By Tan Xian Wen
Cardiovascular disease remains the number one cause of mortality globally. According to the World Health Organization an estimated 17.3 million people died of the disease in 2008. This is expected to increase to 23.3 million by 2030. Such a high mortality rate implies the need for urgent global attention.
Atherosclerosis, the hardening of blood arteries, is often the primary cause of cardiovascular disease. The arteries, blood vessels that transport oxygen and nutrients from the heart to every part of the body, are strong and flexible when they are in a healthy state. The continuous build-up of oxidized fatty plaques on the arterial wall, however, triggers inflammation. This will eventually lead to the thickening and stiffening of the arteries.
The condition worsens when the plaques in the arteries burst, causing the formation of clots which could travel along the blood stream. When the clots are trapped along the narrow blood stream, blood is gradually restricted to the rest of the organs and tissues, much like when water is prevented from going through a hose. The consequence can be fatal.
Atherosclerosis typically begins prior to adulthood and progresses slowly. Both an unhealthy diet and lifestyle are the main contributors to the condition. The slow progression and complicated etiology limit the diagnosis of early atherogenic events for prevention measures.
Although cardiovascular disease may be a leading cause of death, there are many preventive measures one can take to reduce the risk. Some of these measures include proper weight management and regular exercise, but let’s not forget dietary intake matters just as much. Controlling what one consumes has an impact on the body’s physiological chemistry profile as well.
A diet high in vegetables and fruits has been linked to low incidence of chronic diseases. This is generally attributed to the presence of active constituents such as vitamins, resveratrol, ?-carotene and flavonoids. These are actually antioxidants and have credible effects in the prevention of chronic diseases by scavenging free radicals within the body.
Free radicals are by-products the body makes when it breaks down food for energy. They may also come from the environment and the food we consume. Free radicals are often short of an electron in their configurations so that they often “grab” electrons from the body’s cells to fill the empty slot. Through a series of domino effect, cells become vulnerable to oxidative injuries and eventually die when they fail to recover. This consequently leads to chronic diseases such as heart disease, cancer and diabetes.
High cholesterol levels particularly LDL or low density lipoprotein, which is also known as bad cholesterol, and oxidative stress are two factors involved in the progression of atherosclerosis. When cholesterol increases, it penetrates into the arteries and undergoes oxidation to form oxidized LDL as they interact with free radicals in the body. Oxidized LDL is highly immunogenic and causes arterial inflammation and later triggers the body’s inflammatory and immune responses.
Antioxidants are the scavengers of free radicals. They act as soldiers that eliminate free radicals and terminate the chain reactions that cause oxidative stress. By donating an electron, antioxidants neutralize free radicals. This prevents the binding of free radicals and LDL, and hence decreasing the formation of oxidized LDL. In short, antioxidants and cardioprotection are linked in such a way that antioxidants target the early stage of atherosclerosis by halting the formation of oxidized LDL and ultimately resulting in cardioprotection. However, after the free radicals are eliminated antioxidants become free radicals. This is why antioxidants are needed to be replenished and supplied daily.
Various cell cultures, studies on animals and clinical trials have been used to test the effectiveness of antioxidants for cardioprotection. The majority of the outcomes from these studies have been relatively positive. Antioxidant treatments have been shown to inhibit oxidation of LDL by 40 to 60 fold, significantly improves antioxidant status in human blood plasma, and substantially reduce the formation of oxidized fatty plaque in the hearts of mice. Although these positive effects have been evidently proven, the exploration of antioxidant treatment in the area of cardio protection continues to attract much research interests. So, could antioxidant treatment possibly be the key to the prevention and treatment of atherosclerosis? Only further research will tell.
Tan Xian Wen is pursuing a Master of Science at Swinburne University of Technology Sarawak Campus. He is contactable at email@example.com