Best Sippy Cup Selection Guide – Part 2 of 2

Summary

Some of the main qualities to consider when selecting the materials used in your sippy cup include food and fall safety, appeal, easy cleaning, and durability. Silicone, polypropylene, stainless steel, and glass are safer materials recommended for kids. Polypropylene with embedded graphics is good overall. Plain stainless steel offers many excellent properties, but it poses a greater fall hazard, and isn’t very appealing to kids. Painted stainless is more appealing, but toddlers can teethe on or eat flaking paint. Some toddlers have even been known to chip a tooth whilst drinking from these kinds of cups, which is obviously not ideal. If this did happen to your child, you should visit a pediatric dental care practice as soon as possible. Hopefully, if you choose the right sippy cup for your child, this won’t happen! Glass has many excellent properties, but it poses a greater fall hazard, and shards can be ingested or cause lacerations. Silicone is the superior rubber material for straws, spouts, and valves.

Background

This is part 2 of a 2 part sippy cup selection guide (read part 1 here). In this part, we’ll review sippy cup material options (plastic, steel, glass, etc.) so you can choose what’s best for your family. Listed below are many of the qualities that must all be balanced in a good sippy cup.

A good sippy cup balances these qualities

Parents don’t and probably won’t ever agree on what makes the “best” sippy cup… just check the passionate and contradictory love/hate reviews for your current favorite! This guide emphasizes the safest choice wherever practical, but shows all the performance trade-offs so you can decide what’s best for your particular needs.

Cup Material Comparison

This section compares the safest materials currently in use for sippy cups: 1) uncolored silicone rubber, 2) polypropylene plastic with barrier over graphics, 3) painted stainless steel, and 4) painted borosilicate glass.

Polypropylene with embedded graphics is good overall, glass has excellent properties but has durability and safety concerns for toddlers

Easy to Drink From – Transparent materials (silicone, polypropylene, and glass) have the advantage over stainless steel since parents can easily see when the cup is empty and refill it.

Food Safe – Silicone, polypropylene, stainless steel, and glass are safer materials recommended for kids.¹⁰ Silicone rubber has no known health hazards for use in cookware.⁸ Polypropylene has a long track record of safety, and has never required endocrine disrupting chemicals (e.g. BPA, BPS, phthalates) to function properly.¹² Stainless steel contains iron and chromium which are healthy in low doses, and nickel which is not poisonous at low doses, and doesn’t release enough of these chemicals to cause concern.⁸

Inks and paints are not recommended for surfaces in direct contact with food (e.g. the inside of a cup), and are also not ideal for use on the outside of a sippy cup, since toddlers can teethe on or eat flaking paint. Adding a food safe barrier over such graphics is the industry standard method to achieve higher safety, so some polypropylene sippy cups add a polypropylene barrier over the graphics. Stainless steel is generally decorated by painting on the outside, with no barrier, so the paint is more susceptible to being teethed on and eaten. The only health concerns for glassware comes from minor components such as pigments, lead, or cadmium.⁸ Although pigments, lead, and/or cadmium are used to color and decorate glassware, the decoration can be made safe and durable (e.g. dishwasher safe and abrasion resistant) by selecting stable colorants and processing (firing) the glassware correctly.¹¹

Fall Safe – Two thousand children per year are given emergency treatment for injuries from a bottle, pacifier, or sippy cup, and the majority (86%) of those injuries are due to falls with the product.⁷ Most injuries are to the mouth, head, face, or neck. Silicone and polypropylene are more flexible than steel and glass, and should be less harmful to fall onto. Further, glass may chip or shatter, increasing the possibility of injury from lacerations or ingestion.

Appeal – Ideally, your newer, safer cup will be appealing enough that your kids will happily trade in their old bottle or spouted sippy for it. Kids like cute and colorful products. So although clear silicone rubber (no added dyes or pigments) may be safer than colored silicone, it is likely less appealing to kids. Likewise, although natural stainless steel is the safer option, it is much less appealing than painted steel. In contrast, clear polypropylene can be made very appealing by adding graphics, and still retain the safer status by encapsulating those graphics with a food safe barrier.

Easy to Clean & Durability – Silicone is dishwasher safe and resistant to heat, cold, sunlight, and chemicals, but is sensitive to biting and tearing. Polypropylene is generally top-rack dishwasher safe, fairly resistant to heat (e.g. steam sterilizing is ok, but boiling is often not), fairly resistant to cold (more fragile when cold), more sensitive to sunlight (uv), and fairly resistant to chemicals. Natural stainless steel is very resistant to heat, cold, and sunlight, and has good chemical resistance (although it can be susceptible to acid and corrosion). Painted stainless steel can be dishwasher safe (depending on paint), but will be more sensitive to sunlight and chemicals, and requires care not to chip or scratch the graphics. Glass is dishwasher safe, and is very resistant to heat, cold, sunlight, and chemicals. However, glass is the most brittle among these materials, so durability suffers when in the hands of a toddler.

Straw & Valve Material Comparison

This section compares the safest rubber materials currently in use for straws, spouts, and valves: 1) uncolored silicone rubber, 2) uncolored thermoplastic olefins (TPE-o), and 3) uncolored natural rubber (latex).

Silicone is the best rubber material for straws, spouts, and valves

Food Safe – Silicone is the safer rubber material recommended for kids.¹⁰ Silicone rubber has no known health hazards for use in cookware.⁸ Natural rubber generally contains proteins that are allergenic and may develop sensitivity upon repeated exposure⁹, and may leach nitrosamines¹⁰ (a carcinogen).

Colorants (dyes and pigments) can be added to modify the color of rubber, but they also modify the chemical makeup and food safety. Each colorant is different, some have regulated maximum concentrations set by the FDA for food contact. Covering each colorant individually is beyond the scope of this guide, but as a blanket statement, uncolored rubber is generally the more certain option.

Easy to Clean & Durability – Silicone is dishwasher safe and resistant to heat, cold, sunlight, and chemicals (including acids and fats). Silicone has a smoother surface than natural rubber, and so is less likely to be colonized with microorganisims.¹³ TPE-o can be dishwasher safe, but tends to degrade and stain more when exposed to heat, sunlight, and chemicals (sometimes becoming tacky). Natural rubber is not dishwasher safe and deteriorates faster than silicone when heated¹⁴, and is less resistant to sunlight and chemicals (such as fats from milk). All three rubber options are sensitive to biting and tearing, so have limited lifespans when in the hands (and teeth) of toddlers.

Continue Reading

Best Sippy Cup Selection Guide – Part 1 of 2. Part 1 of this series compares the various types of sippy cups (straw vs spout, valve vs valve-free, etc.).

Resources and References

1. Mann, Denise. So Long Sippy Cups, Hello Straws. WebMD, Feb 11, 2008. Retreived May 18, 2016.
2. Potock, Melanie. Step Away From the Sippy Cup! ASHA Sphere, Jan 9, 2014. Retreived May 18, 2016.
3. Drinking Straws Fight Tooth Decay. American Dental Education Association. Retreived May 18, 2016.
4. Hitti, Miranda. Sipping Soda Through a Straw May Cut Cavities. WebMD, June 17, 2005. Retreived May 18, 2016.
5. From Baby Bottle to Cup. Journal of the American Dental Association, Vol. 135, March 2004. Retreived May 18, 2016.
6. Sippy Cup Do’s and Don’ts. Babycenter. Retreived May 18, 2016.
7. Keim, Sarah A. et al. Injuries Associated With Bottles, Pacifiers, and Sippy Cups in the United States, 1991-2010. American Academy of Pediatrics, January 24, 2012. Retreived May 18, 2016.
8. The Safe use of Cookware. Health Canada, March 18 2015. Retreived May 18, 2016.
9. Potential for Sensitization and Possible Allergic Reaction to Natural Rubber Latex Gloves and other Natural Rubber Products. OSHA, January 28 2008. Retreived May 18, 2016.
10. Choosing Safer Products: Baby Bottles, Sippy Cups, and Pacifiers. Washington Toxics Coalition. Retreived May 18, 2016.
11. Klages, Karen. Getting the Lead Out. Chicago Tribune, October 21, 2007. Retrieved June 3, 2016.
12. Decoding the Mystery of Safer vs Toxic Plastic. The Soft Landing, January 27, 2016. Retrieved May 31, 2016.
13. Recommendations for the Use of Pacifiers. Paediatr Child Health, Vol 8 No 8, pg. 515-519, October 2003.
14. Pacifier Buying Guide. Consumer Reports, November 2012. Retreived May 18, 2016.