Breastfeeding is the best for both mother and baby, and should be practiced exclusively for the first six months as recommended by the World Health Organisation (WHO). At some point, most babies will transit to become bottle-fed, be it expressed breast milk or infant formula milk. At that point, what kind of baby bottles should you purchase?
Not all baby bottles are created equal. Like most parents, we want our milk bottles to be safe and non-toxic (e.g. BPA-free, BPS-free, no estrogenic activity etc), but that is not sufficient. We also want a milk bottle that is practical for frequent daily use. This is where the material of your baby’s bottle plays an important part. There are 2 main categories of milk bottles - Glass & Plastic.
Glass has been used as a material for baby bottles for ages and should always be the first choice. At its highest boiling points, borosilicate glass material does not release toxic chemicals or leach and has excellent transparency.
However, the biggest downside of glass bottles is it is heavier and more fragile. An average glass 160ml milk bottle weighs between 200g to 350g. This makes up 10% of a baby’s weight, given that newborn weighs between 2.5 to 3.5 kg! Due to its fragility, you have to be careful not to break or crack the glass when washing. In addition, it is a good practice to always take a good look at the bottle’s surface before use, especially if you use a glass bottle.
Glass would be my first choice for newborns in their first month or two, as feeding will largely be done by the parents. This is when most parents will be more conscientious with washing and sterilising the bottles after each use. Glass however, is not practical. I personally prefer a bottle that can withstand an inevitable drop or slip from either the caretaker or the baby as they grow older. This is one less worry when handling a fussing baby in one hand, and literally, everything else in the other.
While plastic seem more practical than glass, different kinds of plastics can quite different. There are 4 main kind of BPA-free plastic used for baby bottles: TRITAN, PP, PES & PPSU. If the bottle does not indicate the type of plastic, it is likely to be PP.
The biggest problem with plastic bottles is leaching as a result of ageing, wear and tear arising from high temperature and repeated washing with detergents. Given that milk bottles are frequently washed and sterilised using heat, some plastic components breakdown and release harmful chemicals.
Let us next understand more about the differences between these four types of plastics.
Polypropylene (PP) are the most common kind of plastic material used in feeding bottles. They are durable, flexible and economical. They are often used to manufacture household items, PP milk bottles are available in both clear or transparent color-tinted. While PP bottles can withstand temperatures of up to 120°C, they tend to lose transparency over time following repeated sterilization and boiling.
This loss in transparency indicates a change in the physical characteristics of the plastic - something one would shudder at the thought of using it as a milk bottle. For this reason, it is recommended to change your PP milk bottles once every 3 months or once changes in the bottle’s texture or clarity is observed.
Polyethersulphone (PES) is a tougher and safer plastic than PP as it comes from a family of thermoplastic polymers. This means PES can withstand heat as high as 180°C without chemically breaking down. However, as with all plastic, micro scratches from repeated washing increases the crevices that allow milk deposits to sit, causing it even harder to thoroughly clean the bottle over time. In addition, as with all plastics, repeated high temperature will eventually degrade the plastic. Again, it is advisable to change your PES milk bottles less than every 6 months.
PPSU (polyphenylsulfone) is a high performing thermoplastic that is more durable and heat-resistant than PP and PES. Not only that, PPSU plastic does not absorb odor or color. It is naturally BPA free. Due to its even higher melting point than PES, PPSU plastics are commonly used in medical devices requiring repeated sterilization. PPSU material is also microwavable.
The downsides of PPSU is that it has a yellowish tint and is significantly more expensive than PP and PES, hence PPSU products are less frequently used in consumer products. Despite its supreme durability, it is still advisable to change your PPSU milk bottles within a year.
TRITAN, produced by Eastman Chemical Company, similar to PPSU, is one of the highest performing new amorphous thermoplastic. Not only is TRITAN naturally BPA-free like many other plastics nowadays, it does not contain BPS and other Bisphenols. In addition, TRITAN has an even higher melting point than PPSU. As such, TRITAN plastics are also used in medical devices such as blood therapy devices and IV system components. Other key attributes of TRITAN such as its glass-like clarity, dishwasher durability, odour- and stain-resistance, makes TRITAN a perfect material for baby milk bottles.
While more expensive than PP and PES, TRITAN is more affordable than PPSU. As a result, we are starting to see more TRITAN-made products coming onto the consumer markets as they provide a more cost-effective solution compared to other materials.
Find out here why we think Tritan is the ideal material for baby bottles!