Study Findings Suggest Liver Creates Palmitic Acid, Maintaining Brain Health

According to new research, palmitic acid—one of the most common fats in human milk, meats, and dairy products—is made by the liver and sent to the developing brain. These findings suggest the importance of palmitic acid for brain health while emphasizing the need for further research on lowering levels in infant formula, which is a step that some manufacturers are already taking to reduce costs.

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“When we changed the levels of palmitic acid in the diets of developing mice, it didn’t do a thing to the brain,” said principal investigator Richard Bazinet, PhD, professor and acting chair of nutritional sciences, Temerty Faculty of Medicine, University of Toronto, in a press release. “The results were surprising because when you lower a lipid in the diet, it usually becomes lower in the brain. But here the liver was able to upregulate production to ensure the brain gets enough of it, despite extreme differences in dietary intake.”

Palmitic acid, a saturated fat that supports brain health in multiple ways, contributes to the structure and function of myelin sheathing, which shields neural connects and acts as a precursor to molecules that regulate inflammation while promoting cell signaling. Further, investigators have previously known that humans and other mammals can get palmitic acid either from food or a process called de novo lipogenesis; however, less is known about the source that the body depends on.

The source is also relative to diet and varies at different stages of growth, and according to the authors, the findings indicate a significance of palmitic acid for brain health during development because this is when the need for it is the highest. Further, the results also suggest that manufacturers should look to reduce the amount of palmitic acid present in infant formula.

“It’s possible that we can lower levels in formula, which could have a positive ecological impact, but we don’t yet know the potential health effects,” said first study author and doctoral student Mackenize Smith in the press release. “Are there implications for behavior or development when the liver produces so much? Might there be negative effects for the liver?”

According to Smith, the mice that received the lower amounts of palmitic acid in their diet had higher levels of fat than some manufacturers of formula use. In addition, the inconsistencies further emphasize the need for additional preclinical studies as well as research in human populations, according to the authors.

There is a depleted carbon ratio signature in the brains of mice which indicate a dietary source of palmitic acid, whereas an enriched signature suggests de novo lipogenesis. The investigators uncovered this by applying a carbon isotope technique based on how plants absorb carbon in photosynthesis to determine the differences in carbon isotope ratios in the environment.

“Most plants use the same path to fix carbon from the atmosphere and have the same carbon ratio, but sugars such as corn and sugar cane — which the liver uses to generate palmitic acid — have a different ratio,” said Smith in the press release.

Further, the investigators determined the signatures in different stages throughout the mouse’s development, which indicates that the liver was the main source of palmitic acid in the brain. This finding was confirmed by examining changes in genetics. To extend the research and further confirm the findings, the investigators are now applying the same technique in tissue from adult human brains. According to the authors, can provide a new method of measuring and tracking the dietary sources of other fats and nutrients within the tissues.

“Nutrition researchers often rely on people reporting their food intakes, which can lead to unreliable data,” said Bazinet. “Those problems could potentially be flagged with this kind of technology, to track the source and amount of added sugars, for example. It could be very fruitful for nutritional science.”

Reference

University of Toronto. Liver can generate palmitic acid to maintain brain health, study suggests. News release. January 17, 2024. Accessed January 19, 2024. https://www.eurekalert.org/news-releases/1031845