The cholesterol controversy

Over the past several years, an increasing number of studies have started to raise doubts about this presumption. Cholesterol, a fatty chemical compound produced by the liver and found in some foods, is necessary to build cells and manufacture hormones but too much in the blood has been shown to clog arteries, increasing the risk of heart disease and stroke. But many experts now believe factors like nutrition and fitness play a more meaningful role in heart health and that having high lipid levels could be harmless for many people.

"The typical scenario is that you have a cholesterol test and your LDL comes back high, so your doctor tells you, 'Try exercising and eating less saturated fat'," says John Abramson, a physician, author and lecturer at Harvard Medical School. "You do, your LDL doesn't drop, so your doctor says, 'OK, let's put you on a statin and you won't have to worry about it.' But the truth is that eating a healthy diet and exercising, even if they don't lower LDL, will reduce your risk of heart disease many times more than taking a statin ever will."

In other words, most research hasn't shown that having high cholesterol alone causes heart disease - instead, it could just be a symptom of that condition, similar to how sweating can be a symptom of the flu.

Doctors point to the fact that 75 per cent of people who have heart attacks have healthy cholesterol, while most people with poor cholesterol numbers never suffer the heart trauma. The National Heart, Lung and Blood Institute's Framingham Heart Study - one of the US's largest, longest and most influential pieces of cholesterol research - did find that having high cholesterol before age 40 was associated with premature death but having the same numbers at age 50, 60, or 70 actually correlated with living longer.

All in all, says Christopher Gardner, a researcher at the Stanford University School of Medicine, having high cholesterol - even high LDL - is an "overblown risk factor" for heart disease.

Statins, one of the most commonly prescribed classes of medication in the West, have some controversial implications, too. Traditionally, doctors have viewed statin drugs as the most effective way to lower high LDL cholesterol. But today, researchers are starting to believe that statins may not be the magic bullet they've always been made out to be.

While studies show that statins can lower LDL cholesterol and reduce the risk of heart attack in people already diagnosed with heart disease, the drugs have not been conclusively shown to help those without a pre-existing heart condition - the majority of people on statins. This is according to several studies, including an analysis of 11 drug trials involving more than 65,000 people.

Of course, taking statins can help save the lives of some people diagnosed with heart disease. But anyone considering statin therapy should weigh the risks, because it does have side effects, including muscle pain, muscle damage, liver damage and potential memory loss.

A recent study also found that taking statins can cause muscle pain during and after vigorous exercise, to the extent that "statin therapy and top athletics seem to be almost incompatible". Research from the University of California found that statin medication can reduce a patient's ability to orgasm.

Ultimately, a healthier diet may be one of the best weapons against heart disease - even better than taking statins. But if you think eating heart-healthy means shunning saturated fat and dietary cholesterol entirely, you could be misguided.

It's becoming more widely understood that eating cholesterol-rich foods such as eggs, once thought to raise blood cholesterol, has minimal effects on lipid levels, while recent research found that eggs could even improve healthy cholesterol levels.

Similarly, science has been unable to establish a link between consuming saturated fat - present in foods such as red meat, pork and butter - and heart disease. Although eating saturated fat and fewer carbohydrates raises LDL cholesterol, doing so also elevates healthy HDL cholesterol and lowers triglycerides, or potentially bad blood fats.

What, then, can you do to prevent heart disease if high LDL isn't the best predictor and taking statins hasn't been shown to limit problems? Here are four tips to help you gain control of your heart health - and future.

1. GET A BETTER

CHOLESTEROL TEST

Knowing your HDL and LDL numbers only tells you a little about your heart health. Many doctors now test patients for additional risk factors, such as triglycerides and C-reactive protein, a blood marker for inflammation that's been linked to hardening of the arteries. Or you could ask your GP for a full cholesterol test, detailing all cholesterol components.

2. EXERCISE

Even if only a little. If there's one thing that predicts the risk of heart attack, it's being out of shape, Abramson says. A 10-year study of 25,000 men found that men who were entirely unfit had the highest risk of heart attack, regardless of their cholesterol numbers.

But you don't have to be a top athlete to reap benefits. Many studies show significant heart-protective effects from modest workouts, such as a brisk three-kilometre walk daily or running eight to 13 kilometres a week. One Harvard study found that men who ran for an hour or more just one day a week reduced their risk of heart attack by 42 per cent and those who lifted weights for 30 minutes or more once a week had a 23 per cent risk reduction. The greater the exercise intensity, the bigger the risk reduction, so aim for at least one hard aerobic workout a week, along with a solid half-hour of weight training.

3. REALISE THAT SOME BAD FOOD MAY BE GOOD

Adopting a healthier approach to nutrition is one of the most effective lifestyle changes you can make to prevent heart disease. Many cardiologists recommend a Mediterranean diet of fruit and vegetables, olive and canola oils and lean fish and chicken, with minimal amounts of saturated fat, red meat and pork.

This is a good starting place, says Stanford's Gardner, but avoiding all red meat and eggs may not be as effective as doctors believe. He points to a major study he helped conduct that found the Atkins Diet, low in carbohydrates and high in animal protein and fats, was better for heart health than three other eating plans: a low-fat, calorie-restrictive approach; the Ornish Diet, a vegetarian plan created by cardiologist Dean Ornish; and the Zone Diet, on which people consume 40 per cent of their daily calories from carbohydrates, 30 per cent from protein and 30 per cent from fat.

At the end of the year-long study, Gardner, a vegetarian, was surprised that those who followed the Atkins Diet raised their good HDL cholesterol levels and lowered their blood pressure and blood triglycerides far more than participants on the other diets.

The lesson? You don't have to avoid animal products if you're at risk of heart disease. Instead, limit your intake of refined, processed or starchy carbohydrates, including white rice, white bread and pasta and potatoes. Opt for beef, eat small amounts of egg if you like and increase your intake of fish, nuts and produce.

4. LOSE A COUPLE OF KILOS

Tipping the scale beyond what's considered healthy correlates with an increased risk of heart disease. How can you tell if you're too heavy for your heart? Most doctors rely on the Body Mass Index (BMI). To calculate it, take your weight in kilograms and divide that figure by your height in metres squared. A BMI of 25 or higher means you're overweight and have an elevated risk of heart disease.

But since BMI doesn't account for differences in body composition (muscle is more dense than fat, so a lean, muscular athlete can register as overweight), consider other factors, such as waist circumference. As a general rule, a waist measurement of less than 80 centimetres for women and 94 centimetres for men is considered healthy. These figures, however, apply to Caucasians and Asian women only. Waist measurements are yet to be determined for all ethnic groups.

CHECK YOUR

VITAL STATS

Most people know that high cholesterol levels have been linked to heart disease but many people are confused about the way cholesterol levels are measured and what the different numbers mean.

Cholesterol levels are measured in millimoles of cholesterol per litre of blood (mmol/L)

2 or less: Low-density lipoprotein (LDL) is bad cholesterol and is thought to be a key marker for heart-disease risk. It should be no higher than 2mmol/L.

1 or more: High-density lipoprotein (HDL) is considered good cholesterol. It is thought to help remove LDL particles from blood. Higher numbers here are better  above 1mmol/L. High levels are strongly associated with a lower risk of heart attack.

Below 1.5: Cholesterol includes triglyceride, a component of cholesterol that relates to blood sugar, and that number should be lower than 1.5mmol/L. High triglyceride levels can cause fatty deposits to build up in the liver and are believed to lead to diabetes and heart disease.

C reactive protein: This is a blood marker for inflammation. Elevated CRP levels have recently become a new critical marker for heart-disease risk. The value is not standard on most cholesterol tests.

SURPRISE STATISTIC Seventy-five per cent of people who have heart attacks have healthy cholesterol. Most of those who have unhealthy cholesterol never suffer the trauma.