Last evening, I cited research indicating that people may acquire much of their daily exposure to brominated flame retardants—ubiquitous and potentially toxic chemicals used to render many plastics, fabrics, and other materials resistant to burning—from the air in our homes. Well, today's post points out that wildlife also accumulate these chemicals, byproducts of humanity's love affair with plastics and foam-based goods.
The new paper, published Tuesday online—and slated to appear soon in a print edition of Environmental Science & Technology, reports Canadian research on fetal exposures to herring gulls (Larus argentatus) living around each of the Great Lakes. Not only did eggs of the birds contain anywhere from around 185 to 400 parts per billion (ppb) of polybrominated diphenyl ethers (PBDEs), but they also carried low-ppb concentrations of other types of brominated flame retardants as well.
Many of these are agents that manufacturers have been turning to now that two of the three major classes of PBDEs have been phased out in the United States and Europe. These replacements for PBDEs include chemicals with long, intimidating names, such as hexabromobenzene, pentabromoethylbenzene, and hexabromocyclododecane.
Lewis T. Gauthier of Environment Canada in Ottawa and his colleagues argue that since mother gulls are depositing these chemicals into their eggs, these newer non-PBDE flame retardants must taint the birds' freshwater prey.
What makes the findings potentially troubling: Almost no toxicity data exist for these non-PBDE flame retardants, despite the fact that they are starting to show up in measurable amounts in wildlife.
Friday, May 25, 2007
Thursday, May 24, 2007
Flame Retardant Air?
A fairly ubiquitous class of flame retardants—chemicals used to keep products from readily burning—have been showing up in the environment, in animals, and in ourselves. Studies are just beginning to tease out the potential toxicity of one of the more prominent classes of these agents: They're PBDEs, an acronym which stands for a chemical mouthful—polybrominated diphenyl ethers. A new study now reports data suggesting that roughly one-fifth of the exposure of urban residents may come from the air in their homes.
Isn't that a pleasant thought.
Joseph G. Allen of the Boston University School of Public Health and his coworkers installed air-sampling devices in the bedrooms and main living rooms for each of 20 local volunteers. The devices ran for a week whenever the individuals were at home. The researchers also fitted each recruit with a personal air sampler that traveled with him or her around the home. Its intake was clipped to the recruits' shirt collars so that it would sniff the air at roughly nose level. At bedtime, the personal air sniffer was placed at bed height in the bedroom.
What's rather disturbing: The personal air sniffers picked up significantly more PBDEs than did devices just randomly sampling room air. For instance, the average concentration of these chemicals sniffed in the vicinity of the volunteers' heads was ~765 picograms per cubic meter in air—some 300 pg/m³ higher than in bedroom- or living-room air. The findings appear in a paper published online today and due to appear in print soon in Environmental Science & Technology.
The good news: Measured concentrations were low. However, these pollutants are remarkably persistent, meaning they don't readily degrade. So, there's a distinct possibility that exposures could accumulate, leading to a slow buildup of some of these compounds. What there is no question about is that these compounds do make it into our bodies in measurable quantities. Four years ago, university scientists in this country reported that human exposures begin in the womb and is augmented by breastmilk. That's troubling because studies have suggested that at least of few of these PBDEs can trigger subtle toxicity.
Presumably, the relatively high personal readings reflect individuals spending time in close proximity to household items treated with PBDEs. These might include sofas, mattresses, computer cases, electronics, or any of many other products. However, in this study, Allen's team was unable to correlate air readings with the presence of particular products in the tested homes.
Concern over the potential health effects of these agents led to a U.S. phase-out in the production and sale of two of the three common classes of them. The voluntary move by the manufacturers came after discussions with—and presumably more than a little pressure by—the Environmental Protection Agency. At the time, Europe had already instituted a ban on these chemicals. Together, these two classes comprise nearly 200 different PBDEs, although a few particular ones dominate each mix.
The third class, represented primarily by the deca-brominated PBDE, which is known as PBDE-209, remains in commercial use throughout the United States. In the new study, offgassing vapors of all three PBDE classes were detected in indoor air and by the personal-air sniffers (although concentrations of the deca-PBDE were second highest, on average, of the 12 individual PBDEs assayed).
What's the health significance of the new findings? No one knows. However, one recent study reported that fat cells exposed to brominated flame retardants undergo changes that would appear to foster obesity and type 2 diabetes. Another study showed that sunlight can break down some of these flame retardants into unusual members of the dioxin family. And European scientists, working with lab animals, linked PBDE exposures to reproductive and brain problems.
And what the new study reinforces is that our homes are not necessarily havens from these pollutants.
Isn't that a pleasant thought.
Joseph G. Allen of the Boston University School of Public Health and his coworkers installed air-sampling devices in the bedrooms and main living rooms for each of 20 local volunteers. The devices ran for a week whenever the individuals were at home. The researchers also fitted each recruit with a personal air sampler that traveled with him or her around the home. Its intake was clipped to the recruits' shirt collars so that it would sniff the air at roughly nose level. At bedtime, the personal air sniffer was placed at bed height in the bedroom.
What's rather disturbing: The personal air sniffers picked up significantly more PBDEs than did devices just randomly sampling room air. For instance, the average concentration of these chemicals sniffed in the vicinity of the volunteers' heads was ~765 picograms per cubic meter in air—some 300 pg/m³ higher than in bedroom- or living-room air. The findings appear in a paper published online today and due to appear in print soon in Environmental Science & Technology.
The good news: Measured concentrations were low. However, these pollutants are remarkably persistent, meaning they don't readily degrade. So, there's a distinct possibility that exposures could accumulate, leading to a slow buildup of some of these compounds. What there is no question about is that these compounds do make it into our bodies in measurable quantities. Four years ago, university scientists in this country reported that human exposures begin in the womb and is augmented by breastmilk. That's troubling because studies have suggested that at least of few of these PBDEs can trigger subtle toxicity.
Presumably, the relatively high personal readings reflect individuals spending time in close proximity to household items treated with PBDEs. These might include sofas, mattresses, computer cases, electronics, or any of many other products. However, in this study, Allen's team was unable to correlate air readings with the presence of particular products in the tested homes.
Concern over the potential health effects of these agents led to a U.S. phase-out in the production and sale of two of the three common classes of them. The voluntary move by the manufacturers came after discussions with—and presumably more than a little pressure by—the Environmental Protection Agency. At the time, Europe had already instituted a ban on these chemicals. Together, these two classes comprise nearly 200 different PBDEs, although a few particular ones dominate each mix.
The third class, represented primarily by the deca-brominated PBDE, which is known as PBDE-209, remains in commercial use throughout the United States. In the new study, offgassing vapors of all three PBDE classes were detected in indoor air and by the personal-air sniffers (although concentrations of the deca-PBDE were second highest, on average, of the 12 individual PBDEs assayed).
What's the health significance of the new findings? No one knows. However, one recent study reported that fat cells exposed to brominated flame retardants undergo changes that would appear to foster obesity and type 2 diabetes. Another study showed that sunlight can break down some of these flame retardants into unusual members of the dioxin family. And European scientists, working with lab animals, linked PBDE exposures to reproductive and brain problems.
And what the new study reinforces is that our homes are not necessarily havens from these pollutants.
Recycling Charitably
Charitopia. I guess what the Stanford University researchers had in mind when they named their website was some vision of a utopia for charitable giving. It's actually a site that matches up individuals having things to donate—from an unopened box of pencils to a car—with charities that can use them. There's no charge for the matchmaking service, either to donors or recipients. The site's developers also promise no advertising or spam.
A news release that went out to reporters, today, recommends the site for students finishing their school year and at wits end what to do with that chair, TV, and bookcase—items that worked well in the dorm but won't fit in the car to go home. Now, instead of pitching unwanted goods on the street, they can be matched up with hospitals, homeless shelters, or schools.
According to Michael Genesereth and Michael Kassoff, the scientists who designed the program, the site's matching abilities depend on the application of a branch of computer science that endows those number crunchers with reasoning skills. Both donors and would-be recipients identify what they have or want, based on descriptions of the goods in terms that both people and computers can understand. Then, the computer applies logical rules to pair up donors and charities. Donors can even select the type of charity they do or don't want to receive their items.
The project receives no outside funding beyond the Stanford computer-science department, and legal services for the site have been "secured" pro bono by Genesereth, who is research director of Stanford's Center for Computers and Law.
I tried contacting the Charitopia people earlier today to find out if their project has a national reach yet, or just works with parties in California. I've yet to hear back, and the website doesn't offer a clue.
Clearly, even though the site went live in March, the project is a work in progress. Today's news release notes that the Stanford team has hired a summer intern to manually update and increase the classifications for goods that can be listed with the site.
It certainly seems like a good idea. As the parent of a college student, I know how much stuff these young adults acquire over the course of 8 to 9 months—far more than our car can retrieve. Which is why I want to know: Is this service available in Pittsburgh yet?
A news release that went out to reporters, today, recommends the site for students finishing their school year and at wits end what to do with that chair, TV, and bookcase—items that worked well in the dorm but won't fit in the car to go home. Now, instead of pitching unwanted goods on the street, they can be matched up with hospitals, homeless shelters, or schools.
According to Michael Genesereth and Michael Kassoff, the scientists who designed the program, the site's matching abilities depend on the application of a branch of computer science that endows those number crunchers with reasoning skills. Both donors and would-be recipients identify what they have or want, based on descriptions of the goods in terms that both people and computers can understand. Then, the computer applies logical rules to pair up donors and charities. Donors can even select the type of charity they do or don't want to receive their items.
The project receives no outside funding beyond the Stanford computer-science department, and legal services for the site have been "secured" pro bono by Genesereth, who is research director of Stanford's Center for Computers and Law.
I tried contacting the Charitopia people earlier today to find out if their project has a national reach yet, or just works with parties in California. I've yet to hear back, and the website doesn't offer a clue.
Clearly, even though the site went live in March, the project is a work in progress. Today's news release notes that the Stanford team has hired a summer intern to manually update and increase the classifications for goods that can be listed with the site.
It certainly seems like a good idea. As the parent of a college student, I know how much stuff these young adults acquire over the course of 8 to 9 months—far more than our car can retrieve. Which is why I want to know: Is this service available in Pittsburgh yet?
Monday, May 21, 2007
A Less Fattening Fat?
Few people have trouble losing weight—especially over the short run. The problem is keeping the shed pounds from returning. A new study suggests that substituting 5 grams per day of gamma-linolenic acid (GLA), an essential fatty acid, for an equivalent amount of olive oil can limit how many pounds are regained in the first years following a major paring down of weight.
Marie A. Schirmer and Stephen D. Phinney of the University of California, Davis, recruited 50 formerly obese people to take part in a year-long, double-blind trial. That means that neither the researchers nor the participants knew which half of the volunteers were receiving olive oil capsules and which were getting capsules of GLA-rich borage oil. The recruits were also encouraged to log food intake and exercise daily.
Periodically, the researchers weighed each volunteer, calculated his or her body's lean-to-fat ratio, and looked at how the supplemented fat was distributing itself into body fat.
In the May Journal of Nutrition, the nutrition scientists report that men and women randomly assigned to receive the GLA gained, on average, 2.17 kilograms (4.8 lbs), during the first year on the supplements. Those who had instead been taking the olive oil capsules gained more—8.78 kg (more than 19 lbs.).
The researchers then selected 12 subjects in each group to continue on for another year and 9 months. In this case, all openly received the GLA capsules. At the end of this phase, each group had gained back even a little more weight, although now at the same rate. The researchers conclude that GLA, a polyunsaturated fat, may help people limit the speed and overall amount of weight regained by formerly obese individuals.
Marie A. Schirmer and Stephen D. Phinney of the University of California, Davis, recruited 50 formerly obese people to take part in a year-long, double-blind trial. That means that neither the researchers nor the participants knew which half of the volunteers were receiving olive oil capsules and which were getting capsules of GLA-rich borage oil. The recruits were also encouraged to log food intake and exercise daily.
Periodically, the researchers weighed each volunteer, calculated his or her body's lean-to-fat ratio, and looked at how the supplemented fat was distributing itself into body fat.
In the May Journal of Nutrition, the nutrition scientists report that men and women randomly assigned to receive the GLA gained, on average, 2.17 kilograms (4.8 lbs), during the first year on the supplements. Those who had instead been taking the olive oil capsules gained more—8.78 kg (more than 19 lbs.).
The researchers then selected 12 subjects in each group to continue on for another year and 9 months. In this case, all openly received the GLA capsules. At the end of this phase, each group had gained back even a little more weight, although now at the same rate. The researchers conclude that GLA, a polyunsaturated fat, may help people limit the speed and overall amount of weight regained by formerly obese individuals.
Protein Helps Curb Hunger
All things being equal, diets higher in protein are better at holding hunger at bay than meals richer in fat or carbs. That's the finding of a set of prolonged feeding trials run by scientists at Purdue University.
John W. Apolzan and his coworkers advertised for volunteers in the local newspapers and ended up enrolling 12 men between the ages of 21 and 43 and another 10 between the ages of 63 and 79. After calculating how many calories it would take for each man to maintain his current weight, the researchers tailored diets to deliver just that much energy to each man over the course of three 18-day cycles. All foods except for water were supplied the participants, and any uneaten food was returned and weighed.
The recommended intake of protein is 0.8 gram per kilogram of bodyweight—or about 2 ounces for a 155 pound man. In one cycle, each man got slightly more than that: 1 g of protein per kilogram of bodyweight per day. In the other cycles, he got 0.5 or 0.75 g/kg day. The ordering of these 18-day dietary cycles were randomly assigned to each participant. At the end of each cycle, the scientists administered hourly questionaires throughout the waking hours of one day to assess hunger and desire to eat in each of the volunteers.
In the May Journal of Nutrition, Apolzan's group reports that the men reported being 20 percent less hungry after the highest protein diet phase than after either of the others. Similarly, each man's desire to eat was, on average, almost 30 percent greater on the mid-level protein diet and 50 percent greater on the low-protein diet than when the volunteers got the high-protein fare.
It now appears that for those of us wishing to curb the siren call of calories, eating too little protein—as 15 to 40 percent of older Americans do—might foster overeating.
John W. Apolzan and his coworkers advertised for volunteers in the local newspapers and ended up enrolling 12 men between the ages of 21 and 43 and another 10 between the ages of 63 and 79. After calculating how many calories it would take for each man to maintain his current weight, the researchers tailored diets to deliver just that much energy to each man over the course of three 18-day cycles. All foods except for water were supplied the participants, and any uneaten food was returned and weighed.
The recommended intake of protein is 0.8 gram per kilogram of bodyweight—or about 2 ounces for a 155 pound man. In one cycle, each man got slightly more than that: 1 g of protein per kilogram of bodyweight per day. In the other cycles, he got 0.5 or 0.75 g/kg day. The ordering of these 18-day dietary cycles were randomly assigned to each participant. At the end of each cycle, the scientists administered hourly questionaires throughout the waking hours of one day to assess hunger and desire to eat in each of the volunteers.
In the May Journal of Nutrition, Apolzan's group reports that the men reported being 20 percent less hungry after the highest protein diet phase than after either of the others. Similarly, each man's desire to eat was, on average, almost 30 percent greater on the mid-level protein diet and 50 percent greater on the low-protein diet than when the volunteers got the high-protein fare.
It now appears that for those of us wishing to curb the siren call of calories, eating too little protein—as 15 to 40 percent of older Americans do—might foster overeating.
Not Enough Time to Cook
There has been the expectation that as income falls, the amount of time a family spends cooking will climb--in part to economize but also because less time employed outside the home leaves individuals more time to cook. However, contrary to patterns seen in the past, it now appears that low-income U.S. families spend very little time preparing meals.
Indeed, a study issued this week reports that low-income families don't allocate nearly as much time to food preparation as would be necessary to implement the Thrifty Food Plan, an Agriculture Department program which shows Food Stamp recipients how to prepare nutritious meals using low-cost foods available under the Food Stamp program.
Preparing meals from scratch that comply with recommendations of the Thrifty Food Plan take an estimated 80 to 130 minutes, on average, per day. In fact, the new study finds, low-income families where all adults work full-time typically reserve only 40 minutes per day for meal preparation.
Studies by the boatload have shown that people tend to down healthier fare when they eat at home. Moreover, meals cooked from scratch tend to have more nutrients, fewer preservatives, less salt, less sugar, and less fat than foods that have been commercially processed.
In their new report, "Who Has Time to Cook?", Lisa Mancino and Constance Newman of the Agriculture Department's Economic Research Service sifted through data collected by the Bureau of Labor Statistics and Census Bureau on how individuals use their time throughout the day. For this analysis, they focused, of course, on time spent cooking.
As might be expected, women who don't work outside the home--people who in the past might have been termed housewives--spent the most time in the kitchen. On average, they devoted slightly more than 70 minutes a day preparing meals. Women who worked part-time outside the home averaged about 55 minutes a day fixing meals, and full-time working women spent a mere 38 to 46 minutes a day cooking.
Single women found less incentive to cook. On average, those that worked spent 15 fewer minutes per day cooking than those who were married or lived with partners. Perhaps surprisingly, single non-working women spent a half-hour less cooking food per day than those who were married or otherwise partnered.
What about men? Fuhgeddaboudit, as my New York relatives would say. Regardless of income level, those with full- or part-time jobs spent 13 to 17 minutes a day cooking; those who were unemployed spent a mere half-hour or less, on average.
The bottom line, Mancino and Newman say, is that the Thrifty Food Plan doesn't account for how little time people now find available for meal preparation. To offer useful guidance, this Plan will need significant a retooling, they argue, finding recipes for alternatives that can be whipped up in far less time.
As a woman who typically spends 11 to 14 hours outside the home at work and in commuting, I can attest that even when the larder is well-stocked, I have little enthusiasm for spending an hour or more preparing dinner. Except on weekends, even breakfast is prepared on the fly.
Indeed, I'm convinced that too little time and motivation to cook has become one major fallout of our overextended workforce. A correllary, those of us who don't have the energy to cook are also unlikely to possess the energy to exercise in what little free time they can find.
It's not even that we're all doing this just to chase the almight buck. Many jobs require long hours--and exist great distances from where the workforce is likely to live. When will society decide to value quality of life? Once we're all fat and sick? Oops...we're already there, aren't we?
Indeed, a study issued this week reports that low-income families don't allocate nearly as much time to food preparation as would be necessary to implement the Thrifty Food Plan, an Agriculture Department program which shows Food Stamp recipients how to prepare nutritious meals using low-cost foods available under the Food Stamp program.
Preparing meals from scratch that comply with recommendations of the Thrifty Food Plan take an estimated 80 to 130 minutes, on average, per day. In fact, the new study finds, low-income families where all adults work full-time typically reserve only 40 minutes per day for meal preparation.
Studies by the boatload have shown that people tend to down healthier fare when they eat at home. Moreover, meals cooked from scratch tend to have more nutrients, fewer preservatives, less salt, less sugar, and less fat than foods that have been commercially processed.
In their new report, "Who Has Time to Cook?", Lisa Mancino and Constance Newman of the Agriculture Department's Economic Research Service sifted through data collected by the Bureau of Labor Statistics and Census Bureau on how individuals use their time throughout the day. For this analysis, they focused, of course, on time spent cooking.
As might be expected, women who don't work outside the home--people who in the past might have been termed housewives--spent the most time in the kitchen. On average, they devoted slightly more than 70 minutes a day preparing meals. Women who worked part-time outside the home averaged about 55 minutes a day fixing meals, and full-time working women spent a mere 38 to 46 minutes a day cooking.
Single women found less incentive to cook. On average, those that worked spent 15 fewer minutes per day cooking than those who were married or lived with partners. Perhaps surprisingly, single non-working women spent a half-hour less cooking food per day than those who were married or otherwise partnered.
What about men? Fuhgeddaboudit, as my New York relatives would say. Regardless of income level, those with full- or part-time jobs spent 13 to 17 minutes a day cooking; those who were unemployed spent a mere half-hour or less, on average.
The bottom line, Mancino and Newman say, is that the Thrifty Food Plan doesn't account for how little time people now find available for meal preparation. To offer useful guidance, this Plan will need significant a retooling, they argue, finding recipes for alternatives that can be whipped up in far less time.
As a woman who typically spends 11 to 14 hours outside the home at work and in commuting, I can attest that even when the larder is well-stocked, I have little enthusiasm for spending an hour or more preparing dinner. Except on weekends, even breakfast is prepared on the fly.
Indeed, I'm convinced that too little time and motivation to cook has become one major fallout of our overextended workforce. A correllary, those of us who don't have the energy to cook are also unlikely to possess the energy to exercise in what little free time they can find.
It's not even that we're all doing this just to chase the almight buck. Many jobs require long hours--and exist great distances from where the workforce is likely to live. When will society decide to value quality of life? Once we're all fat and sick? Oops...we're already there, aren't we?
Sunday, May 20, 2007
Killer Stats II
Last Friday, I reported on lethal trends, mostly in disease, affecting people around the globe. Tonight, I ran across a paper with an interesting chart that compares all causes of mortality in Americans. Heart diseases ranked first, accounting for 27 percent of U.S. deaths. Number 2: cancer, at 23 percent.
Those chart toppers probably come as little surprise. What may raise an eyebrow or two: chronic lower respiratory diseases (#4 on the list) kill 6% of people each year, and accidents (#5) kill nearly 5% more. The next two most frequent causes of death: diabetes at 3% and Alzheimer's at 2.8%. Murder, #15 on the list, accounts for 17,360 deaths, or 0.7 percent, a value just slightly behind the 18,000 lives lost to Parkinson disease. The latter is especially troubling because there is little information on what causes most cases of Parkinson disease--and still no cure.
Source: Jemal, A., et al. 2007. Cancer Statistics, 2007. CA: A Cancer Journal for Clinicians 57(January/February):43.
Those chart toppers probably come as little surprise. What may raise an eyebrow or two: chronic lower respiratory diseases (#4 on the list) kill 6% of people each year, and accidents (#5) kill nearly 5% more. The next two most frequent causes of death: diabetes at 3% and Alzheimer's at 2.8%. Murder, #15 on the list, accounts for 17,360 deaths, or 0.7 percent, a value just slightly behind the 18,000 lives lost to Parkinson disease. The latter is especially troubling because there is little information on what causes most cases of Parkinson disease--and still no cure.
Source: Jemal, A., et al. 2007. Cancer Statistics, 2007. CA: A Cancer Journal for Clinicians 57(January/February):43.
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