I LOVE autumn, with its shades of warm reds, oranges and golden browns. Having just enjoyed a wander in nearby Denbies vineyard, past all the heavily laden vines with gorgeous leaves, and then seen a wonderful display of home-grown pumpkins, it got me thinking about how nature creates such a wonderful palette of colours. So I had a good old nose on the internet and this is what I found ……… all fascinating stuff, which makes me realise that I’m probably more of a geek than I like to make out.
Let’s start with a spot of greenery! What makes green leaves green is a pigment called chlorophyll. It’s a molecule which absorbs certain wavelengths of sunlight (namely the red and blue bits of the visible light spectrum) but reflects green light, so this is the colour that we see. The solar energy captured is used in a process called photosynthesis to produce glucose and much needed (to us humans) oxygen. Another interesting factoid is that chlorophyll’s central atom is magnesium, and hence why greens are a good source of magnesium, a mineral which a lot of us are deficient in (due to poor eating habits, deficient soils and a crazy stressful life which gobbles up magnesium quicker than you can say – well – “magnesium”.) Try eating more greens for a more relaxed, chilled out view on life……….
Chlorophyll is just one of a cornucopia of phytochemicals (= plant chemicals) which act as a plant’s immune system, amongst other things. Other examples are carotenoids, flavonoids, polyphenols, curcumins etc. Like chlorophyll, each photochemical absorbs certain wavelengths of light, whilst reflecting others and hence are seen as different colours. The carotenes (part of the family of carotenoids), for instance, reflect yellow and therefore appear yellow.
During spring and summer, chlorophyll takes centre stage (and hence why there is so much green around), masking other less intense colours. Come autumn, however, it retires for the season, giving other pigments an opportunity to reflect their true personalities (or more exactly the wavelengths of light which they cannot absorb!!)
Chlorophyll isn’t actually a particularly stable compound and is broken down during photosynthesis, requiring the plant to synthesise more, a process which needs sunlight, more readily available in spring and summer. (It is also damaged during cooking, hence why greens can become paler.) During autumn, chlorophyll decomposes and thus the reds, oranges and yellows of the more stable carotenoids are revealed.
It isn’t just in leaves, however, that we see carotenoids play their part. Within the fruit and vegetable kingdom, the beautiful yellow / orange of mangos, carrots, sweet potatoes and pumpkins are due to various carotenes, whilst lycopene provides the red of tomatoes, watermelon and rosehips (which have been plenteous recently in the hedgerows).
Grapes, cranberries and plums can thank the family of pigments called anthocyanins for their gorgeous reds, blues and purples. The anthocyanins are actually formed when the sugar concentration reaches a particular level, thus providing a signal that the fruit is ripe, sweet and ready to eat. A sort of Alice in Wonderland “Eat me” sign for wild creatures!
Nature’s photochemicals, however, don’t just provide us with a stunning palette of rich colours; they also offer great health benefits. For instance, lycopene is protective of prostate tissue; beta-carotene protects the eyes and mucus membranes; whilst lutein (a yellow pigment and fellow carotenoid) plays guardian to the macular of the eye.
Also packing quite a punch in the health department is the family of flavonoids (to which the anthocyanins belong). Many of them act as powerful antioxidants as well as having potent anti-viral, anti-bacterial and anti-fungal properties. Two of the best known are rutin and quercetin. Rutin (found in buckwheat) helps to strengthen capillaries, whilst quercetin (found in apple peel and onions) is anti-inflammatory and inhibits both the manufacture and release of histamine. Perhaps an apple a day does in fact keep the doctor (with his anti-histamines) away, but do buy organic!
Advice to eat a rainbow of colours takes on a whole new meaning when you realise the potent health benefits that these pigments provide, and our UK “5-a-day” looks a little pathetic, if not redundant!! If you are interested in enjoying vibrant good health from top to toe, via eyes, prostrate and other cells, I would strongly recommend aiming for AT LEAST 10 portions of different fruit and vegetables a day, and more if possible. This way you are building up your cellular defences as well as bringing a little colour to each of your lovely cells!
For a lighter look at eating in “rainbow-style”, watch this space next week for an article in verse.