Just as humans have an immune system to help fight disease, plants have something very similar, only instead of antibodies and immune cells, they have phytonutrients, AKA phytochemicals.
What are Phytonutrients?
Phytonutrients (“phyto” translates as “plant”) are the chemical compounds found in plants that help them ward off some of the pests that they may encounter – for instance, some plants produce a bitter taste or a mildly toxic oil when they sense they are being eaten – and help them fight off environment-based diseases; just like us, plants are exposed to the ultraviolet rays of the sun (which can be harmful in excess) and all of the pollution that is in the air – and they are outside 24/7!
Phytonutrients also give vegetables their distinctive colour (e.g. beetroot or carrots) smell (e.g. garlic) and taste (e.g. asparagus) and as a rule of thumb, the more of these they have, the higher their phytonutrient content.
Some common phytonutrients include:
– Ellagic acid
Why are they important for us?
Throughout history, humans have been using plants for the health benefits, whether it is boiling them in water to create a tea, grinding them into pastes and applying them to a wound, or even in some circumstances, using them to plug a troubled orifice – in Ayurvedic medicine a turmeric root can be used to cure constipation (yep, you’ve guessed where it goes!)
Even today, up to 80% of modern medication is derived from the phytochemicals of plants.
Phytonutrients can help with a whole host of ailments including:
– Cell Oxidation (which can lead to cancer)
– Some Cancers
– Coronary Heart Disease
Beware the Phytotoxins
Although there are plenty of benefits that come with eating plants, we have to remember that some of these phytochemicals are produced as a defence mechanism for the plant (i.e. to stop animals eating them or fungus growing in them) and therefore have a detrimental effect on us. These are called Phytotoxins and some have been shown to be carcinogenic (cancer stimulating) at low doses – like aristolochic acid found in wild ginger which has been used in Chinese medicine for centuries, but has recently been found to stimulate liver cancer and kidney dysfunction- while others have been found to hinder the absorption of other nutrients and even increase the instances of free radicals.
This isn’t meant to scare you, merely to educate. And it’s important to understand that the benefits of phytonutrients vastly outweigh the (rare) negative effects they can have, so it’s vital that we all eat our veggies!
How can we make sure we are getting enough?
It is crucial that we get all the phytonutrients we need from whole plant foods, this is because there is little to no evidence to prove that taking a phytonutrient supplement has any positive effect on the body.
The phytonutrient content of a food will vary depending on the growing conditions, geographic location and the time between the plant being picked, and us eating it. So the best way to make sure you have enough, is by filling up on a variety of fresh fruits and vegetables at every chance we get.
And these positive effects only seem to last a few hours, so it’s vital that we take in more with every meal!
Unfortunately there is no simple way to say the best way to get the most phytonutrients, as processing methods effect the concentrations in different ways. For instance, some plants lose phytonutrients through cooking, whereas Carotenoids found in tomatoes actually increase in concentration and availability when you cook them. But as a rule, try to steer clear of boiling or microwaving your vegetables – as this destroys the highest numbers of phytonutrients – but try to steam or pan-fry at a low heat instead.
The best advice I can give, is to make sure we eat a variety of different fruits and vegetables – both cooked and raw – on a regular basis.
Some of the foods with the highest density of phytonutrients include:
– dark leafy greens like kale, spinach and broccoli – raw is best but steaming retains the second highest numbers of phytonutrients
– legumes like lentils and beans – need to be cooked to remove the toxins
– colourful fruits and vegetables like red pepper, carrots, mango, tomatoes – which can be eaten raw or cooked
– nuts and seeds like walnuts and flax seed
– dark chocolate! – the darker the better
– herbal and green teas
Kawale, Mahesh & Koche, Deepak. (2010). Role of Phytochemicals in Modern Medicine: An Insight. Hislopia Journal. 3. 245-253.
Shaw, D (December 2010). “Toxicological risks of Chinese herbs”. Planta medica. 76 (17): 2012–8
Across Asia, liver cancer is linked to herbal remedies – study”. Hong Kong Free Press. 19 October 2017.