Blame it on the brain. Researchers at Yale have found that our brains respond differently to sweet tastes and to calories. The brain is hardwired to seek out sugar to provide itself calories, but it considers sweetness separately, and it will go for the calories - energy - every time. "It turns out the brain actually has two segregated sets of neurons to process sweetness and energy signals," the Yale study’s senior author explained in a press release. "If the brain is given the choice between pleasant taste and no energy, or unpleasant taste and energy, the brain picks energy." The study found that both sweet taste and nutrient value register in an ancient brain region called the striatum, which is involved in processing rewards. In studies with mice and sugar, the researchers found that signals for taste and nutrients are processed in two separate areas of the striatum. One, the ventral striatum processes taste signals while the other, the dorsal striatum responds to energy signals. As far as eating behavior is concerned, the study showed that the brain chose signals that sugar (even sugar made to taste very bad) was delivering calories every time. The bottom line: Our human sweet tooth evolved to ensure that we eat enough to provide our brains with the calories it needs to operate at peak efficiency, but it is our brains desire for calories - not sweetness - that dominates our strong cravings for sugar, the researchers reported.
The trick to putting names and faces together after meeting someone for the first time may be a good night’s sleep. That conclusion comes from a small study at Boston’s Brigham and Women’s Hospital (BWH). Researchers there recruited 14 young adults in their 20s to see how a good night’s sleep affects the ability to match names and faces. During the study the participants stayed at the hospital’s Center for Clinical Investigation. Each study volunteer was shown 20 photos of faces with names attached and asked to memorize them. After 12 hours, they were shown the photos again, matched with either a correct or incorrect name. The researchers asked if the name was correct and also asked the participants to rate their confidence in their answers. Each participant took the test twice, once after sleeping for eight hours and once when they had remained awake during the day. The investigators reported that after sleeping the participants correctly matched 12 percent more of the faces and names than when they had remained awake. The research team now wants to explore how sleep affects memory for names and faces among older adults.
Air pollution is a recognized risk factor for cardiovascular disease, and new research indicates that it is especially detrimental for women with type 2 diabetes. Investigators at Brigham and Women’s Hospital in Boston and the Harvard T.H. Chan School of Public Health reviewed data from more than 100,000 women, comparing rates of cardiovascular disease in connection with air pollution. They found that among women who were affected by air pollution, type 2 diabetes was a more important factor than age, family history of cardiovascular disease, a woman’s weight, smoking, and region of the country. For non-diabetics in the study, long-term exposure to air pollution led to small, but statistically insignificant increases in the risk of cardiovascular events. The researchers reported that for each increase of 10 micrograms per cubic meter of air pollution, a woman’s risk of cardiovascular disease rose by 44 percent if she had type 2 diabetes. The 10 micrograms increase in pollution is the equivalent of the difference in air quality between Los Angeles and St. Louis. The researchers suggested that women at higher risk of cardiovascular disease, and especially those with type 2 diabetes, take precautions to limit their exposure to air pollution. They also suggested following recommendations to lower the risk of cardiovascular disease by not smoking, eating a healthy diet and getting regular exercise.
If you’re overweight, don’t sleep well and lack energy during the day, losing a few pounds might help fix all that. It worked for obese mice. Researchers at the Perelman School of Medicine at the University of Pennsylvania fed half the mice in their study regular mouse chow and the other half chow with more than three times more fat. After 8 weeks some of the mice in each group were switched to the opposite diet. Not surprisingly, those that had been on the high fat diet lost weight while those that had been eating regular mouse chow gained. After the ninth week, the mice on the high fat diet weighed 30 percent more than the other mice, slept an hour longer per day and were more likely to fall asleep during the day. However, the “diet switch” mice in both groups had completely different sleep/wake profiles, leading the researchers to conclude that changes in body weight are a key factor in regulating sleep. If you're overweight and feel tired during the day, losing only a small amount weight may result in better sleep and less daytime fatigue, the researchers reported. Will what works in mice really help humans sleep better? Stay tuned.
Getting regular exercise strengthens muscles and conditions our hearts, and it may also bolster the immune system enough to help us ward off colds and flu. A study from South Korea examined this potential benefit in mice. The researchers reasoned that inflammatory compounds produced in fat cells can weaken the immune system’s response to illness or infection. However, exercise can reduce the number and size of fat cells and thus potentially lower levels of inflammation. To test whether physical activity can actually have that effect, the researchers compared the results of infection with Staphylococcus bacteria in mice that exercised and those that didn’t. They divided laboratory mice into two groups. Those in one went about their usual activities, while those in the other group exercised by swimming. Because they’re not natural swimmers, the mice expended a great deal of energy staying afloat. Even though the strain on their muscles promoted some inflammation, the exercise also led to fewer and smaller fat cells. After putting the mice through the exercise, the researchers inoculated half the swimmers and half the sedentary mice with Staphylococcus. All the infected mice became ill, but the swimmers had lower levels of pro-inflammatory cells and their bodies produced greater numbers of immune system cells capable of fighting the infection. Would this effect be reproducible in humans? The Korean researchers think so.
My take? These findings may help explain how aerobic exercise strengthens the immune system. We know that exercise conditions our hearts and arteries and respiratory systems, increases stamina and general fitness. It also promotes cleansing of the blood by stimulating circulation and perspiration, and leads to a sense of well being, in part by releasing endorphins, the opiate-like molecules in the brain that can make us high, happy, and more tolerant of discomfort. Physical activity also increases the flow of oxygen to all organs, enabling them to work more efficiently. It burns calories, reduces stress, lowers serum cholesterol and tones the nervous system. Given its positive impact on the entire body, it makes sense that exercise would also help us fight off colds and flu.
Women who smoke and those who have been exposed to second hand smoke have more problems getting pregnant and are more likely to reach menopause at an earlier age than women who never smoked or those who were exposed to the least amount of second hand smoke. A new investigation from Roswell Park Cancer Institute reached these conclusions after researchers analyzed data on nearly 89,000 women in the U.S. Women who reported smoking were 14 percent more likely to have infertility (meaning that they were unable to get pregnant for a year) and 26 percent more likely to reach menopause earlier than women who didn’t smoke. Those exposed to the most second hand smoke had an 18 percent increased risk of infertility and reached menopause at an earlier age than women exposed to the least amount of second hand smoke. The analysis didn’t prove that exposure to smoke was responsible for infertility or earlier menopause, although the researchers adjusted the data to account for other factors that could lead to infertility or early menopause.
My take? As lead researcher Andrew Hyland, Ph.D. acknowledged, earlier investigations have linked smoking to reproductive problems in women, but few looked at associations between second hand smoke, infertility and early menopause. But these are not the only smoke-related risks women face. Some studies have suggested that teenage girls who smoke are at increased risk of developing breast cancer before menopause, and by age 50 women who began smoking as teens had a risk of breast cancer that was 80 percent higher than others who chose not to smoke so early in life. In addition, women with a family history of breast and ovarian cancer may increase their own risks of developing these cancers if they smoke. In addition, women smokers are 1.5 times more likely to develop lung cancer than men. If you’re a female smoker, these unique risks to women are all compelling reasons to make a New Year’s resolution to quit now.
Helping someone else - even if that help is as simple as holding a door open or giving directions - can boost your mood and lower stress. A study from Yale University School of Medicine examined how helpful behavior affected daily stress at work or at home. Researchers recruited 77 adults, ages 18 to 44 for the 14-day study. The participants were asked to report daily in response to an automated phone reminder on the stressful events that had occurred that day and whether they had helped someone out. They also rated their mental health daily using a sliding scale ranging from 0 (poor) to 100 (excellent). The results suggested that helping others improved the participants’ daily well being – the more helpful they were, the better they felt about themselves. The researchers noted that laboratory based experiments have shown that providing support to others can help individuals cope with stress and increase positive emotion. This study was aimed at determining whether helping behaviors yield these benefits in the real world. The researchers also suggested that you may be able to diffuse holiday stress in small ways by helping someone out.
Certain antidepressants used to relieve hot flashes, night sweats and other menopausal symptoms appear to increase the risk of bone fractures. The class of drugs, selective serotonin reuptake inhibitors (SSRIs), include Celexa, Lexapro, Prozac, Luvox, Paxil and Zoloft, and are now considered effective alternatives to hormone replacement therapy. Investigators from Boston’s Northeastern University used a pharmaceutical database to identify more than 137,000 women age 40 through 64 who began taking SSRIs for menopausal symptoms between 1998 and 2010 and compared them with some 236,000 women taking prescription drugs for indigestion. After one year, the fracture risk among the women on the SSRIs was 76 percent higher than it was in the women on the indigestion drugs, 73 percent higher after two years and 67 percent higher after three years. The database review didn’t prove that the SSRIs caused the increased risk, but earlier investigations have indicated that bone thinning is a possible side effect of SSRIs. The researchers suggested that, given these findings, women may want to consider taking the drugs for the shortest possible time and that research to determine whether the bone-thinning effect occurs at lower doses of SSRIs should be initiated.