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Quest Vitamins LTD,
8 Venture Way,
Aston Science Park,
B7 4AP.

Tel: 0121 359 0056
Fax: 0121 359 0313
Registered in England No. 2530437

Circulatory System


The function of the circulatory system is to provide a continuous supply of oxygen and nutrients to the body tissues, whilst carrying away carbon dioxide and other waste products for excretion. This is achieved by the heart, a powerful muscular organ, which contracts approximately three billion times during the average life-span. This is accomplished without any rest, except for a fraction of a second in between beats.


The circulatory system is composed of the heart, blood and a network of blood vessels that, if unravelled, would cover approximately 75,000 miles in length. The job of the heart is to generate enough pressure to force nutrientt-rich blood through the narrow blood vessels. The heart beats about 70 times a minute, but this increases during exercise or if the body is in a state of Nervousness or excitement. The heart beats in two stages - systole is when the ventricles contract and diastole when the ventricles relax.

Blood contains oxygen when it flows from the lungs through the left side of the heart and through the tissues; blood contains no oxygen when it flows fron the tissues, through the right side of the heart and returns to the lungs.

There are three main types of blood vessel: arteries, veins and capillaries. Arteries carry oxygenated blood from the heart to the tissues, and these gradually branch out to form countless microscopic vessels called capillaries. The capillaries have thousands of perforations which allow the exchange of nutrients between the blood and the body tissues. Before leaving the tissues, groups of capillaries merge together to form venules, which unite further to form veins. The veins are responsible for carrying deoxygenated blood back to the heart for transportation to the lungs where it can unload carbon dioxide and pick up oxygen again.

The circulatory system is actually two systems - pulmonary circulation supplies the lungs and systemic circulation supplies the rest of the body.


There are a number of factors that may increase the risk of heart disease and circulatory disorders including:

High blood pressure
Raised cholesterol
Elevated homocysteine level
Lack of exercise

Free radicals, potentially dangerous chemicals produced in the body, are thought to play a major role in the development of circulatory disorders. These highly reactive molecules oxidise fats especially the cholesterol carriers Low Density Lipoproteins (LDL) which in turn lead to 'furring' or clogging of the major blood vessels leading to the heart. Cigarette Smoking increases the production of free radicals, a reason why smokers have an increased incidence of circulatory disorders (1).

Antioxidant nutrients found in fresh fruit and vegetables help to neutralise the damaging free radicals. Beta Carotene, Vitamin A, C and E all possess valuable antioxidant activity (2,3). In addition, certain minerals such as Zinc, Manganese, Copper and Selenium are required for the function of body?s antioxidant enzymes.

The level of cholesterol in the blood is influenced by both genetic and dietary factors (4). There is overwhelming evidence to suggest that a raised cholesterol level in the blood leads to the accumulation of fatty deposits in the arteries, increasing the risk of a number of circulatory and heart problems.

An elevated blood homocysteine level is a key risk factor for Coronary Heart Disease and circulatory disorders because it damages the lining of the blood vessels (5). In fact, recent research seems to indicate that keeping levels of this harmful amino acid low is just as important as maintaining a healthy cholesterol level. The body naturally produces homocysteine, but this is usually broken down very quickly so that it does not reach a level high enough to cause any harm. However, some people have a genetic abnormality which causes them to accumulate homocysteine. In addition, a minor deficiency in certain nutrients (Folic Acid, vitamins B6 and B12) required for the breakdown of this amino acid may lead to worryingly high homocysteine levels.


Angina pectoris
Cardiac arrhythmia
Congestive heart failure
Raynaud?s disease
Heart disease
Varicose veins

Arteriosclerosis (hardening of the arteries) occurs as we mature in years, and hampers the body?s ability to pump blood around the body. This condition contributes to high blood pressure and an increased likelihood of Strokes and heart attack.

Atherosclerosis (furring-up of the arteries) is caused by the gradual narrowing of the artery walls as a result of fatty plaque development and is most common in men, smokers, the overweight or people with sedentary lifestyles.

A heart attack (myocardial infarction) describes the sudden death of part of the heart muscle because of a blockage, which restricts oxygen-rich blood to that particular part of the heart muscle. It is usually characterised by unremitting chest Pain and is the single most common cause of death in developed countries.

A Stroke is caused by an interuption of the blood supply to part of the brain leading to tissue death. This can be caused by a blockage caused by a thrombosis or an embolism; or the rupture (haemorrhage) of a blood vessel. Many people choose supplements providing Bioflavonoids as they help to maintain the health of blood vessels.

Raynaud?s disease is a disorder of the blood vessels in which exposure to cold causes the small arteries that supply the fingers and toes to contract suddenly. Moving from a warm to a colder environment sends the small arteries in the body?s extremities into spasms causing numbness, Pain, tingling and colour change. Many people afflicted with the condition opt for supplements containing Ginkgo biloba, which have been found to bring relief from the condition.

Varicose veins is a condition characterised by enlarged twisted, tortuous veins, and the best known type are those that appear on the legs. They can appear in other parts of the body such as the anus (Haemorrhoids), scrotum and oesophagus. Horse chestnut is a traditional herbal remedy taken as a preventative and by those who are troubled with Varicose veins (6).


It may be necessary to address lifestyle and diet to help maintain a healthy heart and circulation.

Whilst it is a good idea to cut down on saturated fat, hydrogenated fat and animal fat, a wealth of research exists demonstrating that certain fats are essential for health. Fish Oils provide an excellent source of essential omega-3 fatty acids (EPA and DHA). These fatty acids are converted into beneficial hormone-like substances, which help to regulate blood pressure, thin the blood and lower cholesterol levels (7).

Sufferers of high blood pressure are advised to reduce their intake of salt and foods that contain Sodium. However, many people find this difficult because salt is added to most processed foods and ready meals that are now a staple part of the diet.

Fruit and vegetables are rich in antioxidant nutrients which mop up the damAging free radicals that may compromise our circulatory health. Ideally one should aim to consume a minimum of 5 portions of fresh fruits and vegetables a day.

Regular exercise regularly is good for strengthening the cardiovascular and circulatory system and an excellent outlet for the pent-up Stresses of modern living.

Vitamin E is an antioxidant that may help reduce oxidation of LDL. Research has shown that 400-800i.u. of vitamin E may help to control the build up of fatty deposits (atherosclerotic plaques) that form in the arteries (8). Vitamin E has also been found to reduce the incidence of heart attacks and maintain healthy circulation.

Vitamin C may protect against heart disease by helping to limit the damage caused by the generation of free radicals. In addition, regular supplementation may help to reduce blood pressure (9).

Selenium deficiency is strongly linked with cardiovascular disease (10). Good intakes of this mineral together with other antioxidant factors (such as vitamins A, C, E, Beta Carotene, Zinc, Manganese, Copper and Coenzyme Q10) will encourage healthy circulation.

Folic Acid supplements are not just for pregnant women. Research in recent years has shown that supplements containing Folic Acid, vitamins B6 and B12 may offer protection against heart problems in later life by maintaining low blood homocysteine levels (11).

Aged Garlic is taken by many for cardiovascular health. Studies have shown that the valuable Sulphur-containing compounds in this type of garlic can help to lower cholesterol levels (by reducing levels of "bad" LDL cholesterol) (12). Aged garlic also helps to thin the blood and reduce the likelihood of clots developing.

Ginkgo biloba acts as a vasodilator and is traditionally taken to improve circulation to all parts of the body including the limbs and brain (6). A number of studies have shown that compounds in the herb help to reduce the ?stickiness? of the blood, thus reducing its chances of clotting.

Other dietary factors include increasing the intake of soluble fibres from oats, beans and lentils which bind to cholesterol and limits its absorption. In addition, a moderate consumption of nuts, particularly walnuts and almonds, has been shown to be helpful in the reduction of LDL levels too.


Ginkgo biloba
Aged Garlic extract
Horse chestnut


Vitamin A
Vitamin B6
Vitamin B12
Vitamin C
Vitamin E
Coenzyme Q10
Folic Acid


1. Nutrition Concepts and Controversies, Sizer F.S & Whitney E.N.
2. The Lancet, 1991, 338:985-992.
3. Am J Clin Nutr, 1991, 53:326S-334S.
4. Coronary Heart Disease, Briefing Paper 30. British Nutrition Foundation, 1993.
5. The Lancet, 1999, 354:407-13.
6. Herbal Medicines A Guide for Healthcare Professionals, C A Newall, L A Anderson, JD Philipson, The Pharmaceutical Press, 1996
7. The Lancet, 1989, 2:756-761
8. JAMA, 1993, 270:2693-2698
9. Annu. Rev. Nutr., 1994, 14:371-91
10. Brit. Med. J., 1997, 314:387-388
11. The Lancet, 1997, 349;9065:1591-1593.

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