Scientists are still uncovering more evidence about how healthy the natural biochemicals are that are found in fruit and vegetables. Every day you find more in the press about one plant or biochemical, and about how eating that fruit may prevent cancer or aid in fighting off disease, etc.
Recently, the attention as gone to a category of natural biochemical called "Salvestrols." These are a class of natural molecules with dozens of different names. Resveratrol was the first to be identified, from grape skins, but scientists are still looking at this one to determine its true value. Other more recently identified salvestrols have turned out to offer what looks like even higher levels of potency than this one.
The problem is, as pointed out in a fascinating article on this topic appearing in the British Naturopathic Journal (Volume 23, issue 1), that modern agricultural methods prevent plants from producing salvestrols since they are not challenged by fungal infection. Salvestrols are anti-fungal compounds produced by the plant when fungal attack is likely. Modern plants (non-organic) are usually low in salvestrols because they are sprayed with fungicides and so do not need to mount their own defence against attacks by fungus.
Also, most processed foods, such as many fruit juices, may have salvestrols removed during processing, to ‘improve’ the flavor of the product. Sometimes the biochemicals that are most good for you have a somewhat bitter taste. They are found heavily in the skins, pulp and stones of the fruit - and commercial juicers, even for healthy plants like the pomegranate, purposely remove these valuable components of the fruit for their juices.
Work continues all over the world, summarized nicely in the British article, on the anti-cancer benefits of salvestrols. Much more powerful plant biochemicals may be identified in the near future which will make for some very interesting future news stories on this topic.
By the way, one method of getting as many salvestrols as possible into your diet is to use organic produce, and to use a device like a Vitamix for making smoothies and juices instead of a typical juicer which leaves the salvestrols behind. The Vitamix basically dissolves anything and everything, and when my family uses ours, the seeds and skin get thrown into the mix with no ill effect on the taste!