Wednesday, August 01, 2012

The pros and cons of selenium intake

Was the largest empire the world has ever seen built by people suffering from  selenium deficiency?  You decide

Who would have thought that the earth beneath our feet could be to blame for health woes ranging from heart disease to thyroid problems to cancer?

Yet that’s the view of some experts who say levels of selenium, a mineral essential for good health, are so low in British soil that it’s affecting the food chain, our diets and, ultimately, our risk of disease.  The body uses selenium to make ‘selenoproteins’, which work like antioxidants preventing damage to cells.  There is a growing body of evidence to show it has a key role in health.

Just last week, researchers at the University of East Anglia found people who eat large amounts of the mineral, along with vitamins C  and E, are 67 per cent less likely to develop pancreatic cancer.

Previous research has shown that in old age a good selenium intake helps enhance brain function, so that cognition remains sharp and active.

The problem is we are not getting enough.  The richest food sources of selenium are Brazil nuts, kidney, liver and fish, but the foods that make the largest contribution to our selenium intake — because we eat proportionately more of them — are cereals, bread, meat and poultry.

However, because levels of selenium in our soil are low, cattle aren’t absorbing as much when they graze, nor are crops or other fresh produce grown on it.  As a result, there is less selenium available from meat, grains and vegetables.

Farming methods have a part to play. In a study conducted at Warwick University’s Horticultural Research Institute a few years ago, it was found that although British and northern European soils have been relatively low in selenium since the last ice age, levels are being further depleted by intensive modern farming methods and the use of chemical fertilisers.

‘Selenium levels in our blood plummeted after the time the government began measuring them in 1974,’ says Margaret Rayman, professor of nutritional medicine at the University of Surrey and a leading researcher in selenium’s effects.  ‘They stabilised at this sub-optimal level in the mid-Nineties as our diets haven’t changed much since.’

She adds: ‘If you live in the UK, the likelihood is you are not grossly deficient, but do have low levels of selenium.’

The problem is compounded by the fact that we import less wheat from America’s selenium-rich soils than ever before, she says.  Soil in the U.S. has higher levels of selenium due both to different geological conditions and the fact that it’s generally more alkaline, allowing better uptake of nutrients by plants.

In fact, the average Briton consumes only half (30-35mcg) of the daily amount recommended by the government (60mcg for women, 75mcg for men).

In the long-term, the effects of low intakes can be devastating, says Professor Rayman.

Earlier this year, in a paper published in The Lancet, she detailed selenium’s links to everything from enhanced fertility and thyroid function to preventing plaque build-up in the arteries and regulating blood pressure.

One study of men with fertility problems showed that 100 mcg selenium supplements taken daily significantly increased sperm cells’ ability to swim, indicating they had been selenium-deficient.  Eleven per cent of men who took the supplement went on to father a child.

‘Selenium is an essential component of two selenoproteins required for healthy sperm,’ says Professor Rayman.  ‘One of these is needed for transportation of selenium into the testes and the other gives sperm a stable structure that allows it to swim.’

But selenium is not without controversy.  Lately, some of the scientists who once hailed it as a small medical breakthrough for serious diseases have backtracked, suggesting their latest findings appear to show its power may have been overstated.

Selenium was, for instance, thought to be able to fight prostate cancer and heart disease, but various studies in the past five years have chipped away at the notions.

One large study in the American Journal of Epidemiology followed more than 1,000 adults for seven-and-a-half years and found those who took 200 mcg of selenium daily had no reduction in their risk of developing heart disease or of dying from it than those who took a placebo.

Indeed, eating large quantities of Brazil nuts was found in one study at the University of Warwick to raise cholesterol levels by 10 per cent and raise the risk of heart disease, not lower it.

And while some scientists have recently shown it protects against bladder cancer in women, others have found it does nothing to help to prevent lung cancer.

Similar conflicting evidence surrounds selenium’s role in the prevention of type 2 diabetes, with some studies suggesting high selenium levels lower the prevalence of the condition by helping to control glucose metabolism.

However, other studies, including research by Saverio Stranges, professor of cardiovascular epidemiology at Warwick University, have found no such benefit and, indeed, that it ‘may increase the risk for the disease’.


£200,000 cystic fibrosis drug 'could transform lives'

They've gots lots of bureaucrats earning in the region of  £200,000 p.a.  You could probably fire the lot of them with no reduction in patient welfare

A drug which could transform the lives of people with cystic fibrosis has been developed, as the health watchdog investigates whether it can be provided on the NHS at an annual cost of £200,000 [per patient].

Trials of the drug Ivacaftor have shown improvement in patients’ breathing and weight gain, with use reducing their need for antibiotics.  It has been shown to help some of those who suffer from cystic fibrosis, and has been hailed by one trial co-ordinator as “remarkable”.

It is now being studied by the National Institute for Clinical Excellence (NICE) to determine whether it is value for money, at a cost of £200,000 per year.

It has already been approved for use in patients over six years of age in the United States, and by EU watchdogs.  It is expected to become available in France, Germany and the Irish Republic shortly, according to the Times newspaper.

Cystic fibrosis currently affects more than 9,000 people in Britain and is incurable, causing internal organs to be “clogged up” with a sticky mucus.

Caused by a faulty gene, it places severe limitations on sufferers and significantly shortens life expectancy.

Ivacaftor works by targeting a particular mutation, G551D, which is present in around 600 people with cystic fibrosis in Britain – around six per cent.

Stuart Elborn, lead coordinator of the trials from Queen’s University, Belfast, told the newspaper: “When the first slide went up, we were speechless.  “The hair was standing on the back of my neck.  “It was the moment the drug went from being one that might not even work to one that will transform thousands of lives.”

According to the Times, the £200,000 a year cost would use more than half of the £110m UK budget currently used on cystic fibrosis.

Vertex, the company which spent 13 years developing and making the drug, says the cost will be offset against money spent on patients’ spending time in hospital or taking time off work.

A spokesman said they were “working with the health authorities to make it available as quickly as possible”.


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