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There is quite a lot of controversy around soya infant formula and at the moment it’s not recommended for babies under 6 months of age.
In 2019 the British Dietetic Association updated their guidance on the use of soya infant formula as new research has come to light.
In this blog I’ll explain what all the fuss is about, and actually what to feed your vegan baby if you are looking for an alternative to breastmilk.
Can you buy vegan baby formula?
In the UK, no you can’t!
In the UK there is no 100% vegan baby formula and that is because even the soya based formula on the market has ingredients taken from animals.
At the time of writing, there is only one soya based formula widely available in the UK which is SMA WySoy and this isn’t suitable for babies under 6 months. When I contacted SMA they were able to tell me that the vitamin D in their formula was sourced from lanolin from the wool of living sheep.
The other ingredient in formula which is usually animal based, is the essential omega-3 fatty acid DHA however in SMA WySoy this is sourced from algae (seaweed) and funghi (mushrooms).
I’m often asked whether formulas prescribed for babies with milk allergies are vegan (hypoallergenic amino acid formula) as they are dairy free, but these types of formulas use other non-plant based ingredients as a source of some of the nutrients, so these are not vegan either.
The only way to feed your baby a truly vegan diet is by breastfeeding them. The next best option is to look at the soya formula WySoy if this is right for your family.
What about outside of the UK?
There is a truly vegan formula, Premiriz Infant Formula, produced by the French company called Premibio.
This formula is based on rice milk and uses vegan sources of vitamin D and omega-3 fatty acids. I have noticed that some families are choosing to import this formula into the UK although this is very expensive.
Rice milk contains a naturally occurring compound called inorganic arsenic [1] which is not suitable for children under 4 ½ years of age as their bodies are too immature to process it. In a recent review, rice based formulas were found to have low levels of inorganic arsenic with levels being similar to that of standard infant formula in the UK. [2]
The UK hasn’t updated their recommendations yet but who knows what’s coming!
Why can’t newborns have soya based formula?
Research into the use of soya formula in the early 2000’s found some concern over the side effects when it was used for a long period of time.
Unusual testosterone levels in male marmoset monkeys were identified, and there was worry about potential sexual developmental issues associated with infants fed soy formula. [3]
An increase in long, heavy periods in adult women who were given soya formula as a baby. [4]
As a precaution, the NHS advises that babies should not have soya infant formulas under 6 months of age but this can be given after 6 months when weaning has started and milk is no longer the sole source of nutrition.


What does newer research say?
Newer research suggests that parents are choosing soya formula anyway as they believe there may be future health benefits for their children due to the phytooestrogen content.
However a large review found that there is no evidence of any health benefits and no real medical need for the use of soya based infant formula and so it remains that it should only be used in exceptional circumstances under strict dietetic supervision where there are no alternatives. [5]
Why specifically under 6 months?
It’s a precautionary measure, but if babies are fed soya based formula exclusively in the first 6 months of life, they will be consuming a very high dose of ‘phytoestrogens’ in relation to their size. The effect of the phytoestrogens appears to cause permanent changes between 4-6 months of age.
Also, if you happen to be reading this because your baby has cows milk protein allergy (CMPA), it’s thought that between 30-50% of these babies may also be sensitive to the protein in soy, meaning they would also react to the soy in soya based formula. [6]
Soya-based formulas are also not recommended for premature infants as there is some evidence that they don’t grow as well as when compared to consuming a cows milk based formula. [7] but, it’s important to note here that the cows milk based formulas used for premature infants are usually made to have more calories to support the additional nutritional needs of these babies.
What are Phytoestrogens
Let’s break the word down:
‘Phyto’ actually means plant in Greek.
‘Estrogen’, which you might have heard of before, is a female hormone that regulates a lot of functions in both men and women, but mainly reproductive functions.
Therefore ‘Phytoestrogens’ are ‘plant-estrogens’, substances which are found naturally in plants, and are available to us in a wide range of everyday foods such as fruit, vegetables, beans, lentils and some grains.
Soya beans contain more phytoestrogens than other foods. [8] Whilst they are natural, we still need to be careful with the amount that babies and children eat. Much of the research into phytoestrogens and their effect on our health is conflicted – some studies say it’s good for us while others say that it is potentially bad for us.
It’s important to be aware that a lot more research is needed in this area as we don’t fully understand the full extent of what phytoestrogens do.


What are the exceptional circumstances when babies can have soya infant formula?
There are instances when there is a need to give babies under 6 months soya-based formula:
Firstly, vegan mothers who can’t or don’t want to breastfeed may consider soya based formula as an acceptable alternative. However, remember this is not truly vegan as the vitamin D comes from sheep’s wool.
Secondly, babies with cows milk protein allergy who repeatedly refuse their specialist formula (called extensively hydrolysed or amino acid formula) due to its bitter taste, and without a formula would not survive. [9]
Finally, there are a few medical conditions such as galactosaemia, where the use of a soya based formula is the only option.
Using Soya Based Infant Formula after 6 months
The guidance changes once a baby turns 6 months and this is when soya-based formulas CAN be given.
This is because the dose of phytoestrogens in relation to your baby’s size is smaller, because they have grown.
In addition, your baby’s organ systems are more mature so there is reduced risk of any lasting changes.
There used to be thought that soya based formula would increase the risk of your baby developing a peanut allergy. However, research has not been able to verify this.
What else should you know before choosing a soya based formula?
All infant formulas in the UK, including soya ones are strictly regulated and so you can be assured they contain the exact nutritional requirements babies need.
If after reading this blog you are still unsure whether a soya formula is right for your baby, you may also want to consider an organic cows or goats milk based infant formula.
These formulas are made from milk from animals that are kept in higher welfare conditions. The soil association has very strict standards for animals that are used to farm organic products.
There are now multiple baby formula brands that have an organic range such as Kendamil, Aptamil, Hipp and SMA to name a few.
Summary
There is no truly vegan baby formula available in the UK. Soya is the next best thing but it’s not recommended for babies less than 6 months old. More research is needed into the long term effects of phytoestrogen exposure in young babies and whether it is safe for them to have. We still don’t have all the answers.
Nutritionally, the most suitable form of milk for most infants is breast milk as breast milk adapts to provide your baby with everything they need when they need it.
There are so many different types of formulas out there and I understand that parents can find it confusing.
If this is the case you are welcome to book an appointment with one of my fully qualified paediatric dietitians on the team who will be able to help you find the best fit for your little one. The link to book is here.


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