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5 March 2010

Low-fat, Mediterranean and low-carb diets 'help heart'

Three diets - Mediterranean, low-fat and low-carbohydrate - are equally effective in helping reverse blocked arteries, say Israeli researchers.

The study of 140 people, reported in the journal Circulation, found diet could reduce the fatty build up in arteries.

The Ben-Gurion University team found that by the end of the two-year study, the arterial wall had been cut by 5%.

Experts said the study was interesting, but diet was not a "magic bullet".

Atherosclerosis is a progressive condition in which the arteries thicken with fatty deposits, increasing the risk of heart attacks and strokes.

The authors of this Israeli study, which was carried out in collaboration with researchers in the US, Canada and Germany, set out to see if this natural part of ageing can be reversed through diet.

Volunteers followed one of three diets - a low-fat diet, a low-carbohydrate diet or a Mediterranean diet, which is based on eating lots of fruit and vegetables, and using olive oil as the main source of fat.

They were asked to stick to the diet for two years, and record what they ate in food diaries.

The study was carried out among overweight volunteers, mostly men, who were aged 40 to 65.

Using three-dimensional imaging, the researchers measured the volume of the wall of the carotid artery, the large artery in the neck which takes blood up to the brain. This was done at the start of the study and again after two years.

Clogged arteries

Lead researcher Iris Shai said: "It was very interesting to see that these very different diets had a similar effect.

"Some people suggest that low-carbohydrate diets are more likely to clog arteries, but we did not see that."

The research paper suggested the link could be related to falling blood pressure caused by the change in diet.

The findings were welcomed by UK experts.

Dr Charles Knight, secretary of the British Cardiovascular Society and a consultant cardiologist, said although the study was "relatively small" and was not able to follow through to find out how many people eventually had heart attacks or strokes, the results were nevertheless "very interesting".

He pointed out that the study adds weight to the growing body of research that suggests that atherosclerosis is a modifiable disease.

Ten to 15 years ago, it was thought that fatty build-up in the arteries was irreversible, but since then drugs trials have shown that it is possible for fatty deposits to be cut.

"This study shows you can do something to reduce plaque build-up, even without pills," Dr Knight said.

"It sends an effective message from a public health perspective."

However, he warned that the scale of reduction in the volume of artery walls was relatively small and that changing diet, although helpful, was "no magic bullet".

Sleep habits linked to fat gain in younger adults

Researchers found that among black and Hispanic adults younger than 40, those who typically slept for five hours or less each night had a greater accumulation of belly fat over the next five years, versus those who averaged six or seven hours.

Those who logged eight hours or more in bed each night also showed a bigger fat gain -- but it was less substantial than that seen in "short sleepers."

The study, reported in the journal Sleep, does not prove that too little or too much sleep directly leads to excess fat gain. But the findings support and extend those of other studies linking sleep duration -- particularly a lack of sleep -- to weight gain and even to higher risks of diabetes and heart disease.

The study adds to past research in part because it focused on black and Hispanic Americans -- two understudied groups who are at increased risk of obesity and its related ills, said lead researcher Dr. Kristen G. Hairston, of Wake Forest University School of Medicine in Winston-Salem, North Carolina.

It also zeroed in on the relationship between sleep and gains in abdominal fat -- both the superficial fat layers just below the skin and the "visceral" fat that surrounds the abdominal organs. Deep abdominal fat is believed to be particularly important in the risks of health conditions like diabetes, high blood pressure and heart disease, Hairston told Reuters Health.

The study included 332 African-American and 775 Hispanic-American men and women ages 18 to 81. At the outset, all reported on their sleep habits, diets, exercise levels and other lifestyle factors. The researchers used CT scans to measure participants' abdominal fat, at the start of the study and again five years later.

Among participants younger than 40, the study found, those who said they slept for five hours or less each night gained more belly fat than those who averaged six or seven hours of sleep.

On average, short sleepers showed a 32 percent gain in visceral fat, versus a 13 percent gain among those who slept six or seven hours per night, and a 22 percent increase among men and women who got at least eight hours of sleep each night.

A similar pattern was seen with superficial abdominal fat. Even when the researchers considered factors like calorie intake, exercise habits, education and smoking, sleep duration itself remained linked to abdominal-fat gain.

The findings, according to Hairston, support the belief that sleep habits affect weight, and health in general. "Sleep is an important part of your overall health -- not just in whether you're tired during the day," she said.

Individuals vary in their sleep needs, so there is no one set prescription. But "extremes of sleep," such as less than five hours per night, should raise concerns, according to Hairston. "And if you're concerned about your sleep," she said, "discuss it with your healthcare provider, just as you would discuss diet or exercise."

As for why sleep duration might affect abdominal-fat gain, there are several theories.

There may be indirect effects; people who get too little sleep may be too tired during the day to exercise, while those who spend a lot of time in bed may spend less time being active, relative to people who sleep fewer hours.

Research also suggests that sleep loss alters people's levels of appetite-regulating hormones -- which could, in theory, spur them to overeat.

Depression, which often affects people's sleep and has been linked to weight gain, could also be a factor, Hairston noted. She and her colleagues had no information on study participants' depression symptoms.

An apple a day? Study shows soluble fiber boosts immune system

URBANA – A new University of Illinois study touts the benefits of soluble fiber—found in oats, apples, and nuts, for starters—saying that it reduces the inflammation associated with obesity-related diseases and strengthens the immune system.

"Soluble fiber changes the personality of immune cells—they go from being pro-inflammatory, angry cells to anti-inflammatory, healing cells that help us recover faster from infection," said Gregory Freund, a professor in the U of I's College of Medicine and a faculty member in the College of Agriculture, Consumer and Environmental Sciences' Division of Nutritional Sciences.

This happens because soluble fiber causes increased production of an anti-inflammatory protein called interleukin-4, he said.

The study will appear in the May 2010 issue of Brain, Behavior, and Immunity and is available online at

In the experiment, laboratory mice consumed low-fat diets that were identical except that they contained either soluble or insoluble fiber. After six weeks on the diet, the animals had distinctly different responses when the scientists induced illness by introducing a substance (lipopolysaccharide) that causes the body to mimic a bacterial infection.

"Two hours after lipopolysaccharide injection, the mice fed soluble fiber were only half as sick as the other group, and they recovered 50 percent sooner. And the differences between the groups continued to be pronounced all the way out to 24 hours," said Christina Sherry, who also worked on the study.

"In only six weeks, these animals had profound, positive changes in their immune systems," she said.

Now Freund has a new question: Could soluble fiber offset some of the negative effects of a high-fat diet, essentially immunizing obese persons against the harmful effects of fat?

Scientists have long known that obesity is linked to inflammatory conditions, such as diabetes and heart disease.

Yet, in a recent study, the U of I scientists demonstrated that fat tissue produces hormones that appear to compensate for this inflammation. "There are significant anti-inflammatory components in fat tissue and, if they were strategically unleashed, they could potentially protect obese people from further inflammatory insults, such as a heart attack or stroke. In obese animals, you can see the body compensating in an effort to protect itself," he said.

Not all fat is bad, the researcher noted. The Mediterranean diet, which receives high marks for its health benefits, includes such foods as olive oil; salmon, tuna, sardines, and trout, which contain important omega-3 and -6 fatty acids; and plant sources of fat, such as flaxseed.

"Now we'd like to find a way to keep some of the anti-inflammatory, positive effects that develop over time with a high-fat diet while reducing that diet's negative effects, such as high blood glucose and high triglycerides. It's possible that supplementing a high-fat diet with soluble fiber could do that, even delaying the onset of diabetes," he said.

This study is one of the first to provide two valuable lessons, said Sherry. The first, already noted, is that soluble fiber has direct anti-inflammatory effects and builds up the immune system. The second is that the amount of soluble fiber necessary to achieve these health benefits is a reasonable, not a pharmacological, amount.

The recommended daily dietary recommendation is 28 to 35 grams of total fiber, but most of the FDA's health claims are for insoluble fiber, and that's where things get a bit complicated, she said.

"Not all fiber is created equal, although you wouldn't know that by reading nutrition labels," said Sherry. "Most manufacturers don't tell you how much of each type of fiber a food contains, and we think it's important that this information be included on a product's packaging."

Good sources of soluble fiber are oat bran, barley, nuts, seeds, lentils, citrus fruits, apples, strawberries, and carrots. "We used a citrus-based pectin in our study," Sherry said.

Insoluble fiber, found in whole wheat and whole-grain products, wheat bran, and green, leafy vegetables, is also valuable for providing bulk and helping food move through the digestive system, but it doesn't provide the boost to the immune system that soluble fiber provides.

2 March 2010

Omega-3, vitamins, minerals may reduce aggressive behaviour

Supplements of omega-3s, vitamins and minerals for prisoners may reduce the number of violent and aggressive episodes in prisoners, according to a new study from The Netherlands.

Nutritional supplements containing vitamins, minerals, omega-3 and omega-6 fatty acids were associated with a 34 per cent reduction in violent incidents, according to findings of a randomized, double-blind, placebo controlled trial with over 200 young adult offenders published in Aggressive Behavior.

On the other hand, a 14 per cent increase in the number of reported incidents in participants in the placebo group were reported by the Dutch scientists, led by Ap Zaalberg from the Dutch Ministry of Justice.

“The prospect of influencing aggression and rule-breaking behavior with nutrients in moderate doses is important enough to warrant further research,” wrote the researchers. “This is particularly true as adequate supplementation may also have beneficial effects on mental health and cognitive functioning.”

Despite the reductions in violent incidents, which were documented by the prison staff, no significant differences were reported by the prisoners themselves when asked to rate their aggression or general health.

“Yet, the results in terms of a substantial reduction in reported incidents seem promising, as this outcome measure in particular may have practical relevance,” wrote Zaalberg and co-workers.

Commenting independently on the research, Professor Michael Crawford, director of the Institute of Brain Chemistry and Human Nutrition at London Metropolitan University told NutraIngredients that the study follows on from a study in England by Bernard Gesch at Oxford University (Br J Psychiat, 2002, Vol. 181, pp 22-28) which found that supplementation of young violent offenders with fatty acids and micronutrients reduced violent offences by some 39 per cent or more.

Dr Gesch’s study was a double blind, placebo-controlled clinical trial, which used the outcome measure was that used by the UK Home Office and Prisons to assess behaviour for legal purposes such as parole. “The measures were pretty robust,” said Prof Crawford.

Milestone research

The area of fatty acid supplementation and aggression was described as “an important development, and about to become more important”, by Prof Jack Winkler, director of the Nutrition Policy Unit at London Metropolitan University.

Talking to NutraIngredients, Prof Winkler said the Zaalberg study extended the data of Gesch and confirms the basic finding: “A good diet reduces aggression,” he said.

With only 200 subjects, the Dutch study would still be classed as small, said Prof Winkler, and “sceptics” have already “nit-picked it on methodological grounds”.

Answers may be forthcoming, said Prof Winkler, noting that Oxford University researchers are currently conducting a double blind, randomised, controlled trial at three locations and planned to include 1,000 subjects. The study is funded by the Wellcome Foundation and supported by the UK Department of Justice and the Prison Service.

“In my view, this could be milestone research, the research that finally makes the world take seriously the connection between diet and mental ill health, in all its forms,” said Prof Winkler.

No challenge to the methods of the new Oxford study has come forward, noted Prof Winkler. “If the results turn out similar to the Gesch and Dutch studies, then it could be a significant breakthrough,” he said.

Professor Crawford added that the link between diet and aggressive behaviour “makes sense on the basis of evidence of links between major depression, suicide and homicide reported by Dr Joseph Hibbeln at the National Institutes of Health in the USA and of course our stuff demonstrating the absolute dependence of the brain on the long chain essential fatty acids.”

Total fat, trans fat linked to higher incidence of ischemic stroke

The incidence of ischemic stroke also increased by 30 percent in the quartile of women consuming the highest daily amount of trans fat (average intake 7 grams per day) compared to those who consumed the least (average 1 gram/day). Two common sources of trans fat are processed foods and fried foods.

Ischemic strokes are caused by blockages in blood vessels in or leading to the brain.

"We found positive associations between total fat intake and ischemic stroke incidence and between trans fat intake and ischemic stroke incidence," said Sirin Yaemsiri, M.S.P.H., a doctoral student in the department of epidemiology in the Gillings School of Global Public Health at the University of North Carolina in Chapel Hill.

The study is the first to examine the associations of different fats and different subtypes of ischemic stroke in post-menopausal women, who face a higher stroke risk than men of a similar age.

Evidence from other studies shows that different types of fat have different effects on the incidence of coronary heart disease (CHD), with trans fat implicated in the development of CHD. However, studies of ischemic stroke and fat have been inconclusive, possibly because earlier studies had small numbers of ischemic stroke cases.

The analysis included data on 87,230 post-menopausal women ages 50 to 79 who participated in the Women's Health Initiative (WHI) Observational Study, a project sponsored by the National Institutes of Health and the National Heart, Lung and Blood Institute. The women answered a food frequency questionnaire when they entered the study and were followed for an average of 7.6 years, the researchers said. During that time, 1,049 ischemic strokes occurred.

Researchers looked for links between dietary fat intake and four ischemic stroke subtypes, which were characterized by their size or point of origin. However, the data on ischemic stroke subtypes fell short of statistical significance, perhaps because strokes are difficult to characterize and 43 percent (445 cases) of the ischemic strokes in the study were of unknown type, Yaemsiri said.

Researchers divided the women into quartiles based on the amount of total dietary fat and types of fat (saturated fat, monounsaturated fat, polyunsaturated fat and trans fat) they reported consuming per day.

Variables included age, race, smoking status, physical activity, alcohol or aspirin use, body mass index, hormone therapy, heart disease history, diabetes, systolic blood pressure and whether the women took medication for high blood pressure or to reduce cholesterol, vitamin E supplementation, fruit/vegetable intake, total calories and dietary fiber.

Women in the top quartile for total fat intake had an average intake of 86 grams of total fat per day. Those in the lowest quartile consumed an average of 26 grams a day.

"I think our findings support the American Heart Association recommendations for keeping trans fat intake at less than 1 percent of energy," said Ka He, M.D., Sc.D., M.P.H., senior author of the study and associate professor of nutrition and epidemiology at the UNC Gillings School of Global Public Health.

Trans fats can be found in many foods – especially in fried foods like french fries and doughnuts, and baked goods including pastries, pie crusts, biscuits, pizza dough, cookies, crackers and stick margarines and shortenings.

Are non-smokers smarter than smokers?

NEW YORK (Reuters Health) - Cigarette smokers have lower IQs than non-smokers, and the more a person smokes, the lower their IQ, a study in over 20,000 Israeli military recruits suggests.

Young men who smoked a pack of cigarettes a day or more had IQ scores 7.5 points lower than non-smokers, Dr. Mark Weiser of Sheba Medical Center in Tel Hashomer and his colleagues found.

"Adolescents with poorer IQ scores might be targeted for programmes designed to prevent smoking," they conclude in the journal Addiction.

While there is evidence for a link between smoking and lower IQ, many studies have relied on intelligence tests given in childhood, and have also included people with mental and behavioral problems, who are both more likely to smoke and more likely to have low IQs, Weiser and his team note in their report.

To better understand the smoking-IQ relationship, the researchers looked at 20,211 18-year-old men recruited into the Israeli military. The group did not include anyone with major mental health problems, because these individuals are disqualified from military service.

According to the investigators, 28 percent of the study participants smoked at least one cigarette a day, around 3 percent said they were ex-smokers, and 68 percent had never smoked.

The smokers had significantly lower intelligence test scores than non-smokers, and this remained true even after the researchers accounted for socioeconomic status as measured by how many years of formal education a recruit's father had completed.

The average IQ for non-smokers was about 101, while it was 94 for men who had started smoking before entering the military. IQ steadily dropped as the number of cigarettes smoked increased, from 98 for people who smoked one to five cigarettes daily to 90 for those who smoked more than a pack a day. IQ scores from 84 to 116 are considered to indicate average intelligence.

Recruits aren't allowed to smoke while intelligence tests are administered, the researchers note, so it's possible that withdrawal symptoms might affect smokers' scores. To address this issue, they also looked at IQ scores for men who were non-smokers when they were 18 but started smoking during their military service. These men also scored lower than never-smokers (97 points, on average), "indicating that nicotine withdrawal was probably not the cause of the difference," the researchers say.

The researchers also compared IQs for 70 pairs of brothers in the group in which one brother smoked and the other did not. Again, average IQs for the non-smoking sibling were higher than for the smokers.

The findings suggest that lower IQ individuals are more likely to choose to smoke, rather than that smoking makes people less intelligent, Weiser and his team conclude.

1 March 2010

Exercise Reduces Anxiety of Chronic Disease

Exercise may benefit the mental well-being of those with chronic illnesses such as heart disease and cancer, a new study suggests.

The results show that patients who participated in exercise training programs reported, on average, a 20 percent reduction in their anxiety symptoms compared to those who did not exercise.

Such feelings of worry and nervousness are common among patients with chronic diseases and may decrease their quality of life and make them less likely to stick to treatment plans, the researchers say. However, the study indicates that exercise may offer a way to treat anxiety without using prescription drugs that may cause adverse side effects, they say.

"Our findings add to the growing body of evidence that physical activities such as walking or weightlifting may turn out to be the best medicine that physicians can prescribe to help their patients feel less anxious," said study-author Matthew Herring, a doctoral student in the department of kinesiology at the University of Georgia.

Low-cost and effective treatments for anxiety will become even more necessary with an increasingly aging population, Herring said.

While much research has focused on the role of exercise in alleviating depression symptoms, comparatively few studies have specifically examined the effect of exercise on anxiety, according to Herring.

Herring and his colleagues analyzed the results of 40 so-called "randomized clinical trials," a type of study that is often looked upon as providing the highest quality research evidence. The studies involved nearly 3,000 patients with chronic conditions, including heart disease, cancer, multiple sclerosis and chronic arthritis pain.

The largest reductions in anxiety were seen in patients who exercised for more than 30 minutes during a single session.

In terms of the entire program length, shorter programs, around three to 12 weeks, were actually found to be more effective than longer ones at decreasing anxiety symptoms. The researchers speculate this result may be due to the tendency for patients not to follow through with longer training programs. "Better participation rates likely will result in greater anxiety reductions," Herring told LiveScience in an email.

The researchers note that many of the reviewed studies did not include sufficient information on how well participants adhered to their exercise program, or whether they were taking other medications, which may have influenced the study's results. Future studies should address these shortcomings to better understand how much exercise is needed to decrease anxiety, the researchers say. In addition, research should include "understudied" diseases, such as lupus and epilepsy, and examine the effects of exercises that are perhaps not as widely used, such as resistant training, they say.

Vitamin B3 Shows Early Promise in Treatment of Stroke

An early study suggests that vitamin B3 or niacin, a common water-soluble vitamin, may help improve neurological function after stroke, according to Henry Ford Hospital researchers.

When rats with ischemic stroke were given niacin, their brains showed growth of new blood vessels, and sprouting of nerve cells which greatly improved neurological outcome.

Now research is underway at Henry Ford to investigate the effects of an extended-release form of niacin on stroke patients. Henry Ford is the only site nationally conducting such a study.

"If this proves to also work well in our human trials, we'll then have the benefit of a low-cost, easily-tolerable treatment for one of the most neurologically devastating conditions," Michael Chopp, Ph.D., scientific director of the Henry Ford Neuroscience Institute.

Dr. Chopp will present results from the animal model study at the International Stroke Conference in San Antonio.

According to the National Stroke Association, stroke is the third-leading cause of death in America and a leading cause of disability.

Ischemic strokes occur as a result of an obstruction within a blood vessel supplying blood to the brain. Ischemic stroke accounts for about 87 percent of all cases. One underlying condition for this type of obstruction is the development of fatty cholesterol deposits lining the vessel walls.

Niacin is known to be the most effective medicine in current clinical use for increasing high-density lipoprotein cholesterol (HDL-C), which helps those fatty deposits.

Dr. Chopp and his colleagues found that in animals niacin helps restore neurological function in the brain following stroke.

In 2009, stroke physicians at Henry Ford Hospital published research which showed that HDL-C is abnormally low at the time stroke patients arrive at the hospital.

Dr. Chopp's research found that in animals, niacin increased "good" cholesterol (HDL-C), which increased blood vessels in the brain and axonal and dendritic growth leading to a substantial improvement in neurological function.

"Niacin essentially re-wires the brain which has very exciting potential for use in humans," says Dr. Chopp. "The results of this study may also open doors in other areas of neurological medicine, including brain injury."

Andrew Russman, D.O., is the principal investigator of the team at Henry Ford Hospital who will evaluate in clinical trials whether niacin improves recovery for human stroke patients.

"If we are able to prove that treating patients with niacin helps to restore neurological function after stroke, we're opening a whole new avenue of treatment for the leading cause of serious long-term disability in adults," says Dr. Russman.