Can draining blood cut cholesterol and ward off cancer
04:35 GMT, 4 December 2012
There may soon come a day when a visit to the GP involves having blood drained from your body — not for a blood test but to help reduce your risk of disease.
It seems astonishing, but bloodletting — long-regarded as a gruesome and misguided practice and largely abandoned since Victorian times — is now emerging as a possible way of reducing blood pressure and cholesterol levels, and even preventing cancer.
Meanwhile, a form of bloodletting is being used in NHS hospitals to treat bowel conditions such as ulcerative colitis.
A study of 60 overweight people found that bloodletting reduced blood pressure, as well as levels of 'bad' LDL cholesterol and increased 'good' HDL cholesterol
For centuries bloodletting was performed in order to reduce the risk of illness, explains Dr Lindsey Fitzharris, a medical historian from Queen Mary, University of London.
‘The thinking was that too much blood in the system could lead to sickness.
'Bloodletting came to be expected — rather like people expect antibiotics when they go to the doctor today.’
Today, bloodletting is regarded more as a possible preventative than a treatment.
Earlier this year a study of 60 overweight people found that the procedure reduced blood pressure, as well as levels of ‘bad’ LDL cholesterol and increased ‘good’ HDL cholesterol.
The results of the study, published in the journal BMC Medicine, amazed even the researchers.
As Professor Andreas Michalsen, who led the study at the Immanuel Hospital, Berlin, says: ‘We thought there might be some benefits, but not to that extent.’
Half the patients in the study had a small amount of blood removed — up to 450ml, the same as when you give blood — twice over a six-week period.
At the end, the bloodletting group had an average drop in blood pressure of 18 mmHg — ‘Double the average drop seen with medication,’ says Professor Michalsen.
The control group, which did not have the procedure, had a drop of 1mmHg.
This latest study was prompted by earlier research which suggested regular blood donors have lower cholesterol and reduced risk of heart problems and stroke.
Other studies showed that diabetics had better blood sugar control when they had blood regularly removed.
Professor Michalsen cautions that more evidence is needed. He is now planning two larger studies, with overweight patients and blood donors respectively.
So what could be causing these improvements in blood pressure and cholesterol
Although the total blood volume would have been reduced by the bloodletting, the fact that the lower blood pressure was seen for weeks afterwards suggests more is going on, says Professor Michalsen.
He believes the evidence points to iron.
Our love of red meat means many of us have too much iron in our bodies
Iron is essential for many biological functions.
Without it, we wouldn’t even be able to breathe (iron is a key component of red blood cells, and allows them to pick up oxygen and transport it around the body).
But too much iron can be bad, triggering the production of harmful molecules (known as free radicals) which damage the cells.
This raises levels of inflammation throughout the body.
‘There is, of course, such a thing as too little iron, but there are even greater problems from too much iron,’ explains Professor Leo Zacharski, a haematologist at the U.S. government-funded Veterans Administration Hospital in Vermont, and the Geisel School of Medicine at Dartmouth College.
Our love of red meat means many of us have too much iron in our bodies, he argues, pointing to studies which suggest that most people have nearly double the ideal levels of iron in their blood.
‘We take in a little bit more iron than we need each day, and over years it accumulates and contributes to the diseases of ageing, such as vascular disease and cancer.’
Red blood cells contain large amounts of iron, so removing blood reduces iron levels in the body.
Professor Zacharski led a study, published last year in the American Heart Journal, which followed more than 1,000 people (average age 67) who had furred-up arteries.
Half the group had blood removed every six months and half didn’t.
At the end of the six-year study, the risk of heart attack and stroke was reduced in the group who regularly had blood removed.
In a separate study on the same group of people (published in the Journal of the National Cancer Institute), bloodletting was associated with a 37 per cent drop in the incidence of cancer.
However, Professor Zacharski says that diet — rather than bloodletting — may be a more practical method of reducing iron levels.
‘I advise my patients to limit red meat to once a week and reduce alcohol intake, as this increases iron absorption.’
Certain foods — tea, coffee, eggs and dairy products — can also reduce iron levels, he says.
Dr Richard Bogle, lead cardiologist at Epsom and St Helier University Hospitals NHS Trust, says the results from the recent bloodletting studies may link in with other evidence.
‘There have been some studies that suggest the blood thinner warfarin may reduce cancer risk,’ he says.
‘This may be due to the medication causing small amounts of blood to leak from the gut, which would lower iron levels.
‘Also, the higher iron levels seen in post-menopausal women could be a factor in why we see more heart problems in this group.’
He adds that more trials need to be done to establish these links.
Meanwhile, a slightly different form of bloodletting is being used to treat inflammatory bowel conditions such as ulcerative colitis and Crohn’s disease.
These conditions are thought to be caused by the immune system mistakenly attacking the bowel.
This attack is orchestrated by a type of white blood cell called neutrophils. Japanese researchers found that removing neutrophils reduced damage to the gut.
This is done using a type of sticky bead that ‘pulls’ the cells out of the blood.
Beads are put into a tube, around 10cm long. The patient’s blood is removed from one arm and then passed through this tube.
The white blood cells stick to the beads, while the rest of the blood passes through back into the patient’s other arm. It all takes around an hour.
Professor Ingvar Bjarnason, gastroenterologist from King’s College Hospital in South London, says: ‘In Japan, it is used as a first-line treatment for ulcerative colitis.
'It’s as effective as treatment with corticosteroids for severe relapse of the disease.’
In a study led by Professor Bjarnason, the relapse rate in patients who received the treatment was just 20 per cent compared with 80 per cent for those in a placebo group.
‘Removing white cells kept the majority of people well for the next six to 12 months,’ he says.
How exactly this works is still a mystery. Only around 40 per cent of the neutrophils in the body are removed, and the white cells are back to normal levels within a couple of hours.
One theory is that the existing white blood cells have been programmed to attack the gut, but the newly made cells are not as harmful.
The treatment is offered at a number of NHS centres across the UK.
Dr Purushothaman Premchand, consultant gastroenterologist at Queen’s Hospital, Romford, was the first doctor in the UK to regularly treat patients with inflammatory bowel disease via this method and started using it at his clinic in 2008.
‘We use it on our hard-to-treat patients, and we have seen a 70 per cent success rate in inducing remission,’ he says.
‘Some have stayed in remission for around four years.
‘More than 10,000 patients have received this treatment across the world, and it does not seem to have any serious side-effects.’
It is not cheap — each ‘tube’ costs around 1,000, and each patient needs around five to ten sessions.
But the costs are much smaller than the price of treating a patient who has suffered a relapse, says Dr Premchand: ‘We’re saving money by keeping patients away from hospital.’