Environmental Medicine Update

by Marianne Marchese, ND

Cadmium Accelerates Aging

A recent study published in the American Journal of Epidemiology by Ami Zota and colleagues showed that low-dose exposure to cadmium can cause shortened telomeres.¹ It looked at the relation between both cadmium and lead and leukocyte telomere length. Shortened telomeres are associated with premature aging and increase risk of diseases related to aging. Utilizing data from the National Health and Nutrition Examination Survey (1999–2002), blood lead and cadmium levels from over 6000 adults in the US (n = 6796) and urine cadmium from over 2000 adults (n = 2093) were examined for changes in telomere length. They divided the participants into four groups based on the concentrations of cadmium found in their bloodstream, finding that people in the group with the highest amount of cadmium had telomeres about 6% shorter than those in the lowest group. There was no association between lead levels and telomere length. This study suggests that cadmium exposure can cause premature aging of cells by shortening telomeres.

Comment : Cadmium is a heavy metal that is ubiquitous in the environment. People are exposed daily at low levels from food sources including leafy vegetables such as lettuce and spinach, potatoes and grains, peanuts, soybeans, and sunflower seeds. Some are exposed to higher levels through cigarette smoking, secondhand smoke, and air pollution from living near industrial areas. The World Health Organization calls environmental exposure to cadmium a “major public health concern” and notes that this heavy metal has been associated with cardiovascular disease, respiratory problems, cancer, and other serious diseases. Exposure to cadmium can weaken bones and cause osteoporosis, and damage the kidneys. It is a known human carcinogen in high doses.²

Cadmium causes inflammation, oxidative stress, and the inhibiting of DNA repair, all of which could promote telomere shortening. Telomeres are the caps on the tips of chromosomes that help protect the genetic code. Telomeres naturally shorten as people get older, but other factors, including cadmium, may speed up that process. When the telomeres get too short, the cell can no longer divide and chronic diseases can be the result. Telomere testing is available to patients through their doctors. This study does not prove that exposure to cadmium actually causes telomeres to get shorter but finds a correlation. The link was strong and independent but must be proved with additional research.

Drinking Canned Beverages Raises Blood Pressure

Most canned food and beverages are lined with bisphenol A (BPA). BPA has been associated with numerous health issues. A recent study looked at whether increased BPA exposure from consumption of canned beverages actually affects blood pressure and heart rate variability.³ A randomized, crossover trial was conducted with noninstitutionalized adults over age 60 who were recruited from a local community center. A total of 60 participants visited the study site 3 times, and they were provided the same beverage in 2 glass bottles, 2 cans, or 1 can and 1 glass bottle at a time. Urinary BPA concentration was measured, as well as blood pressure and heart rate variability, 2 hours after the consumption of each beverage. The urinary BPA concentration increased after consumption of canned beverages by >1600% compared with that after consumption of glass-bottled beverages. Systolic blood pressure adjusted for daily variance increased by ≈4.5 mmHg after consumption of 2 canned beverages compared with 2 glass-bottled beverages, and the difference was statistically significant. There was no difference in heart rate variability. The study concludes that consuming canned beverages increases BPA exposure, thus increasing blood pressure.

Comment : BPA is used in epoxy resins lining food and beverage containers and in polycarbonate plastics in many consumer products. Widespread and continuous exposure to BPA, primarily through food, drinking water, dental sealants, dermal exposure to paper receipts, and inhalation of household dusts, is evident from the presence of detectable levels of BPA in more than 90% of the US population.⁴ The health effects of BPA have focused on its estrogenic activity, but there are other mechanisms of action, including liver damage, disrupted pancreatic beta cell function, thyroid hormone disruption, and obesity-promoting effects.⁵ Other studies have linked BPA to diabetes and cardiovascular disease, showing an association with only 1 standard deviation (SD) increase in BPA concentration in the body.⁶

This study linking BPA in canned beverages to high blood pressure is interesting on many fronts. The researchers used canned soy milk in the study due to the fact that it has no known ingredient that raises blood pressure. The study sample was very small, only 60 participants, and was an older population which could have variable blood pressure throughout the day due to aging. Also, given the age of the study population, we don’t know if they were chronically exposed to BPA earlier in life. We also don’t know the state of kidney function, which also could affects blood pressure. That said, BPA exposure from canned foods and beverages is widespread. Given the known adverse health effects of BPA, people may want to consider eating fresh foods and using glass beverage bottles instead of cans. More research is needed in this area on a younger and larger population.

Vaginal Hygiene Products Are a Source of Phthalate Exposure

Phthalates are a group of chemicals used to soften and increase the flexibility of plastic and vinyl. Diethyl phthalate (DEP) and di-n-butyl phthalate (DBP) are two phthalates found in consumer products that may increase risk of adverse health effects. A recent study looked at

whether vaginal douching and other feminine-hygiene products increase exposure to phthalates among reproductive-aged women in the US. Researchers conducted a cross-sectional study on 739 women (aged 20–49) from the National Health and Nutrition Examination Survey (NHANES) 2001–2004 to examine the association between use of feminine hygiene products (tampons, sanitary napkins, vaginal douches, feminine spray, feminine powder, and feminine wipes/towelettes) with urinary concentrations of monoethyl phthalate (MEP) and mono-n-butyl phthalate (MnBP), metabolites of DEP and DBP, respectively.⁷ More than half of the women in the study were overweight or obese, and many of the women said they hadn’t douched at all in the past 6 months.

Results of the study revealed a greater proportion of black women reported using vaginal hygiene products than white and Mexican American women. Roughly 1/3 of black women said that they douched at least once a month, as did 11% of white and Mexican American women.

Twenty percent of black women reported douching at least twice a month, compared with just 7% of white participants and 3% of Mexican Americans in the study. Douching in the past month was associated with higher concentrations of MEP but not MnBP. No other feminine-hygiene product was significantly associated with either MEP or MnBP. A dose–response relationship between douching frequency and MEP concentrations was observed. Women who douched at least twice a month had 152.2 % higher MEP concentrations than nonusers. Black women had 48.4 % higher MEP levels than white women. Women who douched at least once in the past month had 52% higher levels of MEP in the urine. Adjustment for douching attenuated this difference to 26.4%. The study concludes vaginal douching may increase exposure to DEP and contribute to racial/ethnic disparities in DEP exposure.

Comment : Phthalates are used in cosmetics and personal care products, including perfume, hair spray, soap, shampoo, nail polish, and skin moisturizers. They are used in flexible plastic and vinyl toys, shower curtains, wallpaper, vinyl miniblinds, food packaging, and plastic wrap. Most people are exposed to phthalates whether they know it or not. Diethyl phthalates are often used to bind cosmetics and fragrances and are in plasticizers, detergent bases, and aerosol sprays.⁸ They are used in fragranced personal-care products such as cologne/perfume, hair products, deodorant, lotion, body wash, and nail polish to retain scents. Because of the frequent dermal exposure of humans to DEP, the question of toxicity is crucial. Several studies suggest that DEP can damage the nervous system as well as reproductive organs in males and females.⁹

Feminine-care products that are used vaginally, such as douches, may be an unrecognized exposure source of phthalates. Researchers found no link between DEP and other feminine-hygiene products such as tampons, sanitary napkins, powders, sprays, or towelettes. Most commercial douches contain fragrance, and synthetic fragrances are a mixture of compounds that often contain phthalates. While the study can’t rule out other sources of phthalate exposure or prove that chemicals in douches cause specific health problems, the findings suggest that this vaginal cleansing habit may be unsafe. Health practitioners should consider advising patients against douching to eliminate a source of exposure to phthalates. This study that highlights the presence of environmental chemicals in vaginal douches warrants further examination.

Dr. Marchese is the author of 8 Weeks to Women’s Wellness. She received her doctorate in naturopathic medicine from the National College of Naturopathic Medicine in 2002. Dr. Marchese maintains private practice in Phoenix, Arizona, and teaches gynecology and environmental medicine at Southwest College of Naturopathic Medicine. She was named in Phoenix magazine’s Top Doctor Issue as one of the top naturopathic physicians in Phoenix. Dr. Marchese lectures on topics related to women’s health and environmental medicine throughout the US and Canada. www.drmarchese.com

Notes

1. Zota AR et al. Associations of cadmium and lead exposure with leukocyte telomere length: findings from national health and nutrition examination survey, 1999-2002. Am J Epidemiol. 2015 Jan 15;181(2):127–36; epub December 10, 2014.
2. ATSDR. Public Health statement for cadmium [Web page]. Sept 2012. http://www.atsdr.cdc.gov/phs/phs.asp?id=46&tid=15. Accessed Jan. 16, 2015
3. Bae S, Hong YC. Exposure to bisphenol A from drinking canned beverage increases blood pressure. Hypertension. 2015 Feb;65(2):313–319.
4. Calafat AM et al. Urinary concentrations of bisphenol A and 4-nonylphenol in a human reference population. Environ Health Perspect. 2005;113:391–395.
5. Newbold RR, Padilla-Banks E, Jefferson WN, Heindel JJ. Effects of endocrine disruptors on obesity. Int J Androl. 2008;31:201–208.
6. Lang IA, Galloway TS, Scarlett A, et al. Association of urinary bisphenol a concentration with medical disorders and laboratory abnormalities in adults. JAMA. 2008;300:1303–1310.
7. Branch F et al. Vaginal douching and racial/ethnic disparities in phthalates exposures among reproductive-aged women: National Health and Nutrition Examination Survey 2001–2004. Environ Health. 2015;14:57.
8. Ghorpade N, Mehta V, Khare M. Toxicity study of diethyl phthalate on freshwater fish Cirrhina mrigala. Ecotoxicol Environ Saf. 2002;53(2):255–258.
9. Swan SH. Environmental phthalate exposure in relation to reproductive outcomes and other health endpoints in humans. Environ Res. 2002;108(2):177–184.