How safe is your water bottle?
Published: Tuesday, August 28, 2007 at 3:39 a.m.
Last Modified: Monday, August 27, 2007 at 9:00 p.m.
I thought that carrying bottles of water in my car was good for my health.
Facts
PLASTICS AND FOOD
Plastics have been a boon to modern life in countless ways, but for those concerned about exposure to chemicals from plastics that come in contact with our food supply, here are some suggested guidelines:
Considered safe: Plastics marked in the triangular code on their base with the numbers 1, 2, 4 or 5. Avoid reusing single-use water bottles (marked 1).
As much as feasible, limit use of plastics marked
3, 6 or 7.
Avoid using plastic (containers, wrap or Styrofoam) in the microwave. Some PVC-free plastic wrap (like Glad Cling Wrap or Saran Cling Plus) can be used if it does not touch the food while heating.
Store cooking oil in glass.
Baby bottles should be made of glass, or plastic marked number 4 or 5. Do not use baby bottles with the number 7 on the bottom.
It does allow me to drink more water -- while sitting in traffic I can chug a whole bottle easily, and when I finish one bottle, there's usually another stashed behind the front seat, ready to drink.
But now I find that these convenient plastic bottles getting warm in the car could be harmful to my health.
Recently reported scientific studies question the safety of some plastics, claiming they release toxins when exposed to heat or when reused too many times. The plastics industry, while acknowledging that people routinely ingest traces of chemicals from plastic packaging, says there is no cause for concern. The Food and Drug Administration, so far, agrees.
Not all plastics are in question. How do we decide what is real, what is overreaction, and which plastics are safe to use? Some simple science and consumer awareness can help.
All plastics have a triangular code printed on the base. The number inside the triangle identifies the type of plastic making up the container. Out of seven types of commonly used plastics, three -- numbered 7, 6 and 3 -- are under scrutiny while the other four are still considered relatively safe. Those of concern are:
Bisphenol A, or BPA, is the basic building block of polycarbonate plastics (marked No. 7). When polycarbonate plastic breaks down over time or with exposure to heat, it releases BPA. It is found in most plastic baby bottles, in some reusable sports bottles, in the lining of some single-use metal food and beverage containers, and in many single-use microwavable food containers.
This makes No. 7 plastic almost unavoidable.
A 2004 biomonitoring study by the Centers for Disease Control and Prevention found 95 percent of Americans had BPA in their urine. Concern about BPA exposure has dozens of scientists challenging the plastics industry.
Of 13 studies funded by the industry, none reported any health effects of BPAs at low doses. In contrast, 149 out of 163 government-funded studies found significant effects at very low exposure levels. When a chemical acts like a hormone, it takes very small amounts to affect the human body, so the definition and significance of "low dose" is still being debated.
The government studies found that BPA, an estrogen-like compound, alters childhood development of the reproductive tract and the immune system, increases prostate tumor proliferation, changes brain chemistry and structure and affects an array of behaviors, including hyperactivity.
BPA may be unavoidable, but it's still possible to limit our exposure. It's about awareness of the issue, making choices and changing our behaviors, from drinking water without plastic to paying attention to how our processed foods are packaged.
Polystyrene (plastic No. 6) is found in Styrofoam containers and sometimes in clear disposable takeout boxes. Polystyrene leaches styrene, which is a suspected human carcinogen. The container is more likely to leach styrene if the food has a high fat content, high alcohol content, or if the food is hot. This is why restaurants no longer package french fries in Styrofoam containers.
PVC (No. 3) is found in the plastic wrapping on foods like meat and cheese, and in cooking oil bottles. PVC has chemicals added to it to make it flexible and these additives do leach out.
Many hospitals no longer use PVC tubing in neonatal intensive care units because studies showed chemicals were leaching from the tubing into newborns' blood, causing problems in male reproductive tracts, in lungs, livers and kidneys.
The four plastics still considered relatively safe are those marked with the numbers 1, 2, 4 and 5.
Number 1 is polyethylene terephthalate, or PET or PETE, commonly found in soft drink and some water bottles. Number 2 is high-density polyethylene, or HDPE, found in milk and water bottles.
Number 4 is low-density polyethylene, or LDPE, found in plastic films like PVC-free Saran Wrap and Glad Wrap, and plastic grocery bags. And No. 5, polyprophylene, or PP, is found in yogurt containers, syrup bottles, and most of the plastic food storage containers that are labeled "microwave safe."
These are all relatively stable plastics that are much less likely to leach chemicals into our systems.
The controversy remains. The plastics industry and the FDA continue to reassure us that all plastics are absolutely safe to use as food and water containers.
But I have seen enough well-designed studies to make me wary. As with most environmental health issues, time and more research will tell.
In the meantime, I'm opting to err on the side of caution, so I'm going to get a big stainless steel water bottle for the car. It has to hold enough for rush hour on Highway 101.
Dr. Stacey Kerr, a longtime Sonoma County family physician, graduated from UC Davis Medical School and is certified in her specialty by the American Board of Family Medicine. Her columns are not intended as a substitute for hands-on medical advice or treatment. Consult your health care provider before adhering to any recommendations in this column. E-mail comments to drkerr@the-doctors-inn.com.
All rights reserved. This copyrighted material may not be re-published without permission. Links are encouraged.
Comments are currently unavailable on this article