Which milk is best for babies? A review of infant formula

Every day I’m asked a question about formula.

My gut feeling is that there isn’t enough information and support out there for mums and dads who bottle feed, and I know lots of my healthcare professional colleagues are afraid to share this information for being seen as promoting bottle feeding.

My belief is fed is best and that all parents need access to the right information so they can make an informed choice.

We all know that breast is best but not all can or want to. 

So here’s a quick summary of the different types of formula, which to choose and when. I hope this helps!

Before we dive in, you should know that much about breastmilk remains unknown despite over 100 years of research, therefore, infant formula still cannot claim to be a match for breastmilk, despite what is written on the tin!

How does infant formula differ from breastmilk?

Formula milk is a ‘food’ product that is strictly regulated by law so that there are specific levels of proteins, carbohydrates, fats, vitamins and minerals in order to match babies nutritional needs. 

Therefore whichever formula you choose, nutritionally they are all very similar. There’s not a lot of wiggle room in these regulations.

Most formulas are based on cows milk or goats milk as a starting point,  although other sources such as soya are used too. From here modifications are then made to turn it from milk to formula. 

Stage 1 formula

Stage 1 formula and stage 2 formula are nutritionally very similar. They both contain two types of protein whey and casein.

In stage 1 formula the majority of the protein is whey and the minority is casein. This is easier for little tummies to digest.

In the main, stage 1 formula is best for your baby throughout their first year of life if you aren’t breastfeeding. They don’t need a stage 2 formula.

Stage 2 formula

Stage 2 formula is sometimes also called ‘follow-on formula’ and it’s suggested for babies once they get to 6 months old as a ‘follow-on’ from their stage 1 formula.  

However, stage 2 formula isn’t necessary and may just make little tummies full up for longer, which isn’t always a good thing.

It contains more of the casein and less of the whey protein and forms a thicker curd in the stomach which takes longer to digest and so stage 2 milks are often marketed as being for ‘hungrier babies’.

If your baby does appear to be hungrier, cluster feeding or wanting milk more often than usual, it’s a sign that they just need more of it because they are growing and developing, so my advice would always be to just offer more stage 1 formula.

Stage 2 formula also contains a little more protein, iron and some other vitamins and minerals that match the changing needs at 6 months of age, but they are in such small quantities that it actually does not contribute significantly to your baby’s overall nutrition. And from 6 months with a carefully planned weaning diet
, they’ll be getting this from food anyway.

If you do choose to move on to a stage 2 formula make sure that you only do this after your little one has turned 6 months.

Bottom line: Your baby doesn’t need a stage 2 or follow-on formula, stick with stage 1 for the first year.

What is the best formula for newborns?

Guess what? The best formula for newborn babies is a Stage 1 formula. The whey protein in these formulas means it is easily digested compared to other formula milk. 

Bottom line: There is no need to use anything other than a first stage formula unless advised to do so by your health visitor, doctor or dietitian. [1]

What is the best formula for a breastfed baby?

If you’re combi feeding or trying to wean from breast milk and onto formula you might wonder if one formula might make the transition easier than another. 

Unfortunately not. Formulas don’t taste like breast milk and so your baby will have to learn to accept a new flavour when moving over. 

My advice is to choose any of the stage 1 formulas rather than a Stage 2 or follow on milk, irrespective of your baby’s age.

You can combine expressed breast milk and formula in the same bottle to make the transition easier if your baby is really struggling to get used to the taste.

Bottom line: Use a stage 1 formula for combi feeding or when transitioning over.

Goats milk-based infant formula

Goats milk based infant formula such as Kendamil Goat and Nannycare are not actually very different to standard stage 1 formula milks. 

It’s often thought that a goats milk formula will reduce the incidence of milk allergy but this is an urban myth and is not correct. Both formulae from cow’s milk and goat’s milk have the same level of allergy risk.  

It is often suggested that goats milk protein is gentler on a baby’s tummy and easier to digest as the milk curds from goats milk are softer than cow’s milk but this is not actually correct either! [2]
The digestive process of both goat’s milk and cow’s milk has been scientifically proven to be largely the same. [3]

Bottom line: There is no benefit to using a goats milk formula over a standard one.

Anti-reflux or anti-regurgitation formulas

Anti-reflux or anti-regurgitation formulas can be bought from the big brands Aptamil, Cow and Gate, Hipp and SMA.

If you have a baby with reflux or one who frequently spits up or possets after a feed, these may be something you’d think about trying. 

What you should know however is that spitting up (or posseting) after milk feeds is normal – babies have an immature ‘lower oesophageal sphincter’ – essentially the ring of muscles at the bottom of the food pipe is still open and takes a while for it to function properly.

Often we dietitians may suggest your baby feeding little-and-often or reduce the bottle teat size so the flow of milk is slower, which can be helpful. 

Anti-reflux infant formula should be used with caution. 

You have to use cooler water to make up the bottles, unlike other standard formula milks that require water to be above 70 degrees C.

This means that any harmful bacteria present in the formula (yes it does happen) is not destroyed as it would be when making up bottles with very hot water.

Anti-reflux formulas also contain thickeners that are made from grains and yet the recommendation is for babies to avoid grains till around six months of age. 

If you are thinking about trying one, do ask for professional help from a Registered Dietitian experienced in paediatrics. Your GP can refer via the NHS or you can book in with my team here.

What does reflux look like compared to spitting up or posseting?

Baby’s with reflux tend to be very uncomfortable after feeding, they may be crying, wriggling excessively and arching their backs. 

Another sign is turning their heads to the right as if looking over their right shoulder, elongating their necks; this is called Sandifer’s syndrome. 

Some babies with reflux fail to gain weight or grow, crossing downwards across their centile lines. This is what happened to my second baby Maisie. 

If you recognise any of these signs it’s important to go and see your GP because babies who have true reflux often need medication in combination with these formulas, as the formula alone won’t do the trick. 

Likewise, sometimes there is an underlying issue causing the reflux, with my daughter it was a food allergy.

Bottom line: Only use an anti reflux formula under the advice of a healthcare professional.

What is the best milk for colic?

You can also buy ‘comfort milk’ said to settle babies who have wind, colic and/or constipation.  

There is actually no published research to evidence that these milks work. 

Babies do cry a lot, especially young babies and colic is very, very common. And we don’t really understand what causes it.  

Theories include having an immature digestive system, sensory sensitivity to light and sound, hormone levels changing, emotions and an inability to understand them and a form of baby migraine!

What we do know is that babies need a lot of attention, cuddling and soothing, as this is part of their developmental attachment process, essential for healthy emotional development. 

You might find that smaller, more frequent feeds with more winding and burping during and after, help bring up trapped wind and reduce their discomfort. 

Colic symptoms go away as babies get older and so the best milk to give them is a stage 1 infant formula and lots of cuddles and reassurance.  

Bottom line: The anti colic/comfort milks don’t have evidence to show they work. Stick to stage 1 formula and offer lots of cuddles.

What formula is best for constipation?

Constipation is common in formula fed babies, more so than in babies who are breastfed and if you are switching from breast to formula, this is one of the first things you might notice. 

It’s caused because formula is more difficult to digest in the body [1]
there are more waste products in formula that your baby’s digestive system needs to process and turn into poo.

The colic and constipation comfort milks are labelled as helping with constipation. This is because the proteins in the milk have been partially broken down meaning your baby’s body doesn’t need to work as hard to digest it. 

You should know however that this hasn’t been proven to be effective [1]
although won’t do any harm.

Bottom line: The best for constipation, it’s a stage 1 infant formula.

Soya based infant formula

You can buy soy based infant formula where soya protein rather than cow’s milk is the protein source. These, however, are not suitable for babies under 6 months of age due to their high natural phytoestrogen content. [4]

It’s thought that phytoestrogens may affect the development of sex organs and until we know for sure, the NHS recommend avoiding it in young babies.

Those babies over 6 months can cope with the phytoestrogen load and so older babies can safely have it.

Soy infant formula contains a sugar called glucose (instead of lactose which is in cow’s milk based formula), which is more damaging to emerging teeth.

It is also not vegan (despite it containing no cow’s milk). That’s because by law infant formula manufacturers have to add certain vitamins and minerals and the vitamin D source originates from sheep’s wool. 

Some vegan families choose to accept this as there are no other alternatives except for breastmilk.

Bottom line: Avoid soya formula for babies under 6 months of age.

Lactose-free formula milk

You can also purchase lactose free formula but what I want to say right off the bat is not to use these unless your healthcare professional has recommended them.

Occasionally babies develop transient lactose intolerance if they have had a nasty tummy bug, and lactose free formula can be useful in the short term while their ‘lactase’ enzyme levels are slowly being restored.

There is a genetic condition where some babies can’t tolerate lactose, but this is extremely rare and would be medically diagnosed and the correct formula prescribed. 

Still rare, but slightly more common is cow’s milk protein allergy (CMPA)
. If your baby has diarrhoea, vomiting, or signs of an allergic reaction such as eczema, a rash, red bumpy skin, facial swelling or breathing difficulties seek medical help. 

A lactose free formula won’t help with CMPA as it’s the protein that is the allergen, not the lactose.

Ask your GP for a referral to a paediatric dietitian or book a consultation with my team
, so you can get the right formula prescribed.

Lactose-free infant formula also contains glucose which is potentially damaging to your baby’s teeth.

Bottom line: Your baby can have lactose free formula but under medical supervision.

Cows milk protein allergy

If your baby is diagnosed with cow’s milk protein allergy, you will be prescribed a specific formula. These are only available on prescription from your GP, you can not buy them. 

Often it will be a registered dietitian who will decide on the specific formula to be prescribed, rather than the GP. There are two main categories:

  • Hydrolysed formula

  • Amino Acid formula 

Hydrolysed formula

These include Nutramigen LGG, Similac Alimentum, Aptamil Pepti and SMA Althera, Pregestimil Lipil and are formulas where the protein is broken down into smaller fragments which makes them unrecognisable by your baby’s immune system and therefore don’t trigger an allergic response.

Amino acid formula

These include Neocate LCP, Neocate Syneo, Nutramigen PurAmino, SMA Alfamino and are completely broken down into the individual building blocks of nutrition so your baby doesn’t react. 

These are reserved for the most extremely allergic babies and those with poor growth alongside multiple food allergies or those with a condition called eosinophilic oesophagitis or anaphylaxis to cow’s milk protein.

Bottom line: Your dietitian will advise the best formula for cow’s milk protein allergy.

Formula for protecting your baby from eczema and allergies

There are formula milks such as SMA H.A.  that suggest they offer a protective effect against allergies and eczema. 

A small amount of research (which was quite exciting for dietitians at the time) has suggested these may play a role but much, much more research is needed until this is conclusive.

Bottom line: No need to buy them until we know they definitely work.

What is the best vegetarian or vegan formula?

If you are raising your baby as vegetarian or vegan, you are limited in choice as many formula milks have essential fatty acids derived from fish oils and animal rennet. 

In addition, Vitamin D is added to all formulas by law but it is sourced from sheep’s wool.

This means that there are no vegan formulas available for babies and only the following vegetarian formula:

  • SMA WySoy (contains Vitamin D sourced from the wool of living sheep)

  • Kendamil 1 (vegetarian and based on cow’s milk)

Plant milk drinks such as soya, almond and oat milk are not suitable for babies under 2 years of age unless they are over the age of 12 months and under the supervision of a Registered Dietitian. 

The dietitian will have assessed their diet and a specific plant milk drink will be advised. 

This is because all plant milks are very low in nutrients and what nutrients they do contain differs greatly between them.

All too often I see people giving out tips about plant milks for babies. Best ignore them unless it comes from your baby’s dietitian.

Bottom line: Vegan families who are unable to breastfeed will need to use a soya based formula but be aware that they are not suitable for babies under 6 months nor are they truly vegan.

What type of milk is best for a 1 year old?

When your little one turns one, you can introduce whole (full fat) cow’s milk if you wish. I say this because healthcare professionals sometimes advise that this is a ‘must-do’, but actually, that’s not the case. 

Remember only Registered Dietitians are regulated nutrition professionals, not GP’s, health visitors and anyone can call themselves a nutritionist.

Your baby can continue on formula right up till they are two and actually this isn’t a bad idea, especially if you have a fussy eater. Formula has extra nutrients added whereas whole cows milk does not.

Toddler milks or stage 3 milks, sometimes also called ‘growing up’ milks are also available and because they are fortified with lots of additional nutrients can be super helpful too.

It should go without saying, but if your baby has a prescription formula please do not introduce cow’s milk unless you are advised to do so by their dietitian or doctor. 

Bottom line: Whole cows milk can be introduced and it’s quite alright to stay on formula or try a stage 3 toddler milk if you want that nutritional peace of mind.

What are HMO’s and should I look for a milk that contains them?

HMO’s or Human Milk Oligosaccharide are carbohydrates that are naturally occurring in breastmilk, and are thought to help support the immune system. Some formula companies have been able to produce artificial HMO’s in a lab and have added them to some infant formula to become closer to breastmilk.

They are safe for your baby and clinical trials have been carried out to show this. However, there have not been sufficient clinical trials to show that artificially produced HMO’s have the same benefits as those naturally found in breastmilk.

Bottom line: HMO’s in breastmilk are beneficial for babies but those added to formula haven’t been shown to have the same effect.

Whichever type of milk your baby has, it’s important to feed responsively. This means following your baby’s cues, letting them be in control of how much and how often they feed.

If you are bottle-feeding, use a paced feeding technique
and don’t encourage your baby to finish a bottle. This has been linked with them becoming overweight later in life with health conditions as a result.

If you’ve found this post useful and want to know more about your baby’s nutrition, I’d like to invite you to check out my online course called Happy Healthy Weaning
.  It’s really hard to get weaning right and we only get one chance at it, but with this course, it’s like having a dietitian in your pocket!

Sarah Almond Bushell MPhil, BSc (Hons) RD MBDA – Registered Dietitian & Children’s Nutritionist

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