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Breastfeeding vs Formula Feeding – Advantages & Disadvantages

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Breastfeeding vs Formula Feeding – Advantages & Disadvantages

Here’s everything you need to know about breastfeeding vs formula feeding. Plus, learn the ins and outs of food safety when storing your milk. 

Are you a new expecting mom feeling overwhelmed with all of the information about breastfeeding vs formula feeding? Or maybe you’re already a mom, but need a refresher course on infant care? Although human milk and infant formula both nourish an infant, they are not the same.  Let’s take a look at some advantages and disadvantages.

Mixed Messaging on Formula

As you stroll down the formula aisle in the grocery store, there are endless options to consider. Each brand has various claims that say the formula promotes brain health, supports your baby’s immune system, or my favorite, is “inspired by breast milk.”

But, with all of these options, the decision seems more confusing than ever. Not to mention, supplement companies have mastered the art of marketing and knowing all the right words to appeal to mothers. Most moms commonly have the same age-old question: is providing formula to my baby the same as breastfeeding? Truth is—it’s not. 

The Importance of Breastfeeding vs Formula Feeding

The production of human milk is a dynamic process. In fact, it changes throughout the infant’s development – based on the mother’s diet and the baby’s needs. (1) It’s really amazing! To illustrate the importance of breast milk, babies in the Newborn Intensive Care Unit (NICU) are fed their mothers pumped breast milk by nurses, to ensure adequate nutrition. (14) An added benefit to breastfeeding is the increased release of a hormone called oxytocin. It helps revert your body to what it was before you were pregnant and helps mothers bond with their babies. (13)

Now let’s take a closer look at breastfeeding vs formula feeding, breaking down the components of each, and the advantages and disadvantages.

What is in Breast Milk?

As a baby develops, a mother’s breast milk alters to accommodate this growing process. The first few days after birth, breast milk is a thick, protein-packed, deep yellow fluid that contains antibodies to protect the infant from infection. As the baby grows, breast milk evolves to include more carbohydrates and fat, and less protein. (5) Let’s take a more in-depth look into what is in breast milk: 

  • Water (87%), carbohydrate (7%), fat (3.8%), and protein (1%)
  • Lactose
  • Essential and non-essential fats
  • Protein
  • Vitamins and minerals
  • Immune cells
  • Prebiotics and probiotics

Breast milk’s main nutrients

A mixture of water (87%), carbohydrate (7%), fat (3.8%), and protein (1%). (6) This combination makes it easy for your baby to digest!

Lactose in breast milk

Lactose is the primary source of carbohydrates found in breast milk, which helps infants absorb minerals like calcium. (6). It also helps to establish a healthy gut bacteria, which contributes to your child’s immune system. 

Essential and non-essential fats in breast milk

In other words, these are fats that we need to consume or create in the body. The proportion of each type of fat is dependent on the mother’s diet. For example, if you eat fish and certain seeds and nuts (walnuts, chia, flax), your breast milk will contain omega 3s. (6) Fats are crucial to the development of an infant’s brain, eyes, and psychomotor skills. (5)

Protein in breast milk

Protein is necessary to build muscle and repair tissue. (5) For both formula and breast milk, protein comes in the form of either whey or casein. (5) Compared to formula, breast milk contains a higher proportion of whey, which is easier for the infant to digest and absorb. (6) Whey also contains antibodies and enzymes that protect the infant against harmful bacteria. (4)

Vitamins and minerals in breast milk

These are needed to support your infant’s healthful growth and development. (6) Breast milk supplies the infant with all of the necessary nutrients, with the possible exception of vitamin D. Since an infant’s Vitamin D levels correlate to the mother’s diet, it is recommended that breastfed infants receive 400IUs of Vitamin D daily. (10)

Immune cells in breast milk

These cells protect your infant against viruses and harmful bacteria. (6) Since the bacteria in an infant’s stomach are immature, they need extra immunity. Mom’s immune cells pass through breast milk to help prevent pathogens’ growth and, thereby, infections in your little one. (5)

Prebiotics and probiotics in breast milk

These “good bacteria” that pass through breast milk to baby allow your infant to develop gut flora. A healthy gut leads to a lower incidence of chronic disease and allergies as your child grows. (9)

What is in Baby Formula? 

While breastfeeding has its advantages, it’s not for everyone. Some mothers are unable to breastfeed, while others may simply prefer not to. There are many reasons why people can’t breastfeed, from breast reduction to an unsupportive work environment, to medical necessity. If you fall into one of these categories, don’t stress. As an alternative, a mother can feed their infants with infant formula to enable their child’s growth and development. Let’s take a closer look at breastfeeding vs formula feeding and what’s in baby formula:

  • Water
  • Carbohydrates
  • Fats
  • Protein
  • Vitamins and minerals
  • Immune cells
  • Probiotics and prebiotics
  • Food additives

Main Nutrients in formula

Baby formula has a mixture of water, carbohydrates, fat, and protein. The composition varies by brand but is regulated by the FDA. (11) FAO and WHO are the governing agencies that ensure that the formula is safe and meets the infant’s needs. (3)

Carbohydrates in formula

The carbohydrate source varies depending on the formula. It may contain lactose, corn syrup solids, sucrose, or a combination. (7)

Fats in formula

While fat in infant formula aims to mimic that found in breast milk, it’s far from a perfect match. The fat sources vary depending on the brand but can include vegetable oils, fish oils, animal fat, or milk fat. (8) Some formulas may not contain omega-3 fatty acids. These are vital to brain and eye development. Fat is absorbed less from formula than from breast milk. (5)

Protein in formula

Similarly to carbohydrates, the protein source varies with the baby formula. A cow-based formula will contain whey and casein as the primary source of protein. Although the type of proteins closely resemble breast milk, it does so in different proportions. Formula contains cow’s milk, which is 80% casein and 20% whey, making it difficult for the baby to digest. The protein found in a soy-based formula is soy protein isolate. (5)

Vitamins and minerals in formula

These are added to infant formula and vary by brand. Nonetheless, the nutrients found in formula adhere to the regulations put in place by the FAO and WHO. (3) 

Immune cells in formula

Infant formulas do not contain immune factors that will protect an infant against infection. (1)

Probiotics and prebiotics in formula

Not every infant formula contains probiotics or prebiotics. However, many brands fortify their products with prebiotics to provide similar health benefits as breast milk. (12)

Food additives in formula

Breast milk does not contain food additives, thickeners, emulsifiers (help to mix multiple liquids together – think oil and water) or acidity regulators (to help keep the formula from spoilage). (3) However, infant formula brands do. 

How to Store Breast Milk? 

Breast milk is perishable and must be stored safely to avoid bacterial growth and illness in infants. Here are some general guidelines to store breast milk properly:

  • Date a glass or plastic bottle and place in the back of the fridge or freezer, since temperatures can vary as the door opens/closes
  • Freeze in 2-4 ounces, with an inch left at the top since the milk will expand when it freezes.
  • Consider having multiple 1 oz portions in the freezer in case your infant wants extra milk. (10)
  • Do not use a microwave to thaw frozen breast milk. Instead, thaw it in the refrigerator, or by putting it in warm water. This will keep the milk’s nutrient content intact and avoid possible bacterial growth or burning your infant’s mouth. (10)
  • Throw away leftover breast milk 1-2 hours after the infant feeds. (2)

Methods for Storing Breastmilk

MethodFresh Milk  Thawed Milk
Countertop (room temp)Up to 4 hours1-2 hours
Back of the refrigeratorUp to 4 daysUp to 24 hours
Back of the freezerUp to 6-12 monthsDo not refreeze once thawed

Human Milk Storage Guidelines

Countertop or table Refrigerator Freezer with separate door 
Storage temperatures* 77°F or colder (25°C) 40°F or colder (4°C) 0°F or colder (-18°C) 
Freshly pumped / expressed human milk Up to 4 hours Up to 4 days Within 6 months is best, up to 12 months is acceptable. If you store at the back of the refrigerator it can last longer. 
Thawed human milk 1–2 hours Up to 1 day (24 hours) Never refreeze human milk after it has been thawed 
References for chart: 2, 10

Storage Locations and Temperatures for Breast milk

Type of Breast MilkCountertop
77°F (25°C) or colder
(room temperature)
40°F (4°C)
0°F (-18°C) or colder
Freshly Expressed or PumpedUp to 4 HoursUp to 4 DaysWithin 6 months is best
Up to 12 months is acceptable
Thawed, Previously Frozen1–2 HoursUp to 1 Day
(24 hours)
NEVER refreeze human milk
after it has been thawed
Leftover from a Feeding
(baby did not finish the bottle)
Use within 2 hours after the baby is finished feeding

At the end of the day, it’s a mother’s choice to decide between breastfeeding vs formula feeding. Although solely breastfeeding your infant has the most health benefits, even partial breastfeeding has its advantages.

Breastfeeding is not an all-or-nothing phenomenon. Mothers need to do what they can, or what makes them comfortable. For those who wish to breastfeed their infant, keep our helpful milk storage charts in mind for optimal food safety. 

Looking for more information on the benefits of breastfeeding? See Benefits and Advantages of Breastfeeding and Why Breastfeed? 5 Breastfeeding Benefits.


  1. Cacho, N. T., & Lawrence, R. M. (2017). Innate immunity and breast milk. Frontiers in Immunology, 8, 584-584. doi:10.3389/fimmu.2017.00584
  2. Center of Disease Control and Prevention. (January 22, 2020). Proper Storage and Preparation of Breast Milk.
  3. Codex Alimentarius International Food Standards. (2007). Standard For Infant Formula and Formulas For Special Medical Purpose Intended for Infants.
  4. Lönnerdal, B. (2003). Nutritional and physiologic significance of human milk proteins. The American Journal of Clinical Nutrition, 77(6), 1537S-1543S. doi:10.1093/ajcn/77.6.1537S [doi]
  5. Mahan, L. Kathleen., Escott-Stump, Sylvia., Raymond, Janice L.Krause, Marie V. (2012) Krause’s food & the nutrition care process. St. Louis, Mo. Elsevier/Saunders.
  6. Martin, C. R., Ling, P., & Blackburn, G. L. (2016). Review of infant feeding: Key features of breast milk and infant formula. Nutrients, 8(5), 279. doi:10.3390/nu8050279
  7. Martinez, J. A., & Ballew, M. P. (2011). Infant formulas. Pediatrics in Review, 32(5), 179-189. doi:10.1542/pir.32-5-179
  8. Mendonça, M. A., Araújo, W.,Maria Coelho, Borgo, L. A., & Alencar, E. d. R. (2017). Lipid profile of different infant formulas for infants. Plos One, 12(6), e0177812. Retrieved from
  9. Moossavi, S., Miliku, K., Sepehri, S., Khafipour, E., & Azad, M. B. (2018). The prebiotic and probiotic properties of human milk: Implications for infant immune development and pediatric asthma. Frontiers in Pediatrics, 6, 197-197. doi:10.3389/fped.2018.00197
  10. United States Department of Agriculture. (April, 2019). Infant Nutrition and Feeding: A Guide for Use in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC).
  11. US. Food & Drug Administration. (December 19th, 2017). Regulations and Information on the Manufacture and Distribution of Infant Formula.
  13. Vandenplas, Y., Greef, E., & Veereman, G. (2014). Prebiotics in infant formula. Gut Microbes, 5 doi:10.4161/19490976.2014.972237
  14. World Health Organization. (2009). Infant and Young Child Feeding: Model Chapter for Textbooks for Medical Students and Allied Health Professionals.

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About the Author

Picture of Melissa Halas, MA, RD, CDE

Melissa Halas, MA, RD, CDE

Melissa is a registered dietitian and certified diabetes educator with a master's in nutrition education. She is the founder of SuperKids Nutrition Inc. Read more about her Super Crew children’s books and her experience as a registered dietitian on the About Melissa and Shop page. Discover how nutrition can help you live your best health potential through her plant-based books and newsletter on Melissa’s Healthy Living.

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