That's the bad news. The good news is that simple lifestyle changes can dramatically reduce your risk. Read on to discover the 7 top risk factors for stroke and what you can do to prevent them.

But first, what is a stroke and what are the warning signs?

A stroke occurs when the blood supply to the brain is interrupted and brain tissue is deprived of oxygen and nutrients. Most strokes are ischaemic strokes caused by blood clots blocking an artery to the brain.

About one out of five are caused by a haemorrhage in a blood vessel to the brain. This is a haemorrhagic stroke. It can occur when an artery ruptures causing bleeding into the brain.

A stroke can also happen when a clot from elsewhere in the body becomes dislodged and blocks an artery in the brain {embolic stroke}.

The common symptoms are:

Numbness, weakness or paralysis of the face, arm or leg on one or both sides of the body.

Loss of vision in one or both eyes.

Speech difficulty.

Vertigo, loss of balance.

Sudden, severe headache.

Confusion and memory problems.

Difficulty swallowing.

Seizures or blackouts.

RISK FACTOR NUMBER 1.

High blood pressure or hypertension.

Defined by the US National Institutes of Health as a blood pressure reading of 140/90 or higher.

Factors such as a high fat diet, stress and being overweight can narrow arteries. The resulting pressurized blood flow damages artery walls, making the formation of fatty plaque more likely. Plaque can break off and cause blood clots to form according to studies at the Stroke Prevention and Atherosclerosis Research Centre at Robarts Research Institute London, Ontario, Canada.

Normalizing blood pressure cuts the risk of stroke in half. No other preventative measure is as effective. The Mediterranean diet can lower blood pressure and reduce the risk of stroke by up to 60%.This diet calls for five to nine servings of fruits and vegetables a day. It also emphasizes the importance of whole grains, beans, fish and poultry. It suggests replacing butter and cream with olive oil or oils rich in alpha-linolenic acid.

RISK FACTOR NUMBER 2.

Smoking or exposure to secondhand smoke.

Cigarette smoke is a bigger risk factor than previously thought. Research conducted at the University of Auckland New Zealand divided people into three groups: smokers, non smokers exposed to secondhand smoke and non smokers not exposed to secondhand smoke.

Researchers discovered that smokers had six times the stroke risk of non smokers and non smokers exposed to secondhand smoke had almost double the risk of other non smokers.

The obvious prevention is to quit smoking. Some success has been achieved with nicotine patches, anti smoking medication and hypnosis.

RISK FACTOR NUMBER 3.

Sticky blood or platelet aggregation.

In this process, microscopic components of blood stick together, leading to clot formation. To prevent this, talk to your doctor about taking a low dose aspirin daily. Aspirin inhibits platelet aggregation and can reduce the risk of stroke by up to 30% in some people. Vitamin E can improve blood flow and prevent blood clots. It is possibly the most important vitamin for promoting normal blood circulation, healthy arteries and heart.

RISK FACTOR NUMBER 4.

High cholesterol level.

High total and/or high LDL ["bad"] cholesterol levels contribute to the narrowing of arteries.

Prevention: Have a blood test. If your total cholesterol and LDL cholesterol are high, ask your doctor to discuss options with you. A number of natural options are available. These include a high fiber diet. Psillium husks and ground flaxseed are particularly high in fiber. Garlic can lower cholesterol levels as well as clean the arteries of accumulated fats.

RISK FACTOR NUMBER 5.

Ministrokes.

Before a person has a stroke, he/she might have one or more "ministrokes", or transient ischaemic attacks [TIAs}. The symptoms are the same as a stroke.

Though TIA symptoms go away, those who have had a TIA have about a 30% risk of having a stroke within the next two months.

Prevention: If you think you have had a TIA, see your doctor without delay. It is possible that you have symptomatic carotid stenosis, a severe narrowing of the carotid artery, the main artery leading to the brain. Endarterectomy, a procedure to clear this blockage, reduces the risk of stroke to 9%.

RISK FACTOR NUMBER 6.

High Homocysteine level.

Homocysteine is an amino acid used by the body for many functions including detoxification. Normal blood levels are about 6-8mm for women and 8-12mm for men. As long as the body keeps these levels in check,it is not usually a problem.

According to Dr Kilmer McCully, author of "The Homocysteine Revolution", this amino acid may be toxic and inflammatory when in excess and can lead to serious consequences including heart disease and stroke. It causes cholesterol to "catch" onto ridges in your artery walls. These cholesterol "traps" are the cause of a fatty build up called "plaque", thus reducing the flow of blood and causing high blood pressure.

Some research studies have suggested that high homocysteine level is a more critical marker for heart disease and stroke than cholesterol levels.

Prevention: A blood check will determine your homocysteine level. If it is high the dietary supplement folate {folic acid} combined with vitamins B6 and B12 should help. Dietary improvements also help reduce homocysteine levels. Eliminate processed foods, including flour and sugar and eat more fresh vegetables, fresh fruits and whole grains.

RISK FACTOR NUMBER 7.

Heavy Drinking.

This can increase your stroke risk threefold, so it's vital to limit your intake.

Prevention: A moderate intake of one or two standard drinks daily, may actually decrease your stroke risk.

FINALLY: DON'T IGNORE THE WARNING SIGNS AND RISK FACTORS!

My father died of a stroke at the age of 35. He was strong, physically fit and thought he was indestructible. His warning sign was a severe and persistent headache. Despite requests from my mother to visit a doctor, they were ignored. He rarely suffered from headaches and dismissed it as a passing inconvenience.

John Newcombe, Wimbledon Tennis Champion and former captain of the Australian Davis Cup team, is a stroke survivor.

In his inspirational book "No One's Indestructible", he describes how he believed he was "bulletproof". He had many warning signs and risk factors. He was a smoker, drinker, had high blood pressure, high cholesterol and was regularly under stress. He ignored them. His description of events leading up to and following his stroke, including his recovery program, makes compulsive reading.

Never start a new treatment before consulting your doctor, especially if you are currently taking medication. The information published in this article is not intended as a substitute for personal medical advice from your physician or other qualified health-care practitioner. It is for information only.