THE AMAZING SECRETS OF CAROTENOIDS

In 1981, an article called “Can dietary beta-carotene materially reduce human cancer rates?” was published by world-renowned epidemiologist Sir Richard Peto in the prestigious journal Nature. Along with his co-workers, he addressed the potential role of beta-carotene in reducing the risk of cancer, leading studies on the relation between nutrients and prevention of disease to skyrocket.

Carotenes and carotenoids are the pigments responsible for the strong color of tomato, watermelon, carrot, papaya and sweet potato. They have many health benefits; the main ones being acting as precursors to vitamin A and fighting free radicals. This ultimately helps to prevent many diseases and slow aging. Lycopene, another carotene, is largely found in tomatoes and is associated with decreased risk of cancer and heart disease. Other carotenoids such as lutein and zeaxanthin are yellow pigments found in mango, papaya, orange and melon and play a very important role in protecting human eyes from macular degeneration and cataracts.

Carotenoids are colored pigments that are abundant in green, yellow-orange, and red fruits and vegetables

Benefits for overall health

Unlike drugs, one of the most interest features of natural compounds is their ability to benefit the body in many different ways. Scientists refer to them as multi-target molecules as they have numerous therapeutic effects. For instance, a recent study published in the British Journal of Nutrition showed middle-aged men who followed a diet rich in carotenoids, including beta-carotene, alpha-carotene, lycopene, lutein and zeaxanthin, had lower levels of both oxidative stress and cardiovascular risk, as well as enhanced protection against DNA damage, cancer, atherosclerosis and diabetes.

Prevention of cancer

Interestingly, 26 studies have found high intakes of beta-carotene reduce lung cancer risk by 10 – 70%. Nevertheless, special caution must be taken by smokers as beta-carotene is oxidized by cigarette smoke, producing metabolites that on the contrary promote lung cancer. There is evidence for beta-carotene in decreasing the risk of other types of cancer such as stomach, esophageal, cervical, pancreas and colon, while many other studies suggest that only moderate risk reduction exists.

Lycopene is a bright red carotenoid found in tomatoes.

A lot of research has been done on the benefits of lycopene in cancer prevention with findings tending to be inconsistent across studies; however, a literature review conducted by the World Cancer Research Fund in 2007 supported a probable association between tomato consumption and reduced risk of prostate cancer.

A study published in 2014 found that high lycopene intakes decrease the incidence of lethal prostate cancer partly by preventing the formation of new vessels feeding the tumor – a process called angiogenesis (click here to read how green tea helps fight cancer). A half cup of tomato puree has 27 mg of lycopene, while one slice of raw tomato has 0.5 mg, so besides being delicious, eating tomato puree, home-made spaghetti sauce and organic ketchup is highly recommendable since cooked tomatoes have a higher bioavailability of lycopene, meaning its absorption is easier in the gut.

Eye care

As already mentioned, carotenoids are converted to vitamin A in the body. It is long known that vitamin A is essential for good vision since it protects the surface of the eye (cornea). The macula lutea is an oval-shaped yellow spot in the center of the human retina. This highly pigmented region is formed by lutein and zeaxanthin and is in responsible for a sharp vision and the ability to perceive color. It also protects against age-related macular degeneration, which is the principal cause of blindness in the elderly. Therefore, macular pigments levels are used as indicators of macular health and the likelihood of developing degeneration.

Human macula

Carotenoids’ effects vary according the type of carotenoid being taken and whether it is combined with other ones. A study conducted by Harvard Medical School found that taking daily supplements of vitamin A and lutein delayed loss of peripheral vision in people with retinis pigmentosa. Moreover, Russian researchers found that a supplement containing lutein, zeaxanthin, vitamin A, vitamin C, and minerals like selenium and zinc was effective in preventing and treating diabetic retinopathy in 180 patients.

Know you know. Eat plenty of green leafy vegetables. A half cup of spinach three times a week is good enough to prevent macular degeneration!

Protection against heart diseases

Green and yellow vegetables containing abundant quantities of carotenoids are strongly recommended to lower the risk of coronary artery disease and stroke by 15%, while antioxidant and vitamin supplementation is, nevertheless, proven to have a detrimental effect. Moreover, a 12-year study conducted by Finnish researchers found lycopene lowered the chance of having any kind of stroke by 55% in more than 1000 participants due to its ability to reduce inflammation, cholesterol, and most importantly, blood clots (Click here to learn how cocoa protects the heart and what other foods lower cholesterol.

Read more about carotenoids

In what other ways can carotenoids help us? This is something currently being studied by several research groups. If you want to learn more about the benefits of lycopene, you may be interested in reading the research articles of Dr. Edward Giovanucci, who is Professor of Nutrition and Epidemiology at Harvard Medical School. His work is mainly focus on understanding the role of nutritional, hormonal and genetic factors in prostate and large bowel diseases.