Environmental Factor, December 2011, National Institute of Environmental Health Sciences
Extramural papers of the month
By Nancy Lamontagne
- Chimneys help reduce severe childhood pneumonia
- Aggressive breast cancer responds to blueberries
- Mycoestrogens influence development
- The impact of nutrition labeling
Chimneys help reduce severe childhood pneumonia
An NIEHS grantee, working with rural communities in Guatemala, found that rates of severe childhood pneumonia were reduced by 30 percent in households using cooking stoves with chimneys rather than open, indoor wood cooking fires. The findings suggest that interventions that lower exposure to wood smoke may help reduce childhood deaths from pneumonia in areas of the world where indoor open fires are commonly used.
The results come from the NIH Randomised Exposure Study of Pollution Indoors and Respiratory Effects (RESPIRE) trial, which included 534 rural Guatemala households with a pregnant woman or young infant. The households were randomly assigned to receive a locally developed chimney stove or to act as a control by using open wood fires. In addition to the reduction in severe pneumonia, the researchers found that carbon monoxide exposure levels in the homes equipped with chimneys were, on average, half that of the households with the open fires. The stoves with chimneys did not significantly reduce the total number of diagnosed childhood pneumonia cases, but the reduction in severe pneumonia could likely reduce childhood mortality.
Citation: Smith KR, McCracken JP, Weber MW, Hubbard A, Jenny A, Thompson LM, Balmes J, Diaz A, Arana B, Bruce N(http://www.ncbi.nlm.nih.gov/pubmed/22078686) . 2011. Effect of reduction in household air pollution on childhood pneumonia in Guatemala (RESPIRE): a randomised controlled trial. Lancet 378(9804):1717-1726.
Aggressive breast cancer responds to blueberries
NIEHS grantees report that blueberry consumption lessened the growth and spread of triple negative breast cancer cells in mice. Very few drugs are effective against this aggressive form of breast cancer, which does not express the estrogen receptor, progesterone receptor, or human epidermal growth factor receptor 2 (HER2) protein.
The researchers experimented with mice that were injected with triple negative breast cancer cells. Compared to control mice receiving no blueberry powder, those receiving a diet that included five percent freeze-dried whole blueberry powder had a tumor size 75 percent smaller. Tumor size was 60 percent smaller if the mice received ten percent blueberry powder. Molecular analysis showed that the blueberry consumption altered expression of genes tied to inflammation, cancer, and metastasis in ways that would lower cancer risk. In another experiment, the researchers found a significant decrease in metastasis in mice that consumed a diet including five percent blueberry powder, compared to those that did not consume blueberry.
Although more research is needed to confirm the effect in humans, the amount of blueberry powder used in the experiments could be reasonably consumed. The five percent blueberry powder is equivalent to about two cups of blueberries a day. The researchers are planning clinical trials using whole blueberry powder to determine a suitable human dose.
Citation: Adams LS, Kanaya N, Phung S, Liu Z, Chen S(http://www.ncbi.nlm.nih.gov/pubmed/21880954) . 2011. Whole blueberry powder modulates the growth and metastasis of MDA-MB-231 triple negative breast tumors in nude mice. J Nutr 141(10):1805-1812.
Mycoestrogens influence development
Exposure to mycoestrogens appears to affect the body size and breast development of girls, according to a study from NIEHS-supported researchers. This could have implications for future breast cancer risk.
The researchers looked at zearalenone and zeranol mycoestrogens, which are commonly found in the food supply. Zearalenone is a fungal product that can be found in grains and plant foods consumed by livestock or humans, and zeranol is sometimes used to enhance meat production. They studied 163 healthy girls (ages 9 and 10) participating in the Jersey Girl Study, which is examining factors affecting the onset of puberty in girls.
The mycoestrogens were detected in the urine of 78 percent of the participants, and girls tended to be shorter and less likely to have reached the onset of breast development if urinary mycoestrogens were detected. Preliminary analysis associated intake of beef and popcorn with urinary mycoestrogens. The results point to the need for more research to fully understand the effects of mycoestrogens on development.
Citation: Bandera EV, Chandran U, Buckley B, Lin Y, Isukapalli S, Marshall I, King M, Zarbl H(http://www.ncbi.nlm.nih.gov/pubmed/21975003) . 2011. Urinary mycoestrogens, body size and breast development in New Jersey girls. Sci Total Environ 409(24):5221-5227.
The impact of nutrition labeling
Researchers supported by NIEHS report that nutrition labeling on fast-food restaurant menus increased parent awareness of calories, but did not decrease the calories actually purchased for parents or children. Chain restaurants will be required to post nutritional information at point-of-purchase as part of national health reform, but few studies have examined how these regulations will affect children.
The researchers recruited participants from the Neighborhood Impact on Kids study. They compared restaurant receipts for 75 children (ages 6 to 11) and their parents, before and after menu-labeling regulation in Seattle/King County, Wash., with receipts from 58 children and parents in San Diego County, Calif., where the regulation was not implemented.
In Seattle/King County, the percentage of parents seeing the nutritional information increased from 44 percent prior to regulation to 87 percent after menu labels were added, but the average calories purchased for children did not change after regulation in either county. Although there was an approximate 100-calorie decrease in food purchased for the parents post-regulation, there was no significant difference between the counties.
Citation: Tandon PS, Zhou C, Chan NL, Lozano P, Couch SC, Glanz K, Krieger J, Saelens BE(http://www.ncbi.nlm.nih.gov/pubmed/21961472) . 2011. The impact of menu labeling on fast-food purchases for children and parents. Am J Prev Med 41(4):434-438.
(Nancy Lamontagne is a science writer with MDB, Inc., a contractor for the NIEHS Division of Extramural Research and Training, Superfund Research Program, and Worker Education and Training Program.)