01
Aug 2011

Cat Parasite Linked To Brain Cancer In People

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A third of us are infected with Toxoplasma gondii, a parasite that can be transmitted to us by animals. Cats represent a major source of this organism, and are therefore a common route of infection for us since they continually shed the parasite. Consequently we can become infected with Toxoplasma gondii if we come into contact with anything that is contaminated with the organism as a result of a cat’s shedding. Some ways include:

  • Contaminated soil  (when gardening in an area where cats have defecated)
  • Cleaning the cat litter box
  • Contaminated water
  • Undercooked meat (lamb, pork, and venison especially – these animals are infected by cats in the same way as we are)
  • Cooking utensils coming into contact with undercooked, infected meats

Although many people are infected with this parasite, most are unaffected by it, and show no clinical symptoms since the immune system effectively prevents it from causing disease; however, clinical toxoplasmosis can be a real problem for people with weakened immune systems, such as:

  • HIV infected patients
  • Chemotherapy patients
  • Organ-transplant recipients

Additionally, it poses a particular risk for unborn babies. A  woman who comes into contact with the organism for the first time during her pregnancy may transmit it to the fetus in utero, resulting in birth defects or even infant fatalities. Transmission of the parasite to an unborn baby, however, is less likely if the woman has previously come into contact with the organism at least six months or more, prior to becoming pregnant.

Links With Brain Cancer?

Interestingly, a recent study reports a correlation between rates of infection of Toxoplasma gondii, and the incidence of brain cancer. Global data on brain cancer in people from 37 countries was collected and compared with the prevalence of Toxoplasma gondii infection in those regions. The research group reported that brain cancer rates increased in countries where the parasite was more prevalent.

This ecological study, however, merely points to a correlation between the two events – it does not imply that the parasite actually causes brain cancer in people. And certainly the opposite could be true – it’s not impossible that brain cancer could be the driving factor behind Toxoplasma gondii infection.

So as it stands, this report does not prove cause and association, but is predominantly hypothesis-generating, and does provoke scientific curiosity. In the words of one of the authors:“These were the best data available and we felt they were sufficient to take the first step. Working with actual brain cancer patients is an obvious next step, but it would be an expensive proposition.  It is a lot easier to justify the second, expensive step when you have some evidence for the hypothesis. We are hoping that our results motivate others in the field to do further studies.”

Thomas, Lafferty, Brodeur, Elguero, Gauthier-Clerc & Misse. 2011. Incidence of adult brain cancers is higher in countries where the protozoan parasite Toxoplasma gondii is common. Biology Letters

 

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21
Jul 2011

Managing Anxiety

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Every year, over 40 million people in the US suffer from anxiety disorder, and more than 20 million will experience some depressive illness.

Although anxiety is a natural reaction of the body to any risk, threat, or danger, if your worries become a recurring theme and prevent you from living a normal life, this could suggest an anxiety disorder.

Such disorders can lead to enormous financial costs for the economy, but emotional cost for affected patients is even more important and significant. Symptoms vary from one person to the next, but most will experience both physical and emotional problems, as well as illogical and heightened worries.

Regardless of the stimulus, anxiety attacks can be extremely damaging to a person’s well-being – social and work lives suffer, and one can easily enter a negative spiral with feelings of low self-worth. Such conditions are highly treatable, however, so help should always be sought from a professional – especially in severe circumstances.

Additionally there are numerous self-help methods that you can employ to try to break the cycle. So although such problems can be highly debilitating, the good news is that chronic worrying is a mental habit that can be broken – so don’t let it keep you up each night!

Categories: Medical Tags: , , , , , , ,
07
Jul 2011

Eating Less Salt May Not Cut Risks Of Heart Disease

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A study published online this week in the American Journal of Hypertension has rubbed salt in the wounds of the old belief that excessive salt intake contributes to the development of cardiovascular disease

A group of researchers from the University of Exeter in England analyzed the results of seven clinical studies. Collectively these studies involved over 6,000 adults who had been tracked for at least six months. Patients were assigned to one of three groups, according to whether they had:

  • Normal blood pressure
  • Hypertension
  • Heart failure

All patients were evaluated to determine how their dietary salt intake was associated with blood pressure, incidence of heart disease, and death. Subsequent meta-analysis of the combined data from these studies, however, failed to obtain any firm evidence that reducing dietary salt intake prevents the chances of death from cardiovascular disease.  Reduced salt intake did tend to reduce blood pressure a little, although it had no effect on reducing the rate of cardiac arrest, stroke, or heart surgery.

 

 

The National Salt Reduction Initiative

The World Health Organization currently recommends a maximum salt intake of 5 grams per day, whereas many people in western countries often ingest twice this amount. And indeed the FDA currently suggests not ingesting more than a teaspoon of salt a day – almost 2.5 grams. Although they recommend that people should be trying to reduce their salt use in food, they additionally advise the food industry to remove excess salt from their products. Almost 80% of the salt in our diets apparently derives from that which is added to processed foods and drinks before they are sold.

Such public health initiatives to reduce salt consumption are mostly based on observational studies that have shown a connection between high sodium intake and increased risk of cardiac disease. Such study types, however, are not designed to demonstrate a cause-and-effect relationship – they are only able to show association, and any association could potentially be explained by numerous other factors.

 

In Conclusion

This new report thus introduces more controversy on conventional thinking that a reduced salt intake can prevent heart disease. Subsequently the researchers of this most recent report conclude that additional research is required to clarify the association between heart disease and salt intake – and in particular, larger randomized controlled trials would be beneficial.

 

Taylor RS et al: Reduced Dietary Salt for the Prevention of Cardiovascular Disease: A Meta-Analysis of Randomized Controlled Trials (Cochrane review). (2011) Am J Hypertens, July 6 [Epub ahead of print]

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