Nasturtium officinale, a member of the Brassica family that also includes broccoli and cabbage, has just made news as a powerful preventer of DNA damage in vulnerable blood cells. This research, published in the American Journal of Clinical Nutrition, gives further evidence that the plants of this family, rich in phytochemicals such as glucosinolates that are partially responsible for their flavor, have powerful anticancer and cell-protective activity when consumed at a daily dose of "about a cereal-bowl full".
Previous research had already underlined this point, but this most recent study is the first to show direct DNA and cell-protective effects. Some highlights:

· significant reduction in DNA damage to lymphocytes (white blood cells), by 22.9 per cent.

· reduction in DNA damage to lymphocytes (white blood cells) when a sample was challenged with the free radical generating chemical hydrogen peroxide, by 9.4%

· reduction in blood triglyceride levels, by an average of 10%

· significant increase in blood levels of lutein and beta-carotene, which have antioxidant activity, by 100% and 33% respectively(higher intakes of lutein have also been associated with a lower incidence of eye diseases such as cataract and age-related macular degeneration).

What is most interesting to me, from a relational point of view, is that members of the Brassicaceae produce many of these pungent compounds that are so protective to humans primarily to defend themselves against environmental stressors. This echoes the role of compounds such as resveratrol (red wine, japanese knotweed, of recent life-extension fame) in promoting an ecosystem inside human cells that favors DNA repair and protection, reduces apoptosis (in healthy cells), and increases the presence of antioxidant compounds.
The process whereby the human intracellular millieu is altered by ongoing ingestion of plants is known by the fancy term "xenohormesis". The implication: plants, like canaries in the coal mine, detect environmental changes very early: they are tightly integrated into soil, air, sun and water processes, and respond to changes in this living system with a high degree of sensitivity. These responses include alterations in the chemicals they produce, generally increasing the levels of substances like glucosinolates and sirtuin-activators like resveratrol during times of greater stress. When we consume these plants, we are then given higher doses of these compounds, which in turn protect us from the environmental changes that could potentially damage our cells and DNA.
Understanding this process of co-evolution is a long-term project for me, and this research on the humble watercress provides yet another piece of evidence in the puzzle.

One final note: please ensure that any watercress you consume is from organic sources, or at the very least grown with very pure spring water, as its ability to take up modern pollutants is very strong and would counteract any positive effect.

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