Coffee shown to reduce risk of skin cancer

Coffee has been shown to reduce the risk of skin cancer by helping kill off damaged cells that could otherwise turn into tumours, according to a US study published on Monday.

The findings indicate that moderate caffeine drinking, or perhaps even applying coffee to the skin, could be useful in warding off non-melanoma cancer, the most commonly diagnosed of all skin cancers.

Using mice that had been genetically altered to suppress a protein enzyme called ATR, researchers showed that the mice were able to fend off cancer even when exposed to ultraviolet light.

Previous studies have suggested that drinking about a cup of caffeinated coffee per day has the effect of suppressing ATR and triggering the die-off of cells harmed by UV rays.

The altered mice eventually did develop cancer, but three weeks later than normal mice, according to the study published in the Proceedings of the National Academy of Sciences.

After 19 weeks of ultraviolet light exposure, the engineered mice showed 69 percent fewer tumours and four times fewer invasive tumours than the control group.

However, the protective effects only went so far. After 34 weeks of UV exposure, all the mice developed tumours.

"Eventually, if you treat them long enough, the mice will develop cancer so it is not 100 percent protection forever," Allan Conney, one of the study's authors, told AFP.

"Really, with almost any carcinogen, eventually all the animals will develop tumours," added Conney, who is director of the Susan Lehman Cullman Laboratory for Cancer Research at Rutgers University in New Jersey.

Conney and his team were able to confirm their hypothesis that caffeine - when consumed or applied to the skin - works by inhibiting ATR. Now they say more studies are needed to see how it may work on humans.

"We want to see whether caffeine has an effect in people when you give it topically," he said.

"Caffeine might become a weapon in prevention because it inhibits ATR and also acts as a sunscreen and directly absorbs damaging UV light."

Skin cancer is the most prevalent cancer in the United States, with more than one million new cases each year, according to the National Cancer Institute.

Non-melanoma types of skin cancer, including basal cell and squamous cell types, are the most commonly diagnosed and are often treatable if detected early.

Previous studies have shown coffee drinkers tend to have fewer incidences of breast, uterine, prostate and colon cancers, but the beneficial effects are not seen in people who drink decaffeinated coffee.

What is tuberculosis?

TB most commonly affects the lungs, but can affect almost any part of the body. It can be spread when someone with the infection coughs, sneezes or talks and another person breathes in the bacteria. However, prolonged contact is usually needed for infection to occur.

Some people develop a minor infection, which then settles as their immune system fights it and evidence is only found later incidentally as a scar on a chest x-ray. For others, active TB flares up many years after the initial infection. If the initial infection isn't fought off, it can progress to serious ongoing infection a few weeks after the first contact.

Tuberculosis symptoms

Initially, there may be no symptoms. When symptoms develop, they will vary depending on which part of the body is affected. However, they commonly include:

• A persistent cough, usually for more than three weeks - it may be dry to start with and progress to blood-streaked sputum
• Night sweats for weeks or months
• Weight loss
• Fatigue
• High temperature
• Shortness of breath.
  

  Tuberculosis causes

  It's estimated that one-third of the world's population is infected with the bacteria that causes TB. Each year about nine million people develop the disease and up to nearly two million people worldwide are killed by it. Figures from the Health Protection Agency show there were 8,417 cases in the UK in 2007.

  Anyone can get TB. People at greater risk of developing it include:

• Children and older people
• Smokers
• Those living in overcrowded conditions
• Those who have a poor diet
• People with HIV
• The homeless
• Those who have a weakened immune system because of other medical conditions, such as diabetes, or because of other medical therapy, such as immuno-suppressant medication

Tuberculosis treatments

TB is difficult to treat - normal antibiotics don't kill TB bacteria. Combinations of several special antibiotics treat the infection in the majority of cases. These must be taken for long periods, usually at least six months, to avoid becoming ill with TB again and developing a drug-resistant form of the disease.

Even with treatment, some people develop long-term complications from infection.

Travellers to countries where TB is prevalent are at greater risk. A vaccine is available, which is offered to those at high risk of contracting the disease. Check with your doctor whether your travel plans put you at risk of TB and discuss possible vaccination.