Poor diet 'boosts virus power'

[Guest guest]

Friday, 8 June, 2001, 14:15 GMT 15:15 UK

Poor diet 'boosts virus power'

The genetic structure of the viruses changed

A diet lacking in the mineral selenium may allow viruses to mutate and

become more virulent, scientific research suggests.

A human flu virus used to infect mice given a selenium free diet was found

to have undergone genetic changes.

The virus did not change in mice on normal diets.

Selenium is found abundantly in many wholemeal breads and vegetables,

although there are worries that typical UK diets are beginning to fall short

of recommended levels.

We believe our findings are both important and potentially disturbing Dr

Melinda Beck, report author

The team, from the University of North Carolina in the US, has already found

another virus which behaves in a similar way - and fears that epidemics of

more potent strains of HIV and even Ebola may be made more likely by poor

diet.

However, UK experts say that much work remains to prove that the viruses

behave the same in humans as they do in mice.

The study, published in a journal published by the Federation of American

Societies for Experimental Biology, only looked at a relatively small number

of mice.

Two groups were fed either normal diets or ones in which no selenium was

present.

They were then exposed to a relatively mild strain of human flu.

Severely inflamed

Both groups fell ill - but the malnourished mice had far more severely

inflamed lungs, and were ill for far longer.

If translated to humans, the difference would be equivalent to mild versus

severe pneumonia.

Afterwards, the research teams looked at the flu viruses present in each

group, checking their genetic structure.

There were higher numbers of mutations - in genes normally thought to be

resistant to alteration - in the malnourished mice.

Genetic mutations can lead to new strains of virus, which may be more

virulent than their predecessors.

The researchers believe that selenium may be protecting the body in at least

two ways.

It is known to have a beneficial effect on the immune system, which might

explain why the malnourished group suffered more severe illness.

It also has an anti-oxidant effect, which may protect the body from damage

from " free radicals " , molecules which can cause cell damage.

It does imply that selenium deficiency is associated with more severe

consequences through infection with the flu virus

Professor Alan Shenkin, Liverpool University

It is suggested that the selenium also " protects " the viruses against

similar genetic changes caused by cell damage.

Dr Melinda Beck, who led the research team, said: " We believe our findings

are both important and potentially disturbing because they suggest

nutritional deficiencies can promote epidemics in a way not appreciated

before.

" What we found conceivably could be true for any RNA virus - cold virus,

Aids virus and Ebola virus. "

Professor Alan Shenkin, from the University of Liverpool, said that the

study was " fascinating " .

He said: " It's a very important piece of work because it does imply that

selenium deficiency is associated with more severe consequences through

infection with the flu virus.

" It could be very serious - what we need to know first of all is whether

this is relevant to man, or just something to do with the speed with which

mice grow. "

There is already evidence that adequate selenium in the diet may be

protective against cancer, and perhaps have an impact on male fertility.

Some campaigners want UK wheat to be fortified with the mineral to make sure

everyone is getting the recommended daily amount.