2006年VOA标准英语-Kenyan Coast Gets Shot of Vitamin A With Uncomm（在线收听）

By Cathy Majtenyi
Nairobi
31 May 2006

 
Members of a community group in Kwale District on Kenya's coast show off some of the many local dishes that can be made with the beta-carotene-rich sweet potato
  
The orange-fleshed sweet potato is rich in beta-carotene and helps to eliminate Vitamin A deficiencies in children and adults, a major health concern in Africa.  While widely available in the West, this type of potato is not as common in Africa.  During the past year, researchers from Kenya and other countries have introduced a new, bio-fortified type of orange-fleshed sweet potato as a way of reducing Vitamin-A deficiencies.

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It is orange-fleshed sweet potato day at Lukore Primary School in the Shimba Hills of Kenya's coastal district of Kwale.

A visiting delegation of researchers, government officials and journalists is being treated to a variety of entertainment, all celebrating the virtues of the humble orange-fleshed sweet potato, which is among the highest natural sources of beta-carotene, a precursor to Vitamin A.

Jackson Nzivo Mwaniki, a teacher at Lukore Primary School, stands in front of a plot where he and students grow sweet potatoes   
  
In the school's compound is a small plot with rows and rows of orange-fleshed sweet potato plants.  Teacher Jackson Nzivo Mwaniki explains that he and the students plant orange sweet potatoes and distribute the vines to parents and other homesteads in the area.

Mwaniki says that his school was chosen last year mainly because of the school uniform that the students wear, and that local residents are happy with the orange sweet potato.

"The shorts and skirts are green, while the shirts are orange," he said.  "That is why it [the school] was given first priority.  When they chose us, they saw even the area itself, it is a potato-growing area.  When it was introduced to this area, they welcomed it very highly.  The children were very happy about it, and they even started planting [the sweet potato vines] in their homes."

Lukore Primary School is one of several demonstration sites that researchers have chosen in the district to educate residents about the nutritional value of the orange-fleshed sweet potato and encourage them to include the food in their diets.

According to the World Health Organization, children who suffer from vitamin-A deficiency suffer a dramatically increased risk of death and illness as a consequence.  In communities where the deficiency exists, improving vitamin-A status can, on average, reduce young child mortality by 23 percent and measles mortality by 50 percent.

Students at Lukore Primary School in Kwale perform dances, skits, poems, and even rap songs to pay homage to the sweet potato   
  
About 45 schools in the Kwale district grow and distribute the vines to households.  Roughly 40 percent of households in the district grow the orange-fleshed sweet potato.

Sammy Agili is a sweet potato breeder with the Nairobi office of the International Potato Center.  He says that last year his center and the Kenya Agricultural Research Institute introduced eight varieties of orange-fleshed sweet potatoes into Kwale District.

Up until then, people grew and ate predominantly white-fleshed sweet potatoes.

Agili explains that scientists are able to breed into the sweet potato varieties different levels of beta-carotene, sugar, and what is known as dry matter content (DM), which determines how moist or dry the sweet potato is.

"Consumers have different likes," he said.  "For example, the children would like those varieties that are low DM and high sugar content.  Now when you look at the mothers, their preference is quite different from men also.  Men would like those varieties that have high DM, but slightly low sugar content.  So we had a range of varieties which we introduced to them to select."

Agili says Kwale District has one of the highest malnutrition and Vitamin-A deficiency rates in Kenya, and that by introducing the different varieties of the orange-fleshed sweet potato, scientists are hoping to improve the area's nutritional situation.

 
One of several posters at Lukore Primary School that pays homage to the sweet potato 
  
Young children and pregnant and lactating women are most affected by Vitamin-A deficiency, which weakens the immune system and increases the chances of getting measles, malaria, diarrhea and eye conditions.  About 70 percent of pre-school children in Kenya are believed to be Vitamin-A deficient, one of the highest rates in Sub-Saharan Africa.

Scientists are able to breed desirable nutritious characteristics into the orange-fleshed sweet potato through a process called "bio-fortification". 

Bonnie McClafferty is communications coordinator for Harvest Plus, an U.S.-based international research program that aims to decrease malnutrition by increasing the levels of vitamins and minerals in crops.

McClafferty explains that most poor people cannot afford to purchase a large variety of foods that may contain different vitamins and minerals, nor buy vitamin supplements, nor purchase food that is commercially fortified such as iodized salt.

"The concept of bio-fortification is that you use the powers of modern agricultural plant breeding to breed nutrition directly into the staple foods that poor people eat," she said.  "The reason why this is important is that the predominant food of the undernourished are staple foods, up to 70 percent of the diet consists of either wheat or maize or cassava or beans, yet there is not a lot of micronutrients in those staple foods."

The International Potato Center's Agili says researchers will need to do follow-up studies in a year or two to see the impact of the orange-fleshed sweet potato on Kwale District's nutritional situation.