Cowpeas are one of the top plants listed for a balanced diet (especially for vegetarians) and they are a multi-harvest plant. I grew up on purple hulls and crowder cowpeas, but I don't think my Grandmother had any idea how nutritious cowpea leaves were as well. I remember them being one of my favorite things that she cooked and years later I tried them canned, didn't quite do it for me.
Not only are the home-grown cowpeas nutritious and fantastically tasty, but the LEAVES have the highest percentage of calories from protein and the most zinc, called the intelligence mineral, of any vegetable grown in the US. But that's not the most amazing thing...
Zinc is so important for the body’s energy levels, mood, immune system, cell growth and division, in wound healing, breaking down carbohydrates, and for the sense of taste and smell. Zinc also acts as an antioxidant and is directly involved in the maintenance of hormone levels. It is such a critical element in our health that even a small deficiency can lead to disease. Low zinc is even attributed to accelerated aging and zinc deficiency is widespread in the US.
Grains, legumes, nuts, and oil seeds contain different levels of phytic acid (one of several anti-nutrients) which can bind to some minerals, like zinc and iron, and pass them unused out of the body during that meal. How much of the minerals in your food they bind to, depends on how much phytic acid is in the food. See chart at the bottom to see how low the cowpea is compared to other common foods.
While some say phytic acid has its own health benefits, if you are going for the minerals in plants that contain it, you can reduce the effect it has, or even remove it completely, by soaking prior to cooking, fermenting, slow cooking, and/or sprouting.
Some foods are low and some high in phytic acid. Soy is high, and products like tofu and soy milk would not be as healthy, no matter their other qualities, as fermented soy like tempeh and miso. Don't go crazy with the fermented soy either though, it "must be consumed within the context of an iodine rich diet"... but I digress.
You can also use vinegar in the cooked meal to increase mineral absorption or consume vitamin C foods along with the meal. There are entire books and online articles dedicated to removing phytic acid in many of our foods, and everyone should do their own research.
Now for the really amazing part, according to the book 'Advances in Cowpea Research' by B.B. Singh, the phosphorus in Cowpea leaves is NOT present as phytic acid though, so the minerals are readily bio-available. The leaves are good dried or fresh, and cooked cowpea leaves contain seven times more calcium and three times more iron than the actual peas. Raw leaves have about 20% more thiamine, twice the riboflavin, equal amounts of niacin as the peas, and are a significant source of beta carotene and ascorbic acid.
The leaves have about 15 times the protein as the peas, and the protein is a superior type. Testing has shown that the leaves harvested at 5 weeks contain significantly more protein than the leaves harvested at 7 weeks, and it has been found that sometimes the leaves are canned and sold as spinach in some markets. Leaf recipes to come, but my plan is to infuse in vinegar to pull the minerals and make a field drink (blog post to come on that) and enchiladas!
Recipe for Cowpea leaves (kunde) Luhya-style here at African Aromatics (scroll down till you see the cowpea leaf recipe).
Cowpeas are a drought, heat and humidity tolerant warm-weather crop. They can fix nitrogen in the soil and even grow well in poor soils with more than 85% sand and less than 0.2% organic matter. They are shade tolerant, so can be used in intercropping with other plants such as corn, sorghum, and sugarcane. They like warm soil to germinate, so plant when soil temps reach 65 degrees and succession plant every 2 - 4 weeks.
Though a cross is unusual, "To maintain the varietal purity an isolation distance of 5 metres for certified and 10 metres for foundation seed production is maintained between varieties in cowpea and in soybean an isolation distance of 3 metres is maintained between varieties for certified and foundation seed production. "~ http://www.ciks.org/2.%20Seed%20Production%20Techniques%20for%20Oilseeds%20and%20Pulses.pdf
The dried stalks can be used as animal feed, and the dried leaves provide animal fodder on par with alfalfa hay. Consider this fantastic plant for your family, animal and soil health when planning your next garden and PLEASE help me make 2017 the year of the cowpea!