Are Antioxidant Super Smoothies Actually Better For You? | Earth Science

First up, the orange juices. Then a fresh superfruit smoothie, twice the price but no more antioxidants. Next, two brands of smoothies specifically marketed for their antioxidants. Still no better. Finally, a superfood smoothie. A whopping three times the antioxidant power of any of the others. So what's going on? Antioxidants might have an air of mystery about them, but if you look at the label on the side of one of these drinks, it's clear that most of the antioxidant effect is just coming from plain old vitamin C. Vitamin C is actually a powerful antioxidant. It's found naturally in most fruit and veg, but is also a common additive to stop juice going brown. There's nothing special about the fruits themselves in these drinks. So my next question is, do the antioxidants in these drinks actually do anything inside our bodies? To find out, we recruited 10 volunteers to do an experiment never attempted before. Under the guidance of Dr. Kirsten Brandt, they all drank 360 mils of smoothie. We measured the antioxidant status of each person's blood beforehand, so we have a baseline, and then regularly over the next 24 hours. Did the smoothie give them an antioxidant boost? Well, at first, the antioxidant levels in their blood did go up, only to plummet dramatically after four to five hours. And they even went well below baseline and were only just coming back to baseline after 24 hours. Kirsten was not surprised by the sudden drop to below baseline, as our bodies actually work to keep everything in perfect balance, including antioxidant levels. This balance where the body will keep the level constant, it's called homeostasis, and it's the same for our temperature, for our sugar levels, for everything else in the body that should have a correct level. Our bodies continually produce their own antioxidants. When we take in a big extra dose, our bodies slow down their production to get back to the optimum level. But what Kirsten had not expected was that it would take so long. For almost a day after drinking just a big glass of smoothie or juice, our volunteers' blood contained less antioxidant power than normal. It's the opposite effect from what most of us would expect. And lower antioxidant levels presumably mean more free radicals in our bodies. But Kirsten thinks the messages we get from the adverts are even more misleading, as free radicals are not such a bad thing. So it isn't the case that all of us have got our bodies full of bad free radicals, and the more we slosh the smoothie in, the more they're going to mop up those bad things in our body. No, normal healthy people have exactly the free radicals that they need. Free radicals are actually quite important. For example, they are one of the signal molecules that tells the cells in our body when you need to repair, for example, muscle fibres. So if you want to go to the gym and do some training, if it wasn't for the free radicals, your muscles wouldn't grow. The science and the marketing are poles apart. Your body makes exactly the antioxidants it needs, and taking in a big dose merely throws it out of balance.