The term antioxidant will be familiar to most people. You’ll have an idea that they are good to have in your body to neutralise damaging entities called free radicals.
Both antioxidants and free radicals are naturally present in the body, and each have their roles to play, but free radicals can predominate, particularly if you smoke, drink too much, are exposed to pollution, too much UV radiation, and/or don’t eat very well. An excess of free radicals can lead to cancer, heart disease, type 2 diabetes and skin damage, among other chronic conditions.
Free radicals are unstable because they are missing an electron and will strip them off other molecules, causing all sorts of mayhem in cells, and sometimes destroying them altogether. Antioxidants have electrons to spare, so can donate them to free radicals, thus neutralising each other.
You may also be aware that some foods are particularly rich in antioxidants, such as berries, beetroot and herbs. Happily, dark chocolate is usually included in the list. The message about berries has been effectively communicated by the marketers – export demand for our blueberries and other berry fruits has been growing strongly.
Generally speaking, if you have a diet containing – yes, it’s the same old story – a variety of fruits and vegetables, you should get enough antioxidants to hunt down those anarchic free radicals. Exercise also promotes free radical-antioxidant balance.
However, for a variety of reasons, many people do not have an ideal lifestyle – our western dietary range tends to be quite limited and we look for supplements which are readily available, row on row, in supermarkets.
Often we self-medicate, and take them without really knowing whether we need them or not. The assumption is that if you don’t need them, they won’t do you any harm.
But supplements in pure concentrated form carry a risk of delivering either toxic or ineffectual amounts. Your body is not accustomed to absorbing nutrients in this way. You wouldn’t eat, or need to eat, 10 oranges in 10 seconds.
Too much Vitamin A can cause liver damage, and too much iron can accumulate in, and damage, organs. Again, it comes back to having a balanced diet over a lifetime.
Dr Ali Rashidinejad, a food scientist at the Riddet Institute, a centre of research excellence hosted by Massey University, is interested in how best to deliver supplementary antioxidants and other desirable “bioactive” ingredients (polyphenols, vitamins, carotenoids, trace elements) in foods that people commonly eat and drink – such as milk, cheese, yoghurt, smoothies or protein bars.
Incorporating desirable nutrients in everyday foods is both convenient and safe. You cannot overdose yourself, and they can be digested in the optimal way.
But there are many challenges, says Rashidinejad – will the bioactives be stable during processing and storage, will they be readily absorbed by the body and effective after absorption, will they adversely affect the taste and texture of the food?
He has also made a special study of the bioactive substances in coffee and tea, especially green tea.
The appetite for functional foods and medicinal teas, such as our own kawakawa brew, is ballooning worldwide, in tandem with ageing populations and heightened post-pandemic concerns about immunity.
With ever-increasing rates of diabetes, cancer, and other chronic diseases already swamping our health services, preventive and therapeutic nutrition strategies are vital.
Dr Ali Rashidinejad is a researcher at the Riddet Institute and Glenda Lewis is a science writer. This article was originally published on Stuff on Monday 10th May 2021.