Minute amounts of wax will be ingested into the body with every use. It will be similar to the current situation with microplastics (mostly polyester – coming from the sportswear and clothing in general that fray at the microscopic level) that have been detected in human body organs
pervasively and are being investigated for their side effects on the hormonal system.
Moreover, wax is not one chemical compound but is a broad term for a variety of very different chemical compounds shoved under the «wax» umbrella term due to sharing same properties: being solid, lipophilic and malleable. Anything that shares such properties is a wax.
There are four broad categories of wax:
– Plant based (e.g. soy, carnauba, castor, jojoba, tallow and others)
– Animal based (beeswax, lanolin – from sheep, Chinese wax – from insects)
– Petroleum (paraffin and microcrystalline)
– Mineral waxes (peat and ceresin are most important ones).
Other than beeswax, long term health effects of ingesting a wax are unknown. Plant based waxes can't be completely purified and will contain miniscule amounts of potentially harmful phytochemicals that may have a detrimental effect on the human body. Animal based waxes are already known to cause irritation in some people and are likely to mess up the hormonal system in the long term. They can just a have a rancid or a funny smell – sufficient to be unsuitable to put in one's mouth.
Petroleum based waxes… Food-grade paraffin wax has been used in foodstuffs for a while since it passes the digestive tract unchanged, yet it is an open question whether it also creates microparticles that settle in the body and have a potential to affect our health. Impurities in petroleum and in waxes overall are a major source of concern, and it is a matter of time when somebody unscrupulous quietly swaps out a higher grade product for a cheap and nasty one.
The bottom line is that long term health effects of the wax ingestion on the human body are unknown, and – by extension – wax coated paper straws are probably not a solution, not a safe one anyway until proven otherwise.
Metal straws are the most inert ones, but even then aluminium leeching into food through cookware has already been implicated as a potential contributor to the onset of Alzheimers and steel has an amount (albeit small) of nickel in it… it just never ends.