Friday 30 October 2009
Proof Mounts On Restricted Diet
Cutting calories may delay the ageing process and reduce the risk of disease, a long-term study of monkeys suggests.
The benefits of calorie restriction are well documented in animals, but now the results have been replicated in a close relative of man over a lengthy period.
Over 20 years, monkeys whose diets were not restricted were nearly three times more likely to have died than those whose calories were counted.
Writing in Science, the US researchers hailed the "major effect" of the diet.
It involved reducing calorie intake by 30% while maintaining nutrition and appeared to impact upon many forms of age-related disease seen in monkeys, including cancer, diabetes, cardiovascular disease and brain atrophy.
Whether the same effects would be seen in humans is unclear, although anecdotal evidence so far suggests people on a long-term calorie-restricted diet have better cardiovascular health.
The precise mechanism is yet to be established: theories involve changes in the body's metabolism or a reduction in the production of "free radical" chemicals which can cause damage.
Seventy-six rhesus monkeys were involved in the trial, which began in 1989 and was expanded in 1994.
Half had their diets restricted, half were given free rein at feeding time.
The rate of cancers and cardiovascular disease in dieting animals was less than half of those permitted to eat freely.
While diabetes and problems with glucose regulation were common in monkeys who ate what they wanted, there were no cases in the calorie controlled group.
In addition, while most brains shrink with age, the restricted diet appeared to maintain the volume of the brain at least in some regions.
In particular, the areas associated with movement and memory seemed to be better preserved.
"Both motor speed and mental speed slow down with ageing," said Sterling Johnson, a neuroscientist at the University of Wisconsin-Madison School of Medicine.
"Those are the areas which we found to be better preserved. We can't yet make the claim that a difference in diet is associated with functional change because those studies are still ongoing".
"What we know so far is that there are regional differences in brain mass that appear to be related to diet."
Earlier this year, German researchers published findings from their study of elderly people which suggested that calorie reduction appeared to improve memory over a period of just three months.
Various studies on the positive effects of calorie restriction on the life spans of various organisms - from yeast to dogs - have been published over the last 70 years
But dieticians sounded a note of warning.
"Monkeys may be a close relation but there are significant differences which means not everything we see in them can be translated to humans," said Catherine Collins, spokeswoman for the British Dietetic Association.
"And there should be some serious reservations about cutting calories so dramatically, particularly for anyone under the age of 30. Any such diet would need to be very balanced to avoid malnutrition, and it would be a long-term commitment".
"People would have to weigh up whether they are prepared to compromise their enjoyment of food for the uncertain promise of a longer life, and a life which could be dogged by all sorts of problems - including osteoporosis."
Source - BBC
Copyright 2009
Obesity Drug Fears Investigated
US authorities are investigating concerns an anti-obesity drug widely available over the counter at chemists may cause liver damage.
Orlistat went on sale under the brand name Alli without the need for a prescription in the UK in April.
The US Food and Drug Administration has received more than 30 reports linking the drug to serious liver injury.
However, manufacturer GlaxoSmithKline said there was no evidence the drug caused liver damage.
In six of the cases reported to the FDA patients went on to develop organ failure.
The pill, which works by blocking the absorption of fat in the body, is aimed at adults with a Body Mass Index (BMI) of 28 or more. It is also available on prescription as Xenical.
Clinical trials suggest adding orlistat to a reduced-calorie, lower-fat diet, can help people lose 50% more weight than dieting alone.
Big sales
Since going on sale at UK pharmacies around 200,000 people have bought the drug.
Diarrhoea and gas problems are to be expected if users persist in eating fat while taking the drug.
However, concerns have been raised over the medication's other possible side-effects.
The FDA said the most commonly reported adverse reactions included the yellowing of skin or whites of the eyes, weakness and stomach pain.
Between 1999 and 2008, the agency received 32 reports of liver damage, 30 of which occurred outside the US. Of these 27 resulted in hospitalisation.
The agency said it was now conducting a review of the safety of the drug, but stressed no definite association with liver damage had been established at this stage.
It advised people who used orlistat to seek medical advice if they experience possible symptoms of liver injury, in particular weakness or fatigue, fever, jaundice, or brown urine.
Other symptoms may include abdominal pain, nausea, vomiting, light-colored stools, itching, or loss of appetite.
However, the number of reports of liver damage is very small when compared with the many thousands of people who have used the drug.
Experts also stressed that it is possible that many obese people have underlying physical problems which could increase their risk of liver damage.
Safety a priority
In the UK, the Medicines and Healthcare products Regulatory Agency (MHRA) said it had received a total of 1,295 suspected adverse drug reaction reports associated with orlistat, including 137 involving suspected liver damage, since it was licensed in 1998.
The European Medicines Agency said there was no plan to change the product information at present - but the situation was under review.
In a statement, GlaxoSmithKline (GSK) said patient safety was its top priority, and reports of side effects were constantly monitored.
The statement went on to say the drug had been extensively tested in clinical trials involving 30,000 patients.
"Alli is a 'non-systemically' acting medicine - it is minimally absorbed in the blood and works locally in the gastro-intestinal tract.
"There is no obvious biological mechanism to suggest liver damage can occur with Alli" - GlaxoSmithKline
LIVER DAMAGE SYMPTOMS
* Weakness
* Fatigue
* Fever
* Jaundice
* Brown urine
Source - BBC
Copyright 2009
Eating Late At Night Adds Weight
Late-night snackers are more likely to gain weight, research suggests.
A team from Northwestern University, Illinois, found that when you eat, not just how you eat, could make a big difference.
Scientists found that when mice ate at unusual hours, they put on twice as much weight, despite exercising and eating as much as others.
The study, in the journal Obesity, is said to be the first to show directly that there is a "wrong" time to eat.
Recent studies have suggested that circadian rhythms, the body's internal clock, have a role in how our bodies use up energy. However, this had been difficult to definitively pin down.
Deanna Arble, lead author of the study, said: "One of our research interests is shift workers, who tend to be overweight".
"This got us thinking that eating at the wrong time of day might be contributing to weight gain."
The experiment looked at two groups of mice over a six-week period. Both groups were fed a high-fat diet, but at different times of the mice "waking cycle".
One group of mice ate at times when they would normally be asleep. They put on twice as much weight.
This was despite them doing the same level of activity, and eating the same amount of food, as the other mice.
Groundbreaking
The findings may have implications for people worried about their weight.
"How or why a person gains weight is very complicated, but it is clearly not just calories in and calories out," said Fred Turek, from the Northwestern's Center for Sleep and Circadian Biology, where the research took place.
"Better timing of meals could be a critical element in slowing the ever-increasing incidence of obesity."
Tam Fry, from the National Obesity Forum, agreed. He said: "It is groundbreaking. It really gets you thinking why this has not been done before.
"It could be very dramatic if it affects whether you are going to get fat or not."
At this stage, the results could still be interpreted as controversial when applied to humans.
The scientists now hope they can find out more about how the process works. It is thought that sleep, hormones and body temperature all play a part in how we gain weight.
Source - BBC
Copyright 2009
Saturday 24 October 2009
Coping with Hair Loss
Few fears strike at the hearts of men more than the prospect of going bald, and there are many unproven treatments that prey on this insecurity. Male pattern baldness, or androgenic alopecia, is the most common form of hair loss and is caused by an inherited sensitivity on the scalp to certain normally occurring hormones called androgens. By the age of 30, about one-third of males show signs of baldness, and by 50 half are affected.
So what can you do? Of all the available treatments, only two have been shown to have any effect. These are finasteride (trade name Propecia), which is a drug available on prescription, and the over-the-counter lotion called minoxidil (trade name Regaine). Both can delay loss, or even stimulate some regrowth in some circumstances, but are by no means universal cures. For a start they are most effective in the early stages of hair loss. “If you hardly have any hair left on the scalp, you can’t grow it back, so don’t bother,” says Dr John Gray of the Institute of Trichologists.
To work, they must also be taken for some time – between four months and a year – and if you stop the treatment any effects reverse. There are side effects. For example, about 2% of finasteride users experience decreased libido or reduced ejaculatory volume.
A more expensive long-term option is transplant surgery. Plugs of skin containing 3-6 hair follicles or just one hair are transferred from the back or side of the head to the scalp, where they will continue to grow unaffected by androgens. If you want to try this route, it’s essential first to consult a registered trichologist (see Taking It Further). Sessions over several years may be necessary, and these may cost up to £10,000.
1 How hair loss occurs
Each of the 100,000 hairs on your head grows in a 2-5 year cycle, after which it falls out and is replaced. In some men, a genetic sensitivity to androgens (a type of hormone) causes this cycle to shorten. It also reduces the diameter of each replacement hair. The gene responsible for this sensitivity can be inherited from either parent’s side of the family
2 Where loss occurs
Hair loss usually begins in the front temporal areas, progressing to the crown. The rate of loss varies between people, and the process can take from 5 to 25 years. As part of normal growth cycles, we lose around 100 hairs a day naturally
Source - Times Online
Copyright 2009, All Rights Reserved
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