Appropriating Plant Defenses

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Plants and animals share similar biochemical pathways and signaling systems, which may explain why so many phytonutrients are beneficial to our physiology.

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Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

Plants live the ultimate sedentary lifestyle. “Most of us [usually] think of plants more as objects than as organisms. But because…plants [can’t move],” they’ve had to evolve a whole other way to escape threats to their well-being. Plants can sense and respond dynamically to all sorts of stimuli: chemical concentrations in the air, soil, water, touch, motion, vibration, pathogens, predators, and, of course, light. And how do they respond? They respond biochemically. They manufacture, from scratch, a dizzying array of compounds to deal with specific threats.

If we get too hot, we can move into the shade. But if plants get too hot, they’re stuck—they are the shade! “As a result, the complexity of the plant stress response humbles that of animals. Plants and their stress response have been evolving for almost [a] billion years.” And, in that time, they’ve created a whole chemistry lab of protective substances—some of which can induce similarly protective responses in those that eat them.

Why is it that “the best grapes in terms of…health benefit often result from relatively dry, sun-exposed, infertile soil”? “Similarly, drought-stressed strawberries have [more] antioxidant[s]” and phytonutrients. “Indeed, commonly-consumed foods, like lettuce and fruits, can be nutritionally enhanced by cold stress, light stress, water deficit, or nutrient deficit stress.” Why is it that stressed plants are often the healthiest?

We used to think it was just a matter of using the same tools to deal with the same problems. “[S]tudies suggest that plants and animals largely share the molecular pathways in order to respond to stress, so [it’s] conceivable that a molecule produced in plants [might] also be effective…[in people].” Plants have DNA; humans have DNA. The UV rays in sunlight can damage the DNA in plants in the same way it can damage our DNA—by creating free radicals. Plants figured out how to cook up all these complex antioxidants, and instead of just reinventing the wheel, animals can just expropriate those antioxidants from plants, and commandeer them for the same purpose.

We get attacked by bacteria; plants get attacked by bacteria. So, for example, when this fungus doesn’t like getting muscled in on by bacteria, it creates a molecule called penicillin—provided free to us. What a nice guy, what a fungi! 

When plants get infected, they produce aspirin—which can come in handy when we get infected. Plants heal wounds; we heal wounds, using similar fatty-acid signaling systems. “It is increasingly evident that plants and animals differ less than we thought in [terms of] how [we all] respond,” sharing elements “of fatty acid, protein, steroidal, neurotransmitter, [free radical], nitric oxide, and even plant growth hormone signalling systems.”

So, in a sense, we’re just opening up nature’s drug store when we pull out the crisper in our fridge.

Please consider volunteering to help out on the site.

Images thanks to Noodles and Beef via flickr, purzen via OpenClipArt, and Bios and Miansari66 via Wikimedia

Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

Plants live the ultimate sedentary lifestyle. “Most of us [usually] think of plants more as objects than as organisms. But because…plants [can’t move],” they’ve had to evolve a whole other way to escape threats to their well-being. Plants can sense and respond dynamically to all sorts of stimuli: chemical concentrations in the air, soil, water, touch, motion, vibration, pathogens, predators, and, of course, light. And how do they respond? They respond biochemically. They manufacture, from scratch, a dizzying array of compounds to deal with specific threats.

If we get too hot, we can move into the shade. But if plants get too hot, they’re stuck—they are the shade! “As a result, the complexity of the plant stress response humbles that of animals. Plants and their stress response have been evolving for almost [a] billion years.” And, in that time, they’ve created a whole chemistry lab of protective substances—some of which can induce similarly protective responses in those that eat them.

Why is it that “the best grapes in terms of…health benefit often result from relatively dry, sun-exposed, infertile soil”? “Similarly, drought-stressed strawberries have [more] antioxidant[s]” and phytonutrients. “Indeed, commonly-consumed foods, like lettuce and fruits, can be nutritionally enhanced by cold stress, light stress, water deficit, or nutrient deficit stress.” Why is it that stressed plants are often the healthiest?

We used to think it was just a matter of using the same tools to deal with the same problems. “[S]tudies suggest that plants and animals largely share the molecular pathways in order to respond to stress, so [it’s] conceivable that a molecule produced in plants [might] also be effective…[in people].” Plants have DNA; humans have DNA. The UV rays in sunlight can damage the DNA in plants in the same way it can damage our DNA—by creating free radicals. Plants figured out how to cook up all these complex antioxidants, and instead of just reinventing the wheel, animals can just expropriate those antioxidants from plants, and commandeer them for the same purpose.

We get attacked by bacteria; plants get attacked by bacteria. So, for example, when this fungus doesn’t like getting muscled in on by bacteria, it creates a molecule called penicillin—provided free to us. What a nice guy, what a fungi! 

When plants get infected, they produce aspirin—which can come in handy when we get infected. Plants heal wounds; we heal wounds, using similar fatty-acid signaling systems. “It is increasingly evident that plants and animals differ less than we thought in [terms of] how [we all] respond,” sharing elements “of fatty acid, protein, steroidal, neurotransmitter, [free radical], nitric oxide, and even plant growth hormone signalling systems.”

So, in a sense, we’re just opening up nature’s drug store when we pull out the crisper in our fridge.

Please consider volunteering to help out on the site.

Images thanks to Noodles and Beef via flickr, purzen via OpenClipArt, and Bios and Miansari66 via Wikimedia

Doctor's Note

The aspirin story is fascinating.

This whole co-evolution concept reminds me of Human Neurotransmitters In Plants and The Broccoli Receptor: Our First Line of Defense.

More on the power of plants in Power Plants.

Some of the wilder things that Phytochemicals: The Nutrition Facts Missing from the Label can do are explored in:

We evolved eating a lot of plants: Paleolithic Lessons.

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