Posts Tagged: Africa
When it comes to nursing moms and their babies, an elegant web of cause and effect connects climate, breast milk, gut microbes and infant health.
That web was clearly illustrated by a recently published study involving 33 women and their babies in the West African nation of The Gambia. The research team, including scientists from UC Davis and UC Agriculture and Natural Resources, found that complex breast milk sugars called oligosaccharides helped protect nursing babies from illness and also influenced the mixture of microbes in the infants' guts.
The researchers also showed that changes in food availability from season to season could affect the composition of the women's breast milk and the protective quality of the babies' gut microbiota. And those changes, in turn, impacted the health and growth of the breastfed infants.
Composition of breast-milk sugars and infant health
Oligosaccharides occur abundantly as more than 200 different chemical structures in human breast milk. It's been known for some time that these complex sugars contribute to infant health by supporting the growth of beneficial bacteria in the baby's gut. And these gut bacteria have been shown to play a key role in fending off infectious illnesses.
But little has been known about how changes in the composition of the breast milk sugars might affect the health and growth of infants, especially those living in areas where infection rates are high.
To explore that relationship, the researchers monitored the composition of the oligosaccharides in the mothers' milk and examined the infants' gut microbiota at 4 weeks, 16 weeks and 20 weeks after the babies were born. Then they analyzed the data, looking for possible relationships to the health and growth of the babies and the status of their gut microbes.
They found that two of the oligosaccharides, lacto-N-fucopentaose and 3′-sialyllactose, had a direct relationship to the babies' health and growth. High levels of the former were associated with a decrease in infant illness and with improved growth, measured as height for age, while the latter proved to be a good indicator of infant growth, measured by weight per age.
“Our findings provide evidence that specific human milk oligosaccharides can alter the composition of breast milk, making it more protective against infection and allowing the infant to invest energy in growth rather than fending off disease,” said the study's corresponding author Angela Zivkovic, an assistant professor of nutrition at UC Davis.
Influence of wet and dry seasons
The researchers also were curious how seasonal shifts in food availability, which significantly impact the mothers' diets, might be reflected in breast milk composition and infant health.
The Gambia has two distinct seasons, the wet season from July to October and the dry season from November to June.
The wet season is also known as the “hungry” season because it is the time of year when food supplies tend to be depleted, infection rates rise and the farming workload is highest. In contrast, the dry, or “harvest,” season is characterized by plentiful food supplies as well as significantly higher energy stores and less illness among the local people.
The researchers found that mothers who were nursing during the wet or “hungry” season produced significantly less oligosaccharide in their milk than did those nursing during the dry season.
In examining the makeup of the babies' gut microbiota, the researchers noted that most of the bacteria belonged to the Bifidobacteria genus. They also discovered that higher levels of Dialister and Prevotella bacteria were accompanied by lower levels of infection.
In addition, higher levels of Bacteroides bacteria were present in the infants' guts that had abnormal “calprotectin” – a biomarker associated with intestinal infections.
“We are very interested in which specific dietary factors influence the oligosaccharide composition of mother's milk,” Zivkovic said. “If we can find the mechanisms that change the composition of breast milk sugars, we may have a new approach for modifying the infant microbiota and ultimately influencing the health and vigor of the nursing baby.”
The study by Zivkovic and colleagues appears online in the journal Scientific Reports. The research is part of a long-running, cross-disciplinary project at UC Davis examining milk and its role in nutrition.
Funding for the study was provided by the National Institutes of Health, UK Medical Research Council, Bill and Melinda Gates Foundation, Alfred P. Sloan Foundation, and Peter J. Shields Endowed Chair in Dairy Food Science at UC Davis.
The idea that weeds can be edible pops up periodically, with articles suggesting one person's weeds are another person's salad bar, highlighting chefs who “have a way with weeds,” discussing ways medieval gardeners encouraged weeds, and even suggesting ways to eat away at invasive species. But is this something we should take seriously?
“We call these plants weeds because of the way we interact with them. They're in our gardens, they're in our lawns, and they're competing with plants that we prefer to eat,” said Lynn Sosnoskie, a weed scientist at UC Davis. “But a lot of the plants that are weeds here in the United States were brought here purposefully—to be eaten.”
Sosnoskie's doctoral thesis was on just such a plant, with the tasty name of “garlic mustard.” She has also worked at length on Palmer amaranth, a pernicious weed found in cotton fields that can be glyphosate-resistant. In response to one Georgia farmer asking in exasperation if he should just eat the plant taking over his fields, she did some preliminary research into eating Palmer amaranth.
“It's probably not feasible to eat our way out of a serious weed problem,” she said. “But I certainly feel like we can investigate them as other potential food sources.”
In fact, the Horticulture Innovation Lab at UC Davis has a project that is researching three “indigenous vegetables” in Africa, two of which — amaranth and black nightshade — are considered weeds in the United States. The vegetables can be nutritious and profitable options for small-scale farmers in Kenya, Tanzania, Zambia and elsewhere.
Though he holds a Ph.D. in weed science, Weller is now figuring out the best ways to cultivate amaranth and black nightshade — instead of to eliminate them. Before he started working with these plants, common assumptions held that they should be easy to grow because, well, they “grow like weeds.”
“But we found out that growing them is more intensive than we were initially led to believe — similar to growing any other vegetable,” Weller said. “They need water, they need fertilizer, and pests are a problem.”
Caveat emptor: Though weedy plants can indeed be a source of food, both scientists cautioned against thinking of weeds as a “free-for-all forage buffet.” Some plants may be toxic, and weeds in farm fields may have been sprayed recently. It is important to be knowledgeable of the plants and how they've been grown before trying to eat one.
What will be the new food frontier? An article in the Wall Street Journal with the headline “Next Stop for Food Fanatics: Africa” predicts adventurous American palates may soon be craving sub-Saharan cuisines.
Have you heard of these?
- Nakati (Solanum macrocarpon, S. aethiopicum) Also called African eggplant, some types of nakati are eaten for their leafy greens, while others are eaten for their fruit (which can look like a tomato or eggplant).
- Cowpea leaves (Vigna unguiculata) This plant produces black-eyed peas, but the greens of the plant can also be eaten as a vegetable.
- Bbuga (Amaranthus Gracecizans) You might know this plant by its common American name: pigweed.
- Doodo (Amaranthus Dubius) Like bbuga, this type of amaranth is eaten for its leaves in many parts of Africa. In North and South America, varieties of amaranth are usually used as a grain.
- Jjobyo (Gynandropsis Gynandra, Cleome gynandra) Also called spider plant.
Many of these indigenous vegetables are rich in micronutrients such as iron, vitamin A and vitamin B. When it comes to alleviating malnutrition in developing countries of eastern Africa, indigenous vegetables offer workable solutions because they are not only nutritious, but also familiar to the region’s eaters and farmers.
Recently U.S. researchers have been working with indigenous crops like these in east African countries — with funding and support from the Horticulture Collaborative Research Support Program (Horticulture CRSP), led by Beth Mitcham at UC Davis with funding from USAID. In Kenya, Tanzania and Zambia, Stephen Weller of Purdue University is leading a Horticulture CRSP research project on production practices, seed resources, postharvest handling, marketing and nutrition of varieties of amaranth, spider plant and African nightshade.
Take a look at this short video for a little more background:
Just as bok choy, an Asian vegetable, has become familiar to many American households, perhaps one day you’ll find nakati or another African leafy vegetable on your plate.
In the meantime, researchers with Horticulture CRSP are working to get more African leafy vegetables into the research agendas, fields, markets and plates of our counterparts in eastern Africa.
Read more abut Horticulture CRSP and its projects around the world at http://hortcrsp.ucdavis.edu.
UC Davis is addressing food security and economic development in Africa, Southeast Asia, Central America, and elsewhere, by coordinating an international horticulture program. The Horticulture Collaborative Research Support Program (Hort CRSP; pronounced "hort crisp") is one of 10 CRSP programs that focus on global food production and solving food and nutrition problems in developing countries. UC Davis leads the Hort CRSP, with funding support from the U.S. Agency for International Development (USAID).
Examples of projects conducted by researchers and educators throughout the world include:
- Inexpensive cold storage systems in rural, developing areas to prolong food longevity; see page 2
- Concentrated solar drying of fruits and vegetables in East Africa; see page 3
- Improving safety and quality of tomatoes in Nigeria; see page 3
- Smallholder flower production in Honduras for export markets; see page 3
The overarching goals of the Hort CRSP are to reduce poverty and improve nutrition and health of the rural poor, while improving the profitability and sustainability of horticulture in the developing world. Priorities in the Hort CRSP include gender equity, sustainable crop production, postharvest technology, food safety, market access, and financing. The program awards research funding in the U.S. and abroad to:
- Realize opportunities for horticultural development
- Improve food security
- Improve nutrition and human health
- Provide opportunities for income diversification
- Advance economic and social conditions of the rural poor, particularly women
In the three years since the program’s inception, several projects have been completed, and many are ongoing. The program’s website offers a plethora of information, along with newsletters that highlight individual projects.
The program also has a YouTube channel, with videos on Hort CRSP projects. Some of the videos are about projects that are especially important in developing countries, including:
- The TRELLIS project — bringing together graduate students and in-country development organizations; YouTube link
- Using cell phones to give real-time information to growers in rural areas of India; YouTube link
- Inexpensive cultivation practices for smallholder farmers; YouTube link
- Indigenous products increase incomes in Ghana; YouTube link
- Saving indigenous crop seeds in Southeast Asia for resource-poor farmers; YouTube link
The Africa Nutributter studies found that children preferred a sweet paste, but the scientists believe regional flavors may make the supplement more appealing. For Guatemala, they plan a cinnamon-flavored Nutributter; for Bangledesh, the paste will be flavored with cumin and cardamom.
UC Davis nutrition professor Kathryn Dewey, who leads the project, said it remains to be seen whether Nutributter will be adapted for American consumers.
“I personally think it is marketable,” she said.
Each four-teaspoon serving of Nutributter paste, which comes in a ketchup-packet-like pouch, contains 40 essential vitamins and minerals. Unlike most other nutrient supplements, the product also provides 120 calories of energy plus protein and essential fatty acids. Nutributter is not meant as a replacement for local foods or breast milk, but rather to be added to youngsters’ and pregnant mothers’ traditional diets.
"More than 3 million children die each year of malnutrition due not just to a lack of calories, but also to poor diet quality, particularly insufficient intake of micronutrients like zinc and iron, which are so critical to healthy growth and development," Dewey said.
The idea for the nutrition supplement came from the successful use of Plumpy'nut, a peanut-based food developed by French researchers for famine relief. Each Plumpy-nut packet has 500 calories and children can gain 1 to 2 pounds a week by eating it twice daily. Plumpy-nut is meant to temporarily serve as the sole food source in emergency situations.
The UC Davis Nutributter team heads the International Lipid-based Nutrient Supplements Project (iLiNS). Last year, the project won a $16 million Bill and Melinda Gates Foundation grant. A 2008 UC Davis news release announcing the Gates Foundation grant gives more details about Nutributter and its use in African nations. More information is also available on the iLiNS Web site.