«Red fruits are rich in antioxidants». «Extra virgin olive oil is rich in natural antioxidants». “Antioxidant nutrients can be taken with different foods.” How many times have we heard or read these and other recommendations? Everyone talks about it, everyone recommends its intake in the daily diet… but can we say we know what antioxidants are?
We talked about it with Daniele Del Rio, president of the School of Higher Studies in Food and Nutrition at the University of Parma and full professor of human nutrition. «The molecules that are defined as “antioxidants” are those that tend to oxidize earlier and more effectively than the others when they are exposed to an oxidizing agent – explains Del Rio – In practice, they protect other compounds from oxidation and, if these other compounds are precious for our health, then, in theory, these antioxidants should defend our body. To give an “inorganic” example, let’s take anti-rust, which works as an antioxidant: by oxidizing, it prevents the oxidation of the iron that makes up the pipes or the pieces that are coated with them».
Does it happen in the body too? That is: can a certain food act as an anti-rust agent and counteract oxidation?
«Theoretically, the antioxidants mentioned in the context of nutrition – explains Del Rio – should prevent oxidative damage involving the most important components of our body, i.e. the fats that make up the cell membranes and lipoproteins, the proteins and the DNA. The question is: are the antioxidant compounds contained in foods antioxidants capable of protecting us even after we have ingested them and that they have been absorbed and transformed by our body? The answer is: not always. In many cases, those compounds that are unquestionably antioxidants in the foods we consume then cease to be so when their “metabolites” circulate in our bodies after eating. This does not mean that they are no longer useful or “protective”, but simply that their actions perhaps no longer depend on their antioxidant activity”.
Having said that, what are the main antioxidants in our diet?
«Vitamin E and vitamin C. Vitamin E in particular remains an antioxidant even after being absorbed and serves to protect the membranes of our cells from the “bad weather” they encounter. When we don’t consume enough, our red blood cells risk breaking down because they are no longer able to defend themselves against oxidative phenomena. Many other compounds that are considered antioxidants, such as for example the polyphenols contained in fruit and vegetables, in tea and cocoa, instead drastically change their structure during the stages of digestion and absorption, and if they exercise positive functions for the organism, the they probably do with mechanisms that do not involve oxidative processes”.
In short, antioxidants yes or no?
«The concept has evolved over time: from the protagonist of the late 90s and early 2000s, it changed and we realized that, probably, history, as often happens when human physiology is involved, is more complex than you think. One of the certainties that remains is linked to the protection that these compounds can already exercise in the food, preventing rancidity phenomena that change not only the flavor of a product for the worse, but also its contribution to health. An olive oil rich in polyphenols, for example, will lose less vitamin E during cooking than an oil that is low in it, thus ensuring an adequate supply of the precious vitamin which, as explained above, is certainly useful because it is an antioxidant for cell membranes . It should also be remembered that consumers often associate the concept of antioxidant with fruit and vegetables: if it is a convincing way of making everyone consume more foods of plant origin, it would be good if one insists on their antioxidant power». Monica Rossi