25.000 SUBTITLED BY ANDROMEDA
Britain is in the middle of a health revolution.
We're spending three hundred million pounds a year on pills,
that some believe to be an amazing natural way to prevent, or even cure,
some of our most deadly diseases.
And every day,
millions of people take vitamin supplements,
convinced of their power to keep them healthy.
If you want to lead a long and healthy life,
eat right and take supplements.
But there is a growing anxiety from scientists
that our habit of taking large doses of some vitamins
could have very different consequences.
For most people there's absolutely no benefit
in taking high dose vitamin supplements.
At best, they're a waste of money
and at worst, they could seriously affect your health.
Tonight Horizon examines the vitamin revolution,
and investigates the facts
about the nation's favourite vitamins.
Do they work?
And are they safe?
Maddie Walford is thirty-three
and leads an active life.
She eats well,
and exercises regularly.
And to make sure she stays healthy
she's convinced that she needs to take
three special pills every day.
I'm definitely a pill-popper.
There have been so many jokes going on about,
sort of, me in the office,
because I line up my vitamin jars every morning
and take all the pills.
There have been jokes about me rattling
when I walk.
Some of my family members just think I'm a complete maniac.
Dina West teaches foreign language students in London.
How many syllables in this word?
She has a hectic schedule.
So it's bungalow.
Bungalow.
Bungalow
Perfect, ok well done.
She too is convinced that to feel good
and stay healthy she needs extra vitamin pills.
I take a variety of vitamins,
a cocktail of vitamins,
probably about eleven a day.
I have taken them over a period of twenty-five or more years.
And then there's Carol,
she's fit and healthy and loves hill walking and climbing.
And every morning she takes three vitamin tablets.
On a daily basis,
I take vitamin C and vitamin E,
and I take a general sort of multi-vitamin.
She even carries some around with her in her handbag
in case of emergencies.
And all of them have bought in to the same idea
that vitamins are a simple,
and above all natural, way to stay fit and healthy.
Like millions of people in Britain,
they believe vitamin supplements
are crucial to a happy and vigorous future.
I hope my vitamins will protect me from any form of cancer.
Premature ageing.
Keep my eyesight, hearing,
all my faculties intact as well.
But do vitamins really have such remarkable powers?
Vitamins are nothing more
than chemicals that occur naturally in food.
Our bodies cannot produce them themselves,
and nearly a century ago
scientists discovered just how vital they were
for our health.
Vitamins are essential for a healthy body,
we can't exist without them.
They found that a whole host of diseases
weren't caused by infections from viruses or bacteria,
but simply by the lack of these vitamins.
It's very rewarding when a person comes in
with a medical condition,
or clinical condition,
and we can identify that as a vitamin deficiency,
treat them with vitamins and see them get better.
Just by making sure people ate the right vitamins,
a whole string of what became known as deficiency diseases
could be eradicated.
Vitamin A, found in dairy products,
liver and fish,
prevents blindness and growth deformities.
Vitamin C, from oranges and other citrus fruit,
has all but ended scurvy.
And vitamin D,
found in fish,
means children need no longer grow up with rickets.
Scientists have found our food
contained a cheap and simple way
to end the suffering of millions of people
around the world.
The discovery of vitamins
was a landmark in modern medicine,
it was the first example where we learned
that diseases may be caused not just by infectious agents
but by the simple absence
of a single substance from our diet,
a vitamin.
That a vitamin deficiency could be the cause
of disease and death.
Today, most of us take for granted a life free
from the diseases caused by vitamin deficiency.
Doctors now believe
that a balanced diet, with a mix of fruits,
vegetables, grains and fats,
can give you the tiny amounts of vitamins needed
to keep you in good health,
they have called it the recommended daily allowance.
Only in special cases, such as pregnancy,
do doctors normally recommend taking higher doses of vitamins.
There are times when extra vitamin supplements are useful,
for example, folic acid
is important in preventing birth defects in babies,
so it's very important for women considering pregnancy
to take a folic acid supplement,
before they're pregnant,
and for the first twelve weeks of pregnancy.
But forty years ago,
someone came along who would transform the world's perception of vitamins.
Someone so powerful
that he would take them out of the hospital and the doctor's practice
and into millions of homes and high streets.
Linus Pauling was a scientific superstar.
For example if we consider a helium atom
with the nuclear atom.
As Albert Einstein remarked,
Linus Pauling was a genius.
He was so brilliant
that he is the only man to win two individual Nobel Prizes,
once for chemistry and once for peace.
Two Nobel Prizes gave him astonishing scientific credibility.
In addition to being an incredible genius,
he was also a very charming and charismatic man.
Though he died ten years ago,
his work on the structure of molecules
is still the basis of modern science.
Until Pauling came along to revolutionise chemistry,
the nature of the bond that held atoms and molecules together
really was not well known.
And Pauling provided this foundation
for modern chemistry.
It seemed he could go effortlessly
from one area of science to another.
He had an encyclopaedic knowledge of chemistry,
physics, biology, medicine.
As a chemist,
I have a background of knowledge
that permits me to appreciate the new ideas,
but I also like very much
having new ideas myself.
And in the late 1960s,
the great man had a huge idea.
Pauling became convinced
that vitamins could not only prevent deficiency diseases,
they could do something far, far bigger.
He believed they had the power to prevent diseases
that had nothing to do with deficiency at all,
diseases which threatened every one of us,
like cancer.
Heart disease.
They could even delay ageing.
The key, according to Pauling,
was to take them in huge doses.
It was a very revolutionary idea
because at the time
most conventional scientists and nutritionists
were interested in vitamins
with respect to their associated deficiency diseases,
and not achieving optimal health
by increasing the intake of vitamins.
When Pauling took his message to the world,
the public loved it.
It was after all the 60s,
and vitamins seemed to offer a safe, easy remedy
to the illnesses we most feel.
You didn't always need big pharmaceutical companies and drugs,
you just needed nature's remedy in pill form.
The message was simple.
If the amount of vitamin C required to stave off scurvy was ten milligrams,
and could be found in a slice of orange,
then thousands of times more,
the equivalent of over one hundred oranges,
and more than two hundred and fifty times the recommended daily allowance
was even better.
Because that could prevent you from catching the most irritating of diseases,
the common cold.
The proper intake of vitamin C helps keep one from catching colds.
To this claim, Pauling's claim that huge doses of vitamin C
can prevent you catching a cold is popularly believed to be scientific truth.
It helps ward off colds.
Helps you to prevent colds.
Prevents colds and flu, that's what I take it for.
A Nobel Prize winner says that it cures the common cold.
Pauling's belief in taking large doses of vitamins
has inspired a whole new breed of health advisors.
Patrick Holford is one of the most popular and well known.
He is the author of more than twenty books,
promoting the use of supplements for good health.
This is vitamin A,
it's great for your skin.
He has founded an institute for optimum nutrition.
This is vitamin B,
it's good for energy
and it helps to keep your mood even.
He believes that optimum health
comes from physical activity,
a good state of mind,
and a nutritious diet.
All topped up
with large daily doses
of vitamins.
I believe that taking vitamin supplements,
not only adds years to your life,
but also adds life to your years.
Between them,
Pauling and the nutritionists,
have helped spawn a vast industry.
In supermarkets,
health food shops and chemists,
you can buy vitamin supplements.
All marketed as a safe,
natural way to help you stay feeling good,
looking beautiful,
and being healthy.
In Britain alone,
we spend three hundred million pounds a year
on these pills.
Carol Reed is a typical customer.
She buys some of the twenty million pounds worth of vitamin C tablets
that are sold every year.
It is far and away the most popular vitamin,
and she takes five hundred milligrams a day,
nearly nine times the recommended daily allowance.
And all because
she has complete faith in the theory of Linus Pauling.
I take vitamin C
because I believe it actually builds my immune system
to the extent that I can fight off
the common cold.
But does vitamin C really prevent the common cold
as Linus Pauling believed?
What is the actual scientific evidence?
On America's west coast
is Oregon State University.
It is home to the Linus Pauling Institute,
which was founded to continue his research in to vitamins.
I think Linus Pauling
was one of the first to really
understand the role of vitamins above and beyond
preventing deficiency disease.
And he called that orthomolecular medicine,
so the right molecule at the right concentration,
which can provide optimum health,
and not just prevent deficiency disease.
Professor Balz Frei
is one of the world's leading experts
on vitamin C.
He has studied the evidence
from clinical trials involving thousands of volunteers
from across the world,
designed to investigate Pauling's claim
that large doses of vitamin C
fights the common cold.
And at first it seems
that Pauling really was on to something.
Vitamin C does have an effect
on the common cold,
once you've already caught it.
I think there is a role for vitamin C
in shortening the duration of the symptoms of the common cold,
by about twenty per cent.
And ameliorating the symptoms,
so you're not as sick as without taking vitamin C supplements,
and I think he was right with that.
But then Professor Frei examined Pauling's central claim,
the idea that first sparked the vitamin revolution.
The proper intake of vitamin C helps
keep one from catching colds.
And for this claim,
that huge doses of vitamin C can prevent you catching colds
in the first place,
the results are very different.
I've looked at the evidence
that vitamin C can prevent the common cold,
but for the general population
there is really no evidence from scientific studies
that vitamin C can lower the incidence of the common cold,
or prevent it in the first place.
So taking vitamin C supplements is not going to help
prevent the common cold.
In other words,
the director of the very institute set up to pursue Linus Pauling's work,
now believes that the great man was wrong.
Taking large doses of vitamin C
does not prevent you from catching the common cold.
Of course, that won't stop millions of people like Carol
from taking it.
The results of those trials are not going to influence
the fact that I go out and buy vitamin C on a regular basis,
and take vitamin C,
because for me taking a vitamin C tablet will help my body,
prevent my body catching a cold.
And while Carol is unlikely to be doing herself any harm,
the fact remains that the overwhelming body of scientific evidence
says that for most people in Britain,
taking high doses of vitamin C to prevent getting colds,
is a waste of money.
Of course, there are other reasons why people decide
to take vitamin C supplements.
It's one of a special group of vitamins called antioxidants.
Vitamins of such power,
the believers ascribe to them properties
that are truly remarkable.
I believe they can protect your brain,
your body, your arteries,
and not only slow down the ageing process
but keep you free of diseases,
from heart disease, cancer, Alzheimer's,
all the tragedies of twenty first century living.
These huge claims are all because of how antioxidants work
on something in our body called free radicals.
Free radicals are unstable molecules
that exist in our cells.
They attack other nearby molecules,
stealing an electron and with it an atom
to become stable again.
When the attacked molecule loses that atom,
it becomes a free radical itself,
beginning a chain reaction.
Normally the body can handle these free radicals,
but if there are too many,
cells can be damaged with devastating consequences.
Free radical damage is associated with a number of diseases,
like heart disease and cancer,
and macular degeneration,
but we also think that free radical damage to cells and tissues
is a fundamental part of the ageing process itself,
why we grow old.
It's in part due
to the activity of free radicals.
But antioxidants,
in particular vitamins A, C and E,
mop up the free radicals
and stop them from attacking our cells.
A simple demonstration,
with nothing more than a piece of steak,
can show just how good vitamin E is
at preventing free radical damage,
or oxidation.
When you look at it in the grocery store
it's red and beautiful.
That's the vitamin E that's protecting the meat from oxidation.
What I'm going to show you
is what happens
if you destroy the vitamin E.
So we're going to take this chemical
and place it on the surface of the meat.
That's going to actually destroy vitamin E.
Once the vitamin E is destroyed
the cells in the meat are swamped by free radicals.
Within just a few minutes
the meat starts to turn brown and rancid,
the cells have been fatally damaged.
And the same thing would happen to your body
if you didn't have the protective effect of vitamin E.
Many large studies have shown
that people who eat a diet rich in antioxidants,
found in foods such as fruits, vegetables, grains and fats,
live longer, healthier lives.
The studies that have been done
in respect of food
indicate that individuals with a good quality diet,
with lots of anti-oxidant vitamins present
have a decrease incidence of the major diseases.
But some people think
that the amount of antioxidant vitamins you can get,
simple by eating a balanced diet,
are not enough.
They believe that you need to take much more,
and that means popping high dose pills.
Dina West is one of them,
she takes a high dose vitamin E capsule every day,
it contains forty times the recommended daily allowance.
Vitamin E is an antioxidant,
and it helps to fight the nasty free radicals,
which are toxins.
And I like that,
I don't want anything nasty racing around in my body
thank you very much.
And they help, they help me a lot.
But recently there's been a piece of research
that suggests Dina could be missing any benefit
from her vitamin E supplements.
And it's all because
of how she takes them.
She's often in a rush,
skips breakfast,
and so swallows her pills with a glass of water
on an empty stomach.
The idea that Dina could be missing any potential benefit
from vitamin E
came from Maret Traber at the Linus Pauling Institute.
Vitamin E is a fat soluble vitamin,
that means it has to be eaten with some fat to be absorbed.
So popping a pill just with water on an empty stomach like Dina does,
might be almost no good at all.
In an experiment Professor Traber gave volunteers
a vitamin E pill and a glass of virtually fat free skimmed milk.
She then analysed their blood
to see just how much vitamin E
had been absorbed.
The results were striking.
When the subjects took their vitamin E pill with a glass of milk,
hardly any was absorbed.
I think the implication of our study
is that if you take a vitamin E pill,
you'd better take it with some food,
you'd better take it with some food
that has fat in it,
or you're not doing yourself any good.
In other words,
if Professor Traber is right,
then anyone who takes vitamin E without a fatty meal
could be wasting their time.
But there was something unusual about her experiment.
Professor Traber used specially manufactured pills,
she did not use a commercially available product.
Horizon decided to investigate Professor Traber's ideas further.
Just how important was it
to take a vitamin E pill with a fatty meal?
We commissioned King's College London,
one of the world's leading research centres on vitamin E,
to run the experiment.
In charge was Professor Frank Kelly.
The pills he would test had been bought in a high street chemist.
Dina and four other volunteers
agreed to take part in a ground-breaking study.
Each volunteer was told to make sure they had an empty stomach,
then they were given a vitamin E pill
with three different drinks.
Day 1, a glass of water and no fat at all.
Four days later,
a glass of full fat milk.
After another four days
we upped the fat content again
and gave them a milkshake containing over forty per cent fat.
After each pill was taken,
the volunteers returned every four hours
to give a blood sample
so we could see how much of the vitamin E they had absorbed.
If Professor Traber's theory was right,
the volunteers should absorb very little of the vitamin E
when the pill was taken with water,
and they should absorb it very well
when it was taken with the fatty milkshake.
With the blood samples complete,
Professor Kelly analysed the data.
And after several weeks of nervous waiting,
Dina returned to get the results.
So, it's time for the, the truth.
Good.
Here are the results. You were actually subject number 5 in the study.
Ok.
And you can see here that this is with water.
Yes.
This is with full fat milk, and this is with the milkshake.
So, contrary to our expectations.
Yes.
You actually have absorbed
as much with water
as with either the other two diets.
So, the water was as good for you as the milk and the milkshake,
which as I say was a surprising result to us.
Contrary to every thing Professor Kelly expected,
the amount of fat taken with the pill
had made very little difference to Dina.
And it wasn't just Dina's results that were a surprise.
The group overall showed a similar pattern.
When Dr Kelly looked for an explanation
he found that the capsules used in the Horizon experiment
contained a tiny amount of fat.
The fat is often added
to make the vitamin E more runny
and easier to handle.
But he hadn't suspected
that it was enough to allow absorption,
and it might explain the unexpected results.
The only possible explanation I have at this point is
that there was enough fat in the vitamin E supplement
to allow that absorption to occur.
In other words,
it means that Dina can carry on taking her vitamin E just as she does today.
However, most doctors recommend people
to get the vitamin E they need from food.
And because the Horizon study was small and tested only one product,
for people who decide to take vitamin E supplements,
it may still be advisable to take them
after a meal to give themselves the best chance
of absorbing the vitamin E.
But there is another antioxidant vitamin
which is popular
and about which scientists
are much more cautious.
Vitamin A.
In vegetables there is a chemical called beta-carotene,
which your body converts in to vitamin A.
It is found in carrots and leafy green vegetables.
And it's seen to have an extraordinary health benefit.
Studies have shown
that people who eat a diet rich in beta-carotene
are much less likely to develop lung cancer.
And this seemed to offer
a genuine breakthrough.
Demetrius Albanes is one of the leading cancer experts in America.
He hoped that beta-carotene pills
could be a simple way to fight one of our biggest killers.
So he and his colleagues organised a study
to confirm that high dose pills
really could save millions of lives.
We were thoroughly expecting to see a reduction in lung cancer incidents.
We designed the study actually to be able to detect
at least a twenty five per cent reduction
and I would say many of us at the time
would have estimated we might observe a twenty five to fifty per cent reduction
in lung cancer.
Fifteen thousand people were given high dose beta-carotene pills,
each one containing the equivalent of six carrots.
To have the best chance of seeing whether the pills really could prevent lung cancer,
they were given to people most likely to develop it,
smokers.
For eight years a team of safety experts
monitored the volunteer's health.
And it seemed that everything was progressing normally.
But then, just before the trial was due to end,
they called a surprise meeting.
The key investigators were called in to the committee,
and they informed us that we had some
effect happening with respect to the beta-carotene.
They informed us that we in fact had a small increase in lung cancer
in the beta-carotene group.
It seemed that beta-carotene pills,
which every one had hoped would prevent lung cancer,
were having the exact opposite effect.
I think there was a mass panic to begin with
because this is really the way we expected the science to work.
It was a devastating result.
The people taking the pill had shown
an eighteen per cent increase in lung cancer.
My first response on hearing these results
was being stunned and not really believing it.
I thought the results were a fluke.
But it was no fluke,
eighteen months later the news about beta-carotene
got even worse.
Another similar study was stopped two years early.
An interim analysis
showed that there was a twenty eight per cent increase
in the number of lung cancers
in those taking the intervention.
Scientists still do not fully understand
why beta-carotene appears so beneficial in food
but seemed to have such a devastating effect on smokers
when taken in a high dose pill.
But because of these studies,
in 2003 safety experts in the UK
advise smokers not to take beta-carotene supplements.
And advised everyone
to limit their daily intake from high dose pills.
These studies were a salutary lesson
that vitamin supplements
were not just some harmless natural remedy.
In high doses they could have unexpected
and dangerous consequences.
When the results of the adverse effects of beta-carotene were confirmed in later studies,
we began to understand that high doses
in certain populations and under certain circumstances
really could be harmful.
I think we learned a great lesson.
So great is the fear that large doses of some vitamins can be dangerous,
that some scientists are now sounding the alert
about another common form of vitamin A.
It's called retinol.
Maddie Walford is one of the many people
who take this type of vitamin A supplement every day.
She takes a high strength pill
containing nearly three times
the recommended daily allowance.
The reason I take a high strength vitamin,
to be honest I'm not quite sure,
but I thought it was probably because it had more potency.
And would therefore,
therefore be you know worth the money.
But the idea that the more vitamin A you consume the better
can lead to terrible consequences if taken to excess.
Doctor Rob Goldin is a pathologist
at St Mary's Hospital in London.
He specialises in diagnosing the cause of liver disease
and recently he was given a biopsy
from a sick patient in his thirties.
I was referred some slides on a liver biopsy
from a patient of another hospital
to try and ascertain the cause of liver disease
because there was no obvious cause.
The first thing I did when I examined
the liver biopsy was to look for evidence of viral hepatitis,
or alcoholic liver disease,
the commonest cause of liver damage.
I couldn't see any of these.
So Doctor Goldin had to look
for another explanation,
and he knew that vitamin A
might hold the answer.
If you consume more vitamin A each day
than your body actually require
then the vitamin A will accumulate in your body
because there's no easy way of excreting it
and the place where it accumulates is the liver.
Doctor Goldin then examined the sample
to look for the telltale signs of vitamin A damage.
On this half of the screen
you can see some normal liver
with normal healthy liver cells.
On this half of the screen
you can see the liver biopsy from the patient,
and in this slide the scar tissue stains blue,
and you can see there's blue scar tissue
surrounding the liver cells.
Now the pattern of this scar tissue deposition
in this patient made me think
that the liver disease could be caused by vitamin A,
and that this could be the explanation of his liver problems.
But surprisingly
the patient's medical records
made no mention of him taking vitamin A supplements.
I contacted the clinician at the referring hospital,
to check whether his patient had been taking excessive amounts of vitamin A.
He went back to the patient.
On close examining the patient said they had been taking excessive amounts
but hadn't mentioned this earlier
because he didn't consider vitamin A to be a drug.
Cases like this are extremely rare,
they normally involve taking the equivalent
of many high strength vitamin A pills,
every day, for years.
But they serve to remind us all that vitamin A,
in the form of retinol,
although not a drug,
is a powerful chemical.
And today, the safe level of vitamin A consumption
is the subject of fierce debate.
Patrick Halford recommends
people take 2500 micrograms,
that's over three times the recommended daily allowance,
because he is convinced
that it will lead to better health.
Vitamin A is absolutely essential
for every single cell in the body.
It helps to protect your DNA,
it helps to keep your skin healthy,
it helps to protect your body cells from infection.
So it's an essential vitamin,
you need it every day.
But in recent years
evidence has emerged that suggests
even this amount could be harmful.
And everyone needs to think carefully
about the amount of vitamin A they consume.
Sweden is a prosperous country,
where people live long and healthy lives.
But surprisingly it has one of the world's highest rates
of a debilitating disease, osteoporosis.
It most often affects women over fifty.
And its crippling condition
gradually thins and weakens your bones,
increasing the risk of fracture.
But for years it has been a mystery
why the disease is so common.
When we look at known risk factors for osteoporosis,
such as age, smoking, physical activity,
they can partly explain
why it's so common with osteoporosis and bone fractures in Sweden,
but that can not explain everything.
And then, even more surprising,
is that we have a diet rich in calcium,
which should protect our bones.
So Professor Melhus began to look for another explanation.
And there was something in particular about the Swedish diet
that made him suspicious.
It was exceptionally high in vitamin A.
We eat dairy products,
oily fish,
such as herring and salmon,
we consume cod liver oil,
vitamin supplements,
all which contain high levels of vitamin A,
and on top of that
we are the only European country
which fortifies low fat dairy products with vitamin A.
This triggered an alarm for Professor Melhus.
Because there was evidence
that huge doses of vitamin A damaged animal bones.
Since we knew about these harmful effects of vitamin A
on animal bones,
we wanted to see if this also could be occurring in humans.
So Professor Melhus launched his own investigation.
From a database of sixty six thousand women aged over forty,
he looked for cases of bone fracture.
He then checked the diet of these women
to see if their vitamin A intake
was particularly high.
And the results seemed to confirm his suspicions.
When I saw the results from our study
I was really surprised,
although I knew the experiments done in animals,
it was hard to accept the fact that vitamin A,
a vitamin, had negative effects on bone in humans.
Professor Melhus then went further.
He did a series of bone scans to work out what level of vitamin A
was linked to weaker bones.
His results suggested
that long term consumption of even relatively small quantities of vitamin A
were having a dramatic effect.
What we saw was that a vitamin intake above 1.5 milligrams per day,
which is approximately twice the recommended daily intake,
there was a reduction in bone density about ten per cent,
and the risk of hip fracture had doubled.
If Professor Melhus was right
then the implications were staggering.
An intake of 1.5 milligrams per day
is a level that can be reached from food alone.
And it will be exceeded by taking just a single capsule
of some high strength vitamin A supplements.
So, tablets that people take every day
to improve their health might actually be slowly,
silently, weakening their bones.
For Professor Melhus,
the implication is clear.
Based on our research
I think people should continue to eat a healthy,
normal balanced diet.
But since supplements containing high levels of vitamin A
may have adverse effects,
I cannot recommend people to take them routinely.
Professor Melhus has now done another study
that suggests the same risk also applies to men.
And since his original work,
studies from America have supported his findings,
but there has been some other research
which has not found the same link.
The evidence linking osteoporosis with,
with relatively small amounts of vitamin A consumption,
I'm not convinced by it.
There are, there are studies that show no such link,
and it simply doesn't make sense,
because we're talking about levels
that we could easily eat and have eaten for millions of years.
So at the moment I'm simply not convinced.
But some scientists see the research very differently.
Professor Andrew Renwick
is a clinical pharmacologist
at Southampton University,
and one of Britain's leading experts on vitamin safety.
For four years he was part of an independent committee
advising the government on the safety of vitamins.
He takes the emerging evidence about vitamin A very seriously.
I am concerned,
although the, the evidence is not totally consistent,
there have now been a number of studies showing a link,
and I'm convinced that a high intake of vitamin A
will give an increase risk of bone fracture.
In 2003, the safety committee Professor Renwick was part of
reported that they could not yet define
a safe maximum intake of vitamin A.
But they did sound a warning.
We evaluated all the data,
and concluded that an intake of more than fifteen hundred micrograms per day,
of vitamin A, could be inappropriate.
Primarily because of an increased risk of bone fracture.
Fifteen hundred micrograms is less than the amount found in some
high dose vitamin A supplements,
available over the counter.
Maddie Walford has been taking a pill containing over two thousand micrograms
of vitamin A for more than a year.
We asked Catherine Collins,
chief dietician of St George's Hospital in London,
to analyse her diet and advise her what to do.
What you can see from our dietary analysis
is that you've actually got a very healthy diet.
When we look at your vitamin A level,
we can see that you're getting the full amount of
vitamin A you need in your diet,
from your small amount of animal source
and the rest of the fruits and vegetables that you eat.
Right.
What is of concern is the fact that you're taking
a very high dose supplement of vitamin A.
Oh right.
And at this level there is a potential risk of you developing osteoporosis
and fracture risk with long term usage.
Right.
Do you think that with the amount of vitamin I've been taking
for the length of time I've been taking it I will have done myself any,
any physical damage?
If you've only been taking this for a year or so
it's probably fine.
But it's not a supplement we'd recommend you take long term.
It certainly is associated with an increase fracture risk.
I was very surprised about the link between osteoporosis
and vitamin A
and risk of fracture,
because I'd never associated vitamin A with osteoporosis.
It's definitely changed my mind about taking that,
I'm actually going to be stopping it as of today,
because it clearly doesn't do any good for me personally,
and it might do more harm than good.
Vitamins without doubt
are vital to our health.
And it remains possible
that high dose vitamin supplements
will one day be proven to protect against illnesses
like heart disease and cancer.
But so far, definitive evidence for these claims
remains largely elusive.
And as we discover more about some vitamins,
it is increasingly clear
that in large doses they can have unexpected,
and sometimes dangerous consequences.
Until we understand more about these powerful chemicals,
most doctors would advise everybody
to seek advice before joining the high dose vitamin revolution.