Diet rich in omega-3 fatty acids may lower risk of ICP, scientists say
High blood levels of omega-6 fatty acids tied to greater risk in genetic study
Higher blood levels of omega-3 fatty acids, fatty molecules found in food and shown to have health benefits, significantly associate with a lower risk of intrahespatic cholestasis of pregnancy (ICP), a study into genetic variants linked with those fatty acid levels showed.
In contrast, a likelihood of ICP increased with genetically determined higher levels of omega-6 fatty acid, particularly linoleic acid. Omega-6 fatty acids comprise another group of fatty molecules that are believed to counteract omega-3’s effects.
“The findings suggest that [omega-3] fatty acids may have a protective effect against the risk of ICP, while [omega-6] fatty acids and linoleic fatty acids could be potential risk factors for ICP,” the researchers wrote. As such, “supplementation of [omega-3] fatty acids, as opposed to [omega-6] fatty acids, could be a promising strategy for the prevention and management of ICP.”
The study, “PUFA and intrahepatic cholestasis of pregnancy: a two-sample Mendelian randomisation analysis,” was published in the British Journal of Nutrition.
Intrahespatic cholestasis of pregnancy poses serious risks to mother and child
Occurring typically during the third trimester, ICP, the most common pregnancy-specific liver disease, is a form of cholestasis, a condition wherein the digestive fluid bile doesn’t flow properly from the liver, where it is produced, into the intestines.
This disrupted flow causes bile acids to accumulate in the liver, damaging the organ and interfering with its function, and to leak into the bloodstream, causing disease symptoms such as intense itching.
ICP poses serious risks for the mother and fetus, making early diagnosis crucial.
“Despite ongoing investigations into its underlying mechanisms, effective preventive and therapeutic strategies remain a critical need,” the researchers, all working at hospitals across China, wrote.
While ICP’s exact causes are unknown, some studies suggest that inflammation, immune responses, and fat metabolism may contribute to its development.
Polyunsaturated fatty acids (PUFAs), which include the omega-3 and omega-6 fatty acid families, are essential nutrients for human health that must be obtained through diet.
Omega-3 and omega-6 imbalance can contribute to obesity and diabetes
Omega-3 fatty acids, which are found in fatty fish and some seeds, have been shown to have protective effects, reducing inflammation and levels of triglycerides, a type of fatty molecule.
But omega-6 fatty acids, particularly linoleic acid, which are found in nuts, seeds, and vegetable oils, “have biological functions that often oppose those of [omega-3] fatty acids,” the researchers wrote.
In addition, an imbalance between omega-3 and omega-6 fatty acids has been linked to pro-inflammatory conditions, contributing to obesity and diabetes. “A diet rich in [omega-6] fatty acids shifts the physiological state to one that is risky,” the researchers wrote.
The scientists set out to assess whether there is a cause-and-effect relationship between PUFAs and ICP. They collected data from genome-wide association studies, which are designed to detect associations between genetic variants and a certain trait or disease.
The researchers then applied Mendelian randomization, a method that uses genetic information to find a potential cause and effect between an exposure — in this case, PUFA levels — and an outcome, that is, developing ICP.
In terms of PUFA levels, they specifically looked for genetic variants associated with high omega-3 levels, a high omega-3 to total fatty acids ratio, a high omega-6 to omega-3 ratio, and a high ratio of linoleic acid to total fatty acids.
Results showed that the risk of ICP fell significantly, by 31%, for each prespecified increase in the genetically predicted levels of omega-3 fatty acids and their ratio to total fatty acids.
Omega-3 fatty acids may help by regulating triglyceride and bile acid blood levels
In turn, every increase in the ratio of omega-6 to omega-3 fatty acids, indicative of higher omega-6 levels, was significantly linked to a 51% increased in ICP risk.
Each prespecified increase in the ratio of linoleic acid to total fatty acids, reflecting higher linoleic acid levels, showed an even greater increase in ICP risk, by 138%.
“These results highlight the potential benefits of [omega-3] fatty acids supplementation and suggest avoiding the use of [omega-6] or linoleic fatty acids for preventing ICP,” the team wrote. “This underscores the importance of nutritional interventions in primary ICP prevention.”
Researchers hypothesized that the protective effects of omega-3 fatty acids in ICP may be related to their anti-inflammatory effects and ability to regulate blood levels of triglyceride and bile acids.
While further studies are needed to confirm these findings, they “suggest that preemptive supplementation of [omega-3] fatty acids and maintaining an appropriate [omega-6] to [omega-3] ratio before conception or during early pregnancy may help reduce the risk of ICP and associated adverse outcomes,” the researchers wrote.
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