California fish carry human-infecting parasites that can cause stroke or heart attack, researchers find
More than 90 percent of popular freshwater game fish in Southern California contain a parasite that is capable of inducing strokes or heart attacks in the humans who eat them.
Researchers said the parasites were two species of flatworms known as trematodes. At no more than a few centimeters in length, the flukes – a class of flatworms – can result in weight loss or lethargy. Although rare, infection has also resulted in more severe consequences.
'Americans don't usually think about parasites when they eat freshwater fish because it hasn't historically been an issue here,' Ryan Hechinger, an ecologist and parasitologist at UC San Diego's Scripps Institution of Oceanography, said in a statement. 'But these trematodes have now been widely introduced in the U.S. and that means that doctors and the public should be aware.'
He is the senior author of the study which was published Tuesday in the Journal of Infectious Diseases. It was funded by the National Institutes of Health.
To identify this issue, Hechinger, the University of Nebraska's Daniel Metz, and former Scripps graduate student and Smithsonian Environmental Research Center marine scientist Emma Palmer examined 84 fish from seven different species in 2023. Those fish included largemouth bass and bluegill, which were collected from five frequented fishing locations in San Diego County.
Of those, 93 percent were infected with the Haplorchis pumilio parasite, and some were the host to thousands. Two of the five locations yielded positive results for the second parasite known as Centrocestus formosanus, which occurred in 91 percent of the fish.
Historically, the trematodes have infected people in Southeast Asia and likely arrived in the U.S. more than a decade ago inside an invasive aquatic snail known as the red-rimmed melania. That snail is found in 17 states and Puerto Rico.
Previous work led by Hechinger had found that the red-rimmed melania and its parasites are widespread in the Golden State.
So, what is the risk to Californians and Americans at large? Hechinger says there haven't been any reported cases of parasites infecting Americans yets, but 'nobody is looking for cases and doctors aren't required to report them.' Californians should make sure to monitor fish advisories for any changes.
The risks posed by them are easy to avoid as, if you fully cook your fish or freeze any that's intended to be eaten raw for at least a week, the parasites will die. Although, the authors found that many Americans are likely consuming freshwater fish without taking the proper precautions. The greatest health threats come from repeated infection over many months or years. Foodborne trematode infections cause two million life years lost to disability and death worldwide every year, according to the World Health Organization.
They recommend that fish-borne trematode infection be added to the list of diseases doctors are required to report to public health officials.
'These parasites are here in the U.S., and they're infecting fish that people are eating,' said Hechinger. 'We hope this study can help make public health officials, doctors and the public more aware.'
Hashtags
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
Yahoo
an hour ago
- Yahoo
Opinion - How thousands of unreviewed ingredients got into our food — and what FDA can do about it
At least 1,000 ingredients in food products on our grocery store shelves have never been checked for safety by the Food and Drug Administration. Dozens have raised serious safety concerns among experts. How did the FDA allow this? The answer can be found in the agency's lax interpretation of a little-known legal designation that lets companies decide for themselves if ingredients in their products are safe. Fortunately, there are steps the agency can take right now to stem the flow of potentially unsafe ingredients into our food supply. Environmental Defense Fund outlined these steps in a letter we recently sent to the agency, but first let's take a closer look at how we got here. 'Generally Recognized as Safe' is a designation Congress created in 1958 to allow commonly used food ingredients to bypass the FDA's pre-market safety review process. It was meant for food substances — such as oils, vinegar, baking soda and common spices — that were widely considered safe due to their long history of everyday use. Since 1958, this status has been coopted to cover a universe of foods that extends far beyond its original intent. According to FDA regulations, a chemical can receive the designation if experts widely agree that scientific evidence shows its use to be safe. But because 'Generally Recognized as Safe' wasn't meant for newer ingredients, Congress allowed ingredients so designated to skip the FDA's premarket approval process — despite requiring similar evidence for other additives. Under the agency's current interpretation, companies can designate the use of a substance as safe and take products with that substance to market without informing the FDA or the public of its decision. While companies may voluntarily submit a notice to FDA offering safety evidence, they are not required to — and often don't. Our organization estimated that manufacturers have notified FDA of fewer than half of the ingredients they market as safe under the 'Generally Recognized' standard. Companies that do bother to submit a notice to the FDA are free to withdraw it at any point and take their product to market, provided they can cite evidence of its safe use. But this 'evidence' is often far from independent. Companies can, and often do, enlist their own employees or handpicked consultants to conduct their safety assessments. The result is a process riddled with conflicts of interest that lets unsafe foods into Americans' homes. We analyzed 'Generally Recognized as Safe' notices received by the FDA, obtained via a Freedom of Information request, and found that of the 1,163 submitted by companies between 1997 and April 2024, 192 were later withdrawn, with safety concerns cited in at least a dozen cases. We also identified 31 ingredients that companies have advertised to be recognized as safe, such as in press releases, trade publications and on their own websites (see the Appendix of our letter). However, we were unable to find the scientific evidence required under this standard to demonstrate these ingredients are commonly regarded as safe among experts. This raises red flags that FDA should be taking seriously. Although a comprehensive fix to the 'Generally Recognized' standard will require legislation from Congress, there are significant steps the FDA can take right away to ensure a more rigorous determination process that better protects Americans' health. Starting today, the FDA can use existing authority to remove safe designations from ingredients it deems unsafe and take them off the market. It can also notify manufacturers, importers, distributors and retailers that the substance is no longer recognized as safe. In addition, the FDA can enforce the requirement that companies base safety designations on publicly available data. Although this won't curtail companies' ability to self-declare substances as safe, it will require those who do to be transparent in citing their evidence. Third, the FDA can enforce the requirement that safety assessments consider vital health information such as a substance's dietary sources, potential cancer risks and the cumulative health effects of similar substances. Finally, the FDA can make companies revise and resubmit their data for review when they submit 'Generally Recognized as Safe' notices that fail to comply with the criteria. The 'Generally Recognized as Safe' designation is far from a perfect system, but it can work better if it is interpreted and enforced more comprehensively. If the FDA is serious about protecting public health, it should start by fully exercising the tools already at its disposal. Maria Doa is senior director at the Chemicals Policy at Environmental Defense Fund. Maricel Maffini is an independent consultant focused on human and environmental health and chemical safety. Copyright 2025 Nexstar Media, Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.
The Hill
4 hours ago
- The Hill
How thousands of unreviewed ingredients got into our food — and what FDA can do about it
At least 1,000 ingredients in food products on our grocery store shelves have never been checked for safety by the Food and Drug Administration. Dozens have raised serious safety concerns among experts. How did the FDA allow this? The answer can be found in the agency's lax interpretation of a little-known legal designation that lets companies decide for themselves if ingredients in their products are safe. Fortunately, there are steps the agency can take right now to stem the flow of potentially unsafe ingredients into our food supply. Environmental Defense Fund outlined these steps in a letter we recently sent to the agency, but first let's take a closer look at how we got here. 'Generally Recognized as Safe' is a designation Congress created in 1958 to allow commonly used food ingredients to bypass the FDA's pre-market safety review process. It was meant for food substances — such as oils, vinegar, baking soda and common spices — that were widely considered safe due to their long history of everyday use. Since 1958, this status has been coopted to cover a universe of foods that extends far beyond its original intent. According to FDA regulations, a chemical can receive the designation if experts widely agree that scientific evidence shows its use to be safe. But because 'Generally Recognized as Safe' wasn't meant for newer ingredients, Congress allowed ingredients so designated to skip the FDA's premarket approval process — despite requiring similar evidence for other additives. Under the agency's current interpretation, companies can designate the use of a substance as safe and take products with that substance to market without informing the FDA or the public of its decision. While companies may voluntarily submit a notice to FDA offering safety evidence, they are not required to — and often don't. Our organization estimated that manufacturers have notified FDA of fewer than half of the ingredients they market as safe under the 'Generally Recognized' standard. Companies that do bother to submit a notice to the FDA are free to withdraw it at any point and take their product to market, provided they can cite evidence of its safe use. But this 'evidence' is often far from independent. Companies can, and often do, enlist their own employees or handpicked consultants to conduct their safety assessments. The result is a process riddled with conflicts of interest that lets unsafe foods into Americans' homes. We analyzed 'Generally Recognized as Safe' notices received by the FDA, obtained via a Freedom of Information request, and found that of the 1,163 submitted by companies between 1997 and April 2024, 192 were later withdrawn, with safety concerns cited in at least a dozen cases. We also identified 31 ingredients that companies have advertised to be recognized as safe, such as in press releases, trade publications and on their own websites (see the Appendix of our letter). However, we were unable to find the scientific evidence required under this standard to demonstrate these ingredients are commonly regarded as safe among experts. This raises red flags that FDA should be taking seriously. Although a comprehensive fix to the 'Generally Recognized' standard will require legislation from Congress, there are significant steps the FDA can take right away to ensure a more rigorous determination process that better protects Americans' health. Starting today, the FDA can use existing authority to remove safe designations from ingredients it deems unsafe and take them off the market. It can also notify manufacturers, importers, distributors and retailers that the substance is no longer recognized as safe. In addition, the FDA can enforce the requirement that companies base safety designations on publicly available data. Although this won't curtail companies' ability to self-declare substances as safe, it will require those who do to be transparent in citing their evidence. Third, the FDA can enforce the requirement that safety assessments consider vital health information such as a substance's dietary sources, potential cancer risks and the cumulative health effects of similar substances. Finally, the FDA can make companies revise and resubmit their data for review when they submit 'Generally Recognized as Safe' notices that fail to comply with the criteria. The 'Generally Recognized as Safe' designation is far from a perfect system, but it can work better if it is interpreted and enforced more comprehensively. If the FDA is serious about protecting public health, it should start by fully exercising the tools already at its disposal. Maria Doa is senior director at the Chemicals Policy at Environmental Defense Fund. Maricel Maffini is an independent consultant focused on human and environmental health and chemical safety.
Yahoo
4 hours ago
- Yahoo
Eating more of these plant-based foods could lower your risk of heart disease and diabetes
Eating more nuts, fruits, vegetables, and whole grains may help to reduce your risk of contracting deadly heart disease and type 2 diabetes. Researchers said this week that people who consumed more phytosterols — a natural compound found in plant foods — significantly delayed both of the conditions. Furthermore, eating more of them was linked to reduced inflammation, markers of better insulin regulation, and differences in the gut microbiome that may contribute to healthy metabolism. The study was not designed to confirm why this is the case, but the researchers said their findings strengthen the evidence. More than 7000,000 Americans die from heart disease and some 101,000 die from diabetes. 'Our findings support the dietary recommendation of adhering to healthy plant-based dietary patterns that are rich in vegetables, fruits, nuts and whole grains,' Dr. Fenglei Wang, a research associate at the Harvard T.H. Chan School of Public Health, said in a statement. 'These findings can help people make informed dietary choices.' Wang presented the observational findings on Tuesday at the flagship annual meeting of the American Society for Nutrition. Some phytosterol-rich foods include corn, almonds, broccoli, bananas, and wheat bread. Previous research had found that eating foods with phytosterols can help to improve peoples' health by lowering bad cholesterol, and may reduce the risk of cancer. However, most clinical trials have used high doses of the phytosterols that were beyond what someone might get through just their own diet. The new research is the first to show the benefits as part of a normal diet. To reach these conclusions, Wang and his colleagues looked at data from more than 200,000 American adults that were a part of three studies. All of the participants were nurses or other health professionals and nearly 80 percent were women. Over the course of 36 years, more than 20,000 of them developed type 2 diabetes and nearly 16,000 developed heart disease. The participants' answers to food-frequency questionnaires allowed the researchers to estimate their individual intake of phytosterols, as well as three individual phytosterols known as β-sitosterol, campesterol and stigmasterol. Those who ate the most consumed the most phytosterol had about four to five servings of vegetables, two to three servings of fruits, two servings of whole grains, and half a serving of nuts each day. This made them 9 percent less likely to develop heart disease and 8 percent less likely to develop type 2 diabetes compares to those in the bottom fifth percentage for phytosterol intake, the research showed. Looking at the individual phytosterols, similar associations were observed for β-sitosterol. But, the same was not true for campesterol or stigmasterol. In addition, the researchers analyzed blood samples, looking at the products of metabolism — also known as metabolites — from more than 11,000 people and other metabolic biomarkers in blood samples from over 40,000 participants. They found that phytosterol and β-sitosterol levels were tied to favorable metabolites and metabolic markers relevant to heart disease and diabetes. That signaled a possible reason for the association. 'Our clinical biomarker and metabolomic results suggest the involvement of insulin activity, inflammation and the metabolism of metabolites associated with type 2 diabetes and cardiovascular disease,' said Wang. 'This suggests that phytosterol might reduce risk by alleviating insulin resistance and inflammation.' In a group of just 465 participants, they examined the gut microbiome, or the trillions of microscopic organisms inside the intestines. They found several microbial species and related enzymes linked to higher intake of phytosterols that may affect the production of metabolites associated with a lower risk of diseases. 'We found that the gut microbiome might play a role in the beneficial associations. Some species, such as Faecalibacterium prausnitzii, carry enzymes that could help degrade phytosterol, potentially influencing host metabolism,' Wang said.
