Saturday, October 29, 2011
Should blood type guide your food choices?
Dietary advice has stamina but isn't worth its weight in salt, experts say.
While searching for relief from migraines and general malaise, a friend recently consulted a nutritionist who told her, matter-of-factly, that because she has Type O blood, she should be eating lots of meat and eliminating gluten, dairy and many grains. A Chinese medicine doctor she consulted confirmed the advice, saying, basically: Duh.
For someone who had hoped to go vegetarian — and who is among the 45 percent of people in the U.S. with Type O blood — the news was surprising.
But was it true?
The idea of eating according to your blood type became popular with the 1996 book "Eat Right 4 Your Type" (Putnam Adult) by Peter D'Adamo, a naturopath physician. The theory is that the genes behind blood type also are behind the expression of other proteins in our body, which relate to how we digest foods.
Type O's, having the oldest blood type, draw on our hunter roots and perform best on lean meats (including fish), fruits and vegetables, as well as with intense exercise, while gluten, some beans and dairy lead to weight gain, sickness and sluggishness, the theory posits. The proteins in legumes and dairy tend to cause inflammation in Type O's, goes the theory, so without meat it's difficult to fulfill their protein needs.
Rather than banning Type O's from being vegetarians, D'Adamo said, "a more helpful way of thinking is that people who are blood Type O may want to explore a more high-protein, lower-carbohydrate lifestyle in lieu of their current dietary choices, should they suffer from signs that they are not getting enough protein in their diets: digestive disorders, fatigue, low immunity or slow metabolism."
Meantime, people with blood Type A do best as vegetarians, B's are hardier omnivores and ABs are a combination.
Most nutritionists do not subscribe to eating by blood type because it is not backed by hard scientific data, said Marjorie Nolan, a dietitian and spokeswoman for the American Dietetic Association.
The evidence supporting the blood-type diet is based largely on anecdotes and research showing links between blood type and certain illnesses (for example, Type O's are more likely to have stomach ulcers). There have been no peer-reviewed studies published showing that different blood types perform better on certain foods.
D'Adamo says small-scale studies his team has conducted looking at improvements in digestive malabsorption may serve as templates for larger studies, but those will be expensive, complicated and time-consuming.
Dr. Michael Greger, founder of NutritionFacts.org, said the premise of the blood-type diet is wrong: The blood-type system, which predates humans, is far more complicated than just ABO, he said.
"People crave individualized, personalized science, but this is pseudoscience," said Greger, a general practitioner specializing in clinical nutrition.
People who lose weight or feel better after starting the blood-type diet could actually be uncovering an allergy, or may just be eliminating junk food, Greger said.
While she applauds D'Adamo's marketing, Dr. Ingrid Kohlstadt, editor of the medical textbook "Food and Nutrients in Disease Management" (CRC Press) and an associate at Johns Hopkins Bloomberg School of Public Health, said the connection between blood type and susceptibilities is not strong enough to be meaningful from a medical or public health perspective. She said she would rather prescribe a diet according to a person's gum health, which is strongly associated with heart disease, than his or her blood type.
On the plus side, any of the four blood-type diets is healthier than how most Americans eat, Kohlstadt said.
Source:October 26, 2011|By Alexia Elejalde-Ruiz, Tribune Newspapers
Wednesday, October 26, 2011
Ever wish you could mainline your coffee? Well, here's the next best thing: AeroShot, a new product that delivers "inhalable" caffeinated puffs, and has got productivity-obsessed technophiles buzzing.
AeroShot's delivery system is a light, plastic inhaler that shoots lime-flavored puffs of powdered caffeine to the tongue, where they are instantly absorbed. Each inhaler contains three puffs, providing a total of 100 mg of caffeine — about as much as in a large cup of coffee.
The product also contains 100% of the recommended daily allowance of niacin, vitamin B6 and vitamin B12. It's sweetened with stevia, an herbal sweetener that is up to 300 times sweeter than sugar and has no calories.
AeroShot was invented by Harvard biomedical engineering professor David Edwards, who previously created a no-calorie inhalable chocolate product called Le Whif. "I have a background in developing inhaled drugs and vaccines and I was fascinated about bringing that idea to a new way of eating," says Edwards. "That's how it began."
It took me a few tries to get the hang of using the inhaler (best to read the directions first and not to use it upside down!), but soon I got a dose of seriously sweet lime flavor and found my heart rate and mood lifted in that familiar, caffeinated way — but faster than with coffee. The dosing seemed slightly inexact — sometimes, the inhaler doesn't load the powder quite right — but when it worked, the effect was rapid.
"Frequently, the first time people do it, they laugh," says Edwards. "There's something funny about the act, how it happens in your mouth."
Since caffeine is a legal substance in foods, as are the included B vitamins, AeroShot did not require FDA approval. It will be sold as an energy supplement. The label says it is "not intended for people under 12, sensitive to caffeine, allergic to ragweed, taking medications, who are pregnant or who have a serious medical condition." It also warns against using more than three AeroShots a day.
So, what's the best and safest way to use caffeine? And does it really improve performance?
A 2010 Cochrane review of multiple studies of caffeine's effect on shift workers found that it did indeed reduce the number of errors people made in tasks like driving or operating a flight simulator. It also improved memory, reasoning, perception and attention, compared with placebo. Sadly for us writers, however, caffeine did not seem to affect verbal functioning or language skills, at least in the studies included in the review.
Other research suggests that frequent dosing, with about 20 mg of caffeine an hour, is an efficient way to counter the effects of sleep deprivation and improve brain processing speed. If you're using coffee, adding sugar may also help: one study found that it boosted performance more than caffeine alone.
As for the overall health effects of caffeine and coffee, that's been debated for years. On balance, the research seems to find more benefits than harms associated with drinking coffee, including reduced risks of Alzheimer's disease, diabetes and depression.
Is caffeine addictive? Certainly, it produces tolerance and withdrawal symptoms if it is stopped abruptly. But even though it is the most widely used drug in the world, few caffeine users exhibit signs of serious addiction — namely, compulsive drug-related behaviors despite negative consequences. That could be in part because caffeine is legal and easily and cheaply obtained. Or, it could be because the effects of caffeine use — especially in a hyperefficient society — are generally positive.
So, while previous products, like inhalable aerosolized alcohol, led to bans in multiple states, AeroShot seems more likely to garner praise (especially from employers — and editors).
The new product will hit stores in New York City and Boston in January,2012 and will be available online in several weeks, according to Edwards. The retail price is expected to be $2.99 per inhaler — cheaper than a Starbucks latte.
Source: Maia Szalavitz is a health writer at TIME.com.
Read more: http://healthland.time.com/2011/10/25/what-weve-all-been-waiting-for-zero-calorie-inhalable-caffeine/print/#ixzz1bu2DXUyX
With test-taking season upon us, Sue Shellenbarger on Lunch Break looks at the latest findings from the science of studying. For students approaching SAT/ACTs, midterms and finals, which memory tricks work best and does cramming help?
Chiefly, testing yourself repeatedly before an exam teaches the brain to retrieve and apply knowledge from memory. The method is more effective than re-reading a textbook, says Jeffrey Karpicke, an assistant professor of psychological sciences at Purdue University. If you are facing a test on the digestive system, he says, practice explaining how it works from start to finish, rather than studying a list of its parts.
In his junior year of high school in Cary, N.C., Keenan Harrell bought test-prep books and subjected himself to a "relentless and repetitive" series of nearly 30 practice SAT college-entrance exams. "I just took it over and over again, until it became almost aggravating," he says.
Practice paid off. Mr. Harrell, now 19, was accepted at University of North Carolina-Chapel Hill, a college he's dreamed of attending since the third grade. He scored 1800 (out of 2400) on the SAT, up 50% from 1200 on the PSAT, a preliminary test during his sophomore year.
Taking pretests "felt like hard work," Mr. Harrell says, but seeing steady increases in his scores boosted his confidence. Practice tests also help with test-taking skills, such as pacing, says Paul Weeks, vice president of educational services for the ACT, which creates and administers college-entrance exams.
Repeated practice tests help master test format and pacing.
Sleep also plays a role in test performance, but in two unexpected ways. Review the toughest material right before going to bed the night before the test. That approach makes it easier to recall the material later, says Dan Taylor, director of a sleep-and-health-research lab at the University of North Texas in Denton. And don't wake up earlier than usual to study; this could interfere with the rapid-eye-movement sleep that aids memory, he says.
A common study habit—the all-nighter—is a bad idea. Although 60% of college students stay up all night at some point in school, the practice is linked to lower grades, says Pamela Thacher, an associate professor of psychology at St. Lawrence University in Canton, N.Y., based on a 2008 study of 120 students. It also impairs reasoning and memory for as long as four days.
Write down fears and anxieties before the test to free working memory and prevent distractions during the test.
To combat self-doubts (such as 'I'm bad in math'), remind yourself of proven personal traits and strengths that can propel you to success.
Practice in advance facing all the pressures you will face on exam day, such as driving to the testing center or visiting an unfamiliar testing room.
Test yourself by recalling broad concepts rather than trying to memorize facts or re-reading textbooks.
Before the test, envision yourself answering questions calmly and with confidence.
Everybody knows you should eat breakfast the day of a big test. High-carb, high-fiber, slow-digesting foods like oatmeal are best, research shows. But what you eat a week in advance matters, too. When 16 college students were tested on attention and thinking speed, then fed a five-day high-fat, low-carb diet heavy on meat, eggs, cheese and cream and tested again, their performance declined. The students who ate a balanced diet that included fruit and vegetables, however, held steady, says Cameron Holloway, a senior clinical researcher at the University of Oxford. The brain requires a constant supply of energy and "has only a limited backup battery," he says.
While many teens insist they study better while listening to music or texting their friends, research shows the opposite: Information reviewed amid distractions is less likely to be recalled later, says Nicole Dudukovic, assistant professor of psychology at Trinity College, Hartford, Conn.
In her research, college students categorized and made judgments about pictures of more than 100 items. Then, they were tested on a new mix of pictures and asked to recall which ones they had already seen and how they had categorized them; half the time, they were also asked to listen and respond to a set of rhythmic sounds. When the students were tested later, they were more likely to remember correctly what they had studied without distractions.
"Students do have this belief that they can do it all and they aren't really being distracted" by music or sounds from a noisy cafe, Dr. Dudukovic says. But while the sounds may "make them feel more relaxed," she says, they won't help them ace the midterm.
Bryan Almanza says he did poorly on the PSAT as a high-school sophomore because he didn't know how to prepare. He got too little sleep the night before and ate only a bowl of cereal for breakfast. On the test, some hard physics questions made him nervous and distracted, says Mr. Almanza, 18, a senior at Campbell High in Smyrna, Ga. "I'm going to fail," he remembers thinking at the time. A test-prep program at his school taught him to get plenty of sleep, eat a good breakfast and pace himself on the test. By staying calm, optimistic and focused, he raised his score significantly on the SAT.
Source: Wall Street Journal 10/26/11
Tuesday, October 25, 2011
RESEARCHERS in the United States have said they had found a "shocking" association - if only a statistical one - between violence by teenagers and the amount of soda they drank.
High-school students in inner-city Boston who consumed more than five cans of non-diet, fizzy soft drinks every week were between nine and 15-percent likelier to engage in an aggressive act compared with counterparts who drank less.
"What we found was that there was a strong relationship between how many soft drinks that these inner-city kids consumed and how violent they were, not only in violence against peers but also violence in dating relationships, against siblings," said David Hemenway, a professor at the Harvard School of Public Health.
"It was shocking to us when we saw how clear the relationship was," he told AFP in an interview.
But he stressed that only further work would confirm - or disprove - the key question whether higher consumption of sweet sodas caused violent behaviour.
The new study was based on answers to questionnaires filled out by 1878 public-school students aged 14 to 18 in the inner Boston area, where Hemenway said crime rates were much higher than in the wealthier suburbs.
The overwhelming majority of respondents were Hispanic, African-American or mixed; few were Asian or white.
Among the questions were how much carbonated non-diet soft drink, measured in 12-ounce (355ml) cans, the teens had drunk in the previous seven days.
They were also asked whether they drank alcohol or smoked, carried a weapon or showed violence towards peers, family members and partner. What emerged, said Hemenway, was evidence of "dose response," in other words, the more soda was consumed, the likelier the tendency towards violence.
Among those who drank one or no cans of soft drink a week, 23 percent carried a gun or a knife; 15 percent perpetrated violence towards a partner; and 35 percent had been violent towards peers.
At the other end of the scale, among those who drank 14 cans a week, 43 percent carried a gun or a knife; 27 percent had been violent towards a partner; and more than 58 percent had been violent towards peers.
Overall, teens who were heavy consumers of sugary fizz were between nine and 15 percentage points likelier to show aggressive behaviour compared with low consumers, even when ethnicity and other confounding factors were taken into account.
This is a magnitude similar to the link found, in previously researched, with alcohol or tobacco. Hemenway said the study had included a couple of questions aimed at taking a children's home background into account, including whether the teen had taken a meal with his family in the previous days.
As it was only intended as a preliminary investigation, the questionnaire did not ask what kind of sodas the teens drank, he said. "This is one of the very first studies to examine" the question, said Hemenway.
"We don't know why (there is this strong association). There may be some causal effect but it's also certainly plausible that this is just a marker for other problems - that kids who are violent for whatever reason, they tend to smoke more, they tend to drink more alcohol and they tend to maybe drink more soft drinks. We just don't know.
"We want to look at it more carefully in following studies."
The study, published in a British journal, Injury Prevention, will revive memories of the "Twinkie Defence," a US legal landmark in which a killer successfully argued that his behaviour had been swayed by eating junk food.
The defendant in this case, Dan White, had been charged with homicide. His lawyer's successful pleading led to conviction of a lesser charge, of voluntary manslaughter.
Several studies elsewhere have established a link between very high sugar consumption and lack of social bonding or irritable and anti-social behaviour. Some diet research has also pointed the finger at the lack of micro-nutrients as a source of aggression, but this work is still in its early stages.
Source:Australian News 10/25/11
Friday, October 21, 2011
The nutrition label on the front of a box of cereal, a frozen dinner or any other food should be as quick and easy to read as the Energy Star label on a clothes washer or an air-conditioner, according to a study released Thursday that was requested by Congress.
In a report to federal regulators, the Institute of Medicine called for a simplified label that would go on the front of food packages and show the number of calories per serving and contain zero to three stars or checkmarks to indicate how healthful a food was.
“It’s simple,” said Alice H. Lichtenstein, a nutrition professor at Tufts University, who served on the committee that prepared the report. “It’s interpretive. People don’t need to look at numbers or do any calculations to figure out what they mean. Three stars are better than no stars.”
The report was done at the request of Congress and submitted to the Food and Drug Administration, the Centers for Disease Control and Prevention and the Department of Agriculture. It calls on the agencies to establish a uniform labeling system to replace the confusing proliferation of front-of-package labels greeting consumers on store shelves today.
Margaret Hamburg, the F.D.A. commissioner, has said she wants to improve front-of-package labels, but the agency is not expected to move quickly on the institute’s recommendations. The F.D.A. said it was continuing to assess the topic.
The report is the latest salvo in a long battle over labeling involving food companies, public health advocates and regulators. At stake is how nutrition information is presented and how it might affect the way consumers spend their money.
The Grocery Manufacturers of America, an industry group that represents major food companies, brushed aside the report’s findings and said its members would go ahead with their own labeling plan, called Facts Up Front.
Under that plan, labels show the amount of various nutrients in grams or other units and, in many cases, the percent of a recommended daily value for each nutrient that they supply.
“We have a road-tested, ready-to-roll front-of-pack system that is already in the marketplace,” said Scott Faber, a vice president of the food makers’ group. “We should not keep consumers waiting. We should provide them more nutrition information on the front of their packages now.”
Critics say that the industry’s label can be confusing to consumers, burying them in a blizzard of numbers that can be hard to understand.
The institute modeled its recommendations on the easy-to-interpret Energy Star symbol that appears on many appliances to show they have met government standards for energy efficiency.
“I really don’t know a whole lot about appliances and kilowatts, but when I see the Energy Star on a stove I want to buy, I know it’s energy-efficient and that’s all I need to know as a consumer,” said Ellen A. Wartella, a professor of communication and psychology at Northwestern University and the chairwoman of the committee that wrote the report.
Under the plan recommended in the report, a food could earn up to three stars or checkmarks — one each for falling below a threshold amount for sodium, added sugar or saturated and trans fat.
If a food contained an excessive amount of any one of those nutrients, however, it would get no stars at all.
Some sweetened foods, including sugary soft drinks and candy, would automatically receive zero stars.
Source: William Neuman, New York Times: 10/20/11