Stomach 'Clock' Tells Us How Much to Eat

University of Adelaide researchers have discovered the first evidence that the nerves in the stomach act as a circadian clock, limiting food intake to specific times of the day.

The discovery, published today in The Journal of Neuroscience, could lead to new information about how the gut signals to our brains about when we're full, and when to keep eating.

In the University's Nerve-Gut Research Laboratory, Dr Stephen Kentish investigated how the nerves in the stomach respond to stretch, which occurs as a consequence of food intake, at three-hourly intervals across one day.

"These nerves are responsible for letting the brain know how much food we have eaten and when to stop eating," says Dr Kentish, who is the lead author of the paper.

"What we've found is that the nerves in the gut are at their least sensitive at time periods associated with being awake. This means more food can be consumed before we feel full at times of high activity, when more energy is required.

"However, with a change in the day-night cycle to a period associated with sleeping, the nerves in the stomach become more sensitive to stretch, signaling fullness to the brain quicker and thus limiting food intake. This variation repeats every 24 hours in a circadian manner, with the nerves acting as a clock to coordinate food intake with energy requirements," he says.

So far this discovery has been made in laboratory studies, not in humans.

"Our theory is that the same variations in nerve responses exist in human stomachs, with the gut nerves being less sensitive to fullness during the day and more sensitive at night," Dr Kentish says.

Study leader Associate Professor Amanda Page says this research could lead to further discoveries about how changes in people's circadian clocks affect their eating habits.

"We know that shift workers, for example, are more prone to disruptions in sleep and eating behavior, leading to obesity and other health problems. We are now conducting further research to see what kind of impact such changes to the circadian rhythm will have on eating behavior, and how the nerves in the stomach react to those changes," Associate Professor Page says.

Source: science Daily

N.H.Khider

'Healthy and overweight' is a myth, study suggests

Excess fat still carries health risks even when cholesterol, blood pressure and sugar levels are normal, according to a study of more than 60,000 people.

It has been argued that being overweight does not necessarily imply health risks if individuals remain healthy in other ways.

The research, published in Annals of Internal Medicine, contradicts this idea.

The study looked at findings from published studies tracking heart health and weight in more than 60,000 adults.

This really casts doubt on the existence of healthy obesity”

Dr Ravi Retnakaran Mount Sinai Hospital, Toronto

Researchers from the Mount Sinai Hospital, Toronto, found there was no healthy pattern of increased weight when heart health was monitored for more than 10 years.

They argue that people who are metabolically healthy but overweight probably have underlying risk factors that worsen over time.

Study leader Dr Ravi Retnakaran told BBC News: "This really casts doubt on the existence of healthy obesity.

"This data is suggesting that both patients who are obese who are metabolically unhealthy and patients who are obese who are metabolically healthy are both at increased risk of death from cardiovascular disease, such that benign obesity may indeed be a myth."

Heart risk

The British Heart Foundation says obesity is a known risk factor for heart disease and the research shows there is no healthy level of obesity.

Senior cardiac nurse, Doireann Maddock, said: "So, even if your blood pressure, cholesterol and blood sugar levels are normal, being obese can still put your heart at risk."

She said it was useful to think of lifestyle overall rather than individual risk factors.

"As well as watching your weight, if you stop smoking, get regular physical activity and keep your blood pressure and cholesterol levels at a healthy level, you can make a real difference in reducing your risk of heart disease.

"If you are concerned about your weight and want to know more about the changes you should make, visit your GP to talk it through."

Source : BBC

N.H.Khider

Human Stem Cells Converted to Functional Lung Cells

For the first time, scientists have succeeded in transforming human stem cells into functional lung and airway cells. The advance, reported by Columbia University Medical Center (CUMC) researchers, has significant potential for modeling lung disease, screening drugs, studying human lung development, and, ultimately, generating lung tissue for transplantation. The study was published today in the journal Nature Biotechnology.

"Researchers have had relative success in turning human stem cells into heart cells, pancreatic beta cells, intestinal cells, liver cells, and nerve cells, raising all sorts of possibilities for regenerative medicine," said study leader Hans-Willem Snoeck, MD, PhD, professor of medicine (in microbiology & immunology) and affiliated with the Columbia Center for Translational Immunology and the Columbia Stem Cell Initiative. "Now, we are finally able to make lung and airway cells. This is important because lung transplants have a particularly poor prognosis. Although any clinical application is still many years away, we can begin thinking about making autologous lung transplants -- that is, transplants that use a patient's own skin cells to generate functional lung tissue."

The research builds on Dr. Snoeck's 2011 discovery of a set of chemical factors that can turn human embryonic stem (ES) cells or human induced pluripotent stem (iPS) cells into anterior foregut endoderm -- precursors of lung and airway cells. (Human iPS cells closely resemble human ES cells but are generated from skin cells, by coaxing them into taking a developmental step backwards. Human iPS cells can then be stimulated to differentiate into specialized cells -- offering researchers an alternative to human ES cells.)

In the current study, Dr. Snoeck and his colleagues found new factors that can complete the transformation of human ES or iPS cells into functional lung epithelial cells (cells that cover the lung surface). The resultant cells were found to express markers of at least six types of lung and airway epithelial cells, particularly markers of type 2 alveolar epithelial cells. Type 2 cells are important because they produce surfactant, a substance critical to maintain the lung alveoli, where gas exchange takes place; they also participate in repair of the lung after injury and damage.

The findings have implications for the study of a number of lung diseases, including idiopathic pulmonary fibrosis (IPF), in which type 2 alveolar epithelial cells are thought to play a central role. "No one knows what causes the disease, and there's no way to treat it," says Dr. Snoeck. "Using this technology, researchers will finally be able to create laboratory models of IPF, study the disease at the molecular level, and screen drugs for possible treatments or cures."

"In the longer term, we hope to use this technology to make an autologous lung graft," Dr. Snoeck said. "This would entail taking a lung from a donor; removing all the lung cells, leaving only the lung scaffold; and seeding the scaffold with new lung cells derived from the patient. In this way, rejection problems could be avoided." Dr. Snoeck is investigating this approach in collaboration with researchers in the Columbia University Department of Biomedical Engineering.

"I am excited about this collaboration with Hans Snoeck, integrating stem cell science with bioengineering in the search for new treatments for lung disease," said GordanaVunjak-Novakovic, PhD, co-author of the paper and Mikati Foundation Professor of Biomedical Engineering at Columbia's Engineering School and professor of medical sciences at Columbia University College of Physicians and Surgeons.

Source: Science Daily

R.Sawas

Late starters' still have much to gain by exercising

Taking up exercise in your 60s will still help stave off major ill health and dementia, research suggests.

The study in the British Journal of Sports Medicine followed 3,500 healthy people at or around retirement age.

Those who took up exercise were three times more likely to remain healthy over the next eight years than their sedentary peers.

Exercise cut the risk of heart disease, stroke, diabetes, Alzheimer's disease and depression.

People who took up exercise in their 60s were also less likely to struggle with day-to-day activities such as washing and dressing.

Healthy agers

After eight years of follow-up, a fifth of the participants were defined as healthy - not suffering from any major chronic mental or physical illness.

This group was largely made up of people who always exercised and relative newcomers to exercise. Few were people who did no exercise at all.

Doing regular exercise throughout your life is ideal, say the researchers, but there are health benefits to be had even if you are a late starter.

Lead investigator Dr Mark Hamer, from University College London, said: "The take-home message really is to keep moving when you are elderly.

"It's [a] cliche, but it's a case of use it or lose it. You do lose the benefits if you don't remain active."

In the study, those who had regularly indulged in moderate or vigorous physical activity at least once a week were three to four times more likely to be healthy agers than those who had remained inactive, even after taking into account factors such as smoking.

Dr Hamer says physical activity does not necessarily mean going to the gym or going for a run - gardening or walking to the shops also counts.

The Department of Health recommends all adults, including those over 65, do 150 minutes of physical activity a week.

Doireann Maddock, of the British Heart Foundation, said: "It's well worth getting into the habit of keeping active, as we know it can help reduce the risk of heart disease along with many other conditions.

"Every 10 minutes counts, so even hopping off the bus a couple of stops early or taking a brisk walk on your lunch break will help."

Source : BBC

N.H.Khider

Walnuts are the healthiest nut, say scientists

Eating raw walnuts gives the full benefits of antioxidants.

Walnuts are the healthiest of all the nuts and should be eaten more as part of a healthy diet, US scientists say.

Scientists from Pennsylvania told the American Chemical Society that walnuts contain the highest level of antioxidants compared to other nuts.

Antioxidants are known to help protect the body against disease.

The scientists said that all nuts have good nutritional qualities but walnuts are healthier than peanuts, almonds, pecans and pistachios.

Dr Joe Vinson, from the University of Scranton, analysed the antioxidant levels of nine different types of nuts and discovered that a handful of walnuts contained twice as many antioxidants as a handful of any other commonly eaten nut.

He found that these antioxidants were higher in quality and potency than in any other nut.

Antioxidants are good because they stop the chain reactions that damage cells in the body when oxidation occurs.

Roasted nuts

The antioxidants found in walnuts were also two to 15 times as powerful as vitamin E, which is known to protect the body against damaging natural chemicals involved in causing disease, the study says.

Nuts are known to be healthy and nutritious, containing high-quality protein, lots of vitamins and minerals as well as dietary fibre. They are also dairy and gluten-free.

Previous research has shown that regular consumption of small amounts of nuts can reduce the risk of heart disease, some types of cancer, type two diabetes and other health problems.

Dr Vinson said there was another advantage in choosing walnuts as a source of antioxidants: "The heat from roasting nuts generally reduces the quality of the antioxidants.

"People usually eat walnuts raw or unroasted, and get the full effectiveness of those antioxidants."

Source ; BBC

N.H.Khider