There are plenty of reasons why people begin incorporating nutritional supplements into their daily regimen. In many cases, it’s to help ensure they’re getting the recommended amounts of vitamins and minerals. Others do so in the hopes that it could help stave off serious health issues like cardiovascular disease. But now, a pair of studies show that fish oil supplements could play a part in protecting against two major diseases.
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For some people, fish oil supplements decreased the risk of Alzheimer’s disease.
The first batch of data comes from a clinical study published in the journal JAMA Network Open. In it, a team of researchers from Oregon Health & Science University (OHSU) used 102 participants aged 75 and older whose bloodwork showed low levels of the omega-3 fatty acids found in fish oil supplements. They then took MRI scans of each participant’s brain to mark white matter lesions, which can affect blood flow in the brain and represent an increased dementia risk.
Then, half of the participants were given fish oil supplements to take daily, while the other half took a placebo. After three years, they were brought in for another round of MRIs to assess any changes to the lesions over time. However, the results didn’t exactly move the needle for most participants.
“Our findings showed that over three years, there was not a statistically significant difference between placebo and the group that took fish oil,” Lynne Shinto, professor of neurology in the OHSU School of Medicine, said in a press release. “I don’t think it would be harmful, but I wouldn’t say you need to take fish oil to prevent dementia.”
However, the researchers noted that those who tested positive for the APOE4 gene—which is an indicator of a significantly increased dementia risk—saw a considerable reduction in the white matter brain lesions when taking fish oil supplements.
“This is the first dementia prevention trial to use modern prevention tools, such as a blood test and brain scan, to identify not only people at high risk for dementia, but also those well-suited to receive a specific nutritional intervention,” Gene Bowman, director of clinical trials and instructor of neurology at the McCance Center for Brain Health at Massachusetts General Hospital and Harvard Medical School, said in a press release. “The fact that neuronal integrity breakdown was slowed in people randomized to omega-3 treatment who are also at high risk for Alzheimer’s disease is remarkable and warrants a larger clinical trial in more diverse populations in the future.”
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Fish oil also had positive effects on diabetes risk.
But this wasn’t the only scientific foray into fish oil lately. In a separate study recently published in the journal Nutrients, a team of researchers used rats with hypoglycemia (or elevated blood sugar) due to insulin resistance, similar to type 2 diabetes. The scientists administered fish oil to the rats based on a percentage of their body weight thrice weekly for two months.
At the end of the study, researchers observed reduced insulin resistance and hypoglycemia in the rodents, a decrease in unhealthy lipids such as triglycerides and “bad” LDL cholesterol, and a drop in inflammatory markers in the blood. Doctors said the results could be shedding light on the relationship between omega-3 fatty acids and diabetes.
“Our experiments involved Goto-Kakizaki [GK] rats, an animal model for non-obese type 2 diabetes. We found that insulin resistance can be reduced in these animals by modulating the inflammatory response so as to change the profile of defense cells [lymphocytes] from a pro-inflammatory state to an anti-inflammatory state. This process parallels the response of obese individuals with insulin resistance to omega-3 fatty acid supplementation,” Rui Curi, PhD, Director of Butantan Institute’s Education Center, Professor of Interdisciplinary Graduate Studies in Health Sciences at Cruzeiro do Sul University (UNICSUL), and the study’s coordinator, said in a press release.
The latest study is part of a series of similar studies probing insulin resistance in animals. Other findings from the group have hypothesized that diabetes in non-obese rats could be caused by chronic low-level inflammation that affects the passage of food through the intestines. Another found that fish oil could help suppress inflammation markers in the blood that could promote insulin resistance.
However, scientists said there is still a while to go before the findings could be interpreted towards treatments.
“These studies involved well-established experimental models that mimic insulin resistance in non-obese individuals,” Curi said in the press release. “Trials in humans are needed to estimate the ideal dose and the most indicated type of omega-3 fatty acid.”
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The takeaway:
A pair of studies has shed some light on how fish oil supplements could potentially protect against two major diseases. The first looked at how a daily supplement could potentially affect the growth of white mass lesions on the brain, which serve as an indicator of high risk for dementia. While there was no significant decrease in brain growth for most participants in either the placebo or supplement groups, participants who are carriers for a high-risk marker gene did see some reduction as a result.
The second study probed how omega-3 fatty acids in fish oil might play a part in treating insulin resistance, which is a factor in type 2 diabetes. Using rats, the team found that a daily dose of the nutrient aligned with a reduction in insulin resistance, as well as a drop in inflammatory markers in the blood and lipids. However, the team concluded that more research on humans was necessary to truly understanding the link.
