The Absolute Importance of Eating Greens

David Kennedy, Director of Leaf for Life, reflects on the enormous – and largely neglected – food potential of green leaves

The December 17th issue of the usually staid Economist magazine had a short article on the diet in South Africa. It reports that, like most of the world, South Africans are getting fatter and less healthy. Two reliable surveys showed that over 60% of adults in that country are clinically overweight or obese and that the rate of fat accumulation is accelerating. Depressing enough, but what is most disturbing is that 40% of South Africans live on less than $2 US a day.

Many of the newly obese people in the developing countries still suffer from micronutrient deficiencies, especially iron deficiency anemia and vitamin A deficiency. Insufficient iron in the diet saps both mental and physical energy. Vitamin A deficiency weakens the immune system and makes us far more vulnerable to infectious diseases. Sometimes called ‘hidden hunger’ because the symptoms are not always visible, these micronutrient deficiencies affect nearly one-third of the world’s people.

This intersection of extreme poverty, micronutrient deficiencies, and clinical obesity is a scathing indictment of the globalised food system. Even in developing nations, industrially produced food is cheap, brilliantly marketed and full of fat and refined carbohydrates. The great variety of vitamins, minerals, antioxidants, fiber and other beneficial compounds found in naturally occurring foods have been largely removed to improve shelf life and market appeal. The human body doesn’t stand a chance.

Disarming this nightmarish global food system and replacing it with thousands of healthier local systems is surely a daunting task. Many folks, including the Campaign for Real Farming, have begun the critical work of building these new food systems. These new food systems need to be capable of providing all the people all the nutrients they need without diminishing the prospects for future generations to meet their food needs.

Green leafy vegetables will necessarily play a larger role in these food systems. They bring five important attributes to this effort:

1. High Nutrient Density ~ No other category of foods comes close to matching greens for providing so many essential nutrients with so few calories. For example, 100 grams (3 ½ ounces) of vine spinach has just 23 calories, but it can make a significant contribution to our daily requirement for protein, iron, calcium, magnesium, potassium, folate, vitamins A, B, C, E and K, and antioxidants. This makes greens ideal for combating obesity.

2. Low Cost Source of Missing Micronutrients ~ Green leafy vegetables could be the lowest cost food sources of both iron and vitamin A, the two most common and damaging micronutrient deficiencies. They can produce more iron and vitamin A in less space and in less time than any other crops. A study in Taiwan showed that Chinese cabbage produced 13 times more iron than grains in the same space over the same time. The same study showed that the Chinese cabbage was 11 times more cost-efficient than chicken as a source of dietary iron. 1 Some lesser known leaf crops, such as moringa (Moringa oleifera), wolfberry (Lycium barbarum), toon (Toona sinensis), and chaya (Cnidosculus acontifolius) are easy to grow and even richer sources of iron and vitamin A. This makes greens ideal for combating these common and crippling nutritional disorders.

3. Huge Variety ~ There are over 1000 species of plants with leaves that are edible to humans. Our diet and our agriculture have become extremely dependent on maize, rice, wheat, soy and a couple of other plants. Leaf crops could add much needed variety and adaptability to both what we eat and what we grow.

4. Well suited to local and small scale production ~ Leaf vegetables are ideally suited for farmers’ markets, roadside markets and community supported agriculture. Freshness is critical to their quality and there is no reason to ship them long distances. They can be grown almost anywhere including in city rooftops, allotments and vacant lots. With a bit of protection hardy leaf crops can be grown through all but the harshest winters.

5. Able to improve soil while producing food ~ Edible cover crops can be grown which simultaneously improve the fertility of the soil while providing nourishing food.  This is extremely important for low-income growers. They can’t afford commercial fertilizers nor can they afford to take their land out of production to rejuvenate its fertility.

Cowpeas, bell beans, and peas can fix nitrogen from the atmosphere, making it available for other food crops. Turnips, fodder radishes, and sugar beets have powerful tap roots that open up compacted soil allowing better drainage and root growth. Wheat and barley produce dense mats of roots and lush top growth that feed earthworms and beneficial soil microorganisms. This improves the water holding capacity of the soil and the bio-availability of nutrients that our food crops need. All of these plants, and many other cover crops, have edible and nutritious leaves. Growing systems that feed both the soil and the farmer can be developed fairly easily.

Forget about the sheet of pale lettuce that we use to keep our burgers from making the buns soggy. Forget about the tiny sprig of green parsley we use to decorate our whiter-than-white mashed potatoes.  It’s a new year and time to create food systems that can keep both us and our land healthy and happy for thousands of New Years. Green leaf crops are ready if you are.

For more information on how to realize the potential of leaf crops check out our website  You can also buy or download our new book, 21st Century Greens: Leaf Vegetables in Nutrition and Sustainable Agriculture, there.

David Kennedy


Leaf for Life

January 3, 2012

1 The integrated research approach of the Asian Vegetable Research and Development Center (AVRDC) to enhance micronutrient availability;
Mubarik Ali and Samson Tsou; Food and Nutrition Bulletin, vol. 21, no. 4 ©2000, The United Nations University

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