In experiments conducted by the US Dept of Agriculture, volunteers were asked to ingest large quantities of fruits that have been identified as having high levels of antioxidants, and their blood were subsequently tested for antioxidant capacity. One important note is the large amount of fruit required per ingestion – for example – volunteers in the Kiwi fruit group must eat 4 kiwis. The cherry group? 45 cherries. This should give consumers an idea of the potential “starting” dose needed to gain an antioxidant benefit – and this is PER DOSE. (imagine eating 45 * 3 cherries a day – if you want to get the benefit of cherries’ antioxidant properties with every meal.)
This does make for an attractive commercial market to give consumers “concentrated” forms of antioxidants – except most of companies providing these types of nutrition products are not regulated by the FDA – that branch of the government regulating food and drugs to make sure that you as a consumer aren’t being ripped off or worse – physically harmed by ingesting unsafe products. Unfortunately, history has shown that the FDA only steps in when enough people get sick or if a few people begin to die from the so-called “nutraceutical” – just look at the ephedrine cases in the multi-billion dollar weight-loss industry.
Currently there is no agreed projection of antioxidant intake because this can fluctuate based on individual energy intake, caloric consumption, and especially environmental or confounding health related factors like exposure to cigarette smoke or disease (increasing body’s oxidation burden). There are researchers who are trying to determine what these individual needs may be, but for the most part, consumers have been inundated by commercial entities eager to profit on a perceived benefit of “high antioxidant intake”. For example, via Quackwatch:
The verdict? If you like to drink exotic berries for the taste, there’s no problem with indulging yourself but if you’re looking for some of these commercial products for bona fide healthcare benefits, require the claims to be backed up by randomized, double-blind placebo controlled clinical trials, with full disclosure of side effect profiles experienced by the human subjects.
(…and if there is really some miracle plant bearing amazing therapeutic properties, the pharma companies would outrun anyone to isolate the agents, synthesize/mass produce, and submit it through the proper legal govt channels for commercialization! that was how we got cancer drugs from the pacific yew tree.)