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Thursday
Nov202014

Trees Could Save Your Life

Did you know trees help rid the atmosphere of contaminants and reduce air pollution? The effect isn’t great – trees only remove about one percent of airborne pollution – but a new study from the U.S. Forest Service concluded that trees in the U.S. save more than 850 lives a year by performing this important function. They estimate the reduction in pollution prevents 670,000 occurrences of acute respiratory symptoms, adding up to an impact on human health valued at nearly $7 billion. The investigation showed that while pollution removal by trees is higher in rural areas, the impact on human health is greater in urban centers where more than 80 percent of us live. The study looked at four pollutants for which the U.S. Environmental Protection Agency has established air quality standards: nitrogen dioxide, ozone, sulfur dioxcide and particulate matter less than 2.5 microns in aerodynamic diameter. Pollution related to particulate matter was linked to 130,000 deaths, while deaths related to ozone totaled 4,700 in 2005, the study found. In addition to being a primary environmental concern, air pollution is linked to a number of negative effects on health, including increased risks of pulmonary, cardiac, vascular and neurological diseases.

Sources:
David Nowak et al, “Tree and Forest Effects on Air Quality and Human Health in the United States," Environmental Pollution, doi: 10.1016/j.envpol.2014.05.028

Tuesday
Nov182014

Breast Cancer Drug May Work Best in the Dark

New research suggests that exposure to light at night may undermine treatment with Tamoxifen, a drug often prescribed to breast cancer patients after surgery to prevent recurrence of the disease. This finding came from a study with rats that demonstrated inadequate amounts of melatonin render breast cancer tumors resistant to the effects of Tamoxifen. The researchers noted that the same mechanism might be of concern in humans, and pointed out that even dim light in the bedroom can suppress production of melatonin, a hormone that influences sleep-wake cycles. The investigators didn’t pinpoint how much light may cause this effect, but suggested it could be as little as the amount that comes in a bedroom window from a street light. When they gave the rats a melatonin supplement, the animals’ tumors no longer resisted the effects of Tamoxifen. The researchers didn’t recommend that breast cancer patients take melatonin supplements, however, and raised the issue that taking the supplements at the wrong time of day could disrupt the natural cycle of melatonin production. It is darkness, not sleep, that triggers melatonin production. Sleeping in a dark room allows melatonin levels to rise normally, whether or not you’re taking Tamoxifen.

Sources:
Steven M. Hill et al, “Circadian and Melatonin Disruption by Exposure to Light at Night Drives Intrinsic Resistance to Tamoxifen Therapy in Breast Cancer,” Cancer Research, doi:10.1158/0008-5472.CAN-13-3156

Monday
Nov172014

Menopause and Caffeine

First the bad news: women who suffer from hot flashes may be making their symptoms worse if they drink coffee or other caffeinated beverages. The Mayo Clinic recently conducted the most comprehensive study ever to investigate the relationship between caffeine and menopausal symptoms. A total of 2,507 women seen at the Mayo Women’s Health Clinic in Rochester, Minn., participated. The women responded to a health questionnaire devised by the journal Menopause, which published the study online on July 21, 2014. Past studies have reached conflicting conclusions regarding a link between caffeine intake and hot flashes. The good news is that this same study showed that caffeine consumption by perimenopausal women was linked to fewer problems with mood, memory and concentration. While the study’s conclusions were described by its authors as “preliminary,” Stephanie Faubion, M.D., director of Mayo’s Women’s Health Clinic, noted that the results do suggest that limiting caffeine intake may be prudent for women suffering from hot flashes and night sweats.

My take? Hot flashes can make a woman’s life miserable as she enters menopause, but luckily in most cases, the symptoms resolve on their own, usually within six months to a year. For those considering alternative approaches, black cohosh is an effective option and has been well studied, but unfortunately doesn’t work for all women. Dietary measures I recommend include two helpings daily of whole soy foods such as tofu, tempeh, edamame (green soy beans in the pod) and miso, which may help because these foods contain plant-based estrogens. Women can also try the supplements dong quai, vitamin E and evening primrose oil but, like black cohosh, they don't work for everyone. The most reliable treatment is estrogen replacement, which may be worth considering on a short-term basis, at the lowest effective dose, if nothing else helps.

Thursday
Nov132014

How to Get More Good Brown Fat

Unlike white fat cells that store calories for energy and expand as we gain weight, brown fat cells burn calories and generate heat to maintain body temperature. The trouble is, we don’t have many of them. If we had more of these metabolically active cells, we might be slimmer and healthier. A newly published study suggests that sleeping in a chilly room might boost our individual supplies of brown fat. This strategy worked in five healthy young men who agreed to sleep in climate-controlled chambers at the National Institutes of Health (NIH) for four months. By day, the men went about their normal lives and reported to NIH at 8 p.m. During the first month, bedroom temperatures were set at 75 degrees; the next month the thermostats were turned down to 66 degrees, which the researchers suspected could lead to a gain in brown fat. It worked: the volume of brown fat in the men’s bodies almost doubled. The bedroom temperatures were reset at 75 degrees for the third month and to 81 degrees for the fourth month in order to bring the men’s brown fat levels back to where they had been at the study’s start. Over time, tinkering with bedroom temperature could boost your brown fat stores, which might help lower your risk of diabetes and other metabolic problems and burn some extra calories, according to senior study author Francesco S. Celi. In this particular study, the temporary change was not enough to affect the weight of the men during the four weeks they slept in chilly room.

Sources:
Francesco S. Celi et al “Temperature-acclimated brown adipose tissue modulates insulin sensitivity in humans.” Diabetes, June 22, 2014

Tuesday
Nov112014

Sitting is Unhealthy … Unless You’re Physically Fit

Here’s some good news for a change about the health risks of prolonged sitting: a new study has found that it’s not so bad for you if you’re physically fit. Prolonged sitting at your desk, on your couch and in your car has previously been linked to obesity, metabolic syndrome, cardiovascular disease, type 2 diabetes, some types of cancer and premature death. The study, at the Cooper Clinic in Dallas, Texas, enrolled 1,304 men between 1981 and 2012. The participants reported on how much time they spent watching TV and sitting in their cars and took a treadmill test to determine their physical fitness. Results showed that once physical fitness was factored in, prolonged sitting was associated only with a higher ratio of triglycerides to HDL cholesterol, not the long list of health problems identified in earlier studies. This undoubtedly won’t be the last word on the subject, but it does hint that for those with desk jobs, long commutes and some TV time, the impact of sitting on health may not be as negative as earlier studies suggested.

Sources:
Kerem Shuval et al, “Sedentary Behavior, Cardiorespiratory Fitness, Physical Activity, and Cardiometabolic Risk in Men: The Cooper Center Longitudinal Study.” Mayo Clinic Proceedings, doi 10.1016/j.mayocp.2014.04.026

Monday
Nov102014

Surprising Stress Effect on Weight Gain

Stress can send you straight to the ice cream in the freezer or the pizza joint on the way home, but new research has found that the subsequent weight gain is more complex than just packing in extra calories. A study at Ohio State found that you actually burn fewer calories when eating under stress than someone who eats the exact same thing but isn’t stressed out. A group of 58 women, average age 53, participated in the study. They were provided with three standardized meals. The test meal provided 930 calories, including 60 grams of fat, and consisted of eggs, turkey sausage, biscuits and gravy, the caloric equivalent of a fast food meal of a two-patty burger and an order of fries. They were asked to fast for 12 hours before they returned to the Clinical Research Center. They then reported on any stress they had encountered in the past 24 hours. After the standardized meal, measurements of the women’s metabolic rate (how fast they burned the calories) showed that the participants who reported the most stress burned 104 fewer calories than the others. The researchers estimated that the daily effect of this pattern could add up to 11 pounds per year.

My take? We’ve long known that stress can trigger binge eating and lead to weight gain, and this study gives us a window into one of the possible mechanisms involved. The biochemical aspects linking stress and metabolism have yet to be worked out, and may eventually provide a target for intervention, but if you want to decrease the impact of stress in your life and on your weight, you should start by getting regular exercise and sufficient sleep. Incorporate meditation and relaxation techniques into your daily routine. Breathing exercises, particularly performing the 4-7-8 Breath, will help bring calmness throughout your body. Practice it at least twice a day, and try it every time you feel anxious or upset.

Sources:
Janice K. Kielcolt-Glaser et al, “Daily Stressors, Past Depression, and Metabolic Responses to High-Fat Meals: A Novel Path to Obesity,” Biological Psychiatry, http://dx.doi.org/10.1016/j.biopsych.2014.05.018

Friday
Nov072014

What’s Your View of the Hygiene Hypothesis? (Poll)

A recent Q&A discussed the frequency of children getting sick from attending school: Sick of Preschool? Check out the article and let us know what you think about the hygiene hypothesis.

Thursday
Nov062014

Another Good Reason to Eat Avocados

If you add avocado to the menu when you’re enjoying tomato sauce or carrots, you’ll better absorb vitamin A precursors, which include alpha- and beta-carotene. The participants of a study suggesting this were 12 healthy men and women who ate a fresh avocado with tomato sauce high in beta-carotene. The volunteers next consumed the same amount of avocado plus raw carrots. The aim of the study was to see if the avocado would promote the absorption of provitamin A carotenoids, and support the conversion of these carotenoids to an active form of vitamin A, which is involved in reproductive health, growth promotion, skin health, immune function and vision. The study found that eating avocado with the tomato sauce more than doubled beta-carotene absorption and more than quadrupled conversion of provitamin A (an inactive vitamin form) to vitamin A (an active vitamin form). Eating avocado and raw carrots increased beta-carotene absorption 6.6 times, more than quadrupled alpha-carotene absorption, and increased conversion of inactive vitamin A to active vitamin A by more than 12 times. The research was supported by the Haas Avocado Board and published online on June 4, 2014 by The Journal of Nutrition.

Sources:
R.E. Kopec et al,“Avocado Consumption Enhances Human Postprandial Provitamin A Absorption and Conversion from a Novel High-β-Carotene Tomato Sauce and from Carrots.” Journal of Nutrition, June 4, 2014 [Epub ahead of print]

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