Why Fat Structure Matters in Infant Nutrition

Written by Leena Tabaja. Customer Service Coordinator & proud mom of two.

Fats are one of the most important nutrients in an infant’s diet. In fact, they provide approximately 50-60% of the energy babies need to grow, develop, and thrive during their first months of life. Fats also play a key role in brain development, nervous system function, and the absorption of important nutrients.

What many parents may not realize is that it is not just the amount of fat in infant milk that matters, but also the type of fat and how it is structured at a molecular level. Fat structure can influence several aspects of digestion, including how efficiently they are broken down, how well nutrients are absorbed, and how comfortable babies feel after feeding.

Human breast milk is the gold standard for infant nutrition, and its fat structure is uniquely suited to support gentle digestion. One way infant formula has evolved to better reflect this natural design is through the inclusion of OPO (sn-2 palmitate), a fat that closely resembles the structure of fat found in breast milk.

Why Is OPO Needed for Growing Infants?

Babies grow rapidly, and their energy needs are high. Most of the calorie’s infants consume come from milk fat, making the quality of fat especially important during early development.

OPO, which stands for oleic–palmitic–oleic, is one of the most abundant fats naturally found in breast milk and plays an important role in how infants digest and absorb fat. It is a specific type of triglyceride, a fat molecule made up of three fatty acids attached to a glycerol backbone. What makes OPO unique is its structure. The palmitic acid is positioned in the middle, known as the sn-2 position, of the triglyceride.

This arrangement mirrors what is found in human breast milk and differs from many vegetable oil-based infant formulas, which commonly contain a fat structure known as POP (palmitic–oleic–palmitic). In the POP structure, palmitic acid is located on the outer positions (sn-1 and sn-3) of the fat molecule, which can influence how fats are broken down during digestion and how efficiently nutrients are absorbed.

In addition to providing a significant source of energy, OPO supports several essential functions in growing infants, including:

• Providing essential fatty acids needed for healthy growth
• Supporting immune function, including antimicrobial and antiviral activity
• Helping with cellular development, particularly in the brain, nervous system, and eyes
• Supporting healthy gut bacteria, regular stools, and proper bone formation

Because of these benefits, OPO has become an important ingredient for infant formulas and is included in thoughtfully formulated recipes developed to support infant growth and development.

How Does Enriched Formula with OPO Compare to Breast Milk?

While breast milk remains the gold standard for infant nutrition, researchers continue to study why its composition supports such effective digestion and development. One key area of focus has been its fat structure, given the central role fat plays in providing energy and supporting brain and nervous system development in infants.

In human breast milk, palmitic acid makes up approximately 20–25% of total fatty acids, with 60–80% of this palmitic acid naturally positioned in the sn-2 (middle) position. This specific structure has been shown to support more efficient fat digestion and improved absorption of both fats and minerals.

OPO-enriched formulas are designed to better reflect the way fat is structured in breast milk, helping support digestion and nutrient absorption through similar natural processes. In addition, OPO in formulas may provide important components such as phospholipids and cholesterol, which are essential for brain development and normal cognitive function. Observational studies have also shown that the gut bacteria of infants fed OPO-enriched formula can more closely resemble that of breast-fed infants. This is an important factor, as a healthy gut microbiome is linked to long-term health.

How OPO Supports Digestion, Mineral Absorption & Comfort

To understand why OPO plays an important role in babies’ growth and development, it helps to look at how babies process and break down fat.

In many formulas, palmitic acid sits on the outer parts of the fat molecule (sn-1 and sn-3 positions). During digestion, it can bind with calcium and form soap-like compounds in a process called saponification. Because these compounds are harder to absorb, both the fat and calcium are more likely to pass out of the body in the stool. This can leade to reduced calcium absorption and firmer stools.

OPO works differently. When palmitic acid is placed in the sn-2 position, it is much less likely to bind with calcium. This allows both the fat and calcium to be absorbed more efficiently, rather than being passed out of the body in the stool. This more efficient absorption supports: 

• Better mineral absorption, including calcium uptake for healthy bone development
• Softer stools and improved stool regularity
• Improved overall digestive comfort

There is also an added benefit of smoother digestion. When digestion is smoother, babies tend to experience less gastrointestinal discomfort. Less discomfort can often mean less fussiness and crying, which for many families also supports better sleep patterns. Simply put: better digestion often leads to happier, more comfortable babies.

Supporting a Healthy Start

No infant formula is superior to human breast milk. However, when formula is needed, choosing one that recognizes the importance of fat composition and is intentionally formulated to support digestion, comfort, and overall health can make a meaningful difference to your baby’s growth and development.

OPO helps bridge the gap by mimicking the natural fat structure of breast milk, supporting gentle digestion, nutrient absorption, and overall infant well-being. With more than 40% of the fat content in Niuriss infant formula in the form of sn-2 palmitate, the formulation reflects a commitment to designing fat blends that support comfort and healthy growth in early life.

Every baby is unique, and every family’s feeding journey looks different. Thoughtfully formulated nutrition can help support healthy growth, comfort, and development, giving babies the best possible start.

Disclaimer: Please be advised that breastfeeding, when possible, is the optimal choice for infant nutrition. Consult your healthcare provider before transitioning to formula.

References: 

Chen, B., Jia, Q., Chen, Z., You, Y., Liu, Y., Zhao, J., Chen, L., Ma, D., & Xing, Y. (2024). Comparative evaluation of enriched formula milk powder with OPO and MFGM vs. Breastfeeding and regular formula milk powder in full-term infants: A comprehensive study on gut microbiota, neurodevelopment, and growth. Food & Function, 15(3), 1417–1430.

https://doi.org/10.1039/d3fo03392a

Liu, Q., Qiao, W., Liu, Y., Liu, Y., Zhao, J., Fan, X., Li, Z., Hou, J., Liu, Y., Chen, J., Yang, K., Yu, X., Lin, L., Jin, Y., & Chen, L. (2023). Effects of lipids from multiple sources on glyceride composition, concentration, and structure of infant formulas benchmarked to human milk. Heliyon, 9(11), e21611. https://doi.org/10.1016/j.heliyon.2023.e21611 

Wang, Q., Xu, Y., Liu, Y., Qian, F., Mu, G., & Zhu, X. (2022). Effects of Proteins and Mineral Ions on the Physicochemical Properties of 1,3-Dioleoyl-2-Palmitoylglycerol Emulsion to Mimic a Liquid Infant Formula. Frontiers in Nutrition, 9(101642264), 808351.

https://doi.org/10.3389/fnut.2022.808351

Wang, X., Zou, S., Miu, Z., Jin, Q., & Wang, X. (2019). Enzymatic preparation of structured triacylglycerols with arachidonic and palmitic acids at the sn-2 position for infant formula use. Food Chemistry, 283(7702639), 331–337. https://doi.org/10.1016/j.foodchem.2019.01.057

Yuan, T., Zhu, X., Mu, G., Qian, F., & Xiong, H. (2020). Effects of Chemical Composition and Microstructure in Human Milk and Infant Formulas on Lipid Digestion. Journal of Agricultural and Food Chemistry, 68(19), 5462–5470. https://doi.org/10.1021/acs.jafc.0c00745

Zhu, B., Zheng, S., Lin, K., Xu, X., Lv, L., Zhao, Z., & Shao, J. (2021). Effects of Infant Formula Supplemented With Prebiotics and OPO on Infancy Fecal Microbiota: A Pilot Randomized Clinical Trial. Frontiers in Cellular and Infection Microbiology, 11(101585359), 650407. https://doi.org/10.3389/fcimb.2021.650407

    Leena Tabaja 
     Customer Service Coordinator
     & proud mom of two