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The science behind "Eating the Rainbow"

We've always been told to eat the rainbow when it comes to our fruits and vegetables. But what health benefits exactly do the various hues offer? Let’s unravel the colour codes in our foods. 
By Kezlyn Lim

Rainbow Foods

Eating nutritious food positively influences how we function and feel both physically and mentally. Colourful fruits and vegetables contain natural pigmented compounds, known as phytonutrients, that have vital roles in all cells and tissues of the human body. Including a variety of colourful fruits and vegetable will not only make meals look more appetising, it also provides your body with  essential nutrients that contribute to our antioxidative and anti-inflammatory defences.

Decoding the colours
There are five colour categories of fruits and vegetables that are power-packed with goodness to provide diverse health benefits.

Red: Lycopene is the natural pigment found abundantly in red-hued fruits and vegetables (e.g. tomatoes, watermelon, red capsicums). It’s a powerful antioxidant with anti-inflammatory, anti-cancer and anti-diabetic potential1.   

Orange: Carotenoids are a family of orange-coloured pigments that include beta-carotene and beta-cryptoxanthin, and are responsible for the bright tinge of orange in fruits such as mandarins, oranges, papayas and persimmons. Carotenoids act as pro-vitamins and can be converted into vitamin A in our bodies. In addition, carotenoids also have their own unique function as antioxidants2.

Yellow: Like red and orange foods, yellow-coloured foods also contain the same pigmented carotenoids as orange foods, but include bioflavonoids that support gut health and digestion3.

Blue/Purple: Anthocyanins are powerful antioxidants that confer protection against various non-communicable diseases4 and give the distinctive hue of blue/purple in fruits and vegetables such as blueberries, grapes, plums, eggplants and purple cabbage.

Green: Green fruits and vegetables are chlorophyll-filled foods that are rich sources of nutrients beneficial for maintenance of cardiovascular health3.

In the limelight: Bright orange goodness
One important discovery made in the renowned Singapore mother and child health cohort study, Growing Up in Singapore Towards healthy Outcomes (GUSTO), was that a less studied carotenoid, beta-cryptoxanthin, could have a vital role in mood and brain function. All carotenoids absorbed by our body are transported to the brain, helping in the function and protection of neural cells. 

Delving more into the types of carotenoids, it was found that high maternal plasma concentrations of beta-cryptoxanthin was associative with protective benefits against low mood and anxiety in the mothers, whilst boosting brain function in the babies5,6. These anti-stress benefits match what have been previously reported  in Japanese studies of women who eat a diet rich in mandarins, a particularly rich source of beta-cryptoxanthin7,8. The GUSTO team is continuing to investigate this further and ongoing analysis will look more deeply into the relationship between beta-cryptoxanthin and brain function. 

In our ongoing efforts to investigate the benefits of beta-cryptoxanthin more closely, our research team at the Singapore Institute for Clinical Sciences (SICS) is recruiting Singaporean women to explore the associated health benefits of adding a novel beta-cryptoxanthin supplement to one's diet.

Feeling a tad blue? There's no harm adding a splash of [natural] colour to your meals – it might very well help to improve your mental health. Eat the rainbow today!



BETA+ Pre-Screening QR

Participate in our research!
We are currently conducting a beta-cryptoxanthin pro-vitamin supplementation study (the BETA+ study) in healthy women to examine the absorption and health benefits. Click here to find out more or scan the QR code to register your interest.



References

  1. Imran M, Ghorat F, Ul-Haq I, Ur-Rehman H, Aslam F, Heydari M, Shariati MA, Okuskhanova E, Yessimbekov Z, Thiruvengadam M, Hashempur MH. Lycopene as a natural antioxidant used to prevent human health disorders. Antioxidants. 2020 Aug;9(8):706.
  2. Britton G, Khachik F. Carotenoids in food. InCarotenoids 2009 (pp. 45-66). Birkhäuser Basel.
  3. Minich DM. A review of the science of colorful, plant-based food and practical strategies for “eating the rainbow”. Journal of Nutrition and Metabolism. 2019 Jun 2;2019.
  4. Khoo HE, Azlan A, Tang ST, Lim SM. Anthocyanidins and anthocyanins: colored pigments as food, pharmaceutical ingredients, and the potential health benefits. Food & nutrition research. 2017 Jan 1;61(1):1361779.
  5. Lai JS, Cai S, Lee BL, Godfrey KM, Gluckman PD, Shek LP, Yap F, Tan KH, Chong YS, Ong CN, Meaney MJ. Relationships of maternal plasma pro-vitamin A carotenoids and children's neurocognitive outcomes. The Proceedings of the Nutrition Society. 2020;79(OCE2).
  6. Lai JS, Cai S, Lee BL, Godfrey KM, Gluckman PD, Shek LP, Yap F, Tan KH, Chong YS, Ong CN, Meaney MJ. Higher maternal plasma β-cryptoxanthin concentration is associated with better cognitive and motor development in offspring at 2 years of age. European Journal of Nutrition. 2021 Mar;60:703-14.
  7. Unno K, Noda S, Kawasaki Y, Iguchi K, Yamada H. Possible Gender Difference in Anti-stress Effect of β-Cryptoxanthin. Yakugaku zasshi: Journal of the Pharmaceutical Society of Japan. 2016 Jan 1;136(9):1255-62.
  8. Unno K, Noda S, Nii H, Kawasaki Y, Iguchi K, Yamada H. Anti-stress Effect of β-Cryptoxanthin in Satsuma Mandarin Orange on Females. Biological and Pharmaceutical Bulletin. 2019 Aug 1;42(8):1402-8.

ABOUT THE AUTHOR

Kezlyn Lim is an accredited practising dietitian with research interests in gastrointestinal health, metabolic health and personalised nutrition. She is a research dietitian with the Singapore Institute for Clinical Sciences (SICS). One of the research studies she is currently involved in is the BETA+ study, which aims to explore the body’s absorption of pro-vitamin A supplementation and any associated benefits on gut health, brain health and mood.

Posted in : Human Development