BPA Linked to Diabetes

Cash register receipts are a major source of BPAMounting evidence continues to point to pollution's contribution to the obesity epidemic. In yet another study, the pollutant BPA has been identified as a cause of decreased glucose tolerance (ability to break down and eliminate sugar from the bloodstream) and the insulin resistance syndrome associated with diabetes and obesity. Previous studies have linked BPA to deleterious effects on the  brain, behavior and prostrate gland of fetuses, infants and children.

Despite the American Chemical Society's attempts to downplay rising concerns, this study in the National Institute of Health peer-reviewed journal, Environmental Health Perspectives, is yet another nail in the coffin for BPA, which the Centers for Disease control reports can be found in the bloodstream of most Americans and is commonly ingested by consuming foods that come in contact with plastic (either through plastic storage containers, wraps, bottles or cans lined with plastic) or by handling BPA-laden cash register receipts.Eden Organic offers BPA-free canned foods.

In this mouse study, environmentally relevant exposure to BPA (meaning the low level exposure experienced by the average person as opposed to the high level of exposure more commonly used in testing for pollutant's health effects) aggravated insulin resistance produced during pregnancy and was associated with decreased glucose tolerance and increased plasma insulin, triglyceride, and leptin concentrations relative to controls. The authors concluded: "Our findings suggest that BPA may contribute to metabolic disorders relevant to glucose homeostasis and that BPA may be a risk factor for diabetes."

The study was conducted at biomedical research universities in Spain, which may be one clue as to why it didn't make headlines in the U.S. Already, France and Denmark have placed restrictions on BPA in infant feeding bottles. The EU health Commissioner, John Dalli, recently indicated his agency may follow suit.  The Canadian government has added the compound to a list of substances deemed harmful to health, in preparation for further regulatory action. The FDA sends a mixed message: "FDA shares the perspective of the National Toxicology Program that recent studies provide reason for some concern about the potential effects of BPA on the brain, behavior, and prostate gland of fetuses, infants and children." But as yet the agency has failed to take action by recommending any restrictions on manufacturing and production of products that expose people to BPA, not even taking action against BPA-laden baby bottles.

Dr. Merrell's Take: Look for bottles and cans labelled BPA-free. Store food in glass containers. Do not allow saran wrap to touch hot foods (or any food if you can help it.) Keep cash register receipts out of food bags, and make sure to wash your hands after handling them. Finally, don't let your baby suck on plastic toys. 

Hand Washing: For Removing Bacteria, Paper Towels Beat Hand Dryers

Dyson and his Airblade hand dryer.This probably wasn't exactly the result the hand-dryer-making company, Dyson, was looking for when they funded this small study on hand washing. Anna Snelling of the University of Bradford, UK asked 14 volunteers to dry their hands for 15 seconds using either paper towels or three different typs of air dryer, sometimes rubbing their hands together and sometimes not. When volunteers kept their hands still (which is how the extremely loud Dyson dryers work) skin bacteria numbers dropped by roughly 37% compared to just after washing; however, paper towels knocked out the bacteria by half. That's because the towels actually scraped off the bacteria. In a partial victory for Dyson, when volunteers rubbed their hands together under a standard hand dryer, the bacteria count actually rose by 18%. So drying with a Dyson-type dryer was more sanitary than a standard hand-dryer, but paper towels won, hands down.

View the study.

Breast Cancer and Car Exhaust: New Study Finds Possible Link

Women living in the most polluted neighorhoods were twice as likely to develop breast cancer.This may be the news about breast cancer that we've all feared. A new study (ground breaking for its simple, smart design that uses maps of Montreal to correlate air quality and home addresses with the incidence of breast cancer) suggests pollution from traffic may put women at risk for developing post-menopausal breast cancer. The study, published in the prestigious journal of Environmental Health Perspectives, links the risk of breast cancer – the second leading cause of death from cancer in women – to traffic-related air pollution.

“We’ve been watching breast cancer rates go up for some time," says study co-author Dr. Mark Goldberg, a researcher at McGill University Health Center Research Institute. “Nobody really knows why, and only about one third of cases are attributable to known risk factors. Since no-one had studied the connection between air pollution and breast cancer using detailed air pollution maps, we decided to investigate it.”

Dr. Goldberg and his colleagues approached the problem by combining data from several studies. First, they used the results of their 2005-2006 study to create two air pollution “maps” showing levels of nitrogen dioxide (NO2), a by-product of vehicular traffic, in different parts of Montreal in 1996 and 10 years earlier in 1986.

Then, they charted the home addresses of women diagnosed with breast cancer in a 1996-97 study onto the air pollution maps. Their findings were startling. The incidence of breast cancer was clearly higher in areas with higher levels of air pollution. “We found a link between post-menopausal breast cancer and exposure to nitrogen dioxide (NO2), which is a ‘marker’ for traffic-related air pollution,” says Dr. Goldberg. “Across Montreal, levels of NO2 varied between 5 ppb to over 30 ppb.

We found that risk increased by about 25 per cent with every increase of NO2 of five parts per billion. Another way of saying this is that women living in the areas with the highest levels of pollution were almost twice as likely to develop breast cancer as those living in the least polluted areas.”

These disturbing results must be interpreted with great caution, warns Dr. Goldberg. “First of all, this doesn’t mean NO2 causes breast cancer,” he explains. “This gas is not the only pollutant created by cars and trucks, but where it is present, so are the other gases, particles and compounds we associate with traffic – some of which are known carcinogens. NO2 is only a marker, not the actual carcinogenic agent.”

A study of this kind can be subject to unknown errors. While the researchers tried to account as much as possible for them, areas of uncertainty remain. “For example, we don’t know how much the women in the study were exposed to pollution while at home or at work, because that would depend on their daily patterns of activity, how much time they spend outdoors and so on,” says Dr. Goldberg.

Dr. Labrèche adds “Some studies published in the US have also shown possible links between cancer and air pollution. At the moment, we are not in a position to say with assurance that air pollution causes breast cancer. However, we can say that the possible link merits serious investigation. From a public health standpoint, this possible link also argues for actions aimed at reducing traffic-related air pollution in residential areas.”

Read about the study.

Common Environmental Toxin Linked to Obesity, Study Finds

One-quarter of babies born to women with high blood levels of a breakdown product of DDT--a persistent, ubiquitous enivronmental toxin--grew unusually fast for at least the first year of life. Such rapid growth in early infancy has put children on track to become obese. The babies' birthweights were normal, and the mothers were also normal weight, suggesting the toxins' presence triggers a hormonal cascade that accelerates growth and weight gain. 

Increasingly, data suggests that some pollutants — known colloquially as obesogens — can trigger the body to put on the pounds. In animals, these pollutants will sometimes lead a mouse to become rotund despite eating no more and exercising no less than its lean cousins.

Many obesogens — including DDE, the DDT breakdown product — have a hormonal alter ego. In the body, DDE can either turn on or block the activity of natural estrogens, female sex hormones. This pollutant also can block the activity of male sex hormones. Such properties lead scientists to describe this pesticide derivative as an endocrine disrupter. Click here to read about the study in ScienceNews.

Air Pollution and Brain Inflammation

Car exhaust and other forms of big-city pollution seem to lower IQ.Like most scientific tales, this one is partly a detective thriller. Mexico City-based pediatric neurologist, Lillian Calderon-Garciduenas, had a hunch that the megacity's notorious pollution was harming children. She was worried about widespread evidence of childhood lung and heart disease. Perhaps most troubling: something seemed to be ravaging their minds. For children enrolled in her studies, Calderon-Garciduenas was documenting cognitive impairments in memory, problem solving and judgment, and deficiencies in their sense of smell compared with age-matched children from a cleaner city 120 kilometers away. In a move Sherlock Holmes would appreciate, Calderon-Garciduenas conducted autposies of seemingly healthy Mexico City children who had died in auto accidents or from other traumatic events, and she found widespread evidence of deposits of proteins that serve as hallmarks of Alzheimer's and Parkinson's diseases.

Dr. Merrell's Tip: People living in urban environments can help their bodies process pollutants by eating a diet rich in antioxidants and anti-inflammatory substances (found in fruits, vegetablesc, fish and olive oils, dark chocolate and green tea.) Also, reduce exposure to airborne pollutants by using HEPA air filters in the bedroom (which only work when windows are kept closed.) 

Fast-forward through several years of global scientific research, and a picture begins to emerge of pollutions' effects on the brain. Increasingly, studies point to inflammation-provoking nanopollutants as a potential source of nerve cell damage. In studies of Boston 10-year-olds, researchers have found those living in areas with the highest average airborne concentrations of soot, a pollutant primarily associated with traffic, had lower IQs and lower scores on memory tests--comparable to IQ point drops identified in kids whose mothers had smoked during pregnancy.

The nose is crucial to understanding the problem. Research has identified the nasal passage as a front door that allows micro-particles of pollution to march into the brain. If the nasal tissues are inflammed, say, from allergies or sinusitis, the uptake of soot may be maginfiied.

There are mitigating factors. Not all pollution is equal. Mexico City air contains the metal manganese, which has been shown to migrate into the brain through the nose with unusual ease. And manganese is perhaps one of the most neuro-toxic metals. Genetic pre-disposition also play a roll. Calderon-Garciduenas has found that children with a particular gene variant (known as APOE-4) that predisposes them to Alzheimer's exhibit the most inflammation.

There are potential solutions. Short of moving and hoping for governments to clean up the air, the best bet is to eat an anti-inflammatory diet, rich in brightly colored fruits and vegetables and augmented with omega-3 fatty acids and specific anti-inflammatory foods like green tea, dark chocolate and the spice turmeric, which has been shown specifically to reduce the formation of amyloid-beta plaque. Calderon-Garciduenas has recently been feeding dark chocolate rich in polyphenols, a class of natural antioxidants, to inflammation-ravaged lab-mice. She has not published her study yet, but word is her prelimanary data shows great promise.

For a more detailed look at Calderon-Garciduenas research, see Destination Brain, ScienceNews, May 22.