Drinking coffee is beneficial for or detrimental to your health, depending on which study you read. File photo / Hawke's Bay Today

Drinking coffee is beneficial for or detrimental to your health, depending on which study you read. File photo / Hawke's Bay Today

Every week, it seems a scientific study appears disproving what last week's study showed. Yesterday saw a classic medical volte face: aspirin, which has been prescribed to millions of people over the decades as a protective measure against heart disease, may have more drawbacks than benefits, according to a review in the Drug and Therapeutics Bulletin.

Although a daily aspirin helps prevent a second heart attack or stroke in people who have already had one, in healthy people any protection against cardiovascular disease may be outweighed by an increased risk of internal bleeding, researchers say.

Bleeding is a well-known side effect of aspirin and similar drugs that act as irritants to the stomach lining.

After years of headlines about the benefits of aspirin, yesterday's read: "Aspirin is bad for you".

In the last couple of weeks, we have also learnt that a father's presence at childbirth is bad for the mother, that drinking three cups of coffee a day protects against liver disease (for people with hepatitis C) and that consuming alcohol cuts a woman's chances of conceiving by IVF.

Yet fathers have been encouraged to attend childbirth for decades, coffee has been implicated in umpteen health scares, and alcohol is known to be good for the heart.

Here we review the ups and downs of medical research:

A is for alcohol

Good for: moderate drinking is good for the heart, though the effect is chiefly seen in middle-aged men - two or three alcoholic drinks a day cuts the risk of heart attack by at least 30 per cent.

Bad for: drinking to excess, liver disease, dependency - all are rising. Other effects are less obvious: one drink a day increases a woman's risk of all types of cancer by six per cent. This week, scientists from Harvard Medical School presented findings showing couples having IVF who drank one bottle of wine a week cut their chances of a live birth by a quarter.

B is for beta blockers

Good for: they are among the most widely prescribed drugs for preventing heart attacks in people with high blood pressure but without existing heart disease.

Bad for: patients undergoing surgery, millions of whom have been given them to reduce the risk of heart attack following an operation. Last year, an international study concluded that the practice had caused 800,000 deaths worldwide due to an increased risk of a stroke.