How’s this for confusing: Antioxidant nutraceuticals work. But they appear to have no antioxidant effect.
The startling conclusions come from a long European study into whether antioxidant compounds that have been proven to work in laboratories have the same effect when eaten as berries or wine, or in the form of pills.
“In this case, at least in the compounds we have found, the activity found in-vitro (in the laboratory) is lost in-vivo (in the living body),” said Spanish scientist Francisco A. Tomas Barberan of the Centro De Edafologia Y Biologia Aplicada Del Segura, who helped organize the study.
Read Also
Going beyond “Resistant” on crop seed labels
Variety resistance is getting more specific on crop disease pathogens, but that information must be conveyed in a way that actually helps producers make rotation decisions.
Barberan was a keynote speaker at an international conference on polyphenols held in Winnipeg. The conference drew more than 200 scientists from 44 countries.
The study began in 1995-96.
That means antioxidant claims made by many nutraceutical food and supplement makers are on shaky ground, and Barberan thinks companies should think again before continuing to make such claims.
“You cannot put (forward) a claim based only on the test tube analysis. You have to put the claim following the story until the end. You have to do it in-vivo,” said Barberan.
But before blueberry growers fear the worst, they need to hear the rest of his conclusions.
Although Barberan found that the much-touted antioxidant effects of natural compounds were lost when sent through the human digestive tract, their health-promoting effects were not.
“Probably there are other activities, other bio-activities in these compounds. The original ones, they are not present after intake and after passing through the gastro-intestinal tract,” said Barberan.
“But there are other activities, because these compounds are converted into others that are active as well. But they are not antioxidant, so they have another activity.”
Barberan said many studies have shown the health-promoting properties of nutraceutical food substances, but the antioxidant effect may be a red herring and scientists now need to look at what’s really causing them to be valuable for human health.
“It is very relevant to know what happens in these compounds in the person, from the food, when they are in the body,” said Barberan.
“Which compounds are transformed? Once we know the compounds that are relevant, in-vivo, then we can start exploring the biological activity. Why are they good for you? What kind of claim can you put on your product?”
There is a debate in the scientific, pharmaceutical and nutraceutical industries over whether antioxidants and nutraceuticals have any value for human health.
New Scientist magazine made a big splash this month with an article written by a person with the Novartis Foundation that concluded that nutraceutical supplements “don’t seem to work,” while suggesting people continue to eat foods that are said to have health-promoting properties.
At the same time, some in the nutraceutical industry say the pharmaceutical industry’s products generally make people sicker.
Barberan said the role of unbiased scientists is to observe effects and then attempt to determine why those effects occur.
“We as scientists have to be very cautious … . We have to prove everything we study. We have to prove any claim we make comes from a really sound scientific basis,” said Barberan.
That means, in the wake of the European study, backing away from making aggressive claims about antioxidant effects. But it also means continuing to research why nutraceuticals appear to have health-promoting effects.
“You put a claim that (this or that product) is antioxidant. In the end, you find another activity. (You find) the real compounds that are really active. And they are not antioxidant. They are real compounds and they have no antioxidant activity,” said Bargaran.
“I do agree that there is some activity that is very health-promoting … but the reasons why these compounds are very active is not known.”
