From Foods to Supplements

By: 

Stephanie Fox, DipION, Nutritional therapist and health writer

 

Issue: 
Autumn
Year of publication: 
2010

Scientists have become excited about food pigments, colourful phytochemicals that protect plants from free radicals, toxins and pollutants. Research is revealing that these colourful plant chemicals protect our health too. So what exactly are these compounds, which one makes a tomato red, a beetroot purple and broccoli green and how do they influence our health? One of the groups of phytochemicals that scientists have been researching is the carotenoids, a group of naturallyoccurring fat-soluble plant pigments largely responsible for the bright colours of fruits and vegetables with a range of structural diversity and a variety of biological functions. There are more than 600 carotenoids, 40 of which are regularly consumed in our diet. Carotenoids are split into:

• carotenes - orange and red pigments which are very fat soluble including lycopene

• xanthophylls - yellow pigments including lutein and zeaxanthin

• astaxanthin - a pink pigment

Lycopene

Lycopene provides the red colour in fruits and vegetables such as tomatoes, watermelon, papaya, pink grapefruit, pink guava, carrots and apricots. Its antioxidant activity is twice that of beta-carotene and studies in the 1990’s showed that cooked tomatoes provide more bioavailable lycopene, hence the headlines in national papers saying that tomato sauce and puree are good for you. Lycopene is deposited in the liver, lungs, prostate gland, testes, colon, adrenal glands and skin so it has the potential to work its effects in all of these areas. Research has shown that lycopene prevents cancer cell growth and helps to prevent heart disease through its potent antioxidant activity. A large prospective study in 1999 involving men enrolled in the Physicians Health Study linked a higher plasma lycopene with a lower risk of developing prostate cancer. Interestingly, a number of studies have shown that eating foods high in lycopene or taking a lycopene supplement is associated with lower rates of prostate cancer. A small study in 2001 showed that taking 15mg of lycopene, twice daily, reduced prostate tumour growth. Lycopene has also been identified as the most protective carotenoid against cardiovascular disease due to its cholesterol synthesis-inhibiting effect, which may enhance low-density lipoprotein (LDL) degradation. More recent research has been mixed on its anti-carcinogenic properties, with a large study in 2007 finding that lycopene had no protective effect against prostate cancer and a more recent one in 2009 finding that high serum levels of lycopene were protective against overall cancer incidence but not prostate cancer.

Lutein and zeaxanthin

Lutein and zeaxanthin provide the yellow colour in fruits and vegetables such as yellow peppers and corn. These pigments are also rich in dark green leafy vegetables such as spinach and kale. Lutein can only be obtained through diet, whilst zeaxanthin can be converted from lutein in the eye. Lutein and zeaxanthin are the spectacles of the pigment world, playing an important role in eye health. The macula (part of the eye where the retina is found) is composed of these two pigments which help to absorb blue light, protecting the eye from free radical damage. If the retina becomes damaged, a loss of sight begins leading to difficulty seeing at night or in bright conditions. Research has focused on the protective effects of lutein and zeaxanthin against age-related macular degeneration (AMD) with a 2003 study finding that supplementation of both increased macular pigment optical density. Another study in 2006 showed that supplementation with either lutein or zeaxanthin improved human visual performance. Another study found that a diet high in these pigments was associated with a lower risk of AMD in healthy women below the age of 75. As lutein and zeaxanthin are also found in the skin where they exert a protective effect from sunlight, topical application and oral supplementation of these carotenoids may also help protect the skin from oxidative damage. In addition to this, a study in 2000 involving over 2400 subjects found lutein to be the most protective carotenoid against the risk of colon cancer.

Astaxanthin

Astaxanthin is a dark pink pigment found in phytoplankton and algae providing the fish and birds which eat them, such as salmon, trout, shrimp, lobster and flamingos, with their beautiful pink colour. Astaxanthin, often referred to as nature’s sunscreen, is a potent antioxidant with far greater antioxidant activity than betacarotene and vitamin E. It helps to block sun damage to the skin and is now being discovered to reduce ageing, increase cellular energy, protect against cancer and damage to the brain and nervous system and help to boost immunity! Researchers in Japan found in a recent study that astaxanthin decreases oxidative stress, and in doing so may help to protect against diseases such as cancer. They also discovered that it improved the energy potential of the mitochondrial membrane and this may be the role astaxanthin plays in anti-ageing. Astaxanthin may also be important for neurological health as research has shown that it is able to cross the blood brain barrier perhaps helping fight against the oxidation of the fats found in the nervous system, potentially protecting against diseases such as Alzheimer’s. Animal studies have also shown that it may help to fight inflammatory diseases such as asthma and Crohn’s disease.

Anthocyanidin

Anthocyanidins are part of the flavonoid family, which provide the purple colour to many flowers, fruits and vegetables and provide many health-promoting benefits. Of the anthocyanidins, the most active are the proanthocyanidins found in purple, blue and dark red berries like cherries, beetroot, dark grapes and the extracts of grape seeds and pine bark. Proanthocyanidins are known to have potent antioxidant properties, far more so than vitamin C and vitamin E, and they enhance the function of vitamin C, improving absorption and protecting it from oxidation. These pigments become incorporated into cell membranes where they protect against water and fatsoluble free radicals. Proanthocyanidins may play a preventative role in many diseases and conditions such as cancer and atherosclerosis. Grape seed proanthocyanidins may help to protect normal tissues from the toxic effects of chemotherapy. Recent research concentrates on the collagen-protecting properties of anthocyanidins which help to defend capillary integrity. Since collagen supports the dermis and blood vessels, anthocyanidins may also reduce vascular conditions such as varicose veins and haemorrhoids. Proanthocyanidin extracts also help in anti-cancer, antioxidant, antiinflammatory and wound-healing properties. Cooking destroys much of the chlorophyll in green plants so it’s best to eat sources raw or lightly cooked or take as a supplement to reap the benefits. Chlorophyll is rich in green leafy vegetables such as alfalfa, broccoli, spinach, Swiss chard, Brussels sprouts, beet greens, green peppers, kale and leeks, with its highest concentrations being found in chlorella – a single-celled fresh water green algae.  

Keywords: 
FOOD, food pigments, phytochemicals, carotenoids, carotenes, xanthophylls, astaxanthin, lycopene, lutein, zeaxanthin, anthocyanidin
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