The new animal study, reported in the American Journal of Physiology-Endocrinology and Metabolism, used newborn pigs as a model to study liver development. Associate Professor Samer El-Kadi of Virginia Tech led the team that fed two simplified formulas identical in calories and protein but differing in fat type: one rich in medium-chain fatty acids derived mainly from coconut oil, the other rich in long-chain fatty acids from animal fat, a profile closer to whole sow milk.
Pigs fed the medium-chain fat formula accumulated liver fat more rapidly. El-Kadi said fat was visible within seven days and that by about two weeks the condition had progressed from simple steatosis to a more inflammatory form. Importantly, the developing livers showed increased activity in both fat-making and fat-burning pathways; in contrast, adult fat accumulation often reflects a slowdown in fat burning. These adaptive metabolic responses nonetheless failed to prevent fat buildup in the young livers.
The findings are relevant because steatotic liver disease, formerly called non-alcoholic fatty liver disease, is being diagnosed more often in children and has been identified in some infants. Infant formulas generally use plant-based oil blends to approximate breast milk, and newborn pigs are commonly used in nutrition research because their digestion and fat metabolism resemble human infants.
El-Kadi emphasized that the results do not mean parents should avoid formula; he called breast milk the "gold standard" and said formula is a vital alternative when breastfeeding is not possible. The research team is continuing to investigate how specific medium-chain fatty acids affect liver metabolism and whether different fatty acids or quantities have distinct effects.
Difficult words
- medium-chain fatty acid — fat molecules with medium-length carbon chainsmedium-chain fatty acids
- long-chain fatty acid — fat molecules with long carbon chainslong-chain fatty acids
- steatotic — describing a liver with excess fat
- accumulate — to build up or gather over timeaccumulated
- inflammatory — relating to swelling or immune response
- metabolism — all chemical processes in a living body
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- How much weight would you give to animal-model studies (like pigs) when evaluating infant nutrition? Explain your reasons.
- What additional information about specific fatty acids or amounts would you want before changing infant feeding recommendations?
- If formula manufacturers changed fat composition, what effects on health or practice would you expect or worry about? Explain.
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