Infant Formula

Infant Formula

Infant Formula

If your formula-fed baby is irritable, wakeful or refuses to feed at times, this may cause you to wonder if her baby formula is the cause. You might be considering switching formula but are unsure which to choose. This article may help you to select the most suitable formula for your baby.

Reasons to switch formula 

When the reason for a bottle-fed baby’s unsettled or distressed behavior is unclear, most parents will at some point worry that the cause is pain linked to their baby’s formula. And so they are inclined to switch formula, sometimes multiple times, in the hope that this will help. Usually, it doesn’t. In most cases, the source of a baby’s distress is due to reasons other than pain, and therefore changing formula won’t help.

There are however, some compelling reasons to change the type of formula a baby receives, such as:

  • Milk allergy. Signs include vomiting, diarrhea, a rash, difficulty breathing and poor growth.  (See Milk allergy for more.)
  • Constipation.  Signs include infrequent, hard, dry, pebbly stools.  (See Constipation for more.)
  • Lactose intolerance. Signs include frequent watery diarrhea following a recent gastro-intestinal infection. (See Lactose intolerance for more).

If your baby is suffering discomfort or pain as a result of one of these digestive problems, there will be clearly visible signs as listed. Without these signs, the chance that troubled behavior such as irritability, sleeplessness or fussing with feeds, is due to her baby formula disagreeing with her, is remote.

Other valid reasons to switch a baby’s formula may be cost or because a particular formula is easier to purchase.

Types of formula 

The majority of infant formulas are based on cows' milk, goats' milk or soybeans, which is modified to be made suitable for babies. Protein quality is improved, salt levels are reduced, and a range of different fats, vitamins and minerals are added to make the nutrient content as similar as possible to breast milk. It's far from being a perfect match because the exact chemical make-up of breast milk is largely unknown. 

There are a number of different types of infant formula currently on the market.  These fit within 3 broad groups:

  • Standard formulas. Suitable for most healthy babies.
  • Specialized formulas. Developed for babies with specific nutritional needs.
  • Novelty formulas. Produced by formula manufacturers in a bid to gain a greater share of the market.

NOTE: If breast milk is not available, infant formula is the only milk suitable as the main milk source for babies. 

Standard formulas 

Standard formulas include variations of the following: 

  • Cows' milk
  • Goats' milk
  • Soy infant formula

Cow’s milk formula

The American Academy of Pediatrics (AAP) says cows' milk-based baby formula is the closest to breast milk. Most health authorities worldwide recommend cows' milk-based infant formula when breastfeeding is not an option. 

Cows' milk formulas are classified as whey-dominant or casein-dominant, which describes the main protein type in the formula. Whey-dominant formula is easier to digest. Although providing the same number of calories per ounce, casein-dominant formula takes longer to digest. Casein-dominant formula is associated with an increased risk of constipation compared to whey-dominant formula.

Goats' milk formula

Some parents prefer goats' milk baby formula to cows' milk baby formula because they believe it's healthier. Its not! Goats' milk has a nutritional content similar to cows' milk.

Food allergy and food intolerance are different conditions. Some babies who are intolerant to cows' milk protein can tolerate goats' milk protein. However, babies with milk protein allergy are usually allergic to both cows' and goats' milk protein. If a baby has developed a milk protein allergy, a hypoallergenic formula is recommended.

The European Food Safety Authority (EFSA) and UK Food and Drug Administration (FDA) states “Goats' milk-based formula should not be given to infants under 1 year”. 

Soy protein formula

Strictly speaking soy is not milk as it is produced from whole soybeans or soy protein isolates. Soy-based baby formulas don’t contain cows' milk protein or lactose. Soy infant formula was originally developed for management of lactose intolerance and as an alternative for some babies troubled by cows' milk protein allergy. Approximately 50% of babies who are allergic to cows' milk protein also react to soy protein.

According to the American Academy of Pediatrics, “Healthy full-term infants should be given soy formula only when medically necessary”. The UK Food and Drug Administration (FDA) says in a report from 2011 “Soy-based formula should not be used unless prescribed by a GP”.

Specialized formulas

There are a number of different types specialty formulas for babies with special nutritional needs. These include: 

  • Lactose-fee and lactose-reduced formulas
  • AR formulas
  • Partially hydrolysed formulas
  • Low-iron formulas
  • Extensively hydrolysed formulas
  • Amino-acid based formulas
  • High-energy formulas
  • Other specialty formulas

Lactose-free formula (LF)

Lactose-free means all of the lactose (the main source of carbohydrate in milk) is removed and replaced with other sugars such as corn syrup and sucrose (table sugar). Lactose-reduced (LR) formula, sometimes referred to as low-lactose formula, means only some lactose is replaced.  Most LF and LR formulas are based on cows' milk formula will some or all lactose removed. 

Babies can develop a secondary lactose intolerance following a gastro-intestinal infection, when the ability to digest and absorb lactose is lost temporarily.  LF or LR infant formula may be recommended for a few weeks, after which time baby can usually return to her regular formula.

NOTE: Irritable newborns are commonly misdiagnosed with lactose intolerance when the source of the problem is lactose overload (a problem related to overfeeding). LF and LR formula will mask gastro-intestinal (GI) symptoms associated with lactose overload, and as a result causes many parents and health professionals to mistakenly believe baby is lactose intolerant.

Anti-regurgitation (AR) formula

AR formulas are modified cows' milk formula. Some of the lactose is removed to adjust for the extra calories provided by the thickening agents, such as carob bean gum, rice starch or cornstarch. As a result, the number of calories per ounce is the same as regular formula.

AR formulas are designed to help reduce milk regurgitation (spitting up) associated with gastro-esophageal reflux. AR formulas thicken further in the stomach when in contact with stomach acid. Acid suppressing medications reduce effectiveness of AR formulas.

AR formula may be helpful if a baby throws up so much milk that it negatively impacts on growth. In the case of healthy, thriving babies, AR formula may reduce the laundry load for parents. Keeping milk down by means of thickened feeds does not help a baby who is thriving on regular formula. 

NOTE: Reflux is commonly blamed but rarely the reason for troubled behavior, e.g. irritability, sleep disturbance, and feeding refusal, displayed by thriving babies. The cause is usually due to unrelated reasons. (See Reflux for more). AR formula can mask GI symptoms associated with lactose overload.  So if baby appears more content with an AR its possible its for this reason. Thickened formulas can cause some babies to become constipated. Adding thickening agents such as food thickeners, rice cereal or cornstarch to formula increases calorie-content, which means baby is likely to drink less over the course of the day. Thickening agent also mask GI symptoms associated with lactose overload.

Low-iron formula

Infant formulas currently available in the USA are either ‘iron-fortified with approximately 12 milligrams of iron per liter or ‘low-iron with approximately 2 milligrams of iron per liter. The AAP Committee on Nutrition strongly advocates for iron fortification of infant formulas as a way of reducing the prevalence of iron-deficiency. 

Unfortunately, low-iron formulas are sometimes used for healthy babies experiencing problems with constipation. Infant constipation is rarely due to excess iron. Although low-iron formulas can be purchased over-the-counter in many countries, it should only be given to a baby on medical advice. 

NOTE:  Iron is essential for growing babies. Iron-deficiency can result in serious health consequences.

Partially hydrolyzed formula (HA)

Partially hydrolyzed formulas are based on cows' milk, but the protein molecules in these formulas have been partially broken down into smaller molecules that are less likely to trigger an allergic reaction.

If a formula-fed baby has a family history of allergies, e.g. a parent, brother or sister who has an allergic condition such as eczema, asthma or a food allergy, baby may be genetically susceptible to developing an allergy as well. In this case, a partially hydrolyzed formula might help reduce the risk of milk allergy. If a baby has already developed an allergy to cow’s milk, partially hydrolyzed formulas should not be used. A hypoallergenic formula, where the protein is more completely broken down, is recommended. 

Extensively hydrolyzed formula (EHF)

EHFs such as Nutramigen, Progestimil, Alimentum, Alfare and Pepti-Junior are processed to be ‘hypoallergenic’. EHFs are usually the first choice for babies with suspected cows' milk protein allergy (CMPA), cow’s milk protein intolerance (CMPI) or milk, soy protein intolerance (MSPI).

EHFs are made from cows' milk protein or soy protein, but the protein has been extensively hydrolysed (broken down) into small molecules. As a result the proteins in EHFs are less likely to trigger an allergic reaction compared to other formulas mentioned above.

Babies with milk protein allergy are susceptible to developing secondary lactose intolerance due to inflammation of the lining of the small intestines. Hence, EHFs are also lactose-free.

Babies will often initially reject these formulas because of they have a bitter taste, but they will usually come around to accepting them. 

90 to 95 percent of babies with CMPA, CMPI and MSPI will do fine with EHFs. The remaining 5 to 10 percent of babies who continue to experience symptoms like vomiting, diarrhea, eczema, breathing problems and poor growth while on an EHF can be given amino-acid formulas. (See Milk allergy versus intolerance).

Amino-acid formulas (AAF)

These formulas are sometimes called elemental or ultra-hydrolyzed formulas. Brand names include Neocate and Elecare. These formulas are not made from milk; rather they are synthetically produced from amino acids, the non-allergenic building blocks for all protein. AAFs are balanced to meet the nutritional needs of infants and children and therefore promote healthy growth for most children with CMPA, CMPI, and MSPI. AAFs also have a bitter taste and may be initially rejected.

NOTE: Many babies are switched to EFFs and AAFs without clearly visible signs that point to allergy, as a trial to see if a hypoallergenic resolves problematic behavior such as irritability, milk regurgitation, wakefulness or feeding refusal. Hypoallergenic formula will make no difference to these behaviors if the cause of these behaviors is due to reasons other than milk allergy. (See Milk allergy versus intolerance).

High-energy infant formula (HEIF)

HEIF has a higher a calorie and nutrient content per ounce compared to regular formula. The energy content of HEIF can range from 10 to 50 percent more calories per ounce than regular formula. Most also contain higher levels or protein. HEIF is designed for babies who have increased energy requirements; who are weak, physically unable to feed effectively or who refuse to consume sufficient quantities of regular formula; and those who require fluid restriction. For example: 

  • Pre-term and low birth weight babies.
  • Babies with cardiac or lung conditions.
  • Babies with physical disabilities affecting feeding.
  • Babies troubled by an unresolved feeding aversion.

NOTE: Resolving baby’s feeding aversion will be far more effective than using high-energy feeds.

Other specialized baby formulas

There are a number of infant formulas available for babies with specific dietary needs due to genetic disorders. 

Novelty formulas 

Formula manufacturers are allowed to manipulate the composition of standard formulas within the regulations to produce a range of formulations. As a result the number of novelty infant formulas on the market, which claim to be effective at easing problems commonly experienced by healthy babies, continue to increase every year. Examples include: 

  • Colic formula
  • Hungry Baby formula
  • Sleepless baby formula
  • Diarrhea formula
  • Constipation formula
  • Follow-on or Step 2 formula
  • Toddler formula

While the minor manipulations in formula composition are unlikely to be harmful to a baby, there is no evidence that these formulas make any difference in regards to management of common problems compared to standard infant formulas. 

Colic formula

This is basically a whey-dominant cows' milk-based infant formula with reduced lactose. Low-lactose milk is believed to help relieve symptoms of colic based on the theory that immaturity of newborn babies’ digestive tract may result in the inadequate digestion of lactose. 

NOTE: There are many theories on what causes colic. A lactose-reduced formula might relieve GI discomfort associated with lactose overload. But it will make no different if the baby’s distress is due to overtiredness, which is the most common of all reasons for infant distress. 

Diarrhea formula

These formulas are lactose-free formulas with minor modification to the protein type. They are marketed for short-term use following or during a gastro-intestinal infection. However, there is no evidence they are any more effective than other lactose-free formulas. (See Diarrhea for more on reasons for frequent watery stools).

Constipation formula

Constipation formula is a whey-dominant cows' milk formula with increased lactose to promote fluid retention in stools. Some formulas include slightly increased levels of magnesium, which claims to soften stools.

NOTE: This type of formula might be helpful if baby becomes constipated on standard whey-dominant cow’s milk-based infant formula. A baby is constipated when she passes hard, dry and pebbly stools. Babies are often mistakenly assumed to be suffering from constipation when they strain, but straining does not mean a baby is constipated. (See Constipation for more).

‘Hungry Baby’ formula

‘Hungry Baby’ formulas are casein-dominant, cows' milk-based formulas. Casein takes longer to digest compared to whey protein and therefore may sustain a baby for longer. Some ‘Hungry Baby’ formulas also contain carbohydrates that take longer to digest. 

There is no evidence that babies are more content or sleep longer as a result of receiving a ‘Hungry Baby’ formula. See ‘Hungry baby’ for reasons why babies appear to be insatiably hungry at times.

Sleep formula

This is basically a ‘Hungry Baby’ formula with a different name. Sleep formula is a casein-dominant formula. There may also be minor changes to the amount and type of carbohydrates to lower GI (glycemic index) level. Again, there is no proof that these formulas satisfy baby for longer. 

NOTE:  Hunger is not the only reason a baby wakes during the night. See Sleep Associations

Follow-on formula

The main difference between a Follow-on (or Step 2) formula recommended for babies aged 6 to 12 months and Starter (or step 1) formula recommended for babies aged birth to 6 months is that a Starter formula is whey-dominant and Follow-on formula are casein-dominant. Follow-on formulas also contain higher levels of protein and iron. 

Follow-on formulas are not recommended for babies under 6 months because of the higher level of protein. Switching a baby from a Starter to Follow-on formula at 6 months of age has no proven benefits. The World Health Organization (WHO) says Follow-on formula is unnecessary. It’s okay to give your baby a Starter formula until he’s 12 months old.

You might wonder why Follow-on formula is produced if there is no need for a baby to switch. Critics believe that Follow-on formulas were only produced in order to circumvent regulations, which were implemented to prevent the advertisement of of infant formula for babies from birth to 6 months (as this has been shown to undermine breastfeeding). Regulations have since been amended to prevent advertisement of infant formula for babies under the age of 12 months.

Toddler milk

Toddler milk is a relatively recent addition to the market.  It is advertised as providing all the nutrients needed by children aged 1 to 3 years, and helpful for children who don’t eat well. Some brands add iron and omega 3 and 6 fatty acids’, claiming this promotes brain development, visual acuity and growth. However, evidence from external sources (other than the formula companies themselves) does not support these claims.

World Health Organization claims toddler milk is unnecessary because children can safely drink regular cows' milk from 1 year of age. Toddlers receive all the nutrients they need for healthy development from breastfeeding or drinking regular cows' milk and eating a healthy diet.

Toddler milk first presented on the market soon after legislation was changed to prevent the advertisement of infant formula for babies from birth to 12 months. Brand recognition is a powerful form of advertising!  By advertising toddler milk, formula companies are surreptitiously promoting their brand of baby formula.

More about infant formula


Infant formula comes in 3 different forms:

  • Ready-to-use (the most expensive)
  • Concentrated liquid
  • Powder (the cheapest) 

One form of infant formula is no better than the other. When prepared for feeding according to the formula manufacturer's recommendations these different forms of infant formula are equivalent in nutritional content.


Regulations on the manufacture of infant formula are very strict in most countries. This means the different brands of the same type of formula are very similar in nutritional content. Apart from some hypoallergenic and high-energy infant formulas, the variations in infant formulas between brands generally reflect only minor manipulations to the carbohydrate, protein, fats, and/or vitamin content.

Bear in mind that the production of infant formula is a multi-billion dollar a year industry. Formula companies constantly compete for a larger share of the market and will use clever marketing strategies in a bid to persuade consumers to believe that their formula is superior to others. When choosing a formula for your baby, the most expensive formula is not necessarily the best. 


With the exception of high-energy infant formulas, all baby formulas provide the same amount of energy (calories) per ounce (20 calories per ounce or 67 calories per 100ml). 

Most healthy baby will regulate their daily dietary intake according to calories not volume. Change anything from the formula company’s instructions, such as adding more scoops to the recommended amount of water, or add anything to your baby’s formula, e.g. thickening agents, rice cereal, additional carbohydrates or oils after preparation, and this will increase the caloric content. Increase the calorie content and you may find it reduces the volume of milk your baby consumes over the course of the day. (See ‘How much milk does a baby need?’)

Written by Rowena Bennett.

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