Rainbow-Coloured Foods: Red

Featured in: Education

Food Colour: RED

By Frema Asiedu (Registered Nutritionist)

So what makes your fruit or vegetable red?….Anthocyanins and Anthocyanidins1. These are water soluble naturally occurring pigments that CAN change colour when the pH increases. So basically when the pH is acidic (pH <7) the fruit or vegetable containing these pigments remain red. But, when the pH becomes basic (pH >7) they turn…wait for it…PURPLISH BLUE1.

Yes, all your red fruits such as: watermelon, strawberries, cherries, raspberries, apples; and vegetables like tomatoes, red peppers2, etc. fall in this bracket. Have you noticed how ‘sobolo’ (Ghanaian spicy drink made from the brew of red hibiscus flowers) comes out red when made but after drinking it, you tongue turns purplish blue? This is because the pH in your mouth is somewhat basic (“6.2-7.6 with 6.7 being the average pH”3). Now why should we care…?

It will interest you to know that these pigments that were traditionally extracted and used as natural food colorants or dyes have massive health benefits that include anti-oxidant properties, anti-microbial activity, improved visual and neurological health, and protection from some non-communicable diseases1.

Why are antioxidants important?When we breathe in oxygen, our body uses it to produce energy.In so doing it produces “molecular species capable of independent existence that contains an unpaired electron in an atomic orbital.”4 These are simply called free radicals. Free radicals are unstable and very reactive causing a lot of damage5.Uncontrolled free radicals have been linked to many chronic illnesses such as cardiovascular diseases (heart diseases, stroke, intestinal ischemia), cancer, aging, neurological disorders (Alzheimer’s disease, Parkinson’s disease, muscular dystrophy), diabetes4, 7,8. In addition, many inflammatory diseases such as: (arthritis, vasculitis, glomerulonephritis, lupus erythematous, adult respiratory diseases syndrome), hemochromatosis, gastric ulcers, hypertension and preeclampsia, and many others7 can be linked to the damage from free radicals. Anti-oxidants however, reduce the damage done to the body due to generation of free radicals6.Isn’t it interesting to note that, by including some amount of red-coloured foods in your diet, your risk for developing these conditions are markedly reduced due to the many beneficial properties these foods possess?

Our admonition: Don’t forget to add some red to your food this week. Eat that tomato!

References:

  1. Khoo HE, Azlan A, Tang ST, Lim SM. 2017. Anthocyanidins and Anthocyanins: Colored Pigments as Food, Pharmaceutical Ingredients, and the Potential Health Benefits. Food & Nutrition Research. Aug 13; 61(1):1361779. doi: 10.1080/16546628.2017.1361779.
  2. Derocha, G. 2011. Using Color as a Guide to a Better Diet: 9 Health Benefits of Red Fruits and Vegetables. A Healthier Michigan. Retrieved on 12th March 2018 from https://www.ahealthiermichigan.org/2011/03/22/using-color-as-a-guide-to-a-better-diet-9-health-benefits-of-red-fruits-and-vegetables/
  3. Baliga S, Muglikar S, and Kale R. Salivary pH: A Diagnostic Biomarker. Journal of Indian Society of Periodontology: 17(4): 461–465. doi:  10.4103/0972-124X.118317
  4. Lobo V, Patil A, Phatak A, Chandra N. 2010. Free radicals, antioxidants and functional foods: Impact on human health. Pharmacognosy Reviews;4(8):118-126. doi:10.4103/0973-7847.70902.
  5. Cheeseman KH, Slater TF. 1993. An Introduction to Free Radicals Chemistry. British Medical Bulletin;49:481–93.
  6. com. 2018. Medical Definition of Antioxidant. Retrieved on 12th March 2018 from https://www.medicinenet.com/script/main/art.asp?articlekey=11291
  7. Lovell MA, Ehmann WD, Buffer BM, Markesberry WR. 1995. Elevated ThiobarbituricAcid Reactive Substances and Antioxidant Enzyme Activity in the Brain in Alzheimer’s Disease. Neurology;45:1594–601
  8. Stefanis L, Burke RE, Greene LA. 1997. Apoptosis in Neurodegenerative Disorders. Current Opinion in Neurology;10:299–305.