Atherosclerosis is a common form of hardening of the arteries due to plaque deposition. The arteries are the vessels that carry oxygen and other nutrients from heart to the other parts of body. Plaques are patches of fatty tissue that collect in the arteries and damage artery walls. As the fatty deposits accumulate, they reduce the elasticity of the blood vessels and narrow the passageway, thus interfering with the blood flow. The Atherosclerotic vascular disease leads to decreased circulation in the blood vessels of the brain, heart and extremities.
Signs and symptoms of Atherosclerosis
Symptoms are often absent until atherosclerosis reaches advanced stages. Symptoms depend on which part of the body has decreased blood flow, and the extent of the disease.
Presentations of atherosclerosis:-
- Angina pectoris (Cardiac pain)
- Myocardial infarction (Heart attacks)
- Transient ischemic attacks (TIA)
- Strokes (Brain attacks)
- Intermittent claudication which may progress to gangrene of the organ / site involved.
Risk factors for atherosclerosis
- High blood pressure
- High cholesterol levels
- Positive family history
- Diabetes mellitus
- Cigarette smoking
- Sedentary lifestyle
- Oxidative Stress
- High levels of plasma homocysteine
Oxygen, the most critical nutrient for life, is the main source of free radicals. Free radicals are highly reactive oxygen fragments which are created by normal chemical processes in the cells. During cellular respiration (the process which creates energy), some oxygen molecules are converted into “free radicals” – when one of the electrons in the molecule is lost. This turns our “friend” oxygen into a hyperactive chemical that cannot rest until it gets an electron back. The only way it can replace the missing electron is to take it from another molecule. Now, if that other molecule happens to be a part of one of your healthy cells, then the cell will be damaged possibly leading to a number of diseases or worse inducing it to grow uncontrollably and form a tumor. Increased production of free radicals in the body is known as oxidative stress.
Free radicals are continuously formed as a consequence of many oxidative biochemical reactions in the body. In addition, the environment is also a source of free radicals. These include:
- lonizing radiation-Sun
- Ozone and Nitrous oxide – Automobile exhaust
- Heavy metals – Mercury, Cadmium, Lead etc.
- Cigarette smoke
- Alcohol consumption
- Emotional stress
Damages caused by free radicals
Free radicals attack, damage and ultimately destroy almost any material. The rusting of metal, the browning of a fresh cut apple, or the hardening of paint are all examples of the constant bombardment of free radicals and the resultant damage.
Free radicals are inherently unstable, since they contain ‘extra’ energy. To reduce their energy load, free radicals, react with certain cells in the body, interfering with the cells’ ability to function normally. Free radicals if left undestroyed would quickly enter into oxidative reactions with different vital cellular components containing lipids, proteins, nucleic acids and carbohydrates.
Free radicals attack blood fats which may lead to heart and blood vessel diseases. The body contains two main types of cholesterol – The “Good” cholesterol (HDL) and the ‘Bad’ cholesterol (LDL). When the LDL type of cholesterol reacts with free radicals, it becomes damaged (oxidized), and this may lead to atherosclerosis. Undamaged (native) LDL cholesterol does not seem to be as harmful. Thus, the free radical mediated oxidation of LDL cholesterol is a critical link between high blood cholesterol and build up of vessel-blocking plaques. In addition, free radicals may lower the levels of HDL cholesterol, which protect against cardiovascular diseases.
Free radicals have the capacity to alter cell architecture and metabolism causing a variety of disabling and life threatening disorders. Free radicals may be involved in the following:
- Loss of transparency of the lenses of the eye, leading to cataracts
- Inflammatory responses seen in rheumatoid arthritis and asthma
- Nerve and brain damage as seen in Parkinson’s disease
Normal Body response to the free radicals
The human body which has to endure the constant production of free radicals also has natural protection from their harmful (oxidizing) effects – antioxidants. The body makes a series of antioxidant enzymes which can neutralize these free radicals. In addition to these enzymes, many vitamins and minerals act as antioxidants in their own right; these include Vit.C, Vit.E,Vit.A and Selenium. These may stop the free radical from forming in the first place, or interrupt an oxidizing chain reaction to minimize the damage due to free radicals. However, these natural enzymes and vitamins are not always enough to overcome today’s continuous onslaught of natural and environmental free radicals.
Protection from free radicals
To have protection from free radicals there are two ways in which one can reduce the damage caused by free radicals. Avoid factors which encourage the production of free radicals. These include substances such as cigarette smoke, ultra violet radiation from the sun, excessive pollution etc. The second course of action is to make sure that we receive plenty of antioxidants in our daily diet.
Adequate quantities of antioxidants require at least five servings of fruits and vegetables.
Angina Pectoris Free Radicals and Antioxidants Natural sources of Antioxidant Vitamins and Minerals