Vitamin D could help the body fight infections of deadly tuberculosis,
according to doctors in London.
Nearly 1.5 million people are killed by the infection every year and
there are concerns some cases are becoming untreatable.
A study in Proceedings of the National
Academy of Sciences showed patients recovered
more quickly when given both the vitamin and antibiotics.
More tests would be needed before it could be given to patients
routinely.
The idea of using vitamin D to treat tuberculosis (TB) harks back to
some of the earliest treatments for the lung infection.
Before antibiotics were discovered, TB patients were prescribed
"forced sunbathing", known as heliotherapy, which increased vitamin D production.
However, the treatment disappeared when antibiotics proved successful at
treating the disease.
Drug resistance
There is widespread concern about tuberculosis becoming resistant to
antibiotics.
The World Health Organization (WHO) says 3.4% of new cases of TB are
resistant to the two main drug treatments - known as multiple drug resistant
tuberculosis.
That figure rises to nearly 20% for people who have been infected
multiple times in their lives.
One analysis said that in some countries about half of all cases were
resistant.
There is also concern about extensively drug resistant tuberculosis,
which is resistant to the back-up drugs as well.
The WHO says 9.4% of all drug-resistant TB is extensively drug
resistant.
In this study, patients all had non-resistant TB. The researchers said
adding vitamin D to treatments may be even more valuable for patients when the
drugs do not work as well.
Heal faster
This study on 95 patients, conducted at hospitals across London,
combined antibiotics with vitamin D pills.
It showed that recovery was almost two weeks faster when vitamin D was
added. Patients who stuck to the regimen cleared the infection in 23 days on
average, while it took patients 36 days if they were given antibiotics and a
dummy sugar pill.
Dr Adrian Martineau, from Queen Mary University of London, told the BBC:
"This isn't going to replace antibiotics, but it may be a useful extra
weapon.
"It looks promising, but we need slightly stronger evidence."
Trials in more patients, as well as studies looking at the best dose and
if different forms of vitamin D are better, will be needed before the vitamin
could be used by doctors.
Vitamin D appears to work by calming inflammation during the infection.
An inflammatory response is an important part of the body's response to
infection.
During TB infection, it breaks down some of the scaffolding in the lungs
letting more infection-fighting white blood cells in. However, this also
creates tiny cavities in the lungs in which TB bacteria can camp out.
"If we can help these cavities to heal more quickly, then patients
should be infectious for a shorter period of time, and they may also suffer
less lung damage," Dr Martineau said.
The doctors suggested this might also help in other lung diseases such
as pneumonia and sepsis.
Prof Peter Davies, the secretary of the charity TB Alert, said the
findings were "excellent" and vitamin D could play "an important
role in treating tuberculosis".
However, he thought there could be an even greater role in preventing
the disease.
One in three people have low levels of tuberculosis bacteria in their
lungs and have no symptoms, known as latent tuberculosis. However, this would
turn to full blown TB in about 10% of people. Prof Davies's idea is that giving
vitamin D supplements, for example in milk, could prevent latent TB developing.
"That would be a massive revolution if it was shown to work,"
he said.
Prof Alison Grant, from the London School of Hygiene and Tropical
Medicine, said: "Drug-resistant TB is an increasing concern world-wide and
so new treatments to reduce the length of TB treatment would be very welcome.
"Vitamin D supplements are often given to patients who are short of
vitamin D and these low doses are generally very safe.
"In
this study the researchers were giving higher doses of vitamin D, and I think
we would need larger studies to be confident that there were no negative
effects of this higher dose."
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