http://tinyurl.com/az2zj

[still missing the SDOH boat though... dr
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The Sunday Times January 01, 2006

Focus: Kill or cure?
First we were told to keep out of the sun to avoid skin cancer. Now a study
suggests the resulting vitamin D deficiency can give us other cancers. Is
health advice doing us harm? Lois Rogers reports

 Rachel Jennings is one of millions of women who have invested heavily in
protecting their children from the perils of skin cancer.

For years she has taken care to limit their exposure to the sun during the
hottest periods of the day; for family holidays to sunny destinations she
has always gone weighed down with the latest sunblocks.

Now she is dismayed to discover that while protecting her children from
sunburn and skin cancer, she might have also inadvertently put them at risk
of other cancers, heart disease and further illnesses by depriving them of
sunlight.

This is because the sun’s ultraviolet radiation is our main source of
vitamin D — and scientists now believe that vitamin D deficiency is closely
linked to a range of cancers and other diseases.

This week an American analysis of 63 studies published over the past four
decades concluded that cancer tumours of the colon and breast are linked to
low levels of vitamin D. Other studies have found a link between vitamin D
deficiency and schizophrenia, multiple sclerosis and lung diseases.

“It really is impossible to know what to do,” said Jennings, 38, who has
two sons: Joe, 9, and Charlie, 6. “I don’t necessarily believe that I have
increased their risk of all these horrible things, but it is impossible not
to worry as a mother.”

Like many other consumers Jennings is baffled: the more health advice that
we receive, the more confusing, if not downright contradictory, it can
seem.

In the past few months, for example, scientific journals have reported that
coffee might cause fatal heart disease — and that it is full of
cancer-preventing antioxidants.

Milk, which contains calcium, is good for the bones — but its fat is bad
for the arteries. Red meat is bad for the heart — but high-protein diets,
claim some, can help to avoid obesity. A high-fibre diet is good — except
that an American study now says that it does not, after all, prevent
cancers of the digestive system.

Within days of each other last month, one study was published claiming that
an aspirin a day reduced heart disease in women by 25% — but another said
that one in 10 of those who take aspirin is at risk of intestinal bleeding
and a possible early death.

Science is complex and good health involves balancing one risk against
another. But for ordinary consumers, sifting the plethora of different
advice is becoming an ever more complex task.

“When you see these headlines you can’t help wondering if we should be
looking for the vested interests behind all health advice,” said Jennings,
a former marketing executive who now works part-time near her home in
Hersham, Surrey. “Have we been peddled the scare about skin cancer by a
cosmetics industry that just wants to sell more sunblock, and the vitamin D
message by the dietary supplement manufacturers who want to sell more
pills?

“The trouble is, it is impossible not to be influenced by it.”

THE vitamin D debate illustrates how health advice evolves. A decade ago,
doctors discovered that low intakes and blood levels of vitamin D were
associated with arthritis and osteoporosis, the bone-thinning disease.
Vitamin D assists the body in the absorption of calcium, which is vital to
maintain healthy bones.

Tablet supplements of vitamin D were heavily promoted as a method of
preventing bone and joint disorders. But after a flurry of excitement, it
became clear that some people still get such diseases whatever they do. It
was not long before concerns about vitamin D were overtaken by the rush to
avoid the risk of skin cancer inherent in sunlight exposure.

The results of scientific research are, however, cumulative. Studies on
vitamin D continued and the latest report draws on decades of research.
Cancer specialists led by Cedric Garland of the University of California,
San Diego reviewed almost every study of the link between vitamin D and
cancer published since the 1960s.

As a result, Garland claims that his analysis has proved a clear link
between the vitamin and raised cancer risk, and he is exhorting everyone to
begin taking daily vitamin D supplements in tablet form.

“The high prevalence of vitamin D deficiency combined with the discovery of
increased risks of certain types of cancer in those who are deficient,
suggest that vitamin D deficiency may account for several thousand
premature deaths from colon, breast, ovarian and other cancers annually,”
he said.

It may be the best available information, but there is still a problem.
Most studies that link diet or lifestyle with disease are epidemiological
rather than empirical: they examine trends among large numbers of people
rather than being based on experiments designed to reveal precise causes
and effects.

This has its limitations. Karol Sikora, professor of cancer medicine at the
Imperial College School of Medicine, says that to prove that a deficiency
of vitamin D causes cancer it would be necessary to stage a 20-year
experiment involving, say, 1,000 people with 500 receiving high doses of
vitamin D and the rest receiving low doses.

In addition, all other aspects of lifestyle and diet would have to be taken
into account.

“Quite apart from the logistics, the boredom factor in this kind of
research is just too high,” said Sikora, who has participated in several
abortive studies of this nature.

The new study on vitamin D also shows just how difficult it is to identify
cause and effect in such research.

A huge European study on diet and cancer found lower rates of cancer among
Mediterranean people. It prompted experts to advise that a Mediterranean
diet high in fish, fruit, vegetables and olive oil was better than the diet
high in meat and dairy fat more common in northern Europe.

Although that still holds, there is now a question about how much of the
difference in cancer rates might be down not to diet but to higher levels
of sunlight and vitamin D in the Mediterranean regions. “The biggest
problem with research in this area, is what we call confounding,” said Tom
Sanders, professor of nutrition at King’s College, London.

“Fruit and vegetable intake may be just a marker for some other lifestyle
factor, like lower alcohol.” He points out another complication: “Fat
people may be at greater risk of disease for other reasons, but vitamin D
is stored in fatty tissue so they have a greater capacity to hold on to it.
Nothing is ever as straightforward as it seems when you are talking about
diet.”

Commercial pressures must also be taken into account since scientists and
institutions are constantly battling for publicity and funding. Some
complain of university press officers ringing research teams to find out if
there is any study they can promote, as well as researchers anxious to
raise their own status by promoting weak studies.

Others blame the scientific press. “The British Medical Journal and The
Lancet will often send out press releases highlighting the research they
consider to be most newsworthy, not necessarily the best science,” said
Susan Jebb, head of nutrition and health at the Medical Research Council in
Cambridge.

Sikora also warns that the public should always look for the vested
interest. “There is no such thing as unbiased advice in health,” he said.
“People are either promoting an industry, or their own careers, which may
depend on promoting a particular theory, or more directly on funding from
vested interests.”

He points out that the skin cancer campaign has been funded largely by the
cosmetics industry which makes sunscreens and that research promoting the
value of vitamins is frequently subsidised by the food supplements
industry.

SUCH caveats leave one question: how, armed with suitable scepticism about
health messages, can you achieve a healthy diet and lifestyle? The solution
seems to be to follow the weight of scientific evidence in areas that have
been researched thoroughly over a period. “The two biggest lifestyle
killers are smoking and obesity, and alcohol is an increasing concern,”
said Sikora. “Most health experts would agree on that.”

Avoidance or moderation is the rule and there is broad agreement on diet,
too. “A diet with at least five servings of fruit and vegetables a day, and
moderation in everything else, is a philosophy we should all aspire to,”
said Frankie Phillips of the British Dietetic Association. “If people keep
that in mind, they should be able to cut through the worst scare stories.

“Sugar, fat and processed foods with high additive content should be
avoided. Most people know all this already: it is just a matter of doing
it.”

Advice from the government’s Food Standards Agency follows the same thread.
Snacks should be fruit or vegetables; alcohol intake should be no more than
a couple of glasses of wine or a pint of beer a day; meat consumption
should be reduced with products such as sausages and bacon eaten only once
a week.

Fatty foods such as chips, along with butter, cream and lard, should be
generally avoided and sweets should be an occasional treat rather than a
daily indulgence.

As for sun: you need some but not too much. Don’t burn.

A similar message applies for exercise: regular, moderate activity is
preferable to sudden bursts followed by inertia. Today Sport England is
launching an “everyday sport” campaign to reinforce the idea that new year
resolutions based on guilt are not the way to achieve long-term change and
that exercise should be built into daily life.

It is possibly no coincidence that the world’s longest-living people have
tended to be slim and modest in their dietary habits, with many subsisting
on Mediterranean-style foods. The record for longevity is held by Jeanne
Louise Calment, from southern France, who died in 1997 aged 122.

Mind you, she, too, is confusing for scientists and consumers: she was a
lifelong smoker, apart from a few months when she tried to give up when she
was 117.

A GUIDE TO THE THINGS YOU NEED TO DO – AND AVOID DOING – TO LIVE A LONG AND
HEALTHY LIFE

FOOD

A good diet is one that is high in nutrients and which keeps your body mass
index (BMI) — a ratio of height to weight — low and stable. Repeated
studies suggest that diets high in fresh fruit, vegetables, fish and
fibrous, starchy foods such as brown bread, rice and pasta are best. The
European Prospective Investigation into Cancer and Nutrition (Epic), one of
the biggest studies of its type, also advises against over-consumption of
red meats and dairy produce such as full-fat milk and butter, as these are
high in animal fats and linked to a greater incidence of illness, including
cancer. Also avoid processed foods which tend to be low on nutrients and
high in fat, salt and sugar. When cooking try to steam, not boil, and to
grill, not fry. Do not char food since this can produce potent mutagens
that can cause cancer.

DRINK

Keep yourself well hydrated during the day by regularly drinking water.
Milk is rich in calcium, which is particularly important for women who are
more prone to bone disease. Intake should be limited, though, because of
its animal fat content. Coffee contains antioxidants, believed to reduce
the risk of cancer-cell formation, but the consensus is that these benefits
are offset by the increased stress that caffeine causes. Office workers are
being advised by many doctors to switch to green tea, which is high in
antioxidants. As for alcohol, repeated studies have suggested that a small
daily intake — especially of red wine — is beneficial and may reduce heart
disease by up to 25%.


EXERCISE

People should ensure they build cardiovascular exercise and stretches into
their fitness regime, but most experts agree there is no need to go
anywhere near a gym. Moderate exercise taken daily has greater long-term
benefits, not least because it is more likely to become habitual over time.
Swimming, walking, dancing, cycling and using stairs instead of escalators
or lifts are all good low-impact options. A nine-month study published last
year, involving hundreds of overweight middle-aged Americans, found that
those on a walking regime achieved higher levels of fitness than those
doing short bursts of intense activity in a gym. The older you get,
however, the more important it is to do some light lifting to maintain
muscular strength. Stretch each morning.

SNACKS

Britain is at the top of the European league for consumption of crisps and
other savoury snacks, sweets and fizzy drinks — almost all of which are
full of fat, salt and sugar. The artificial sweeteners used in so-called
“diet” drinks may also carry health risks if consumed to excess. Best
advice is to stock up early each week on fresh fruit, raw vegetables and
nuts so that if you do graze throughout the day you reach for those first.
If you must treat yourself, go for dark chocolate as it contains
antioxidants (but not too much as it is also rich in caffeine).

SUPPLEMENTS

If your diet is balanced and you spend a good few hours outdoors each week
you should not need extra vitamins and minerals. However, the latest
research on vitamin D suggests a supplement may be beneficial to those who
do not get enough daylight. There is also evidence that fish oil
supplements can be beneficial if you do not include oily fish such as
herring in your diet. Vitamin E supplements are recommended by some doctors
as they contain powerful antioxidants, while aspirin is a supplement
recommended to thousands of middle-aged adults because it thins the blood
and reduces the risk of strokes. It can cause serious stomach problems,
however, so consult a GP first.