A first (of many, we hope) guest post from our friend and colleague Colin Khoury.
In the field of conservation of plant genetic resources, it is commonly stated that a very limited number of plant species feed the world.1 A number of publications, especially in the 1970’s and 1980’s, provided different angles on how many crops or species provide just how much of the human diet. And there are a lot of ways to try to answer the question. Most of the publications end up with numbers around 7, or 15, or 20, or 30 crops that feed the world. Prescott-Allen and Prescott-Allen (1990) found global aggregate statistical data unsatisfactory in telling the full story for peoples of all countries:
Crops such as fonio, Digitaria exilis Stapf, and quinoa, Chenopodium quinoa Willd., are lost in global production data; but to conclude that they are unimportant is to conclude that the people of Guinea, Gambia, and Bolivia who rely on them are unimportant.
Instead, they worked with national level Food Balance Sheets from FAO, and looked at the question in four ways to determine just how many species make up 90% of the total intake of food weight, calories, protein and fat in each country.
The result is “85 species commodities and 28 general commodities contribute 90% of national per capita supplies of food plants.” After a bit of tinkering, they come up with this final statement: “the total number of species commodities is 82. These consist of 103 species. Fifty-six of the species commodities, consisting of 75 species, account for 5% or more of the national supply of a nutritional category in at least one country.”
Still confused? Well, it’s a difficult question to answer. And answers are often underestimates, as statistical data rarely account well for local markets, home production, etc. Prescott-Allen and Prescott-Allen provide some interesting food for thought2 in working with statistics at the national level, and in doing so perhaps include more species/crops than studies working with global aggregate data.
Has much changed since 1990? A full re-run of their analysis, country by country, is still to be done. But what happens when we aggregate the country statistics from the latest Food Balance Sheets (2007)? Again including the four categories (weight, calories, protein, fat), and counting those crops and food products that comprise 90% of the diet, we find that about 25 crops/species, plus about 7 general commodities, do the job (not listed in any particular order of importance):
Rape and Mustard Oil
Rice (Milled Equivalent)
Oilcrops Oil, Other
A further note, if the alcoholic beverages happened to have caught your eye:3
Average alcohol consumption (= beer + beverages, alcoholic + wine + beverages, fermented) = 70 kcal/cap/day = 3% total calories from plant sources. Alcohol consumption is much higher in some countries, such as Czech Republic: 282 kcal/cap/day, or 11.9% of total calories from plant foods.
Here’s the top 10 countries in providing calories from alcohol: Luxembourg, Ireland, Estonia, Czech Republic, Portugal, Austria, Germany, Lithuania, Bosnia and Herzegovina, Hungary. No surprises there.