Why You Should Avoid Substituting Breast Milk With Soy-Based Formula

Shelves of baby formula.
If you are looking to make the healthiest choice for your infant, you may want to avoid substituting breast milk with soy-based formula. (Image: Roman Tiraspolsky via Dreamstime)

In the recent past, soy has gained much popularity as a superfood. Unsurprisingly, it has found its way to many people’s dining tables for its health benefits. Soy milk is cholesterol-free and lactose-free, making it a great choice for those with lactose intolerance and for people who can’t digest galactose, the sugar found in milk. 

Due to its great nutritional content, soy milk is now available in stores as a soy-based formula. It has even replaced cow’s milk formula and breast milk in some households. Parents giving their infants soy milk believe it has many health benefits. They think it may prevent the risk of developing diseases such as diabetes, cancer, hypertension, and cardiovascular disease. 

They also believe soy formula reduces colic and lowers the risk of developing allergies later in life. But there are no evidence-based studies to support these claims. Also, soy formula has been associated with some risk factors and may not be as safe as you thought for your newborn. 

Below are some reasons you may want to avoid soy-based formulas for babies. 

Disadvantages of soy milk for babies

Reproductive health issues

Soy formula contains high levels of genistein, an estrogen-like compound. This compound may affect the development of the reproductive system of your baby. 

Soy formula contains high levels of an estrogen-like compound that may affect the development of the reproductive system of your baby.
Soy formula contains high levels of an estrogen-like compound that may affect the development of the reproductive system of your baby. (Image: Rene Jansa via Dreamstime)

According to research conducted by the National Institute of Environmental Health Sciences (NIEHS), babies fed soy-based formula had a different morphology in reproductive tissues and cells compared to those who were not fed soy-based formula. 

It’s worth noting the difference in reproductive cells and tissues was insignificant in the short-term use of soy-based formula. So further studies need to be conducted to establish its long-term effects on infants.

Genistein can also affect normal hormone development in babies. A study by the Children’s Hospital of Philadelphia looked at its effects on female infants. In the study, those fed soy-based formula for 36 months had abnormal developmental growth curves similar to those expected when exposed to estrogen. 

Other studies have also found that girls on soy-based formula as infants experienced heavier, more painful, and longer periods later in life than those who were not given soy-based formula. 

Increased risk of osteopenia

Soy-based formulas contain high amounts of aluminum. This increases the risk of developing osteopenia in infants who consume it compared to those who drink cow’s milk formula or breast milk. Osteopenia occurs when people lose their bone mineral density leading to weaker bones. 

Aluminum also competes with calcium during absorption. So it may decrease calcium absorption. Low calcium can lead to osteoporosis, low bone density, and increased risk of fractures. 

Premature breast development in females

The soy-based formula has also been linked to premature breast development in females. A controlled laboratory study on rodents showed a high rate of negative effects in females. They include infertility, stunted growth, and abnormalities in the development of sexual organs. 

But other researchers argue that the quantities of genistein consumed by infants are much lower than those given to rodents in a controlled study, so further studies are needed to establish whether soy-based formulas pose a serious health risk for babies or if they are safe for consumption by infants. 

Is soy formula any good?

The soy-based formula on the market must meet the Food and Drugs Administration (FDA) regulations. This ensures it provides adequate nutrients and calories for your baby’s normal growth and development.

On the plus side, soy-based formula provides adequate nutrients and calories for your baby's normal growth and development.
On the plus side, soy-based formula provides adequate nutrients and calories for your baby’s normal growth and development. (Image: Teeraphat Sirisatonpun via Dreamstime)

Who can use soy-based formula?

Soy-based formula is particularly good for vegan families that can’t consume cow’s milk. That said, it’s always advisable to breastfeed your child, even if you are on a vegan or vegetarian diet. However, if, for unavoidable reasons, you choose not to breastfeed, then a soy-based formula can be an alternative.

Soy-based formula is also recommended for children born with galactosemia or lactose intolerance. Galactosemia, or the inability to digest the sugar found in milk, is fatal and causes brain damage, liver failure, or even death. Under such circumstances, your baby can’t consume breast milk or cow’s formula, so soy-based formula is the only safe option. 

Some children are allergic to proteins present in cow’s milk formula. In this case, soy formula comes in handy. However, about 50 percent of children allergic to cow’s milk proteins are also allergic to soy protein.

Final remarks

It is recommended to breastfeed your newborn baby for at least six months before weaning. But there are circumstances where you can’t breastfeed due to unavoidable reasons. And your infant may be allergic to cow’s milk formula or suffer from certain conditions. Here, you should talk to your doctor or healthcare provider to discuss the best options. 

A soy-based formula can come in handy in some situations. But studies have shown that it may not be as healthy for babies as previously thought. Also, soy-based formula is not recommended for babies born prematurely or those with poor renal function.

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  • Nathan Machoka

    Nathan is a writer specializing in history, sustainable living, personal growth, nature, and science. To him, information is liberating, and it can help us bridge the gap between cultures and boost empathy. When not writing, he’s reading, catching a favorite show, or weightlifting. An admitted soccer lover, he feeds his addiction by watching Arsenal FC games on weekends.

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