It's a bit of a challenge to get an apples-to-apples comparison because not all "weeds" have nutrition info readily available, and of the ones we were able to find, not all of the same metrics were available for each (for example, some were missing vitamin K or some of the B vitamins). On top of that, some of the benefits of eating wild greens are attributed to factors that aren't quantified in normal nutritional analyses, such as content of phenolics, flavonoids, and mucilaginous substances. But, for what it's worth, we can make a few legitimate comparisons.
And fortunately, there's enough data to make some charts and graphs!
|However, those same sources claim mallow is rich in vitamin C, and the only quantitative measure we could find put it at about 1% RDV. (Although the flowers have a lot more than the leaves.) But it looks like we'll have to shoot for dandelion, sorrel, or lambsquarter greens if we catch the scurvy and there's no kale around.|
|Protein is where the wild greens really start to shine, and finally find a metric where they can beat kale, at least for lambsquarter and stinging nettle.|
Did we miss your favorite wild or cultivated leafy green? Let us know in the comments section below!
Now, the sources of the numbers, in case anyone is interested:
Dandelion, lambsquarter, purslane, and all the cultivated greens came from the self.com nutrition facts database. In the spreadsheet, when figures were available for cooked greens, we used the 'no salt' option.
Sorrel came from the USDA national nutrient database.
Mallow came from this paper and this paper, using the moisture content to back calculate nutrient content in the fresh leaves. For the second paper, the moisture content was listed as only 2.8%, which is not typical of fresh green biomass! So the moisture content from the first paper was used in back calculations of the mineral contents. Also, vitamin A proper was not given, so the total carotenoid content, which provides an upper limit on the possible vitamin A content, was used. Also, some interconversion between mg and IU was required for vitamins A and E, which we got from here and here. Finally, note that the two papers analyze different species of mallow (Malva sylvestris in the first and Malva neglecta Wallroth in the second), so there is some uncertainty in the numbers reported here. This paper also appears to have the data we're after, but only for a price.
Stinging nettle came from this paper, using the spring data because in the fall, there are so many other things to eat.
EDIT 10/19/15: A recent article (covered also here) took a more sophisticated approach, but came up with chard and spinach ranking much higher than kale, which was on par with dandelion greens. Evidently, they were able to find more complete nutritional data than we did, but they also mention that their ranking system is similarly limited by lack of data on things like phytochemicals. But we also wanted to mention that watercress, which topped their list, is an excellent wild green, too! Now if only they had included some of our other favorite wild greens, they would have a perfect article...