- Carotenoids are natural pigments in many fruits and vegetables associated with good heart health.
What do we mean by carotenoids ? Well, these are natural pigment compounds which give fruits and vegetables a beautiful yellow, orange and red colour. Take a good look at sweetcorn, squashes, a carrot or a tomato because their colour shouts out – I contain carotenoids ! These compounds are also found in algae and they are a superb commercial source.
The chemical names for such compounds are lycopene, lutein and beta-carotene which we’ve discussed before when we talk about the nutrition of certain vegetables and fruits. Humans cannot synthesize them so we rely on consumming them. There are a few animals that produce them such as salmon and crustaceans like lobster and prawns.
Many carotenoids are precursors of vitamin A but not all such as canthaxanthin, lutein, lycopene and zeaxanthin. Many of these carotenoids along with vitamin A are involved with biochemical signalling pathways in the cells. These regulate gene expression in various organs and tissues.
These compounds are active against a range of chronic diseases.
There are well over 600 different types of carotenoid in plants, fruits and vegetables and more are regularly being discovered today.
Many dieticians advise eating some vegetables such as squashes (butternut squash, pumpkin and courgettes) at least three times per week.
Types Of Carotenoids.
Xanthophylls are strongly yellow pigments with an oxygen atom in their chemical structure. They include lutein and zeaxanthin. They are mainly associated with eye health and protection from excessive sunlight.
The best foods that contain these xanthophylls include:-
- egg yolks
Whilst beta-carotene is one of the most heavily researched carotenoids, there are some alpha variants and alpha-carotene is one good example. It is usually found in the same food as beta-carotene. A number of research studies have inadvertently included alpha-carotene in their assessments of carotene generally. This compound has benefits for longevity. It is also converted to vitamin A but only half as much as beta-carotene.
The value of carotenoids is in their antioxidant behaviour and in plants they deactivate singlet oxygen which means they reduce the impact of free radicals which damage DNA and cells generally (Milani et al., 2017). As in plant cells, they have exactly the same function in humans so we will undoubtedly benefit form them in our diet. We know that lutein is helpful for reducing the impact of age-related macular degeneration in the eye.
Carotenoids And Improving Heart Health
When it comes to heart health, their is a very strong association between consumption of carotenoids which raises their level in the blood and the improvement of biomarkers for cardiovascular disease. Generally, all these carotenoids are soluble in fats so they help reduce the breakdown of cellular lipids as a result of oxidation (Cocate et al., 2015). The more carotenoids we ingest it seems, the higher their level in blood and with it a lowering of the issues associated with heart health (Wang et al., 2014; Gajendragadkar et al., 2014). Indeed, supplementation studies show that lutein and lycopene improve various biomarkers associated with good cardiovascular health (Zou et al., 2014).
One other piece of evidence comes from a study with a water-soluble extract of tomato and branded as Fruitflow® that significantly inhibits platelet aggregation which means blood flow in the arteries and veins is maintained or improved (O’Kennedy et al., 2017). It is reasonable to assume this directly prevents the occurrence of CVD. Lycopene in its own right is a highly effective oxygen quencher (Di Mascio et al., 1989).
Carotenoids And Cancer Reduction
Carotenoids do not prevent cancer ! A number of web-sites very often claim that carotenes can do this but there is evidence that particular types of carotenoid which contain acetylenic groups might slow down tumor development (Kuklev et al., 2013).
The better news is that a regular intake of carotenoids is linked to a lower risk of developing cancers such as in the mouth, pharynx and larynx. One major review of studies found that those of us with the highest intakes of carotenoids had a 21% lower risk of developing lung cancer then those with the lowest intake level. However, the evidence from some large epidemiological studies on beta-carotene intake and the reduction in lung cancer have been mixed in the past. There is no clear indication that beta-carotene supplementation actually protects fully against lung cancer and there have been some instances where it actually increased the risk in some high-risk populations (Omenn et al., 1995; Virtamo et al., 2003).
The risk of developing cancer of the larynx was 57% lower in those with very high intakes of beta-carotene.
Carotenoids And Improving Eye Health
How often were we told as children to eat our carrots so we could eat in the dark ? Very often I would suggest so as to get us to eat all our vegetables in truth. If we lack vitamin A, the deficiency leads to night blindness. Whilst this is rare in the Western world it is still an issue in Asia – the most cause of blindness actually.
There is considerable merit in eating carrots because they have plenty of carotenoids including pro-vitamin A, the precursor of vitamin A and retinol (Perusek & Maeda, 2013). Both these compounds help in fighting degenerative diseases of the retina including macula degeneration. Other good sources do apply ! Spinach, orange-fleshed sweet potato and many squashes like butternut also do well here.
Carotenoids And Skin Health
Some people take carotene supplements to actually make their skin slightly orange so that it replaces a suntan. Many bodybuilders were renowned for this practice but it is rather far fetched.
There is an association that carotenoids could risk the incidence of skin cancer. Carotenoids are converted to vitamin A which helps prevent premature aging of skin especially when damaged by sun. Sun damage is a risk factor for melanoma and premature wrinkling.
We also know that prolonged vitamin A deficiency produces skin bumps often seen on the back so people’s arms. A condition called hyperkeratosis.
What has been shown in clinical studies is that beta-carotene and a compound called beta-cryptoxanthin help to protect the skin including internal tissues from environmental pollutants and from sun exposure related diseases. Lutein is said to help skin cells called keratinocytes to produce scaffold proteins which keep skin relatively healthy (Sayo et al., 2013).
Acne treatments include retinoic acid on prescription.
Commercial Value Of Carotenoids
In commercial terms the carotenoids especially beta carotene are major nutraceuticals (GMI, 2016). In 2015 the market for beta carotene in Germany was USD4 million. They are being consumed for treating mainly age-related macular degeneration, cataract formation and preventing heart disease. Carotenoids are relatively cheap to produce and so cheap to purchase. In the Asia Pacific region, carotenoids are bought for cosmetic applications and now represent USD6 million dollars in that industry alone.
The main suppliers of carotenoids for the pharma nd health industries are DSM and BASF which largely dominate globally holding 50% of the global capacity. Other businesses include Allied Biotech, Chr. Hansen, Brenntag, Carotech, Cyanotech, Divis Laboratories, Naturex SA, D.D. Williamson, and LycoRed.
Always discuss changes to diet or the taking of dietary supplements with your doctor/physician.
Sayo, T., Sugiyama, Y., Inoue, S. (2013) Lutein, a nonprovitamin A, activates the retinoic acid receptor to induce HAS3-dependent hyaluronan synthesis in keratinocytes. Biosci Biotechnol Biochem. 77(6) pp. 1282-6.
Trejo-Solís, C., Pedraza-Chaverrí, J., Torres-Ramos, M., Jiménez-Farfán, D., Cruz Salgado, A., Serrano-García, N., … Sotelo, J. (2013). Multiple molecular and cellular mechanisms of action of lycopene in cancer inhibition. Evidence-based complementary and alternative medicine : eCAM, 2013, 705121. doi:10.1155/2013/705121 (Article)
Virtamo, J., Pietinen, P., Huttunen, J. K., Korhonen, P., Malila, N., Virtanen, M. J., … & Albert, P. (2003). Incidence of cancer and mortality following alpha-tocopherol and beta-carotene supplementation: a postintervention follow-up. JAMA, 290(4), pp. 476-485.