Phytonutrients: the rainbow principle in nutrition
What are phytonutrients
Plants (vegetables, fruits, legumes, grains, nuts and tea) produce chemical compounds that scientists have coined the term phytonutrients (or phytochemicals). Sources cite some 4,000 to more than 25,000 phytonutrients.
Unlike vitamins and minerals, phytonutrients aren’t essential, meaning we can live without them without too much trouble. But they are thought to reduce the risk of cardiovascular disease and some cancers, as well as support healthy skin, bones, immune system, eyesight and more.
These benefits have been attributed to the chemical composition of the phytonutrients themselves, their antioxidant activity, the presence of fibre in the plant or the combination of various plant chemicals.
If you recognize flavonoids, flavones, isoflavones, catechins, anthocyanins, glucosinolates, phytoestrogens, carotenoids and polyphenols, these are all phytonutrients.
What phytonutrients are there?
When it comes to the phytonutrients of fruits and vegetables, they are generally categorized into 5 or 6 groups based on the colour they impart:
- Red,
- Yellow (often combined with orange),
- Orange,
- Green,
- Purple/blue,
- White/beige/brown.
Ideally, we should consume at least one serving of fruit and vegetables from different “colour” categories every day (in total, not separately 6 colours of vegetables and 6 colours of fruit). This is in line with the recommendation to eat at least 5 servings (400g) of fruit and vegetables a day.
Scientists have even coined the term “phytonutrient gap” because the National Health and Nutrition Examination Survey (NHANES) found that 8 out of 10 Americans are deficient in each colour (the biggest deficiency is in purple fruits and vegetables).
The rainbow principle in nutrition
Red – contains the cardinoids lycopene and astaxanthin, anthocyanins, ellagic acid, floretin, quercetin. Red has been associated with reduced inflammation, antioxidant properties and immune system support.
Yellow/orange – Carotenoids alpha-carotene, beta-carotene, beta-cryptoxanthin, lutein and zeaxanthin as well as curcuminoids, bromelain, gingerol. Orange is associated with the maintenance of reproductive function, endocrine system and eye health. Yellow is associated with enzymatic activity, regulation of gastric motility, and the formation of healthy intestinal microflora. Both orange and yellow have antioxidant properties.
Green – sulforaphane, glucosinolates, isocyanates, indoles. Able to inhibit carcinogen activity and protect blood vessels from damage. And the carotenoids lutein and zeaxanthin can reduce the risk of the development or progression of age-related macular degeneration (an eye disease).
Purple/blue/blue – anthocyanins, pterostilbene, resveratrol, kaempferol, quercetin, myricetin. Purples are thought to slow cell aging and prevent blood clots from forming, as well as support our memory, thought processes and good mood.
White/beige. The most frequently mentioned is allicin, which has anti-carcinogenic properties (allicin is found in garlic, but is only released if chewed/grinded).
To get the most phytonutrients, vitamins, minerals and fibre, you should eat fruits and vegetables with their peel. Try to follow the rainbow principle. Eat fruits and vegetables of different colours every day. This way you will get a mix of different nutrients that work like an organised gang – for the benefit of our health.