This presentation was created by a graduate student as part of a Trellis Fund project, led by Send a Cow Ethiopia.

This presentation was created by Lauren Howe in August 2018 as part of the Trellis Fund project "Sweet potato leaves for improved family nutrition," in partnership with the NGO Send a Cow Ethiopia. This project was carried out in the Wolaita Sodo area of Ethiopia. This presentation is an overview of the research conducted around the nutrition and culinary uses of sweet potato leaves around the world. Full references can be found in the slide deck PDF.

The presentation starts with an introduction from the speaker and a personal reflection around food consumption. It then goes into the basics of nutrition, including micronutrients and macronutrients, food-based dietary guidelines, nutritional needs (malnutrition and nutritional status), and demographics of who is most vulnerable to poor nutrition. It includes tips to help change food habits in a local community. The first 15 slides draw extensively on content from the New Extensionist Learning Kit (NELK) Module on Nutrition Sensitive Extension. The presentation then goes into more specifics around sweet potato leaves:

Why grow sweet potatoes?

• They grow well in many different climates and seasons, including hot, humid and even drought conditions
• The leaves grow even better than some introduced western vegetables, which can suffer from high moisture, tropical pests and diseases
• The leaves can grow quickly and can act as a mulch, covering the ground, protecting the soil, conserving moisture, preventing erosion and reducing the need to weed and requiring minimal labor
• The vines can also be preserved as silage or hay and fed to livestock as a nutritious animal feed
• With a yield much higher than many other green vegetables, farmers can sell both the leaves and roots to earn more income
• Sometimes, local sweet potato varieties have leaves that are more nutritious than exotic varieties.

Harvesting and handling the leaves

• Begin harvesting leaves 45-90 days after planting, 1-2 times per month until the roots are harvested
• Don’t harvest the leaves too frequently or you may reduce the root growth, or the leaves may be less nutritious
• If you are mainly growing sweet potatoes for their leaves, then don’t plant them too close. Try planting them on flat land with 30-40 cm spacing between plants and 40-50 cm spacing between rows
• The best way to harvest multiple vines is to cut 1-2 of the longest branches of each plant, leaving about 10 cms for the plant to regrow
• When harvesting, transporting or marketing the leaves, handle them carefully to reduce bruising, and store them in cool shady conditions
• Sell the leaves or use them as soon as possible

Sweet potato leaf nutrition: Macronutrients

• Carbohydrates, protein, and fiber
• Low in saturated fat and cholesterol
• Omega 3 fatty acids, which contribute to all tissues in the body functioning normally, including the heart, lungs, blood vessels, immune system, and hormone production

Sweet potato leaf nutrition: Micronutrients (vitamins and minerals)

• Vitamins: A, C, K, B1, B2, B3, B9
• Minerals: calcium, iron, magnesium, phosphorus, potassium
• Also contains zinc, manganese, copper
• Low in sodium
• The slides include bar graphs to compare nutrient levels of other common leafy greens including cabbage, kale, lettuce, spinach and Swiss chard

Disease prevention and defense

• High in antioxidants, which can help prevent or delay damage to cells in the body
• Consumption of the leaves can also help prevent some chronic diseases like inflammation, heart disease, hypertension, diabetes and some cancers

Cooking tips

• For the most nutrients, choose sweet potatoes with deep green leaves and dark flesh
• The whole tips of the sweet potato are edible, including the leaves, stems, and leaf stalks
• The leaves, however, are the most nutritious
• Use sweet potato leaves immediately for the best use and most nutrients. Otherwise, store the leaves properly (refrigeration or cool, dark place with stems in water)
• Fat is important for the absorption of vitamin A, so cook the leaves with some fat (e.g. small amounts of oil or butter) to help the body absorb vitamin A. The amount of fat required can vary (2.4 to 5 g/meal) for cooked vegetables. If you consume the leaves raw as a salad, eat them with a dressing that has some fat (e.g. oil)
• To make nutrients more available and to make the leaves taste better, cook the leaves with heat (e.g. lightly steam, blanching, stir fry, boil, etc.) for short periods
• Cut them up into smaller pieces
• Don’t cook the leaves for too long or some nutrients may be lost
• In general, the smaller the food particle size, the better so lightly cooked, pureed green leaves, or finely chopped cooked green leaves are better than raw, whole leaves
• Different preservation methods may be used such as solar drying, adding lemon, juicing, etc.

Consider substituting sweet potato leaves in any traditional recipe instead of another leafy green

Sweet potato leaves around the world

Can be found in dishes in the Philippines, Japan, South Pacific, Taiwan, Cameroon, Nigeria, Malawi, Ghana, Côte d'Ivoire, Burkina Faso and the United States