Herbs Are Not Your Friends

By Neuroskeptic | April 4, 2011 10:20 am

Rather than nasty artificial drugs, wouldn’t it be nice if we could just take some herbs and get better? A lot of people think so. Indeed, a large proportion of our drugs and medicines come from plants, or are closely related to plant chemicals. There’s aspirin, morphine, caffeine, cocaine, quinine, and many more. It’s as if plants were going out of their way to help us.

In fact, it’s more like the opposite. Most of these drugs are poisons, produced by the plant to stop animals (that means you) from eating them. As a plant, you don’t want to get eaten, but being, well, rooted to the spot, you can’t exactly run away. All you can do is to make animals not want to eat you. So you fill yourself with noxious, or at least nasty-tasting, chemicals.

By contrast, many plants do want their seeds to get swallowed (but not chewed) by animals and birds, because this ensures that they are spread over a wide area. So they wrap them in delicious, colourful packages. This is why, with only a few exceptions, fruit are sweet and safe while while plant leaves, roots and stems are unpleasant, and often toxic.

In fact, this is quite possibly why the taste of bitter is so unpleasant. Plant toxins are usually alkaloids. Animals must have evolved to find alkaloids nasty, because many of them are poisonous and you survive longer if you don’t enjoy eating poison.

Caffeine, for example, is found in the seeds (“beans”) of the coffee plant, and it makes them taste bitter, to deter herbivores. But those seeds are themselves wrapped in a fruit called the coffee cherry, which is apparently sweet and tasty, although most of them get thrown away in the production of coffee. Coffee wants you to eat the fruit, but swallow the seeds whole, and thereby help spread its DNA. Quinine is one of the bitterest substances on earth, and it’s there to protect the bark of the tree. Nicotine is a bitter insecticide. And so on.

There are some plant chemicals which have medicinal effects which are entirely coincidental: St John’s Wort for example contains some molecules with interesting effects on animals, which are probably quite unrelated to its role in the plant (it absorbs light). It’s also true that plants contain lots of nutrients and the non-toxic ones are, by and large, “healthy” foods, compared to animal products. I say this as a vegetarian. But that doesn’t mean that they cure anything.

So the idea that herbal medicines are “natural”, and thereby safe, is completely backwards. They are natural; that doesn’t make them safe; nature is red in tooth and claw and even the plants are out to get you.

CATEGORIZED UNDER: animals, evopsych, science, woo
  • Anonymous

    There's been a related post elsewhere…

  • http://www.blogger.com/profile/10561769322524106600 Ragamuffin

    this post could easily have been called “In Defense of Pharmaceuticals”. thanks for your (as per norm) well-put take on this subject.

  • http://www.blogger.com/profile/12525104555859213125 Socrates

    Oh cripes, Neuroskeptic is a Vegetablearian!

  • http://www.blogger.com/profile/05660407099521700995 petrossa

    Socrates you beat me to it, Who'd have thought, the blog is for the rest so reasonable :)

    I eat quite a lot of herbs, most of them with animal/in vitro studies showing 'some' effect.

    Boswellia, Withania, Curcumin. Placebo maybe, but it sure did me a world of good for my arthritis compared to NSAID's.

    As a carnivore with collitis who eats anything but vegetables i also eat herbal protein enzymes (papaine and ananas) to ease the load on my digestive system.

    Some passionflower to ease the nerves, some natural vitamins to top it off.

  • Anonymous

    I'm not in the medical field but have been reading a lot of “introduction to pharmacology” articles for personal health reasons.

    What I'm learning is that some of the herbals interfere with how the body metabolizes other drugs.

    St. John's wort seems to be a particular problem in this regard — it causes some other drugs to clear from the body faster than normal so they don't work as prescribed and dosing may need to be adjusted.

    So, those of you taking herbals may want to discuss with your doctor or pharmacist whether other medications are being affected and if anything needs to be adjusted.

  • http://www.blogger.com/profile/11156250444026317037 antianticamper

    Well, I'd like to give an appreciative shout-out to plants for some of their more remarkable alkaloids, in particular the Amazonian entheogens. Even the term “poison” need not be considered entirely negative. For example see this book: http://www.amazon.com/Pharmako-Gnosis-Plant-Teachers-Poison/dp/1562791303

  • http://www.blogger.com/profile/06647064768789308157 Neuroskeptic

    Oh, I'm not knocking plant-based drugs, I am a big fan of many of them. But they're no safer or nicer than artificial ones. It's a lot easier to kill yourself with morphine, or say digitalis, than it is with many artifical drugs.

  • http://www.blogger.com/profile/11156250444026317037 antianticamper

    I'd also like to comment that there is interesting preliminary evidence that Banisteriopsis caapi (the Ayahuasca vine) is potentially useful for anti-depressant effects, which may not be too surprising given the natural MAOI content. If I had another depressive bout I'd experiment with Caapi before taking the standard pharmaceutical anti-depressants, given their dubious efficacy.

  • http://marilynmann.wordpress.com/ marilynmann
  • Anonymous

    My buddy, Herb, took great offense to this post.

  • OrchidGrowinMan

    Not all plant antifeedant chemicals taste/smell “nasty,” at least not to us: menthol, thymol, eugenol….

  • http://www.blogger.com/profile/05660407099521700995 petrossa

    I'd stay away from maoi's in any shape or form. Their potential for mayhem for outweighs the iffy potential for doing good.

    St Johnsworth can indeed seriously make you ill, but so can their pharmaceutical equivalents.

    As such the argument is more 'lot's of molecules regardless their origin can do you in' rather then herbs/chemicals

    The site Erowin is a good source of information with a lot of user experience and a high level of chemical knowledge. Beats any 'study'anyday.

  • Anonymous

    “Oh, I'm not knocking plant-based drugs, I am a big fan of many of them. But they're no safer or nicer than artificial ones. It's a lot easier to kill yourself with morphine, or say digitalis, than it is with many artifical drugs.”

    Cannabis seems nicer and safer than just about any artificial drug. Even the synthetic cannabanoids are dangerous in comparison. But I guess it's an exception.

    These plants are using gesture through biosynthesis, and while many of them seem to be simply saying “stay away”, it's clear that some are offering a more complicated and profound message.

  • http://emmiscafe.wordpress.com/ Emmy

    I'd agree that substances found in nature are not necessarily less toxic than artificial ones, with a few caveats. Aspirin has been used in some form or another since Native Americans obtained it from the bark of the pacific willow; how this makes it safer is that it's been in the human food supply longer than some newer drugs like Aleve.

    We know by real-world example over a long period of time how it's metabolized by many individuals. Also you'd think that a plant that evolved in nature and is consumed by primates, would not alarm the immune system as much as an artificial substance with completely foreign proteins.

  • http://www.blogger.com/profile/03264372096005888618 Instituto Psicofarmacología

    The problem is not whether to use drugs or herbs Síntesi, this is not the choice. The real question is will my problem must be involved chemically?. More prevañentes mental problems: depression, anxiety, psychosis, impaired ersonal … Are Altering a iana siimple that I can access and correct with a bullet majic?
    EPY

  • http://www.blogger.com/profile/03264372096005888618 Instituto Psicofarmacología

    The problem is not whether to use synthetic drugs or herbs, this is not the choice. The real question is will my problem must be involved chemically?. More prevañentes mental problems: depression, anxiety, psychosis, personality disorders … are simple alteration of a target that I can access and correct with a bullet majic?
    EPY

  • http://cheapmeizitang.com/ cheap meizitang

    Absolutely. I rely on them most of the time.

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About Neuroskeptic

Neuroskeptic is a British neuroscientist who takes a skeptical look at his own field, and beyond. His blog offers a look at the latest developments in neuroscience, psychiatry and psychology through a critical lens.

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