Why Does Baby Formula Taste So Bad [Metallic, Fishy, Bitter]

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Baby formulas are designed to be nutritionally similar to breastmilk, providing babies with the necessary nutrients to grow and thrive, but parents are often concerned because it can taste metallic, fishy, and bitter. What causes this off-taste in baby formula, and does it mean that it has spoiled?

Although infant formula is designed to provide the same (and sometimes more) benefits of breastmilk, it does not taste the same. To mimic the composition of breastmilk, formula must contain an abundance of nutrients, vitamins, and minerals. Some components of baby formula such as iron, amino acids, and fatty acids can impart an unpleasant taste. 

Bad tasting baby formula can be concerning to parents, but it is not always a cause for alarm. Read on to learn more about the potential causes of bad-tasting baby formula. 

Why doesn’t my baby like the taste of formula?

Breastmilk is broadly considered the gold standard for infant nutrition. It is complex, dynamic, and rich in nutrients. These factors make creating an alternative a large undertaking.

When baby formula manufacturers are composing baby formula, their most important task is creating something that will healthfully sustain an infant. In most formulations, there is not a lot of attention paid to the taste. 

If you’re noticing an off-taste in your baby’s formula, it is still important to make sure that it’s not expired or prepared incorrectly. However, it is very common for baby formula to taste metallic, fishy, or bitter. Though unpleasant, the taste is probably due to healthy additions such as iron, omega fatty acids, and amino acids. 

Baby’s formula tastes bad – is it expired?

If you are new to baby formula, you may be surprised to discover that it can have a distinct, off-putting taste. This can create confusion if you are trying to determine whether your formula has spoiled. 

Your baby formula may be bad if:

  • Your opened ready-to-feed liquid formula was out of the refrigerator for over two hours or has been in the refrigerator for over 48 hours. 
  • Your prepared powder formula has been out for over an hour or in the refrigerator for over 24 hours. 
  • There has been a change in the taste or smell of the formula.
  • You have surpassed the expiry date or the powder formula has been opened for over a month. 
  • The formula is clumpy or separating. 

Do all baby formula brands taste the same?

Though all baby formulas are designed to mimic the benefits of breastmilk, there is a wide variety available.

Depending on the brand and whether or not the formula is meant to fulfill an additional need (such as those developed for sensitive digestive systems or lactose-free versions), the taste of different types of formula may vary significantly.

Most baby formulas fall into three main categories: Cow’s Milk Protein, Hydrolyzed Protein, and Soy.

Cow’s Milk Protein Formula

Cow’s Milk Protein Formula is the standard formula given to most infants.

To mimic the taste of breastmilk, formula is usually sweetened; however, it typically tastes more medicinal and sour than breastmilk. Added iron can impart a metallic taste, and added fatty acids can cause a fishy taste.

Here are the best tasting options based on taste, similarity to breastmilk, and overall popularity:

Prices pulled from the Amazon Product Advertising API on:

Hydrolyzed Protein Formula

Hydrolyzed Protein/Amino Acid/Elemental Formula, often referred to as hypoallergenic, is processed so that the milk proteins are broken down or “pre-digested.”

This is recommended for children with severe allergic reactions to milk protein and is known for its unappealingly sour taste.

These are the most palatable options based on taste, similarity to breastmilk, and overall popularity:

Prices pulled from the Amazon Product Advertising API on:

Soy Formula

Soy Formula is a plant-based alternative to standard formulas.

It tastes much saltier than traditional formulas or breastmilk, as it contains 33 percent more sodium. Soy formula requires added sweeteners to make it more palatable. 

Here are the best options based on taste, similarity to breastmilk, and popularity.

Prices pulled from the Amazon Product Advertising API on:

Does formula taste the same as breastmilk?

Breastmilk is considered to be a perfectly balanced source of nutrition for infants. Unlike formula, breastmilk can vary greatly based on the individual, their diet, and their baby’s needs.

The taste of a mother’s breastmilk will change day-to-day based on what she is eating. Breastmilk even varies within a single feed: foremilk and hindmilk. By contrast, the taste of baby formula should remain consistent. 

Along with its ability to change and adapt, the nutrients found in breastmilk are complex, and some are not fully understood. These factors make breastmilk impossible to synthesize. Though baby formula is a great alternative to breastmilk, the compositions are dissimilar in many ways, making the tastes vastly different.

Differences between Breastmilk and Formula

NutrientBreastmilkFormula
Fats- Contains Arachidonic acid (AA) and Docosahexaenoic acid (DHA)
- Contains cholesterol
Contains lipase to aid in digestion
- Easily absorbed
- May not contain AA or DHA
- Does not contain cholesterol
- Does not contain lipase
- Harder to absorb
Proteins- Higher in whey protein 
- Contains lactoferrin, which protects against viral infection, aids in iron absorption, among other benefits
- Lysozyme, which is antimicrobial
- Easily absorbed
- Rich in growth factors and other beneficial proteins
- Higher in casein protein
- No lactoferrin
- No lysozyme
- Harder to absorb
- Deficient in many beneficial proteins found in breastmilk
Carbohydrates- Contains large amounts of lactose, which aids in brain development
- Contains oligosaccharides, which promote gut health
- May contain no lactose (sometimes replaced with artificial sweeteners like corn syrup)
- Lacks oligosaccharides
Immune Factors- Contains white blood cells
- Contains immunoglobulins
- Does not contain white blood cells
- Does not contain immunoglobulins
Vitamins and Minerals- Easily absorbed - Not as easily absorbed
Hormones- Contains over fifteen hormones- Does not contain human hormones

Why does formula taste bad?

The FDA regulates baby formula to ensure that they provide enough nutrition to serve as an alternative to breastmilk.

These regulations include minimum amounts for 29 nutrients and maximum amounts for 9 nutrients. Though it is important for the taste to be tolerable, the nutritional content is what makes baby formula useful.

Unfortunately, many of the “off-tastes” are directly tied to beneficial ingredients. 

Baby formula tastes bitter

Broken down peptides and amino acids can impart a bitter “off-taste” in baby formula.

Hypoallergenic formulas that are composed of hydrolyzed proteins or amino acids have the strongest bitter taste. Though the taste and smell might be off-putting to parents, young infants typically tolerate the bitter flavor.

Babies that took formula containing hydrolyzed proteins and amino acids did better with savory, bitter, and sour flavors when eating solids compared to babies who took standard formula or breastmilk. 

Baby formula tastes metallic

Infants absorb about 70 percent of the iron in breastmilk and only 10 percent of the iron in formula.

To avoid iron deficiency and anemia, baby formulas are fortified with additional iron. This added iron can cause baby formula to taste metallic. 

Baby formula tastes like fish

Many formula brands on the market contain added DHA and AHA. Though the FDA suggests further studies are warranted, DHA and AHA are said to be important for brain and eye development.

These fatty acids that are found in breastmilk are also found in fish oil and some algae. Depending on the source, DHA and AHA can cause baby formula to have a “fishy” taste. 

What can I do to make baby formula taste better?

Many parents assume that baby formula will taste like milk and are alarmed when they find out baby formula has a distinct, oftentimes unpleasant taste. As a parent, you might think “How can I give this to my child?”

If your baby is not rejecting their formula, avoid succumbing to these thoughts.

Your baby’s taste buds are still developing. Though you might find the taste of formula off-putting, your baby might enjoy its familiar taste.

Though it is not always the taste that causes a baby to turn away their bottle, some babies do dislike the taste of their formula. This aversion is frequently seen when babies switch from one formula to another due to allergies or other factors.

In these cases, there are some tricks you can do, under the guidance of your pediatrician, to help make baby formula more palatable. 

Prepare it properly

Before assuming that bad-tasting baby formula is due to its makeup, check to make sure you are preparing it properly

Along with the directions provided on your formula, here are some additional tips:

  • Wash your hands thoroughly.
  • Ensure that your bottles and workspace are clean and sanitized.
  • Never warm formula in the microwave; use a water bath or bottle-warmer.
  • Ensure that your water source is safe and clean. 
  • Measure water accurately, then add the formula powder or concentrate. 
  • Use the prepared formula quickly or store it safely.

Mix in some breastmilk

Mixing breastmilk with your formula can help breastfed babies tolerate the taste of formula.

When mixing breastmilk and formula, it is important to first prepare the formula as instructed, then add it to breastmilk. Adding formula powder or concentrated formula directly to breastmilk will increase the concentration of its nutrients, which can be dangerous.

If you are weaning your baby, you can start with a higher breastmilk-to-formula ratio and gradually reduce the amount of breastmilk until they are taking formula alone. 

Add flavors

Some parents experiment with adding different flavors to their baby’s formula to make it more appealing, but this is not always recommended.

The safety of these additives depends on the individual child, so consult your pediatrician before adding flavoring to your baby’s formula. 

Here are some common additions used to flavor baby formula:

  • Vanilla – choose a non-alcoholic extract or essence
  • Fruit juice – avoid fruit juice with added sugar
  • Purees – use purees that your baby has already tried
  • Spices – try small amounts of aromatic spices like cinnamon or nutmeg

Don’t use

If your pediatrician gives you the okay to make additions to your baby’s formula, it is important to keep in mind that there are many flavorings and mixes that can be dangerous to your baby.

You should never mix the following into your baby’s formula:

  • Cow’s milk – Milk is not easily digested by babies under one year of age, and it can be hard on their kidneys.
  • Water – Using extra water in your baby’s formula will dilute the nutrients, making your baby feel more full but decreasing the overall nutritional value.
  • Honey – Babies under one year of age should never be given honey as it puts them at risk for Clostridium botulinum exposure.
  • Sugar and artificial sweeteners – Children under two years of age should not be given added sugar or artificial sweeteners.

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