Beta carotene

As an antioxidant, beta carotene has beneficial effects in protecting against oxidative damage including that caused by ultraviolet light. Beta carotene has been shown to stimulate and enhance many immune system processes. It increases the numbers of immune cells such as B and T lymphocytes and natural killer cells. T cells play a very important role in determining immune status and are produced by the thymus gland, which is particularly sensitive to free radical and oxidative damage. Beta carotene protect macrophages, white blood cells which engulf and destroy foreign substances. It also facilitates communication between immune cells and makes the stimulatory action of interferon on the immune system more powerful.

Beta caroteneProtection against cancer

As with other carotenoids, research suggests that low levels of beta carotene increase the risk of certain types of cancer, including those of the lung, stomach, breast, prostate, colon, ovary and cervix. Several population studies have shown that cancer victims have lower dietary and/or blood beta carotene levels than healthy people. The evidence from these studies is strongest for lung cancer. In a study done in Wellington, New Zealand researchers investigated the links between beta carotene and cancer. They compared levels in 389 people with cancer to those in 391 hospital patients without cancer. They also assessed the family members of the study participants to compensate for the fact that changes in beta carotene levels may have occurred after the cancer developed. Low levels of beta carotene were found in people with a number of cancers, including those of the lung, stomach, esophagus, small intestine, cervix, and uterus. Low levels were also found in the relatives of these cancer patients and the links were strongest in those with lung cancer. In this study patients with cancers of the breast, colon, prostate, and skin did not have lower levels of beta carotene and neither did their families. These results suggest that the cancer sites associated with beta carotene levels are, in general, sites for which smoking is a strong risk factor.

Lung cancer

Researchers at Yale University School of Medicine compared diets in 413 nonsmokers suffering from lung cancer and compared these with 413 people without cancer. The results of the study, which were published in 1994, showed that high dietary intake of fruit and vegetables and beta carotene was linked to a decreased risk of lung cancer in both men and women.

Breast cancer

In a study published in 1996, Italian researchers investigated the relationship between selected nutrients and breast cancer risk in 2569 women with the disease and 2588 women with no history of cancer. The results showed significantly less risk in women with high beta carotene intakes.

In another recent study published in the British Journal of Cancer, West Australian researchers investigated the effect of increased intake of beta carotene on survival in breast cancer patients. Over a six-year period only one death occurred in the group with the highest consumption of beta carotene, while there were eight and 12 deaths in the intermediate and lowest groups of consumption respectively.

Prostate cancer

Results from the Chicago Western Electric Study published in 1996, suggest that surviving prostate cancer is more likely in men with higher beta carotene intakes. The study involved 1899 middle-aged men who were followed for a total of 30 years. During that time 132 men developed prostate cancer and survival was found to be less likely in those with low beta carotene intakes.

Cervical cancer

Research suggests that women with low beta carotene levels in their cervical tissues may be at increased risk of cervical cancer. Laboratory studies show that beta carotene can slow the growth of cervical cancer cells. Increasing intake of beta carotene may help to overcome this tissue-specific deficiency.

Protection against heart disease and stroke

Several studies suggest high dietary beta carotene intake can protect against

cardiovascular disease. As an antioxidant, beta carotene has been shown to inhibit oxidative damage to cholesterol and protect against atherosclerotic plaque formation. The relationship between intake of dietary antioxidants and risk of stroke was investigated as part of the Chicago Western Electric Study. The researchers found a moderately reduced risk in those with high beta carotene intakes.
In a 1997 study, researchers in Italy investigated the relationship between non-fatal heart attacks and dietary intake of beta carotene. The study involved 433 heart attack patients and 869 women without cardiovascular disease. The results showed that women with high beta carotene intakes had around half the risk of heart attack of those with low intakes.

Autoimmune diseases

Free radical damage may also contribute to the development of autoimmune diseases such as arthritis. Increasing dietary levels of antioxidants may help to prevent this damage. Researchers at Johns Hopkins University examined the links between dietary intake of beta carotene and rheumatoid arthritis and systemic lupus erythematosus. The study involved people with the disorders that developed two to 15 years after donating blood for a serum bank in 1974. The results showed that disease sufferers had significantly lower blood concentrations of beta carotene than those without the disorders.


Oxidative stress is linked to inflammation and may contribute to secondary tissue damage and impaired immune function after burns and other kinds of injuries. As beta carotene has antioxidant and anti-inflammatory properties it may help to promote wound-healing.


Free radical damage is implicated in the formation of cataracts and as an antioxidant, beta carotene may exert protective effects by reducing this damage. It may also act as a filter and protect against light-induced damage to the fiber portion of the eye lens. Beta carotene may also protect against macular degeneration, a disease of the retina to which older people are particularly susceptible.

Finnish researchers recently compared the differences between beta carotene levels in patients admitted to eye wards for senile cataract with those without eye disorders. The results showed that those with low concentrations of beta carotene were 1.7 times as likely to suffer from cataract.

Mental function

In a study reported in 1996, Dutch researchers looking at the effect of foods rich in beta carotene on memory impairment and mental function found that these had protective effects. The researchers studied 5182 people aged 55 to 95 from 1990 to 1993. They found that those with intakes of less than 0.9 milligrams of beta carotene per day were almost twice as likely to have impaired memory, disorientation and problem solving difficulty as those with intakes of 2.1 milligrams of beta carotene.

Researchers involved in a 1997 Swiss study found similar results. The study which was reported in the Journal of the American Geriatrics Society, involved 442 men and women, aged from 65 to 94 in 1993. Antioxidant levels were originally tested in 1971 and then again in 1993, when the participants were also given memory related tests. Higher vitamin C and beta carotene levels were associated with higher scores on free recall, recognition and vocabulary tests.


Lower levels of beta carotene have been seen in the cells of women with vaginal candidiasis (thrush). In an American study done in 1994, researchers compared beta carotene levels in vaginal cells from women with candidiasis to those in women without the infection. They found significantly lower levels in women with candidiasis. Women are more susceptible to Candida infection when the immune response is suppressed and as beta carotene has been shown to boost immune response the high levels may protect against the overgrowth of Candida.

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Other Vitamins:

Vitamin A
Beta carotene
Vitamin B6
Vitamin B12
Pantothenic acid
Vitamin C
Vitamin D
Vitamin E
Vitamin K