Let’s explore this hypothesis:
A whole plant is more effective than a phytochemical from that plant. Written by Dr. David Kiefer, Executive Director of Beneficial Plant Research Association
I was about to begin with ginger. This plant recently saved me from gastrointestinal (GI) distress, when I was curled up in a ball with severe nausea. Thank you, ginger. And, ginger is this fascinating plant that can serve as an anti-inflammatory while protecting and supporting healthy GI function. Contrast this to another well-known anti-inflammatory, ibuprofen, which, although effective for many people in combating their pain and inflammation, tends to cause problems with the stomach through well-documented gastritis and ulcerations. Ginger contains many phytochemicals, but two in particular, shogoals and gingerols, provide many of its effects. These compounds interchange with each other in that one can be converted into the other and vice versa, and the levels present depend on how ginger is processed, whether it’s simply boiled as an infusion, or dried and powdered.
OK, that was all just an aside because I like ginger so much. But, I don’t think it’s the best example of whole plants being the “bomb dot com,” mostly because the isolated phytochemicals aren’t used in clinical practice that often. Ideally, I would be able to point to studies using whole ginger and compare them to studies using isolated ginger phytochemicals in order to conclude which is best. However, I am not aware of such studies that would help me to make an evidence-based recommendation to all of you. Alas, I think I have to move on from ginger.
Then, because my mind thinks in patterns and relationships, after ginger I thought about its cousin, turmeric. Both ginger and turmeric are in the Zingiberaceae family, and both have underground stems (rhizomes) that provide humans with plant medicines effective for many things. Turmeric, like ginger, is used as a spice and a pain-relieving plant. Turmeric, like ginger, is used as a whole plant, throughout the world, across cultures, its yellow-pigment commonly known it various foods like curries and mustard (I have to admit that growing up in Wisconsin, my primary childhood intake of turmeric was as a coloring agent in mustard that I reluctantly - I didn’t actually like mustard - ate on hotdogs and hamburgers). Yes, turmeric is ingested by humans as a whole plant. But, to prove this theorem, we would have to have proof that whole plant turmeric is more effective as a healer than its isolated phytochemicals.
This is where we run into trouble. Turmeric, like all plants, contains more than one phytochemical. A group of them is called the curcuminoids, which are polyphenols and have a variety of well-proven physiological activity in humans. The primary curcuminoid is called curcumin and, unfortunately for this whole plant proof, curcumin has been the focus of most of the clinical trials showing positive benefits of turmeric (curcumin) supplementation for people with arthritis. The medical literature is all about curcumin, and I can’t find a head-to-head analysis of whole plant turmeric versus its isolated phytochemical curcumin showing that whole plant turmeric is better. It seems as if this is another “dead end” trying to prove this whole plant theorem.
I wasn’t going to give up though! As I was reviewing the literature and thinking about all of the amazing plants that I consume in whole plant form, I ran across an interesting review article about green tea that approximates what I’m hoping to see more of in scientific publications. Mancini and colleagues scoured the literature for studies on cognition (and other brain functions) where humans ingested whole green tea, either as an infusion or extract, as well as studies examining the effect of either of green tea’s primary phytochemicals, EGCG or L-theanine. The authors ultimately found 21 convincing studies that met their criteria; five were observational and 16 experimental (please listen to the BPRA podcast to learn more about the research types).
What did they find? To quote the researchers, “The research findings on habitual, daily green tea consumption of at least 100 ml per day suggest that the principle long-term benefits are improved mental facilities, a more relaxed state of mind and a lower risk of dementia.” This is pretty spectacular, and truly a vote in favor of the whole plant hypothesis. The results did show some benefits for EGCG and L-theanine on cognition and brain functions, but, again I quote the authors, “While this systematic review found a reasonable amount of evidence that both EGCG and L-theanine exhibit neuroprotective activity and that L-theanine (and to a lesser degree of EGCG) influence mood, the extracted data suggests that the various improvements in cognitive faculties linked to green tea consumption are not the consequence of a single component.” For example, as I mentioned above, whole green tea itself seems to work well, as did L-theanine when combined with caffeine (there is a small amount of caffeine in green tea), but less so L-theanine by itself. Please note that this is a very specific review, one focusing on cognitive effects, and I am sharing this review to highlight an example of the surfacing evidence supporting the ingestion of a whole plant versus a purified, isolated phytochemical.
After enjoying Mancini’s review article on green tea, I felt like I was gaining some momentum in my search for other examples of preferential whole plant benefits. I thought of the many plants that we use in whole plant form, mostly, from what I can tell, because of convenience (the mint growing in your garden, for instance), cost (turmeric is an example of a plant, the spice powder, that is significantly less expensive than the capsule form), and tradition (hundreds fall into this category). Examples abound, such as Asian ginseng, cat’s claw, nettles, chamomile, oregano, rosemary, lavender, and echinacea. Now what we need are systematic reviews, and individual research trials, for these plants just as we have for green tea.
In summary, it can be a challenge to prove, in an evidence-based format, and one which would stand up in the “herbal medicine courtroom,” (see earlier Substack for context!) that whole plants are more effective than the isolated phytochemicals. Not impossible, but a challenge, and it requires a slew of well designed research studies that detail clear clinical outcomes from randomized, placebo-controlled trials on whole plants compared to their isolated constituents. As I reflect on this topic, it strikes me that whole plants seem to be just what we happen to do more often, though that seems to be changing as plant medicine becomes commercialized and people also seem to want their plants in a convenient capsule, tablet, or tincture format. And, as I discuss above, there is a paucity of head-to-head clinical trials comparing a whole plant to one (or more) of its isolated phytochemicals.
Perhaps one of the other upcoming sections in this Substack will help to make our case for that steaming cup of peppermint tea!
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References
Aggarwal BB. Healing Spices. Sterling; New York: 2011
Johnson RL, Foster S, Low Dog T, Kiefer D. Nation- al Geographic Guide to Medicinal Herbs. Washing- ton D.C.; National Geographic: 2010
Mancini E, Beglinger C, Drewe J, Zanchi D, Lang UE, Borgwardt S. Green tea effects on cognition, mood and human brain function: A systematic review. Phytomedicine. 2017;34:26-37
Tayyem RF, Heath DD, Al-Delaimy WK, Rock CL. Curcumin content of turmeric and curry powders. Nutr Cancer. 2006;55(2):126-31
Thomas-Eapen N. Turmeric: The Intriguing Yel- low Spice With Medicinal Properties. Explore. 2009;5(2):114-115