In a new study, scientists have discovered the hidden properties of a compound called phytoene, commonly found in tomatoes, carrots, apricots, red peppers, oranges, mandarins and passion fruit—and found in high amounts in some types of algae—could extend one's life and prevent Alzheimer's disease.
Phytoene is a plant chemical—called a phytonutrient—that, up to this point, had not been studied much, with many believing it didn't do much when eaten, even though it's present in many tissues in the body, including skin.
But scientists at the University of Seville, Spain, and the University of Kent, England, have discovered it may reduce the risk of Alzheimer's disease and promote longevity after they tested the compound on tiny worms called Caenorhabditis elegans (C. elegans).
Their research suggests phytoene could extend lives and prevent Alzheimer's—but further studies are needed to confirm it would have a similar effect on humans.
Alzheimer's disease is the seventh leading cause of death in the United States, according to the Centers for Disease Control and Prevention (CDC). It killed 6.9 million Americans in 2020—a figure expected to rise to 14 million by 2060.
The most common form of dementia, it is characterized by memory loss, confusion, impaired judgment, losing things and mood changes, and currently there is no cure.
"Historically, there has been a lot of focus on the health benefits of fiber and vitamins produced by plants, but now we are starting to understand that plants produce thousands of molecules that affect our health, and that there is much more to plants that just fiber and vitamins," study co-author Marina Ezcurra, biologist at the University of Kent, told Newsweek.
She continued: "With a growing human population and a changing climate, it is becoming increasingly difficult to produce sufficient plant foods. An alternative could be algae, which grow naturally in the sea, streams and lakes. In particular, microalgae can be grown sustainably and there is growing evidence for their health effects. In this study, we wanted to better understand the health effects of compounds from microalgae."
This team of scientists, led by Professor Antonio Jesús Meléndez Martínez from the University of Seville, tested phytoene and extracts of two types of microalgae that contain very high levels of phytoene, on C. elegans: tiny worms that live in soil and compost, and don't grow bigger than a grain of salt, but still have muscles, nerves, sex organs and digestive systems.
"By using C. elegans, we could avoid the cost, time and complexity of conducting human trials, and the ethical and regulatory implications of using mice," explained Ezcurra. "Working with C. elegans is inexpensive and fast, as well as more ethical and sustainable. Also most of their genes are the same as the genes humans have, so C. elegans is a great tool to study health and aging."
The scientists found that phytoene extended the lifespan of C. elegans by between 10 and 18.6 percent, and reduced the damage done by amyloid plaques by between 30 and 40 percent.
Amyloid plaques are believed to be a key hallmark of Alzheimer's disease, substances that build up in the brain, sometimes decades before the disease becomes detectable.
So, the fact that phytoene seemed to reduce plaque-related damage in C. elegans may present phytoene as a promising strategy for preventing Alzheimer's in future.
The scientists also found that phytoene was effective against oxidative stress, wear and tear that occurs as a byproduct of chemical reactions in the body, that can contribute towards inflammation, disease risk, and aging.
They suggested that supplements could be developed, perhaps using the phytoene-rich microalgae they used in their study, to promote longevity and reduce the risk of Alzheimer's.
"To our surprise, we found that the microalgae extracts improved all the aspects of health that we tested," Ezcurra said. "The animals that ate the microalgae extracts lived longer, were more resistant to physiological (oxidative) stress and were protected against a humanized model of Alzheimer's disease."
She added: "This suggests that compounds from microalgae can have profound effects on health. What was more surprising was that we could show that a single molecule, phytoene, which exists in high levels in both microalgae and plants, had all these health effects."
Microalgae, they said, have many nutritional benefits beyond phytoene, that could make them an important future source of nutrients as the food system adapts to a changing climate.
Rich in healthy fats and proteins, microalgae are quick and easy to grow, without the need for farmland as they grow in water, so they are an eco-friendly, ultra-nutritious crop, the scientists wrote—not to mention their beneficial phytoene content.
"Many algae in general, and microalgae in particular, are sustainable sources of many compounds that are beneficial for humans," Meléndez Martínez told Newsweek. "Their consumption, and the development of algal-based products is expected to continue growing steadily as the food industry must tend to the production of health-promoting foods that are more sustainable."
Phytoene is a type of carotenoid, which is a beneficial nutrient found in many foods—usually orange in color—that can convert to vitamin A in the body and has been linked to a long list of health benefits, including reduced risks of cancers, heart disease, skin conditions, eye disorders, metabolic disorders, and more.
But phytoene has not usually featured as part of nutritional research, under the assumption that it is not a particularly beneficial carotenoid.
Studies on tomatoes, for instance, have found an association with reduced risks of heart disease and cancer, but attributed this to a carotenoid called lycopene, ignoring the possibility that phytoene—which tomatoes contain in high amounts—may play a part.
"There is a wide agreement in the scientific community that the consumption of plant-based foods should be increased to promote health and sustainability," said Meléndez Martínez. "Carotenoids such as phytoene and other bioactive compounds are at high concentrations in plant foods. Specifically, tomato and its derivatives is one of the best sources of phytoene, although there are others, such as carrots, apricots, watermelon, certain citrus, etc."
This study was published on Thursday in the scientific journal Antioxidants and forms part of first author Ángeles Morón Ortiz's doctoral thesis.
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Reference
Morón-Ortiz, Á., Karamalegkos, A. A., Mapelli-Brahm, P., Ezcurra, M., Meléndez-Martínez, A. J. (2024). Phytoene and Phytoene-Rich Microalgae Extracts Extend Lifespan in C. elegans and Protect against Amyloid-β Toxicity in an Alzheimer's Disease Model, Antioxidants 13(8). https://doi.org/10.3390/antiox13080931
Sun, J., Aballay, A., Singh, V. (2016). Cellular Responses to Infections in Caenorhabditis elegans, Encyclopedia of Cell Biology 2. https://doi.org/10.1016/B978-0-12-394447-4.20074-6
Hampel, H., Hardy, J., Blennow, K., Chen, C., Perry, G., Kim, S. H., Villemagne, V. L., Aisen, P., Vendruscolo, M., Iwatsubo, T., Masters, C. L., Cho, M., Lannfelt, L., Cummings, J. L., Vergallo, A. (2021). The Amyloid-β Pathway in Alzheimer's Disease, Molecular Psychiatry 26, 5481-5503. https://doi.org/10.1038/s41380-021-01249-0
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