They occur in plants as photosynthetic dyes that give some fruits and vegetables their deep red, orange or yellow colour. Carotenoids are natural antioxidants that fight certain diseases. Their effect can be reliably exploited in combination food supplements.

Although more than 600 carotenoid dyes have been identified in food so far, only six can be used by the human body. Which ones are they?

• alpha-carotene
• cryptoxanthin
• lycopene
• Lutein
• zeaxanthin

While carotenoids are found in a wide variety of fruits and vegetables, the foods with the highest concentrations may not be part of your diet. Alpha-carotene is found in carrots and pumpkin, while lycopene is found in excess in red fruits such as watermelon, red grapefruit, red currants,chokecherries. Lycopene and zeaxanthin are abundant in dark green vegetables, pumpkin and red peppers. Cryptoxanthin is found in mangoes, oranges, apricots and peaches. For the prevention of certain diseases, supplements providing a mixture of all six key carotenoids are best suited.

Carotenoids may reduce the risk of certain cancers, including prostate and lung cancer. They may provide protection against heart disease. Carotenoids slow the development of macular degeneration. Increase overall immunity.

The main beneficial effect of carotenoids lies in their antioxidant abilities. Antioxidants are substances that protect cells from damage by unstable oxygen molecules, called free radicals. Although carotenoids are similar, each has a specific effect on a particular tissue. In addition, alpha-catenin and cryptoxanthin can be converted to vitamin A in the body, but not to the same extent as beta-carotene.

Carotenoids may provide protection against certain cancers, probably by limiting abnormal cell growth. For example, lycopene inhibits the development of prostate cancer. Lycopene is probably also effective against gastric and digestive tract cancer. Studies show that high intakes of alpha-carotene, lutein and zeaxanthin reduce the risk of lung cancer and that cryptoxanthin and alpha-carotene reduce the risk of cervical cancer. Carotenoids are also likely to help fight heart disease. Scientists believe that all carotenoids, especially alpha-carotene and lycopene, block the formation of harmful cholesterol that can lead to heart attacks and other vascular diseases.

The carotenoids lutein and zeaxanthin promote sharp vision by absorbing harmful ultraviolet rays and neutralizing free radicals on the retina. This probably helps to reduce the risk of macular degeneration and age-related visual impairment, which are the leading causes of blindness in the elderly. Other carotenoids are likely to prevent damage to the lens of the eye, reducing the risk of cataracts. Preliminary studies also suggest a link between low carotenoid levels and menstrual disorders. Again, other studies show that even in the early stages of cancer, a diet high in carotenoids may improve prognosis somewhat.