What exactly is cholesterol and do you need to be concerned about yours? Claire O'Connellreports on the real health indicator
This month as you tuck into fry-ups, five-course meals and endless tins of chocolates, spare a fleeting thought for your besieged cardiovascular system. A diet laden in saturated and processed fats combined with a lack of exercise can push up levels of cholesterol in your blood which, in the longer term, increases your risk of heart attack or stroke.
Although the odd festive splurge won't cause too much harm, experts suggest you steer back to everyday moderation as soon as possible to help keep your arteries clear.
But what exactly is cholesterol? Does it really deserve all its bad press? And do you need to be concerned about yours?
Cholesterol is a waxy, fat-like substance that plays an important role in how our bodies function. It's in the membrane barrier that surrounds our cells, we use it to make hormones and it also plays a role in digestion. But it has a not-so-saintly side: too much cholesterol in the blood, and particularly the type called low-density lipoprotein, or LDL cholesterol, can build up plaques on the inner walls of blood vessels.
This furring can strain the heart as it tries to pump blood through narrowed vessels, and plaques can also break away and trigger heart attacks or strokes.
To help reduce your risk, you need to keep blood levels of cholesterol in check, according to Janis Morrissey, dietitian with the Irish Heart Foundation.
"Many people don't realise that we do need a certain amount of cholesterol, it's pretty much in every cell of our body.
"But the problem is when we have too much of it," she explains.
Our livers can make enough cholesterol to meet our needs, then ideally excess LDL cholesterol is eliminated with the help of "good" or HDL cholesterol, says Morrissey.
But surprisingly, eating cholesterol-laden foods directly in our diet doesn't play a huge part in raising cholesterol in our blood. "The main thing that makes the cholesterol go up in our blood is eating saturated fats," she says, listing animal-based foods such as the visible fat on meat, butter, lard, cream and cheese.
Worse again are trans fats that crop up when vegetable oils are hydrogenated to improve their mouth-feel and shelf life in processed foods such as cakes, biscuits and ready meals. "The trans fats are thought to be even worse than the saturated fats because not only do they decrease the amount of good cholesterol, they also increase the amount of bad cholesterol, so there's a double whammy," says Morrissey.
A sedentary lifestyle, smoking and being overweight also push up the risk of high LDL or "bad" cholesterol, and Morrissey warns against the creep up the scales as we go from one celebration to the next.
"Two weeks isn't going to make or break your cholesterol levels but how you deal with festive situations can," she says. "If you are going for a couple of holidays and then there's Christmas and the family celebrations and you are going from one to the next, it's easy to creep up."
But the good news is that trimming off a few pounds can cut cholesterol substantially. "We know that even losing a small amount, 10 per cent weight loss, can have a very positive effect on cholesterol level.
"You don't have to lose stones and stones - even losing a few pounds will have a benefit for your heart. And exercise has a particularly important role in bringing up your HDL, the good cholesterol," says Morrissey.
However, that's not an invitation for people of a healthy weight to ignore their cholesterol, she notes. "While being overweight certainly increases your chances of having high cholesterol it doesn't mean that if you are a healthy weight you won't have high cholesterol."
Some people also have a genetic make-up that makes it more difficult to keep their cholesterol in check and they may need cholesterol-lowering drugs, which are widely prescribed and effective, adds Morrissey.
But she advises consumers to be circumspect about new products or superfoods billed as cholesterol zappers.
"You hear about things like garlic and lecithin, there's always something new," she says. "The messages about saturated fat and fruit and vegetables have been around for so long people get tired of them, and then you hear about some new product and think this will do the job. But we have to be evidence-based in what we are saying, and eating fruit and veg and lowering your saturated and trans fat has been shown to work."
The evidence also stacks up that functional drinks containing plant stenols and sterols can effectively reduce cholesterol by up to 10 per cent, but again Morrissey warns against relying on them to make up for a poor diet.
"Our concern in the Irish Heart Foundation would be that people think they can knock back their yoghurt drink every day and that's their cholesterol sorted," she says. "Instead you have to look at the whole lifestyle. The functional drinks can help but they are expensive, and you are better off putting that money into some extra fruit and vegetables, getting the basics right."
Meanwhile, she suggests that people over 30 have their cholesterol levels checked every five years to keep tabs on their heart health. And while cholesterol is not the last word in predicting heart disease, she notes that it is a good target to keep in your sights if you want to improve your health.
"Cholesterol has been around for a long time but that doesn't mean it's old and tired. It is a very important indicator and changing your habits to bring down cholesterol will also have benefits in other areas like weight and blood pressure. It's about the food pyramid and keeping an eye on the fat, the exercise and smoking. It's the same old public health message but that's what the evidence is saying."