By ROGER DOBSON

Last updated at 08:17 30 October 2007

Can jet lag trigger mental illness? It sounds absurd, but in fact it's just one of the many strange medical theories that could actually be true. Here, Roger Dobson looks at other extraordinary claims and the evidence

behind them...

DOGS GIVE WOMEN BREAST CANCER

Could it really be true that keeping a

dog increases the risk of the disease?

Analysis of breast cancer cases by

researchers at the University of Munich

showed that patients with this type of

cancer were significantly more likely to

have kept a dog than a cat.

In fact, 79.7 per cent of all patients had

intensive contact with dogs before they

were diagnosed.

Only 4.4 per cent of the

patients did not have pets at any time

compared to 57.3 per cent of a healthy

control group — so there was a 29-fold

increased risk for pet owners.

Another study in Norway reported a

very high level — 53.3 per cent — of breast

cancers in 14,401 dogs.

In looking for a

reason, scientists found a virus common

in both dogs and humans.

The one they homed in on is the mouse

mammary tumour virus (MMTV), which

triggers breast cancer in mice and which

has been investigated for possible links

to human breast cancer.

The theory is

that dogs, and possibly other pets,

harbour and transmit MMTV or MMTVlike

viruses that can induce human

breast cancer.

The researchers say the theory may help

to explain why women from Eastern

countries are at increased risk of breast

cancer when they move to Western nations

— Asian or Oriental women seldom keep

dogs as pets.

Migration to Western countries

may cause them to alter their

lifestyle, including keeping pet dogs.

NUTS CURE TOOTHACHE

It'a not just in science fiction novels and

horror movies that scientists experiment

on themselves.

The dentist Horace Wells

tested the effects of nitrous oxide by

having some of his teeth extracted while

breathing in the gas; William Morton, a

pioneer of anaesthesia, almost died

during his experimentation.

In the same honourable tradition,

Charles Weber, from North Carolina,

put his oral health on the line when he

tried cashew nuts as a cure for an

abscess under a tooth.

He says research shows that Gram-positive

bacteria, the bugs that cause tooth

decay, acne, tuberculosis and leprosy,

are killed by chemicals in cashew

apples (the swollen stalk the nut is

attached to), cashew shell oil and

probably cashew nuts.

The suggestion is that the active

chemicals in the nuts are anacardic

acids, which in test tube experiments appear to be active against Streptococcus

mutans, the cause of tooth decay.

Weber says the acids can be lethal to

bacteria in 15 minutes.

"I have made

raw cashew nuts the main part of my

diet for 24 hours on four occasions and

have eliminated an abscessed tooth

each time.

"There were no obvious

side-effects. A fifth time required

several day"

BEER BELLIES PROTECT MEN IN OLD AGE

When you hit your 30s, the poundsually start piling on, regardless of

diet or exercise.

The average Western

adult starts to get wider and thicker

after their 20s, putting on 6lb to 11lb a

deccade.

By age 50 we've gained, on

average, an extra 1st 8lb to 2st 5lb.

Obesity epidemic aside, this pattern is

consistent in nearly every Western

country.

While it could be due

to men becoming less

active or eating and

drinking more as they

get older, Israeli

researchers suggest it's

down to what they call

young hunter

hypothesis.

They believe

that age-related weight

gain is a major driving

force behind human

longevity.

They argue

that the muscle of the

young hunter is turned into fat stores

the non-hunting older man to

survive on in old age.

In ancient times, the food providers

needed to be muscular for dangerous

hunting expeditions.

To develop the

necessary muscles, body fat was

diverted from the lower limbs, and

energy was targeted at bulking up the

muscles.

At the end of their hunting careers,

the metabolic processes changed

focus to energy conservation in

anticipation of ageing.

Muscle mass

drops by around 15 per cent after the

age of 30, and there is a gradual

increase in fat levels, particularly

around the central area.

The Israeli hypothesis is that the

weight gain is a way of compensating

for muscle mass loss, guaranteeing

survival and longevity, even now.

HUMMING 120 TIMES A DAY CURES BLOCKED NOSES

Chronic rhinosinusitis can cause a

blocked nose, breathing difficultiesand a reduced sense of smell, as well

as the formation of nasal polyps in

more severe cases.

It's thought that

fungus in the nose could be to blame.

In an attempt to zap the fungus, the

immune system triggers an inflammatory

response that causes a runny

nose, cough, sore throat, pain in the

teeth and headache.

One way of treating the fungus could

be to use nitric oxide.

Toxic to

bacteria and fungi, the gas is naturally

released in the human respiratory

tract, so in theory it should be the way

to kill the fungus.

But how do you get

high enough concentrations at the site

of the fungal infection?

The answer is simple: hum.

According

to researchers in Texas, levels of nasal

nitric oxide are increased up to 20-fold

by humming.

They cite a man who had

rhinosinusitis with severe headache,

cough and insomnia, who had failed to

find anything to relieve his symptoms.

He then tried humming.

Done at a

low frequency — around 130 Hz — and

at regular intervals, it apparently

produces the greatest amount of nitric

oxide.

The man hummed strongly for

one hour at a rate of 18 hums a minuteat bedtime the first night, and

hummed strongly at a low pitch

between 60 and 120 times, four times a

day, for the next four days.

The humming increased nasal vibrations.

The morning after the first humming

session, the man awoke with a clear

nose and was breathing easily.

The

only side-effect with the treatment

was dizziness that can be brought on

by excessively vigorous humming.

According to the report, half an hour

of humming might also help with

symptoms of the common cold.

"By humming 60-120 times, four times per

day — including a session at bedtime

— symptoms were essentially

eliminated in four days."

WORMS PREVENT DISEASE

If one group of people have a much

higher or lower prevalence of disease,

there may well be something about

their environment or lifestyle that

either increases or reduces the risk.

In their research into the causes of atherosclerosis, the hardening of the

arteries, a team of Israeli

researchers found a significant geographic

difference in prevalence.

In

areas with a high level of intestinal

worm infections in humans, the

risk of heart disease was lower, and

the suggestion is that worms may

protect against heart disease and

stroke.

Atherosclerosis is a major health

problem.

The build-up of plaque, a

fatty substance, usually affects

large and medium-sized arteries

and can increase to a level where it

significantly reduces blood flow.

Plaque can rupture or break away,

creating blood clots that cause

heart attacks or stroke.

Just how worm infections affect

heart disease risk is not clear, but

one theory is that it may be down

to the worms' survival mechanism.

The tiny worms evade or suppress

the human immune system by

producing anti-inflammatory

compounds, which might also, it's

suggested, have a protective effect

on the arteries.

EATING PORK CAUSES MULTIPLE SCLEROSIS

For years, the wide geographic

differences in the prevalence of

multiple sclerosis have baffled

researchers.

Most studies have

shown that rates are higher closer

to the North and South Poles

compared to places nearer the

equator.

The UK, for example, has

higher rates than Spain.

The cause has remained elusive,

but now research by the University

of Ottawa suggests pork may be to

blame.

The scientists found a clear geographic link between total fat

eaten and MS prevalence.

The link between the numbers of

cases of MS and pork eating was

highly significant, but no such

relationship was found for beef,

which was also tested.

The results are in line with

reports that MS is rare in

countries where pork is forbidden

by religious customs, and that it

has a low prevalence in countries

like Brazil and Australia where

beef consumption far exceeds

pork.

One reason could be that the

fatty acids in pork and beef are

different.

Each have different

effects on the protective sheath

that surrounds and protects

nerve fibres in the brain which

become damaged in patients with

MS.

One suggestion is that the

fatty acids in pork increase

vulnerability to damage, while

those in beef do not.

JET LAG TRIGGERS MENTAL ILLNESS

Researchers at the Hebrew

University and Hadassah Medical

School in Israel say the link

between jet lag and psychiatric

disorder has been underestimated.

They suggest it could trigger

existing or new cases of affective

disorders such as depression,

anxiety disorder, panic attacks and

various phobias.

It might also be

involved in schizophrenia.

The scientists say many

examples of psychotic symptoms

occur during long-distance trips,

including cases of transit paranoid

reaction — a condition blamed on

changes of environment, such as

unfamiliar surroundings and the

presence of strangers, and a sense

of isolation.

Just how jet lag triggers new

episodes of mental illness, or even

the illness itself, is not clear, but

the hormone melatonin could be

the villain.

Secreted by the pineal gland

deep inside the brain, melatonin is

a key player in the regulation of the

circadian rhythm — the

24-hour cycle of living beings —

because it tells the body when it's

time to sleep and wake up.

In

synthetic form, as a supplement,

it's widely used in some countries

to combat the symptoms of jet lag.

But changes to the circadian

rhythm and melatonin secretion

abnormalities have also been

linked to a number of mental

disorders, say the researchers.

They also cite studies suggesting

that abnormal melatonin metabolism

may be directly related to

schizophrenia.

It's also suggested that sleep

deprivation affects melatonin

production and may be linked to

manic episodes.

SHOE HEELS CAUSE SCHIZOPHRENIA

Not only did

shoemakers start a trend

that led to generations of

women being condemned

to wearing high heels, they

could also be responsible

for the increasing number

of cases of schizophrenia.

The theory is that heeled

shoes may have led to the

first cases of the disease

and the establishment

of the first mental

hospitals.

Researcher Jarl

Flensmark says that the

schizophrenia only

appeared after heeled

shoes were introduced

into a population.

The oldest heeled shoe known

to man, made over 1,000

years ago, comes from

Mesopotamia — the same

area where the first

institutions dealing with

mental disorders appeared.

As industrialisation of shoe

production spread from NorthAmerica to Western Europe,

there was a remarkable rise

in cases of schizophrenia.

In England, the heeled shoe

emerged at the start of the

17th century, and a large

increase in the number of

mental illness cases followed.

This is compared with Native

Americans, who wear flat

moccasins and have a

relatively low frequency of

schizophrenia.

The science? When we walk,

the movement stimulates

receptors in the lower

extremities which increase

activity in brain cells.

Wearing heeled shoes

weakens the

lengthening

contractions in the

lower leg and foot, so

the receptors are

stimulated less.

This

drop in stimulation

leads to changes in the

dopamine system in the

brain.

This tallies with the

knowledge that

schizophrenics' brains

produce more dopamine.

CHEST PAINS ARE CAUSED BY THE MOON

The condition spontaneous

pneumothorax is a collection of air or

gas in the chest, which can cause the

lung to collapse.

It usually occurs in

tall, thin men aged 20 to 40 and is often

caused by the rupture of a small air or

fluid-filled sac in the lung called a bulla.

In many cases there is no apparent

reason for the condition, which causes

chest pain, shortness of breath and a

cough.

Several potential causes have been

suggested, including pressure changes

triggered by the weather and the effects that they have on the sacs in the

lungs.

When pressure increases, it's

been argued, sacs are more likely to

rupture.

Doctors in Bratislava reviewed the

cases of 244 patients treated with the

condition.

They found the timing and

frequency of admissions operated over

a two-week cycle.

There were two distinct peaks for men

and women: one came exactly one

week before the new moon, and the

second one week after.

It's thought the moon might exert an

influence through gravitation, the

same way that it affects the tides on

Earth.