High cholesterol levels are a worry, says Dr John Briffa. But oily fish can tip the scales to a healthier heart

Many doctors will confess to feeling frustrated by occasional patients who complain about some aspect of their health but nonetheless appear to have no hard signs of disease. Members of the medical profession generally have their hands full dealing with those regarded as genuinely sick, and therefore tend not to have too much time for individuals labelled the 'worried well'. However, we doctors can be the instigators of a health neurosis in our patients, a prime example of which is cholesterol testing. While there may be merit in this form of screening, a fair few individuals see a raised cholesterol level as some sort of Sword of Damocles - poised to cut short their lives.

Despite its death-inducing image, there is good reason to believe that a lofty cholesterol level need not be a health disaster. This is because cholesterol comes in more than one form, and not all of it is bad for the body. The majority comes in low-density lipoprotein (LDL) form. This is believed to be responsible for the narrowing of the arteries that may lead to heart disease and stroke. However, the other major type, high-density lipoprotein (HDL) cholesterol, is believed to help clear cholesterol from the system - a quality that actually protects against any gumming up of the circulation.

Just last month, a study published in the Archives of Internal Medicine found that higher levels of HDL were associated with a halving in the risk of heart disease and stroke in a group of elderly individuals. Other studies have found that elevated levels of HDL are protective for heart disease and overall risk of death. Because LDL and HDL have antagonistic actions in the body, it is the relative amounts of these two substances (rather than the total amount of cholesterol) that seems to be the critical factor.

A good guide to cholesterol's likely impact can be had by dividing the total cholesterol (TC) level by the HDL score. Ideally, this number should be less than five, and the lower the better. I've seen quite a few individuals who, despite having cholesterol levels considered higher than ideal, still have decent quantities of HDL in their blood streams, and have reassuringly low TC:HDL ratios, too. Some researchers are keen for HDL levels to assume greater importance in the interpretation of cholesterol tests, and are calling for more emphasis to be placed on interventions that enhance HDL levels in the body.

Those keen to boost their HDL score through diet should eat more fish. Studies show that the consumption of oily fish (or fish oil supplements) can elevate blood levels of HDL. Exercise may also help, with one study showing that running as little as seven to 14 miles a week was associated with higher HDL levels. A better understanding of HDL's disease-protective role, and taking steps to raise its profile in the body, mean that high cholesterol levels need not always be taken to heart.