Although functional foods such as milk enriched in vitamins, margarines to lower cholesterol or lactose-free foods are present in more than 50% of Spanish households, they present two problems. On the one hand, almost all brands repeat the same formulations, so the products are almost identical. On the other hand, many of the healthy properties that functional foods have advertised for years have not been shown to be supported by science and the EU has demanded that dozens of healthy claims be withdrawn such as “favors the development of the immune system”, “lowers the blood pressure”, “improves intestinal health” or “reduces osteoporosis” that appeared on their packaging.
Researchers from all over the world are working on the development of functional foods rich in new bioactive ingredients . One group of these are the stilbenes , compounds that include the famous resveratrol , but also other molecules with great potential such as oxiresveratrol, pterostilbene, pinosylvin, gnetol, etc. Their advantages are that they are not part of the existing functional foods on commercial surfaces and that they present interesting biological activities.
Stilbenes are low molecular weight phenolic compounds that are synthesized in a number of plant families, including Vitaceae , Pinaceae , Myrtaceae , Fagaceae , Liliaceae , Moraceae , and Papilionaceae . In food we find them in grapes, red wine, blueberries, some nuts, etc. and its synthesis depends on several factors such as the response to environmental stress such as infection by UV radiation, attack by pathogens, wounds, etc. In fact, stilbenes act in plants as antifungal compounds, allowing them to defend themselves against external attacks.
Despite all the potential that stilbenes possess — antimicrobial, antiviral, antioxidant, anticancer , cardioprotective, anti-inflammatory, antidiabetic, neuroprotective, immunological effects, etc. are attributed to them — these molecules present a series of drawbacks for their use as ingredients of Functional Foods. Among them, its low solubility stands out —which makes it difficult to enrich hydrophilic foods with these molecules—, its low bioavailability ; its ease of oxidation , its alteration by physical-chemical agents —pH, temperature, light…— and the scarcity of in vivo scientific studies that demonstrate its effectiveness as an ingredient in this type of food. All of the above has led the European Food Safety Authority (EFSA) not to grant any health claim to stilbenes.
And how is the scientific community solving these problems presented by stilbenes to receive the blessings of the EFSA? Through its characterization, its stabilization and, above all, through in vivo studies that corroborate the biological activity demonstrated in in vitro models. One of the animals accepted in the scientific community for carrying out in vivo experimental models is Caenorhabditis elegans , a nematode used as a model in questions of aging, cancer and the role of antioxidant molecules and considered ideal for evaluating the potential of bioactive molecules, since It is an animal with a short life cycle and on which experiments can be carried out with a high number of replications under highly controlled conditions.
C. elegans is outside the work restrictions imposed on laboratory animals. It is grown in Petri dishes by growing on Escherichia coli bacteria. Its simplicity of handling makes it possible to cultivate it in a conventional laboratory and its transparency makes it an ideal system with which to work with fluorescent molecules —such as stilbenes—, since the fate of the molecules ingested by this nematode can be followed with microscopy of fluorescence.
Well, recent studies show how the administration of previously characterized and stabilized stilbenes —as required by the EFSA— to C. elegans are capable of delaying cell aging, reducing oxidative stress levels and lengthening the half-life of this peculiar nematode. And these results are important? Yes, because if they manage to extrapolate to humans —which is very likely— we will soon be able to see functional foods on commercial surfaces enriched in original bioactive compounds whose properties have been approved by the highest European organism in food matters. Problem solved.
José Manuel López Nicolás is vice-rector for Scientific Transfer and Dissemination at the University of Murcia and author of the Scientia blog.
