crucial for protecting the neurons from damage. Additionally, they modulate neuroinflammation, which is another major player in AD pathology, by inhibiting proinflammatory pathways. Research has shown that polyphenols, such as hydroxytyrosol and oleuropein, can mitigate amyloid-beta (Aβ) aggregation, a hallmark of AD. These compounds also preserve synaptic integrity and prevent hyperphosphorylation of tau protein, which leads to neurofibrillary tangles. These two pathological features are central to the development and progression of AD.
5. From Waste to Wealth: The Sustainable Value of Olive Oil By-Products
One of the most compelling aspects of this study is its alignment with sustainability principles. By valorizing olive oil by-products, the industry can reduce environmental waste, while creating high-value health products. This approach supports a circular economy by transforming waste into bioactive compounds that can be utilized in the pharmaceutical, nutraceutical, and cosmetic industries. Large-scale production of olive oil generates vast quantities of by-products, which, if not managed properly, can contribute to environmental degradation. However, these byproducts are rich sources of bioactive compounds. By developing efficient extraction methods, the olive oil industry can convert these waste materials into valuable resources that can contribute to both health and environmental sustainability.
Figure. Overview of olive oil production.
6. Challenges in Research and Future Directions
Despite promising in vitro and in vivo evidence supporting the role of olive-derived polyphenols in AD prevention, several challenges remain. Variability in extraction methods and the complex nature of polyphenols can lead to inconsistencies in the bioactive profiles of the extracts. Moreover, human clinical trials are currently limited, and there is a pressing need for robust and well-designed studies to confirm the neuroprotective effects of these compounds in humans. Future research should focus on standardizing extraction protocols to ensure the consistent bioactivity of phenolic compounds. Additionally, large-scale clinical trials are essential to establish the efficacy of these compounds in preventing or slowing AD progression in humans. These efforts will help bridge the gap between preclinical findings and clinical applications, bringing us closer to utilizing olive oil by-products as therapeutic options for AD.
7. Conclusion
This study presents a compelling case for the potential of olive oil by-products as a novel source of bioactive compounds with promising applications in the prevention of Alzheimer’s disease. By focusing on the neuroprotective effects of these polyphenols, this study not only highlights a new avenue for AD prevention, but also underscores the importance of sustainable practices in the olive oil industry. As the global burden of AD continues to rise, innovative solutions are crucial for developing effective preventive strategies. The valorisation of olive oil by-products represents a convergence of health benefits and environmental sustainability, offering a path forward in the fight against neurodegenerative diseases. By harnessing the power of these natural compounds, we can move closer to a future in which AD prevention is both accessible and sustainable.
Read all at:
Gonçalves, M.; Costa, M.; Paiva-Martins, F.; Silva, P. Olive Oil Industry By-Products as a Novel Source of Biophenols with a Promising Role in Alzheimer Disease Prevention. Molecules 2024, 29, 4841. https://doi.org/10.3390/molecules29204841