Module 4: Formula-Feeding
There are so many different types of formulas that it can feel overwhelming trying to find the right one. This guide offers advice on choosing a starting formula, safe storage, and how to troubleshoot for common medical issues that may arise.
Overview: Choosing A Starter Formula & Formulations
What Are The Most Common Formulas To Start With?
A standard formula is one that is 20 calories/ounce, includes iron, has lactose as the main sugar (carbohydrate), and contains intact cow’s milk protein. The most common are Enfamil Infant and Similac Advance. In choosing between these two, I’d opt for whichever is cheapest (or covered by WIC) and most accessible, since they’re reasonably similar formulas.
Gerber is another major brand, though the majority of its formulas are hydrolyzed (which means that the cow’s milk protein has been broken down) to some degree. While there’s nothing wrong with this, it often costs more. If your budget allows, however, it’s also a great starter formula.
Just remember, the best formula is the one that is right for your child and family. All infants have different nutritional requirements and varying abilities to tolerate formula ingredients. It’s a good rule of thumb to start with one of the standard formulas, and then work your way down to more hydrolyzed versions in consultation with your Pediatrician if your infant is struggling.
What’s The Difference Between Concentrate, Powder, and Ready-To-Feed?
There are three main types of formula. All are the same nutritionally, it just depends on what’s the right fit for your family!
Powder: The cheapest option and most common, though the one that involves the most effort. You’ll add 1 scoop of formula to 2 fluid ounces (60 mL) of water, and can either mix a new bottle with each feed, or make multiple and keep refrigerated for up to 24 hours. Closely read directions, since improper ratios can lead to dehydration or issues with electrolytes.
Liquid Concentrate: More expensive, though less messy since there’s no powder to clean up. A set number of ounces of concentrate is diluted with an equal amount of water, and the two are combined. You can mix larger volumes to create several ready-to-feed bottles that are easily accessible throughout the day, and refrigerate for up to 48 hours.
Ready-To-Feed: The most convenient and expensive. The upside is that there’s no room for error since there’s no mixing (you give the bottle as-is) and it’s cleaner/faster. Once opened (assuming unused), it can be stored in the refrigerator for up to 48 hours. However, the cost does add up quickly, so you have to decide how important the ease factor is for you.
What Should I Consider When Choosing A Formula?
Cost: A powdered / standard formula is cheaper than a ready-to-feed / specialized formula.
Prematurity: Infants <37 weeks have more complex nutritional requirements and will require a high-calorie formula as a result.
Medical Issues: Cow’s milk protein allergy, reflux, or eczema may need tailored formulas.
Dietary Preferences: If you’re strictly vegan, this will limit your available formula options.
Troubleshooting: Medical Issues & Tailing Formula Selection
What If My Child Isn’t Tolerating A Formula Due To Medical Issues?
I’ve included some examples of formulas that may work for different intolerance situations. As always, check with your Pediatrician before any major changes to make sure they’re in agreement with the switch and don’t have additional concerns (such as a declining weight trend).
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In infants, reflux is super common, since muscle tone is weaker (including in the digestive tract) and they are often laying down rather than upright. Most babies outgrow this as they get older and it usually doesn’t require treatment. However, it can cause concern for parents, and sometimes affect weight gain depending on the severity.
Some formulas are thickened to help them settle down into the intestines, rather than regurgitate upwards. They are still thin enough to pass through a bottle nipple opening. They can be a good option if your baby is struggling with frequent large-volume spit ups. An alternate option is a whey- (rather than casein, which is the main protein in cow’s milk) dominant formula, since it goes through the stomach faster, leading to less formula in the stomach available for spit-ups.
Try: Enfamil AR | Similac For Spit Up | Gerber Good Start Gentle Pro
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In infants with more notable digestive issues (fussiness around feeds, looser stools, gassiness) or eczema, a partially-hydrolyzed formula is an ideal option to trial. Note that dairy sensitivity is not true lactose intolerance (having a congenital deficiency of the lactase enzyme, which breaks down lactose into its component sugars, is rare), nor is it a true milk protein allergy. However, it can cause discomfort with meals, so it is always worth a discussion about formula.
If your child has these symptoms, you should also talk to your provider to make sure there’s no other diagnoses in the background and to verify a healthy weight trend.
Try: Enfamil Gentlease | Gerber Good Start GentlePro | Similac Pro-Total Comfort
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3-4% of infants will have CMPA, which is a true allergy to the proteins in cow’s milk. Symptoms include eczema, blood or mucous in stools, diarrhea, vomiting, issues with gaining weight, and severe fussiness. In these infants, the proteins need to be broken down into their basic building blocks (amino acids) so that they don’t cause an immune response.
These formulas are called extensively hydrolyzed or elemental formulas. They are extremely expensive and have an awful smell and taste. However, they are the recommended option for this condition (soy is not advised since many of these babies will also be allergic to soy).
Try: Enfamil Nutramigen | Similac Alimentum | Gerber GoodStart Extensive HA
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In general, soy formula isn’t recommended except for few circumstances. If you are vegan and have a strong preference for maintaining that lifestyle for your child, soy is an option. It’s also used in the conditions galactosemia and hereditary lactase deficiency. Soy formulas shouldn’t be used in premature infants since some of the nutrients are inadequate for their needs, especially for bone development.
There’s a lot of research about estrogens found in soy and their effect on hormonal response in children, though there’s still not enough evidence to make a recommendation for or against safety. This is something else to consider.
Try: Enfamil Prosobee | Similac Soy Isomil | Gerber Good Start Soy
How Do I Switch Formulas?
You can do either a cold-turkey or a gradual approach. Cold-turkey is easier from a mixing standpoint, and is ideal when you’re switching due to an allergy so that symptoms resolve quickly. However, when switching so suddenly, your infant may take time to adjust or not tolerate the new formula right away. You may notice some fussiness / gas / stool changes during the transition. These shouldn’t last more than a week.
If attempting to switch gradually, the goal is to slowly change the ratio of old to new formula over 1 week so that your infant gets used to the new formula’s taste and to digesting it.
Example: Mix 3 scoops of the old formula and 1 scoop of the new (this would make 8 ounces of formula once mixed with water, so some could be stored for later) and offer until tolerated. After, move to a 1/2 and 1/2 ratio, then 1/4 old and 3/4 new. This should occur over a week or two. Make sure to use the scoops for each respective formula, since the sizes may differ. While this is a general guide, you should consult with your PCP for specific instructions.
Feeding Amount and Frequencies
Storage & Heating & Cleaning Bottles: Important Safety Considerations
How Do I Store Formula?
Once mixed, use within two hours at room temperature (or within 1 hour from the start of the feed). If mixing multiple bottles, you can refrigerate for up to 24 hours. Make sure to label them with the date and time that they were made. In general, formula isn’t frozen.
Throw out any remaining formula after finishing a feed, since an infant’s saliva can contaminate it and can increase risk of bacterial growth.
Should I Heat Up Formula Before Feeding My Child?
You don’t need to heat formula. If you want to warm it up, you can run the bottle under running warm water, or set it in a bowl of warm water for a few minutes. Test the temperature by applying a few drops of formula on your inner wrist before feeding your infant. You shouldn’t microwave formula, since it can lead to uneven heating and “hot spots,” which can cause burns.
Can I Add Breastmilk To Formula?
You can! Some families will choose to do this when they don’t have enough milk to fully breastfeed, but still want the immunity benefits of breastmilk to get passed down to the infant. Just make sure to combine the formula and water as you normally would first, shake to mix, then add the breastmilk. This ensures we don’t end up with any electrolyte abnormalities that could lead to strain on the kidneys, dehydration, or seizures.
It’s important to note that if you’re adding breastmilk to formula and would like to store a bottle in the refrigerator for later, you need to follow the formula storage rules listed in this module, rather than those for breastmilk (which typically allow for longer storage durations). You would not be able to freeze this bottle for later use.
How Often Should I Clean & Sterilize Bottles?
Clean bottles after every use. Wash your hands first for 20 seconds, then separate all the parts and rinse them of any leftover milk. Set them inside a designated container filled with hot water and soap that is only used for this job (if you set them directly into the sink, which is constantly in contact with germs and food, it can cause contamination). Use a scrubbing brush (again, used only for this job) to get into nooks and crannies, and make sure you have water flow through the nipple to cleanse that area thoroughly. Set everything to dry on a clean paper towel or washcloth, or a drying rack used only for this purpose.
Sterilization is recommended by the CDC daily until 3 months, or longer if your child is premature or has medical issues. You can sterilize via dishwasher on the hottest water setting and the heated / sanitizing dryer cycle, or by placing all bottle parts into a boiling pot of water for 5 minutes and removing with tongs, then allowing to air dry on a clean paper towel). I’ve seen a lot of variance in how often families sterilize, and I think it’s OK if you want to sterilize less frequently in a full-term and healthy infant (like once a week), knowing that hygiene and water standards have improved. Always, however, sterilize new bottles you’ve just purchased prior to their first use.
Special Considerations: Prematurity & Toddlerhood
What About Premature Infants?
Most premature infants will be on a preterm (<34 weeks gestational age, <1800 grams) or enriched (34-36 weeks gestational age, >1800 grams) formula. These formulas have more calories (usually 24 cal/oz and 22 cal/oz , respectively, to allow for catch-up growth), in addition to extra minerals usually transferred from mom to infant during the last trimester (such as magnesium, phosphorus, and calcium).
Most of these babies are on their specialized formulas until around 9 months, though the exact duration may vary depending on weight trend, kidney development, and stability of medical issues.
Common discharge formulas for these infants are Similac Neosure or Enfamil EnfaCare.
Should I Transition To Toddler Formula After 12 Months?
I wouldn’t if you can avoid it. While they can have a role in select cases, I rarely recommend toddler formulas. They tend to have unnecessary additives and sweeteners, aren’t FDA-regulated, and often replace calories that should come from food. They’re also very expensive compared to the recommended alternative at this age, which is whole-fat milk.
Once your child turns 1, you can use the same approach for transitioning to whole milk as with switching formula (slowly adjust ratio of formula to milk in each bottle over 1 week until fully transitioned over). Avoid reduced-fat milk unless instructed until 2 years of age, since the extra fat is helpful in brain development.
What Shouldn’t I Do With Formula?
Microwaving: You shouldn’t microwave formula. The danger is that it can heat unevenly (think about all the times you’ve reheated food in the microwave and found the top of your meal hot and the middle completely cold). This leads to hot spots, which can cause burns inside the mouth.
Diluting: Never dilute formulas with extra water to make larger volumes or make the formula last for a longer duration. This can throw off the water and electrolyte balance in your infant, leading to seizures. Always mix formula according to package instructions.
Homemade: The FDA strictly regulates formula manufacturers, for good reason. Infants have immature immune systems and formula is very nutrient-rich, which means it’s ripe for bacterial growth if handled in a non-sterile manner. Avoid making your own formula to prevent accidental contamination or incorrect ratios of ingredients.
What About Formula-Making Machines?
These are newer on the market. They aim to offer convenience in mixing formula, especially when you’re overtired. The downside is that there’s been cases of improper mixing (e.g., too much water for formula amount), which can lead to serious health issues in your infant, so always make sure your machine is in working order and to follow the instructions carefully. I don’t usually recommend these since they’re a luxury (there’s other newborn items where I feel like $200 goes further). If you have the means and value the convenience, though, it can be an item to add to the registry.
Product Recommendations:
