Reducing anaemia in the developing world: why researchers are adding nutrients to salt and tea

May 21, 2024

Billions worldwide are affected by a lack of essential vitamins and minerals in their diets, but a team at Canada’s top university has developed a groundbreaking solution – fortifying staple foods with iron and other nutrients

Portrait of Folake Oyewole
PhD candidate Folake Oyewole has fortified zobo – a drink popular in sub-Saharan Africa – with iron in order to tackle anaemia in the region. Photograph: University of Toronto

This article was originally published on as part of the University of Toronto and Guardian Labs What’s Possible? Ask Toronto campaign.

It is estimated that more than 2 billion people worldwide have a micronutrient deficiency. These vitamins and minerals are the building blocks of good health and the impact of not consuming enough can be significant. An Insufficient level of vitamin A, for example, is the leading cause of preventable blindness in children; zinc is good for the immune system; and iron deficiency is the most common cause of anaemia, which can cause poor cognitive and motor development in childhood and low levels of productivity among adults.

The situation is so grave in many developing countries that member states of the World Health Assembly recently adopted a resolution to accelerate efforts to prevent micronutrient deficiencies through food fortification. At the University of Toronto, Prof Levente Diosady and his team at his Food Engineering Laboratory have spent more than two decades working on a way to fortify salt with iron and iodine. Early pilots in India have proven successful and other more recent projects in Africa are also showing promising results.

Of the 3.5 million schoolchildren that took part in a 2004 study in Tamil Nadu, 85% were found to be anaemic. Almost a third had been cured after eight months of eating a hot school lunch cooked with double-fortified salt. Since then, the state government in Uttar Pradesh has spent $40m distributing the salt to 24 million low-income citizens, and there are plans for other states to run their own trials.

“As of today, there are around 50 to 60 million people in India who are receiving double fortified salt, which is pretty good,” Diosady says. “When we first tested in Tamil Nadu, it was unexpectedly successful. The cost per person is also relatively trivial at around 25c per person, per year.”

Portrait of Prof Levente Diosady and his team in the lab
Prof Levente Diosady and his team are working on ways to embed key essential nutrients like iron, folic acid and vitamin B12 into staple foods such as salt and tea. Photograph: Mark Balson

Diosady’s interest in salt dates back to the early 1990s, when he was approached by a senior adviser to Unicef. Venkatesh Mannar came from a salt producing family and had been working with the children’s charity on a successful salt iodisation programme that led to about 89% of people worldwide using salt fortified with iodine. Mannar wanted to see if the same could be achieved with iron. It was a simple vision but not one that was easily achieved. When Diosady first combined iron and iodine, the two reacted with each other and the iodine – along with its benefits – evaporated. “We had to find a way to separate the two, so they couldn’t react,” he says. The solution was microencapsulation – essentially coating the iron particles with a barrier of vegetable fat to prevent a reaction with the iodine.

Once that challenge was solved, the team experimented with adding more nutrients to salt, such as folic acid, zinc and vitamin B12. Each addition presented unique obstacles. “You always hope it’ll be simple but there are stability issues with folic acid, and there’s incompatibility between folic acid and B12,” he says. “So it doesn’t happen immediately. But we now have six things we can put into salt in any combination.” In Ethiopia, a trial using salt fortified with iodine and folic acid already shows promise for reducing the incidence of congenital disabilities. Other pilots are happening in Tanzania.

Diosady has also won recognition for his work adding iron to tea. In 2013, he was awarded a major grant from Saving Lives at Birth: A Grand Challenge for Development, backed by agencies in Canada, Norway, the US and the UK, and the Bill & Melinda Gates Foundation. The work of the Food Engineering Laboratory has also received funding from engineering alumni Dr and Mrs Heuckroth, who would like to see women’s health improved in Tanzania – and worldwide.

Like salt, tea attracted Diosady because of its universal appeal, particularly in developing countries. “We got into tea because everyone in India drinks two cups a day – children, adults, rich and poor,” he says. “We’ve made good progress with salt because even the poorest farmer has to buy it. The same goes for tea. We can reach just about everybody.”

It hasn’t all been plain sailing. Adding iron to tea makes it turn an unappealing blue, says Diosady, but the team has managed to solve that problem and has made good progress with iron-fortified black tea in terms of the taste, colour and texture. It’s trickier once you add milk but Diosady is confident they’ll find the solution. Once it’s robust enough for distribution, he hopes that an existing relationship with the consumer goods multinational Unilever will prove beneficial. “Assuming we get this right, we’ll have the perfect way of introducing it to the world. Unilever produces thousands and thousands of tonnes of tea every year.”

Four people sitting outdoors drinking tea
Tea is an ideal candidate for the team’s work due to its universal appeal. Photograph: Mayur Kakade/Getty Images

Chemical engineering PhD candidate Folake Oyewole is one of 15 researchers working in Diosady’s lab. Her thesis project, which is sponsored by the Schlumberger Foundation, was inspired by zobo, a hibiscus-based drink from Nigeria, which she hopes to fortify with iron. In Nigeria alone, the World Health Organization estimates 55% of women of reproductive age have anaemia. “We started with iron because it’s the most common nutritional deficiency globally,” she says.

“However, my work is targeted more at tackling the issue of iron deficiency in sub-Saharan Africa, as western and central sub-Saharan Africa are two of the top three regions globally that are most affected by anaemia.”

According to Oyewole, anaemia is so prevalent there because of the dependence of the rural poor on a plant-based diet, due to the cost of meat. Many plants also contain polyphenols, compounds that have their own benefits, but come with the downside of limiting the absorption of iron in the body.

In response, her approach was to improve both iron intake and uptake in the region by fortifying a local staple, in this case zobo, the principal ingredient of which is hibiscus sabdariffa. “Fortifying a beverage extracted from a plant that is indigenous to the region has the advantage of being a lower barrier to entry in challenges such as accessibility, affordability and acceptability,” she says.

When Oyewole started analysing the properties of hibiscus sabdariffa, this relationship between the iron and polyphenols within the plant was one of the biggest hurdles. Hibiscus is a relatively iron-rich food, but the prevalence of polyphenols cancels it out. A lot of iron is also lost during the process of making the drink itself.

After much experimentation, she has been able to fortify the drink with an iron salt, and introduce an agent that helps the body absorb iron in spite of the polyphenols. She hopes others can use the approach in the future. “This is about more than just one drink. It’s a solution that can be applied across different foods that are rich in polyphenols. We can prevent that interaction to make iron in food more accessible to consumers.”

Starting his career in chemical engineering in the 1970s, Diosady says he had not set out expecting to work in the developing world, but he has found micronutrients compelling because of the idea that something so little can do so much, improving people’s health, economic and social development. And he feels lucky to have had the experience to see the impact his work has had on the ground – in India, Bangladesh, the Philippines, Indonesia and parts of Africa.

He believes engineers can play a significant role in solving global challenges and creating social change. “Whether it’s food, water, urban technologies or housing – all of these areas relate to engineering,” he says. “And while it’s exciting to see what you can do in the lab, actually getting to see it in the field is the ultimate.”

Find out how University of Toronto Engineering has driven change and innovation for more than 150 years at

By Emma Sheppard