Greetings everyone,
I wanted to start a discussion about perennial sources of protein for human consumption.
Where I live in rural Haiti, almost everyone is a subsistence farmer. Because the climate is so good, people are not often dying here from not having enough calories. Undoubtedly children are stunted by periods of too little calories but mostly the problem here is inadequate protein and some micronutrients. I suspect from what I have seen here so far that over 10% (perhaps well over) of children who are born alive die in childhood. It is very normal here to find families that have had 2 or more children die. In our few years here we have seen a number of children die from malnutrition and I suspect malnutrition is a significant factor in most of the childhood deaths here. The primarily malnutrition here is protein malnutrition (which is really a combination of protein and micronutrient deficiency). Protein sources here for people are primarily common beans (Phaseolus vulgaris) and then pigeon peas and then smaller amounts from lablabs, Phaselous dumosus, eggs, meat, etc… These personal details aren’t necessary to understand my proposed discussion but I want to give some context for why I think this topic is so important.
Perennial food sources provide some significant advantages over annual food sources. Trees have even greater advantages once they grow to a height beyond the reach of grazing animals. In tropical and subtropical climates, lablabs, pigeon peas and runner beans are all well known protein sources that are at least short-lived perennials and can provide a significant amount of protein. I’m interested in a discussion about some less-known perennial plants that can provide a significant amount of protein for human consumption. I’ll list a few I know of and I’m interested to hear any thoughts people have on those or other plants:
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Phaseolus dumosus (which is a common bean/runner bean cross) is a perennial climbing bean.
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Erythrina edulis is a nitrogen-fixing tree that produces edible beans
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Leucaena diversifolia is a nitrogen-fixing tree that produces small seeds. Some people claim these seeds are edible and some say they are dangerous to eat. I’m interested to hear if anyone has experience with this.
- Various tree nuts - I’m especially interested to know of varieties that can yield quickly (2-3 years) in a subtropical or tropical climate.
Please share any thoughts or experiences you have.
Joel
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Hi Joel,
you haven’t written about green leaves. These often have proteins as well (and other nutrients, too).
How about moringa, chaya, katuk, leaf cassava? These have proteins, but also a wealth of minerals and vitamins.
Moringa seeds also can be eaten like nuts (although they taste a little weird), but more importantly, an oild can be extracted that is good for cooking and skin care.
We work in Central Tanzania, in a rather dry environment (~500mm rain/year, 7 months dry season), so our situation obviously is very different from yours, so I don’t really know what would grow in your area.
Hi Joel.
I heartily agree with Martin about moringa and katuk which are a good source of protein. I grow them as well as chaya and casava. All of them are so easy to grow and will keep people alive.
God bless you 
Galen
Hi Joel,
In southern Mexico, people ate the Leucaena leucocephala seeds green as a raw snack. They sold little bundles of green pods in the market. A friend of mine saw a lady at the bank get a bundle out of her drawer to eat in the bank 
They did say that they can cause bad breath.
What is the protein content of avocados? These should be promoted.
Another thing is encouraging people to feed their eggs to their own children instead of selling to market. My technicians really preach to people about selling their eggs to market and then buying packaged food to feed to their children.
In the past, people in Haiti ate sweet potato leaves. What is their protein content. Could sweet potato leaves and/or cowpea leaves be promoted?
Also, chaya should grow at your elevation.
Greetings Martin,
Thanks for the suggestion. Yes, I had forgotten to put these perennial leaves in. I had known that all these leaves are good protein sources as far as greens go but I hadn’t taken the time to crunch the numbers until today. Here is what I found in my research and I’m surprised that the higher protein perennial leaves have percent protein in dry matter that is in the same neighbourhood as beans and peas. I wish I had known that earlier as I would have promoted them more.
Unfortunately some of the journal articles I link to below aren’t freely available but all should be available though a good university library.
Katuk has 7.4 g protein per 100 g green weight, according to this study: Nutritive value ofSauropus androgynus leaves | Plant Foods for Human Nutrition. Katuk leaves have 70% moisture which means that katuk leaf dry matter is about 25% protein.
Chaya leaves vary from 4.2-8.2 g protein per 100 g green weigh, according to this article: The ethnobotany of Chaya (Cnidoscolus aconitifolius SSP.Aconitifolius breckon): A nutritious Maya Vegetable | Economic Botany
Chaya has about 80% moisture so that means that chaya leaf dry matter is about 21-41% protein. Chaya protein is high quality protein in that the amino acid composition is a reasonable match to human needs, according to this article: Use of Chaya (Cnidoscolous chayamansa) Leaves for Nutritional Compounds Production for Human Consumption | Journal of the Mexican Chemical Society
Cassava leaf dry matter varies from 17.7-38.1% protein according to this review article: Redirecting
Moringa oleifera leaves have 6 g per 100 g green weight and 75% moisture according to this study: https://doi.org/10.9734/ejnfs/2019/v11i330155
That means that Moringa oleifera leaf dry matter is about 24% protein.
Sweet potato greens have 2.49 g protein per 100 g green weight, according to the USDA Fooddata central database (https://fdc.nal.usda.gov/food-details/169303/nutrients). It has about 87% moisture so that means that dry matter is about 19% protein.
Mulberry leaf dry matter is between 13.4-24.6% protein according to this article: https://doi.org/10.1080/13880209.2018.1424210
For comparison:
Lablab bean dry matter is about 26% protein.
Black bean dry matter is about 24% protein.
Pigeon pea dry matter is about 24% protein.
Peanut (seed, not leaf) dry matter is about 26-28% protein (depending on variety).
Sorce for those last four is USDA Fooddata Central database.
So far my attempts to grow Moringa oleifera have not been very successful (I think we are both too wet and too cool) but I’m still trying. I still haven’t found a source for Moringa stenopetala seeds. Katuk I am just getting established from some cuttings from ECHO. Cassava leaves we use and are recommending, although issues with cyanogens and how safe it is as a main protein source. We have two different types of Chaya and are trying to scale it up to be a food source.
Joel
Greetings Mike,
Thanks for the info about Leucaena leucocephala. I’ve read that it has higher percentage of toxin than L. diversifolia so should be more useful as food (other than that the seeds are smaller).
About avocados, they have about 10% protein in their dry matter so that they aren’t near as high as the other things I looked at (see my last post) but still not insignificant. They are well used here and I suspect for people that have them (especially tress that produce fruit when people are short on beans) they are part of what keeps children alive during periods where other protein sources are scarce.
Yes, and we are trying to convince people not to sell so many of their beans that they can’t have them for their family for the whole year. As you probably know, getting truthful responses to questions in Haiti can be hard so it is hard to know what everyone’s situation is. However, we are starting to wonder if some of the problem here is that the adults are mostly too selfish to share the high protein foods with the children when there isn’t a lot to go around. We have seen many parents, siblings or other family members sneaking high protein malnutrition rations from a severely malnourished child and we figure if they are willing to do that where we might be able to see them, it is probably happening even more at home. Another part of the problem is that people seem not hungry enough to try foods that seem weird to them. There is a large abundance of snails here during the rainy season and they are over 70% protein by dry weight and people will basically tell me they would rather starve then eat them, even though they are eaten all over the world. I suspect if the adults were starving they would change their mind but their children dying of protein malnutrition sadly doesn’t seem to be enough to get them to reconsider.
Yes, we are promoting sweet potato leaves but will do so more, now that I know the numbers better (see my previous post). We are just trying to grow cowpeas. They seem to grow slowly here, probably not hot enough for them to be a great crop here. Roland Bunch has some good info on blanching and storing lablab or cowpea leaves that I presume could be done for almost any bean plant that we are going to try here. I’m still looking for a good source on lablab leaf nutritional info.
Yes, we are growing both the local variety and one we got from ECHO but it doesn’t seem as vigorous here as were hear about it being at lower elevations.
Joel