Magnetic brain stimulation improves skill learning

The use of magnetic pulses to stimulate the dorsal premotor cortex (PMd) region of the brain results in an improved ability to learn a skilled motor task. Researchers writing in the open access journal BMC Neuroscience show that skilled movements can be stored as memories in the PMd and that magnetic stimulation of this area can facilitate this learning process.

Lara Boyd and Meghan Linsdell, from the University of British Columbia, studied the effect of transcranial magnetic stimulation of the PMd on the ability of 30 volunteers to track a target on a computer screen using a joystick. During the task, the target would move randomly, then enter a programmed pattern and finally return to moving randomly. The participants were not aware of the repeated section, believing that movements were random throughout.

The volunteers received four days of training, during which they were either given excitatory stimulation, inhibitory stimulation or sham stimulation immediately before practicing the motor task. The volunteers were not aware which group they were in. On the fifth day, they were tested to see how well they had learned the task. By comparing the improvements between the random and repeated sections of the task, the researchers were able to separate the general improvement due to practice from the learned motor memory of the repeated section.

Those participants who had received the excitatory stimulation were significantly better than the other groups at tracking the target during the repeated section of the test. They showed no significant difference in improvement during the random sections. The researchers conclude, "Our data support the hypothesis that the PMd is important for continuous motor learning, specifically via off-line consolidation of learned motor behaviors". Read more!

2 dietary oils, 2 sets of benefits for older women with diabetes

COLUMBUS, Ohio – A study comparing how two common dietary oil supplements affect body composition suggests that both oils, by themselves, can lower body fat in obese postmenopausal women with Type 2 diabetes.

The two oils compared were safflower oil, a common cooking oil, and conjugated linoleic acid (CLA), a compound naturally found in some meat and dairy products that has been associated with weight loss in previous studies. Both are composed primarily of polyunsaturated fatty acids, which are considered "good fats" that, when consumed in proper quantities, are associated with a variety of health benefits.

In the study, 16 weeks of supplementation with safflower oil reduced fat in the trunk area, lowered blood sugar and increased muscle tissue in the women participants.

Conjugated linoleic acid supplementation for the same length of time, on the other hand, reduced total body fat and lowered the women's body mass index (BMI), a common health measure of weight relative to height.

All of the women in the study took one oil for 16 weeks, followed by the other oil for an equal amount of time. The participants were instructed not to change their diets or exercise patterns over the course of the study so the research would measure the effects of only the supplementation.

"Making this subtle change in the intake of high-quality dietary fats in an effort to alter body composition is both achievable and affordable to postmenopausal women in the United States who are managing the difficult combination of obesity and diabetes," said Martha Belury, professor of human nutrition at Ohio State University and senior author of the study.

Among the most surprising findings: that in 16 weeks, these women could lose between about two pounds and four pounds of trunk fat simply by taking safflower oil supplements.

"I never would have imagined such a finding. This study is the first to show that such a modest amount of a linoleic acid-rich oil may have a profound effect on body composition in women," Belury said. The dose of either oil taken each day was approximately 1 2/3 teaspoons.

Postmenopausal women tend to lose muscle at the same time that body fat accumulates toward their middle, so this research shows how dietary oils can complement lifestyle and medication in helping older diabetic women manage their health, she said.

The research appears online and is scheduled for later print publication in the American Journal of Clinical Nutrition.

Thirty-five women participated in the study. All were considered obese based on their BMI measures of 30 or higher, were postmenopausal but younger than age 70, and had Type 2 diabetes but did not need to take insulin to treat the disease. Many did take other medications, such as those used to manage blood sugar levels, cholesterol or blood pressure.

The women were randomized into two groups to determine which supplement they took first. Each initial 16-week supplementation was followed by a four-week washout period to remove the first supplement from their systems before the next 16-week supplementation period began. The supplements were contained in eight pills; the women took two pills four times per day, at meals and bedtime.

"The power of the crossover is that it tells you the different effects of the dietary oils in the same woman," Belury said.

The daily supplementation contained 6.4 grams of each oil's active fatty acid: linoleic acid in safflower oil and, in CLA, specific fatty acid isomers – compounds that share the same chemical formula but differ in chemical structure.

The researchers used dual-energy X-ray absorptiometry, commonly known as DXA and usually used to measure bone density, to determine the women's baseline and follow-up lean mass and fat throughout their bodies and specifically in their trunk region.

Researchers asked the participants to keep diet and activity records for three consecutive days at four points over the course of the study to account for the potential for calorie intake or exercise to affect the results, Belury said. Physical activity remained unchanged throughout the study, and no significant differences were seen between the two groups' reported calorie intake.

The study showed that CLA supplementation significantly decreased body mass index and total body fat over both diet periods, typically showing effects in the last half of each 16-week period. The BMI levels of the women taking CLA dropped on average by about half a point, and their total body fat decreased by an average of 3.2 percent, reducing the weight of the fat tissue by an average of between 2.3 pounds and 3.5 pounds.

Safflower oil supplementation showed no effect on total body fat readings, but reduced the weight of trunk fat tissue by between 2.6 pounds and 4.2 pounds, or an average of 6.3 percent. It also increased lean tissue, or muscle, by between an average of about 1.4 pounds and 3 pounds.

Safflower oil also lowered fasting blood sugar levels by between 11 and 19 points on average. Blood sugar is considered normal if it falls below 110 milligrams per deciliter; the women's average blood sugar levels ranged from 129 to 148 after 16 weeks of safflower oil supplementation.

"Lowering fasting glucose is important for these women. The overall effect in just 16 weeks wasn't bringing them back to normal, but safflower oil still improved it significantly," Belury said.

The dietary oils did not have significant effects on other health measurements, such as waist circumference, waist-to-hip ratio and skinfold thickness measures of body fat, Belury noted.

The CLA also did not appear to affect the variety of hormones involved in fat burning. However, safflower oil increased a hormone called adiponectin. Increasing this hormone may have instilled an improved ability to burn dietary fats, said Belury, who hopes to investigate this mechanism in a follow-up study.

Belury said that other work she is conducting in animals suggests that at least in the case of CLA, the fatty acid appears to allow the body to burn calories in a heat-producing way. Questions remain about the long-term safety of any kind of supplementation that lowers body fat, because some research has suggested that the fat that leaves fat tissue ends up in the liver or muscles – a condition that could lead to insulin resistance and diabetes if that fat can't be used.

Neither CLA nor the linoleic acid in safflower oil is naturally produced in the human body, so both must be obtained from food or dietary supplements. Linoleic acid is an omega-6 fatty acid that is important in growth and maintenance of tissues and lipid metabolism. The American Heart Association recently issued recommendations suggesting that omega-6 fatty acids are among the polyunsaturated fats that should be consumed for heart health.

CLA is found naturally in trace amounts primarily in beef, lamb and milk, but obtaining levels comparable to those used in Belury's study likely requires concentrated doses similar to those found in dietary supplements.

"Essentially what we're trying to understand with nutrition is how dietary approaches can complement Westernized medicine," Belury said. "In an ideal world, we'd love it if women like those in our study could use diet, activity and other aspects of a healthy lifestyle to manage their health. But most will probably be on oral medications for the rest of their lives for managing their diabetes and metabolism, which is fine as long as the medications work. We think there's a chance that nutrition can complement medication and help drugs work even better." Read more!

Chlorine in Your Baby Carrots

The small cocktail or “baby” carrots you buy are made using the larger crooked or deformed carrots which are put through a machine which cuts and shapes them into cocktail carrots. You might have known that already. But what you might not know is that once the carrots are cut and shaped into cocktail carrots, they are dipped in a solution of water and chlorine in order to preserve them.

When a baby carrot turns white (“white blushing”), this causes the bags of carrots to be pulled from the shelf and thrown away. To prevent this consumer waste, the carrots are dipped in chlorine to prevent the white blushing from happening.

Chlorine is a very well-known carcinogen. Organic growers instead use a citrus based, nontoxic solution called Citrox. Read more!

What's in that bottle? Congress says water unclear

WASHINGTON (Reuters) - Bottled water makers make millions off people who believe their products are purer than tap water, but consumers do not realize that they are less regulated than plain old tap water, according to a U.S. Congressional report released on Wednesday.

The report from the General Accountability Office also found that the U.S. Food and Drug Administration has little power to regulate the safety of bottled water, and even states with the power to regulate it concentrate more on tap water.

The report was just one piece of ammunition unleashed at the bottled water industry at a hearing of the House of Representatives Energy and Commerce Subcommittee on Oversight and Investigations.

"Of particular note, FDA does not have the specific statutory authority to require bottlers to use certified laboratories for water quality tests or to report test results, even if violations of the standards are found," the GAO report reads.

Jane Houlihan of the Environmental Working Group, an advocacy organization that submitted a second report to the committee, said in a statement: "Many people assume bottled water is healthier and safer to drink than ordinary tap water.

"But some companies have lured consumers away from the tap with claims of health and purity that aren't backed by public data."

Sponsors of the hearing agreed.

"Americans are willing to pay top dollar for bottled water, which costs up to 1,900 times more than tap water and uses up to 2,000 times more energy to produce and deliver," Michigan Representative Bart Stupak told the hearing.

CONTAMINATION

"Over the past several years, however, bottled water has been recalled due to contamination by arsenic, bromate, cleaning compounds, mold, and bacteria. In April, a dozen students at a California junior high school reportedly were sickened after drinking bottled water from a vending machine."

Joseph Doss, president and chief executive officer of the International Bottled Water Association, told the hearing that Americans drank 8.7 billion gallons (33 billion liters) of water in 2008, or 28.5 gallons (108 liters) per person.

"Sales revenues for the United States bottled water market in 2008 were approximately $11.2 billion," Doss said. "Bottled water consumption is about half that of carbonated soft drinks and only slightly ahead of milk and beer.

The GAO found that the FDA does not regulate a compound called DEHP in bottled water. The Environmental Protection Agency regulated levels of DEHP, a so-called phthalate linked to some health risks, in tap water.

"Specifically, FDA deferred action on DEHP in a final rule published in 1996 and has yet to either adopt a standard or publish a reason for not doing so on the safety of bottled water," the GAO said.

Doss said DEHP was unlikely to be in bottled water, which he said was governed by several layers of regulation. Read more!

Obesity health risk cause 'found'

Scientists believe they may have uncovered a key reason why obese people have a raised risk of health complications such as type 2 diabetes.

They blame a specific protein - pigment epithelium-derived factor (PEDF) - which is secreted by fat cells.

The Australian and US research on mice suggests blocking some of PEDF's action may reverse some complications - raising hopes of new drug treatments.

The study appears in the journal Cell Metabolism.


In light of our findings, we believe that blocking PEDF will ameliorate several obesity-related complications

Dr Matthew Watt
Monash University
Because PEDF is produced by fat cells people who are overweight have higher levels of the protein in the bloodstream.

The latest research shows that the protein sends a signal to other tissues in the body, triggering development of insulin resistance - a condition that often leads to type 2 diabetes - in the muscle and liver.

Raised PEDF levels were also linked to a release of fats into the bloodstream, raising the risk of complications such as heart disease.

Metabolism

In tests on obese mice, the researchers found that treatments designed to block the action of PEDF lowered the animals' blood fat level and reversed some of their insulin resistance.

Fat cells are known to play an important role in regulating the body's metabolism by releasing hormones and other chemicals.

This pattern of secretion is also known to change with the size of the fat cells.

The latest study set out to identify which of these secretions had a profound general impact on metabolism.

Tackling insulin resistance directly, even in the absence of weight loss, could potentially strengthen our ability to help obese patients reduce their risk of life-shortening disease

Dr Ian Campbell, medical director of the charity Weight Concern
The researchers took particular interest in PEDF because it was already known that levels of the protein were raised in people with type 2 diabetes, and metabolic syndrome - a collection of risk factors including too much belly fat, high cholesterol and high blood pressure.

They found that of all the molecules secreted by fat cells PEDF was among the most abundant.

They also showed that PEDF levels fell in obese mice when they lost weight, either by using diet or drugs.

When lean mice were injected with PEDF they showed signs of developing insulin resistance and inflammation in both muscle and liver.

And in the long term, PEDF raised fat levels in the animals' blood.

These fats were transported into the muscle and liver, where they accumulated, raising the risk of insulin resistance still further.

Complications

But when obese mice were given treatment to neutralise PEDF their sensitivity to insulin improved, reducing their risk of diabetes, and the level of fats in their blood fell.

Researcher Dr Matthew Watt, from Monash University in Australia, said: "In light of our findings, we believe that blocking PEDF will ameliorate several obesity-related complications."

He said previous research had suggested that PEDF also protects against furring of the arteries and excessive blood vessel growth and helps keep the nervous system healthy.

But he said new drugs could be at least five years away.

Dr Victoria King, of Diabetes UK, said: "While this study has been carried out in mice, there has been some indication from other studies that higher levels of this protein found in overweight people with type 2 diabetes could indicate that a similar process is occurring in humans.

"But this would need to be studied further and verified."

Dr Ian Campbell, medical director of the charity Weight Concern, said: "If we were able to somehow switch off or limit the activities of this, or related compounds it could open up new possibilities for drug treatments, not for obesity, but for the secondary effects.

"To date weight loss drugs though effective are often not effective enough.

"Tackling insulin resistance directly, even in the absence of weight loss, could potentially strengthen our ability to help obese patients reduce their risk of life-shortening disease."

Professor Ian MacDonald, an expert in the chemistry of nutrition at the University of Nottingham, said PEDF was one of many chemicals produced by fat cells and it was unclear how they all interacted with each other. Read more!

When Should You Eat to Fuel Exercise?

No matter what kind of exercise you do, you need food and water to fuel the effort. But when’s the best time to eat before exercise?




According to Leslie Bonci, director of sports nutrition at the University of Pittsburgh Medical Center, your food is just like your running shoes or your skis. If you think of it this way, you’ll have a better outcome when you’re physically active.

There are two common mistakes. One is not eating anything before exercise, and that means you’re not putting fuel into your body -- you’ll be more tired and weaker. The second issue is eating too much. Bonci says the right quantity is a fist-sized amount of food an hour before exercise.



At that same time, you should have about 20 ounces of liquid. It takes about 60 minutes for that much liquid to leave the stomach and make its way into the muscle. If you have liquid ahead of time, you’ll be better hydrated when you start to be physically active. Read more!

Coffee 'may reverse Alzheimer's'

Drinking five cups of coffee a day could reverse memory problems seen in Alzheimer's disease, US scientists say.

The Florida research, carried out on mice, also suggested caffeine hampered the production of the protein plaques which are the hallmark of the disease.

Previous research has also suggested a protective effect from caffeine.

But British experts said the Journal of Alzheimer's disease study did not mean that dementia patients should start using caffeine supplements.

The 55 mice used in the University of South Florida study had been bred to develop symptoms of Alzheimer's disease.

First the researchers used behavioural tests to confirm the mice were exhibiting signs of memory impairment when they were aged 18 to 19 months, the equivalent to humans being about 70.

Then they gave half the mice caffeine in their drinking water. The rest were given plain water.

The mice were given the equivalent of five 8 oz (227 grams) cups of coffee a day - about 500 milligrams of caffeine.

The researchers say this is the same as is found in two cups of "specialty" coffees such as lattes or cappuccinos from coffee shops, 14 cups of tea, or 20 soft drinks.

When the mice were tested again after two months, those who were given the caffeine performed much better on tests measuring their memory and thinking skills and performed as well as mice of the same age without dementia.

Those drinking plain water continued to do poorly on the tests.

In addition, the brains of the mice given caffeine showed nearly a 50% reduction in levels of the beta amyloid protein, which forms destructive clumps in the brains of dementia patients.

Further tests suggested caffeine affects the production of both the enzymes needed to produce beta amyloid.

The researchers also suggest that caffeine suppresses inflammatory changes in the brain that lead to an overabundance of the protein.

Earlier research by the same team had shown younger mice, who had also been bred to develop Alzheimer's but who were given caffeine in their early adulthood, were protected against the onset of memory problems.

'Safe drug'

Dr Gary Arendash, who led the latest study, told the BBC: "The results are particularly exciting in that a reversal of pre-existing memory impairment is more difficult to achieve.

"They provide evidence that caffeine could be a viable 'treatment' for established Alzheimer's disease and not simply a protective strategy.

"That's important because caffeine is a safe drug for most people, it easily enters the brain, and it appears to directly affect the disease process."

The team now hope to begin human trials of caffeine to see if the mouse findings are replicated in people.

They do not know if a lower amount of caffeine would be as effective, but said most people could safely consume the 500 milligrams per day.

However they said people with high blood pressure, and pregnant women, should limit their daily caffeine intake.

Rebecca Wood, chief executive of the Alzheimer's Research Trust, said: "In this study on mice with symptoms of Alzheimer's, researchers found that caffeine boosted their memory. We need to do more research to find out whether this effect will be seen in people.

"It is too early to say whether drinking coffee or taking caffeine supplements will help people with Alzheimer's.

Neil Hunt, chief executive of the Alzheimer's Society, said previous research into caffeine had suggested it could delay Alzheimer's disease and even protect against vascular dementia.

"This research in mice suggests that coffee may actually reverse some element of memory impairment.

"However much more research is needed to determine whether drinking coffee has the same impact in people.

"It is too soon to say whether a cup of coffee is anything more than a pleasant pick me up." Read more!

Walnuts can cut cholesterol

A meta-analysis of walnuts by Harvard scientists has found diets rich in walnuts can significantly reduce cholesterol levels, supporting growing evidence to suggest these popular nuts can improve healthy blood lipid ratios.

In their investigation of thirteen studies, the researchers demonstrated that walnut-rich consumption decreased total and low-density lipoprotein (LDL) cholesterol during short term trials.


However the scientists suggested that "larger and longer-term trials" are needed to observe the effects of eating walnuts, rich in polyunsaturated fatty acids, on cardiovascular risk and weight management.


Their analysis joins a blossoming body of science that has linked nut consumption – including almonds and macadamias – to improvements in markers of cardiovascular health.


Coronary heart disease places a significant financial burden on all European states, and in the UK alone costs the health system more than €5bn per year. Governments, scientists and the food industry itself continue to invest time and money in pinpointing potential dietary solutions that could boost cardiovascular health.

Design of the meta-analysis


Published in a recent issue of the American Journal of Clinical Nutrition, researchers Deirdre Banel and Frank Hu conducted the meta-analysis to, "estimate the effect of walnuts on blood lipids".


Literature databases were searched for published trials that compared a specifically walnut-enhanced diet with a control diet.


"We conducted a random-effects meta-analysis of weighted mean differences of lipid outcomes," said the scientists.


The 13 studies selected represented some 365 participants, with diets lasting between four and 24 weeks and walnuts providing between 10 and 24 per cent of total calories.


"When compared with control diets, diets supplemented with walnuts resulted in a significantly greater decrease in total cholesterol and in LDL-cholesterol concentrations," the Harvard researchers wrote.


Further, the meta-analysis results gave a nod to the widening circle of potential health benefits contained in walnuts.


"Other results reported in the trials indicated that walnuts provided significant benefits for certain antioxidant capacity and inflammatory markers and had no adverse effects on body weight," stated the researchers.


Source: American Journal of Clinical Nutrition


May 2009, Volume 90, Pages 56-63, doi:10.3945/ajcn.2009.27457


‘Effects of walnut consumption on blood lipids and other cardiovascular risk factors: a meta-analysis and systematic review’ Read more!

Lack of sleep 'hits women harder'

Lack of sleep raises a woman's risk of heart disease more than it does for a man, research suggests.

Sleeping less than the recommended eight hours a night has been linked to a raised risk of heart problems.

Researchers found levels of inflammatory markers - indicators of heart disease - vary significantly with sleep duration in women, but not men.

The study, by University College London and the University of Warwick, appears in the journal Sleep.

Previous research has suggested people who sleep less than five hours a night have an increased risk of dying from cardiovascular disease, compared to those who get the full eight hours.

The latest study found levels of a molecule called interleukin-6 (IL-6), which is known to trigger inflammation, were much lower in women who reported sleeping eight hours, compared to those who slept for seven hours.

Levels of another molecule, high-sensitivity C-reactive protein (hs-CRP) - which is linked to heart problems - were significantly higher in women who reported sleeping for five hours or less.

Hormones

Researcher Dr Michelle Miller said the findings added to the growing body of evidence suggesting that sleep duration played a key role in heart health.

She said: "The results also are consistent with the idea that sleeping seven or eight hours per night appears to be optimal for health."

Dr Miller said more work was required to pin down why lack of sleep potentially had a greater effect on women.

However, she said differences in hormone levels might be key. There is work to suggest that inflammatory marker levels are different in pre- and post-menopausal women.

The study was based on data from more than 4,600 London-based civil servants aged 35 to 55, of which 73% were men.

Dr Janet Mullington, of Harvard Medical School, said there were many questions still to be answered about the effect of sleep deprivation.

She said it was possible that the change to inflammatory markers produced in sleep deprivation experiments were merely short-term reflections of the battle against sleepiness.

They might also be influenced by the unusual conditions, such as the interaction between the participants and the researchers.

June Davison, a cardiac nurse at the British Heart Foundation, said: "Previous research suggests that a good night's sleep may help to keep our heart and circulation healthy, and this study could point to an underlying reason behind that finding.

"We should all try to get enough sleep - as it's likely to be good for heart health as well as overall health." Read more!

Vitamin D deficiency is widespead and on the increase

Highest rates in South Asia and the Middle East
A new report issued by the International Osteoporosis Foundation (IOF) and published in the scientific journal Osteoporosis International1, shows that populations across the globe are suffering from the impact of low levels of vitamin D. The problem is widespread and on the increase, with potentially severe repercussions for overall health and fracture rates.

Compiled by IOF's expert working group on nutrition, the report reviews the scope and causes of low vitamin D levels in six regions: Asia, Europe, Latin America, Middle East and Africa, North America and Oceania. Regional reports are available on the IOF website

Vitamin D is mainly produced in the skin upon exposure to sunlight, and, to a lesser extent, is derived from nutritional sources. It plays an important role, through its influence on calcium levels, in the maintenance of organ systems, and is needed for normal bone mineralization and growth. Suboptimal levels of vitamin D may lead to increased risk of osteoporosis and hip fracture and, in severe cases, to the development of rickets, a softening of bones in children that can lead to skeletal fractures and deformity.

Although there is ongoing debate as to what constitutes the optimal level of vitamin D, the report shows that regardless of whether it is defined at 50nmol/L or 75nmol/L, vitamin D status is seriously inadequate in large proportions of the population across the globe.

The main risk factors for low vitamin D levels include older age, female sex, lower latitudes, winter season, darker skin pigmentation, less sunlight exposure, dietary habits, and the absence of vitamin D fortification in common foods. Further factors include the increase in urbanization, where people tend to live and work indoors, as well as cultural practices that tend towards sun avoidance and the wearing of traditional clothing that covers the skin. The severity of the problem in Middle East and South Asia arises from the combination of several of these risk factors.

These findings suggest that prevention strategies must be initiated at the national level - especially given the increasing ageing of populations in many regions of the world. National plans of action should encourage safe, limited exposure to sunlight and improved dietary intake of vitamin D, whilst considering fortification of foods as well. Read more!