Thursday, December 9, 2010

OMEGA-3: FOOD FOR (HAPPY) THOUGHT

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As you do your Thanksgiving shopping this year, notice how many products on the supermarket shelves say “omega-3 fortified” on the label. Foods ranging from pasta to eggs to peanut butter are now enriched with this fatty acid. A stroll down the supplement aisle reveals rows of bottles containing omega-3-rich fish oil capsules.

Should you fill your cart with these products, or is this just another nutritional fad? What is the science behind the omega-3 craze? Just what are omega-3s and why should we care?

Omega-3s are a type of polyunsaturated fatty acid. “These are the most interesting nutrients. Fatty acids are very powerful in terms of health effects,” says Bonnie Beezhold, a professor of nutrition in the College of Nursing and Health Innovation at ASU’s Polytechnic Campus.

Fatty acids are components of most of the fat in your body. Although people often think of fats as something to avoid, everyone needs a certain amount of fat to stay healthy. The human brain, for example, is about 60 percent fat. The next time someone calls you a “fathead,” consider it a compliment!

There are two types of fatty acids that your body cannot manufacture on its own—you have to consume them. These are the essential fatty acids called omega-3 and omega-6.

“In our ancestral diet, we got pretty much of a balance between these two types,” says Beezhold. “Scientists believe it was about a two-to-one ratio of omega-6 to omega-3, or at least less than four-to-one.”

Modern diets, however, are vastly different than those of our prehistoric ancestors. A typical American’s diet today contains a 15- or 20-to-one ratio of omega-6 to omega-3 fat.

“Today, we eat less fish, and we eat meat produced in a factory system. Instead of grazing on grass, these animals are fed corn and soy, which are major omega-6 plant sources, particularly corn. So their meat has lower levels of omega-3 and higher levels of omega-6 fat. Many animals are confined in small spaces and are not free to roam, which increases the fat content as well as the fatty acid proportions of their flesh,” explains Beezhold.

This imbalance has major effects on health.

Fatty acids are essential components of the membranes of every cell in your body. These cell membranes form a protective barrier between the cell and the rest of the body. Membranes regulate what goes into and passes out of the cell. To be effective, these membranes must be strong but also flexible. The structure of omega-3s contribute greatly to the flexibility of the membrane.

The fatty acids in cells also produce eicosanoids. These are signaling molecules, kind of like hormones that work locally. They regulate activities like platelet aggregation and the immune response.

Omega-3 and omega-6 fats both produce eicosanoids that regulate inflammation. Inflammation occurs in response to injury or infection, and as we have all experienced, it involves swelling, heat, redness and pain. It’s not pleasant, but it’s important.

“When you get an injury or infection, you need inflammation. It’s an immune response that ultimately repairs the body. Omega-6s generally make the eicosanoids that promote inflammation. Eventually there’s a resolution promoted by anti-inflammatory eicosanoids that come from omega-3s,” says Beezhold.

A little bit of inflammation is necessary, but too much can wreak havoc on the body.

“All kinds of diseases have an inflammatory component. Our major chronic diseases, like heart disease and arthritis, have inflammation as an underlying process,” says Beezhold, who is particularly interested in the relationship between inflammation and mood.

“When inflammatory chemicals increase, they can also impact the brain. Research shows that there’s such a thing as neuroinflammation,” she says.

She notes that people with heart disease have a higher risk of depression, possibly due to the same inflammatory mechanisms. And studies show that depressed people have lower concentrations of long-chain omega-3s in their blood.

One of the best food sources of omega-3s is fish. Research surveying large populations show that low fish consumption is associated with prevalence of depression. For her Ph.D. dissertation, Beezhold conducted a small community survey on fish consumption and mood. She found, not surprisingly, that fish eaters reported better moods than folks who shunned seafood.

Her results made her curious. Are vegetarians – who don’t eat fish – more depressed than omnivores? She decided to conduct a study with Carol Johnston, director of ASU’s nutrition program. They surveyed Seventh Day Adventists in the Phoenix and Santa Barbara areas. This group is typically about half vegetarian, so the researchers could survey equal numbers of vegetarians and omnivores from a relatively similar population.

“We went into this thinking, ‘This is going to be a slam dunk. People who don’t eat fish can’t possibly have as good a mood as those who do.’ Interestingly, it wasn’t even close. The vegetarians reported substantially better moods than the omnivores,” says Beezhold.

To understand how this could be true, it helps to understand more about plant and animal sources of fatty acids. Both plants and animals provide both omega-3 and omega-6 fatty acids. However, plants only provide the short-chain fatty acid variety with 18 carbons. Animals provide the long-chain variety containing 20 or more carbons.

Research shows that short-chain fatty acids are important in their own right, but not nearly as important as the long-chain variety. It is the long-chain fatty acids, for example, that form eicosanoids and regulate inflammation.

Enzymes in your body can convert short-chain into long-chain fatty acids. However, the omega-6s and omega-3s compete for the same enzymes to do the conversion. When you eat animal sources of these fatty acids, conversion is not needed and these are preferred.

Although the vegetarians in the study weren’t eating fish, they also weren’t eating many sources of long-chain omega-6s (except in dairy products). So the level of long-chain omega-6s may be more important. And while vegetarians typically have a higher intake of the short-chain plant omega-6s than even omnivores, they also eat plenty of the omega-3 variety as well. Apparently they were able to synthesize the long-chain omega-3 fatty acids they needed.

Beezhold cautions, “This is just one study and we surveyed a special group—the Seventh Day Adventists—who are typically very health conscious. Thus, results may not be generalizable to the whole population.”

To get more information, she has conducted a randomized, controlled trial in which she changed the protein sources and then compared the mood of three groups of omnivores. Her results should be available soon.

Based on what we do know about omega-3s, what does all of this mean for your diet?

“If you’re a vegetarian and you’re eating plenty of plant sources of omega-3, you probably don’t have to worry about mood,” says Beezhold. Even so, vegetarians who want to increase their plant-based sources of omega-3s can incorporate more walnuts, pumpkin seeds, flaxseeds and flaxseed oil, canola oil, and leafy green vegetables into their diets to help to balance their omega-6 to omega-3 ratio.

Her advice for omnivores is to eat more fish and reduce consumption of meat and poultry, most of which is raised in factory farms. People who don’t like fish can aim to eat more grass-fed beef and other sustainably-raised meats and poultry, which contain higher levels of omega-3s.

Additionally, omnivores who don’t like fish can take fish-oil supplements. Beezhold says supplements that include vitamin E in them may reduce the incidence of fish-flavored burps.

And, while it is not as important as changing the balance of animal products, omnivores also should increase their consumption of the omega-3-rich plant foods mentioned above.

Beezhold says she herself is an “enthusiastic omnivore” who tries to eat fish as often as possible. But she admits it’s not always easy.

“Fresh fish can be more expensive and difficult to prepare, and there are environmental contamination problems associated with fish. Wild fish that are high in omega-3 fats unfortunately can also be high in mercury. While farm-raised fish are cheaper and more available, they can be high in other toxins like dioxins.”

She says that ultimately we need to take a big-picture look at our food and how we raise it. “We really need to think about our agricultural methods. We can produce a lot of food cheaply, but not without adversely impacting our own health.”

(Photo: Rob Roberson)

Arizona State University

EARLY UNIVERSE WAS A LIQUID

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Scientists are amongst a team of researchers who have found that the very early Universe was not only very hot and dense but behaved like a hot liquid. The discovery is the result of accelerating and smashing together lead nuclei at the highest possible energies in the Large Hadron Collider’s (LHC’s) ALICE experiment, recreating the conditions that existed in the first microseconds after the Big Bang.

Scientists from the University of Birmingham, funded by the STFC, are playing a key role in this new phase of the LHC’s programme which comes after seven months of successfully colliding protons at high energies.

The lead-ion collisions generate incredibly hot and dense sub-atomic fireballs or ‘mini Big Bangs’ with temperatures of over ten trillion degrees. At these temperatures normal matter is expected to melt into an exotic, primordial ‘soup’ known as quark-gluon plasma. The first results from lead collisions have already ruled out a number of theoretical physics models, including ones predicting that the quark-gluon plasma created at these energies would behave like a gas.

Dr David Evans, from the University of Birmingham’s School of Physics and Astronomy, is the UK lead investigator at the ALICE experiment. Dr Evans said, “Although it is very early days we are already learning more about the early Universe. These first results would seem to suggest that the universe would have behaved like a super-hot liquid immediately after the Big Bang.”

Although previous research in the USA at lower energies indicated that the hot fire balls produced in nuclei collisions behaved like a liquid, many expected the quark-gluon plasma to behave like a gas at these much higher energies.

(Photo: CERN)

Science and Technology Facilities Council

GETTING LOST IN BUILDINGS: ARCHITECTURE CAN BIAS YOUR COGNITIVE MAP

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Some people always know which way is north and how to get out of a building. Others can live in an apartment for years without knowing which side faces the street. Differences among people that include spatial skills, experience, and preferred strategies for wayfinding are part of what determines whether people get lost in buildings—and psychological scientists could help architects understand where and why people might get lost in their buildings, according to the authors of an article published in Current Directions in Psychological Science, a journal of the Association for Psychological Science.

When you enter a new building, you build a cognitive map—a representation in your mind of the objects and locations in that environment. Success in navigating in the building may depend upon what information you put into the cognitive map. “For example, imagine visiting a new doctor’s office. You walk in the front door and find your way to the office, storing information about your route and the objects you encounter in your cognitive map. What is most interesting is how this information is then used to direct you back to the front door after the office visit.

“If you paid attention to the sequence of turns along the path, then you may have difficulty because you need to remember to reverse the sequence, and this becomes increasingly difficult as the number of turns increases. But instead, if you paid more attention to the objects that you passed, then you may navigate back to the front door by going from one familiar object to another without considering the sequence of turns. This strategy will work, as long as you can always see a familiar object. If you get lost and enter an unexplored part of the building, you will have difficulty finding your way back,” says Laura A. Carlson of the University of Notre Dame, first author of the article.

In some buildings, the strategies people use and the quality of their cognitive map may not matter very much. “If the building has an obvious structure, with long lines of sight, you won’t have to rely much on this internal representation of your path,” says Carlson.

Some buildings, on the other hand, make it difficult. Carlson and her coauthors, Christoph Hölscher of the University of Freiburg, Thomas F. Shipley of Temple University, and Ruth Conroy Dalton of University College, London, use the Seattle Central Library as an example. The bold building, designed by Dutch architect Rem Koolhaas, opened in 2004 and won awards for its design. But visitors complain that it’s difficult to navigate. People expect floors to have similar layouts, but the first five levels of the library are all different; even the outside walls don’t necessarily line up. Normally, lines of sight help people get around, but the library has long escalators that skip over levels, making it hard to see where they go.

For building users who may find navigating in new environments challenging, there are strategies that are helpful. “I used to worry when I explore a new city by myself that I would not find my way back to the hotel,” Carlson says. “However, this simple trick is effective. At each intersection where I need to turn, I spin around to see what the intersection will look like from my return perspective. That way, I will be able to recognize it from the other direction, and I can store that view also in my cognitive map.” This strategy also tends to work well for indoor navigation.

Architects, on the other hand, may be among the class of people with very strong spatial skills, because their craft requires numerous spatial transformations, such as needing to envision 3D space from 2D depictions. One unanticipated consequence of such abilities is that they may not be very good at taking the perspective of a user with poorer spatial skills, and therefore may not be able to fully anticipate where users may have navigational difficulties within their buildings.

Architects and cognitive scientists could learn from each other, Carlson says. Architects could explain how they use building features to encourage certain patterns of movement within the building, informing research on how people move through space; scientists could contribute data on how we build cognitive maps and what strategies different people use to find their way around.

Association for Psychological Science

ARCHEOLOGISTS FIND 3,000-YEAR-OLD FRUIT CELLAR

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Chinese archeologists have found an ancient fruit cellar containing well-preserved apricot and melon seeds from more than 3,000 years ago in today's Shaanxi Province.

The cellar was a rectangular pit about 105 cm long, 80 cm wide and 205 cm deep, said Dr. Sun Zhouyong, a researcher with the Shaanxi Provincial Institute of Archeology.

Sun and his colleagues found the pit in 2002, about 70 cm underground the Zhouyuan site, ruins of Western Zhou dynasty (1046-771 BC) 100 km from Xi'an. After eight years of research, they concluded it was a cellar used to preserve fruits for aristocrats.

In each corner of the pit, Sun and his colleagues found a little round hole. "We assume the cellar had something like a shade that was fixed on the four holes but had decayed over the years."

Inside the cellar the researcher could see, even with naked eye, huge piles of nuts and seeds.

"We sorted them out with care, and found about 500 apricot nuts -- 108 of which were complete with carbonized pulp, at least 150 melon seeds and 10 plum seeds," said Sun.

They also found millet and grass seeds.

"Most of the seeds were intact and very few were carbonized," said Sun. "It was so amazing that scientists who conducted lab work suspected they were actually put away by rodents in more recent times."

Sun and his colleagues sent three apricot nuts to Beta Analytic in Florida, the United States, last year for carbon 14 test to determine their age.

"The test results indicated they were about 3,000 years old, dating back to a period between 1380 B.C. and 1120 B.C.," said Sun. "Seemingly the fruits had been stored in an acidic and dry environment, so dehydration was extremely slow and the nuts were not carbonized even after so many centuries."

Zhouyuan site, where the cellar was unearthed, was believed to be a dwelling place for Duke Danfu, an early leader of the Zhou clan. It was known as the cradle of the Western Zhou Dynasty, one of the earliest periods of China's written history.

"Presumably, the aristocrats had stored fruits in their family cellar," said Sun.

The cellar, with roughly 1.7 cubic meters of storage, could store up to 100 kilograms of fruits, he said.

The Book of Rites, a Chinese history book compiled in the Western Han Dynasty (202 BC-9), put melons, apricots, plums and peaches among the 31 categories of food favored by aristocrats of the time. It said people in the Zhou Dynasty had also learned to grow fruit trees in orchards.

A poem in the "Book of Songs", a collection of poetry from the Western Zhou Dynasty (11th century -771 BC) to the Spring and Autumn Period (770 - 475 BC), says food kept in "ling yin" -- meaning cool places -- will stay fresh for three days in the summer.
Before the fruit cellar was reported, archeologists in Shaanxi Province found a primitive "icebox" that dated back at least 2,000 years ago in the ruins of a temporary imperial residence of the Qin Dynasty (221 BC - 207 BC).

The "icebox", in the shape of a shaft 1.1 meters in diameter and 1.6 meters tall, was unearthed about 3 meters underground in the residence.

Chinese Academy of Sciences

DIRE MESSAGES ABOUT GLOBAL WARMING CAN BACKFIRE, NEW STUDY SHOWS

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Dire or emotionally charged warnings about the consequences of global warming can backfire if presented too negatively, making people less amenable to reducing their carbon footprint, according to new research from the University of California, Berkeley.

“Our study indicates that the potentially devastating consequences of global warming threaten people’s fundamental tendency to see the world as safe, stable and fair. As a result, people may respond by discounting evidence for global warming,” said Robb Willer, UC Berkeley social psychologist and coauthor of a study to be published in the January issue of the journal Psychological Science.

“The scarier the message, the more people who are committed to viewing the world as fundamentally stable and fair are motivated to deny it,” agreed Matthew Feinberg, a doctoral student in psychology and coauthor of the study.

But if scientists and advocates can communicate their findings in less apocalyptic ways, and present solutions to global warming, Willer said, most people can get past their skepticism.

Recent decades have seen a growing scientific consensus on the existence of a warming of global land and ocean temperatures. A significant part of the warming trend has been attributed to human activities that produce greenhouse gas emissions.

Despite the mounting evidence, a Gallup poll conducted earlier this year found that 48 percent of Americans believe that global warming concerns are exaggerated, and 19 percent think global warming will never happen. In 1997, 31 percent of those who were asked the same question in a Gallup poll felt the claims were overstated.

In light of this contradictory trend, Feinberg and Willer sought to investigate the psychology behind attitudes about climate change.

In the first of two experiments, 97 UC Berkeley undergraduates were gauged for their political attitudes, skepticism about global warming and level of belief in whether the world is just or unjust. Rated on a “just world scale,” which measures people’s belief in a just world for themselves and others, participants were asked how much they agree with such statements as “I believe that, by and large, people get what they deserve,” and “I am confident that justice always prevails over injustice.”

Next, participants read a news article about global warming. The article started out with factual data provided by the United Nations Intergovernmental Panel of Climate Change. But while half the participants received articles that ended with warnings about the apocalyptic consequences of global warming, the other half read ones that concluded with positive messages focused on potential solutions to global warming, such as technological innovations that could reduce carbon emissions.

Results showed that those who read the positive messages were more open to believing in the existence of global warming and had more faith in science’s ability to solve the problem. Moreover, those who scored high on the just world scale were less skeptical about global warming when exposed to the positive message. By contrast, those exposed to doomsday messages became more skeptical about global warming, particularly those who scored high on the just world scale.

In the second experiment, involving 45 volunteers recruited from 30 U.S. cities via Craigslist, researchers looked specifically at whether increasing one’s belief in a just world would increase his or her skepticism about global warming.

They had half the volunteers unscramble sentences such as “prevails justice always” so they would be more likely to take a just world view when doing the research exercises. They then showed them a video featuring innocent children being put in harm’s way to illustrate the threat of global warming to future generations.

Those who had been primed for a just world view responded to the video with heightened skepticism towards global warming and less willingness to change their lifestyles to reduce their carbon footprint, according to the results.

Overall, the study concludes, “Fear-based appeals, especially when not coupled with a clear solution, can backfire and undermine the intended effects of messages.”

Psychological Science

UPPER-CLASS PEOPLE HAVE TROUBLE RECOGNIZING OTHERS EMOTIONS

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Upper-class people have more educational opportunities, greater financial security, and better job prospects than people from lower social classes, but that doesn’t mean they’re more skilled at everything. A new study published in Psychological Science, a journal of the Association for Psychological Science, finds surprisingly, that lower-class people are better at reading the emotions of others.

The researchers were inspired by observing that, for lower-class people, success depends more on how much they can rely on other individuals. For example, if you can’t afford to buy support services, such as daycare service for your children, you have to rely on your neighbors or relatives to watch the kids while you attend classes or run errands, says Michael W. Kraus of the University of California-San Francisco. He cowrote the study with Stéphane Côté of the University of Toronto and Dacher Keltner of the University of California-Berkeley.

One experiment used volunteers who worked at a university. Some had graduated from college and others had not; researchers used educational level as a proxy for social class. The volunteers did a test of emotion perception, in which they were instructed to look at pictures of faces and indicate which emotions each face was displaying. People with more education performed worse on the task than people with less education. In another study, university students who were of higher social standing (determined from each student’s self-reported perceptions of his or her family’s socioeconomic status) had a more difficult time accurately reading the emotions of a stranger during a group job interview.

These results suggest that people of upper-class status aren’t very good at recognizing the emotions other people are feeling. The researchers speculate that this is because they can solve their problems, like the daycare example, without relying on others—they aren’t as dependent on the people around them.

A final experiment found that, when people were made to feel that they were at a lower social class than they actually were, they got better at reading emotions. This shows that “it’s not something ingrained in the individual,” Kraus says. “It’s the cultural context leading to these differences.” He says this work helps show that stereotypes about the classes are wrong. “It’s not that a lower-class person, no matter what, is going to be less intelligent than an upper-class person. It’s all about the social context the person lives in, and the specific challenges the person faces. If you can shift the context even temporarily, social class differences in any number of behaviors can be eliminated.”

Association for Psychological Science

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