Having read about xenoestrogens, their effects and their prevalence, many people who are aware of this have taken certain steps to avoid xenoestrogen-containing products, such as personal care products, certain food products, and plastic.
As active individuals, we TMusclers often consume large amounts of water daily (personally, I consume at least two gallons a day). This helps digest our food, replenish our cells with water, and balance any sodium excess that may be present from higher-calorie diets.
This leads many of us to carry water bottles (especially those here in the drier, higher-elevation states). The bottle brand Sigg has become trendy, though recent research has yeilded that the coating on the inside of these aluminum containers are, as one may have guessed, potentially dangerous. In my own experience with this over-priced brand, the coating actually comes off within the first few months, and in most certainly consumed unwittingly.
While other, cheaper, metal bottles have come out (Stainless steel being the only reliably safe metal used), let's be honest, plastic is far superior in terms of both toughness, as well as affordability.
Now, companies like Nalgene are producing 'BPA FREE' bottles, and many people are returning to plastic with glee, though at a less affordable rate. (In case you did not know, BPA or Bisphenol A is a powerful xenoestrogen that also appears to be toxic).
A similar company, Camelback, now sells "BPA and phthalate free" water bottles. Phthalates are arguably more dangerous and xenoestrogenic than BPA, though less well discussed.
Curiously, Nalgene, one of the best selling of the BPA free bottles, does not speak to phthalate content.
Now, all plastic meant for recycling have symbols indicating what they are made from. These range from 1 to 7. 7 is the catchall "other" plastic, being any plastic not included in #'s 1-6, often made from a resin, including vegetable-based plastics. Unfortunately, #7 can also mean a PVC-based plastic, containing high levels of Phthalates but no BPA.
Nalgene's new bottles are suspiciously #7 plastic, meaning that there could be xenoestrogenic chemicals in the bottle. This is more suspicious due to Nalgene's complete lack of mention of phthalates on either their own bottles, their website, or in the press.
Now, one of the 'safe' plastics widely available is #2, or HDPE (High Density Polyethylene). This is called food grade plastic, and is largely believed to not leach, and does not contain either BPA or Phthalates.
Interestingly, in terms of bottles, Nalgene and others make HDPE bottles for about six buck, less than half of what they are charging for "BPA FREE" bottles.
So, from initial research, it seems that HDPE beats out any of these "designer" plastics, and may not be harmful.
Is this old-school plastic just what the weightlifting/Bodybuilding community needs for our estrogen-free hydration, or is HDPE, like so many others, another dead-end in the fantasy of safe polymers?