EATING IMPROPERLY PROCESSED CASSAVA USED TO MAKE FUFU, GARI OR KONKONTE CAN CAUSE CYANIDE POISONING AND KONZO, AN IRREVERSIBLE NEUROLOGICAL DISEASE THAT CAUSES PARALYSIS

By Dr. (ND) Francis Appiah

Naturopathic Doctor | Public Health Advocate

Kofiappiah803@gmail.com

 

 

WHAT IF THE CASSAVA ON YOUR PLATE COULD RELEASE CYANIDE?

What if one of Ghana's most familiar staple foods could, under the wrong processing conditions, release a poisonous substance into the body?

For millions of people, cassava is simply food. It is affordable, widely cultivated and deeply woven into everyday life. In Ghana, we eat cassava as fufu, gari, konkonte, akyɛkɛ, agbelima, agbelikaklo, yakeyake, boiled cassava, roasted cassava and other traditional foods.

But there is something about cassava that every cassava-eating household should understand.

Cassava naturally contains compounds called cyanogenic glycosides. The most important are linamarin and lotaustralin. When these compounds are broken down, they can release hydrogen cyanide, a poisonous substance.

This does not mean that cassava is automatically poisonous. It means that cassava must be properly processed before it is eaten.

Proper processing can greatly reduce cyanogenic compounds and make cassava safe for consumption. However, when cassava with high cyanogenic potential is inadequately processed, significant cyanide exposure can occur. The World Health Organization recognises improperly prepared cassava as a potential source of acute cyanide poisoning.

There is also a more serious neurological concern.

In parts of sub-Saharan Africa, prolonged dietary reliance on inadequately processed, cyanogenic cassava has been consistently associated with konzo, a neurological disease characterised by sudden-onset, symmetrical spastic weakness and paralysis that can become permanent and irreversible.

So this is not simply a story about a poisonous plant.

It is a story about how a familiar food is processed before it reaches the plate.

 

CASSAVA IS MORE THAN FUFU, GARI AND KONKONTE

When many people hear the word cassava, they immediately think of fufu, gari and konkonte. But cassava appears on Ghanaian plates in many other forms.

In Ghana, cassava is also used to prepare agbelima, akyɛkɛ, agbelikaklo and yakeyake. It is processed into flour and dried chips and can also be eaten boiled or roasted. Cassava is also used to produce a wide range of fermented and dried foods.

Akyɛkɛ is particularly worth mentioning because it is a familiar cassava-based food in Ghana and is commonly eaten with stew and other accompaniments.

Beyond Ghana, cassava is processed into products such as tapioca, attiéké, chikwangue, cassava flour, cassava bread and various other fermented or dried foods.

Cassava is therefore not one food with one method of preparation. It is a crop that can become many different foods depending on how it is processed.

This matters because the safety question should not simply be:

"What cassava food am I eating?"

The more important question is:

"How was the cassava processed before I ate it?"

Different cassava varieties contain different concentrations of cyanogenic glycosides. Some varieties have relatively low cyanogenic potential, while others, particularly bitter varieties, can contain much higher levels and require appropriate processing before consumption.

The concern is cassava that contains significant cyanogenic compounds and has not been adequately processed to reduce them.

 

THE HIDDEN CYANIDE IN CASSAVA

The word cyanide can sound frightening because cyanide is a powerful poison. To understand why cassava can become a source of cyanide exposure, however, we first need to understand what is naturally present in the plant.

Cassava contains cyanogenic glycosides, particularly linamarin and lotaustralin. When cassava tissues are damaged through cutting, grating, crushing or pounding, these compounds can come into contact with enzymes in the plant and contribute to the release of hydrogen cyanide.

In simple terms, cassava contains natural compounds that can generate cyanide, and proper processing helps remove or reduce them before the food is eaten.

That is why cassava processing is not simply a way of changing the taste, texture or appearance of the root. It is also an important food-safety process.

Cyanide is dangerous because it interferes with the body's ability to use oxygen for cellular energy production. At sufficiently high exposure levels, this can cause severe toxicity affecting vital organs.

Acute cyanide intoxication can cause dizziness, headache, confusion, nausea, vomiting, abdominal pain, diarrhoea, rapid breathing, weakness and seizures. Severe poisoning can progress to loss of consciousness, coma and death.

The amount of cyanide exposure can vary according to the cassava variety, growing conditions and processing method. Therefore, the presence of cyanogenic glycosides in cassava does not mean that every cassava meal contains a dangerous amount of cyanide.

The key food-safety principle is simple:

"Cassava must be properly processed before consumption."

 

WHEN CASSAVA PROCESSING GOES WRONG

The traditional processing of cassava serves an important purpose. It helps reduce cyanogenic compounds and makes the root safer for consumption.

Depending on the cassava product, processing may involve peeling, grating, crushing, soaking, fermentation, pressing, washing, drying, boiling, roasting or other heating methods. Different products require different combinations of these steps.

Consider gari.

Cassava roots used for gari are peeled, grated and fermented before the pulp is pressed, sieved and subsequently fried or roasted. These stages do more than transform fresh cassava into the familiar granular food sold throughout Ghana. They also contribute to reducing cyanogenic compounds.

Fermentation, pressing, drying and heating can all contribute to reducing cyanogenic compounds, although their effectiveness depends on the cassava variety and the actual processing conditions.

This is where shortcuts can become dangerous.

If important processing stages are shortened or skipped, particularly when high-cyanogenic cassava is being used, excessive cyanogenic compounds may remain in the finished food.

The World Health Organization has noted that acute cyanide toxicity can result from inadequately processed cassava and that high-cyanogenic cassava combined with insufficient processing is particularly concerning, especially in situations of food shortage.

This also means that saying "it was cooked" is not always enough to establish that cassava has been adequately processed.

Different cassava foods require different processing methods. For some products, soaking or fermentation is an important part of the process. For others, drying, pressing or heating plays a major role.

This is why traditional knowledge surrounding cassava preparation should not be dismissed as unnecessary. Those processing steps exist for a reason.

When cassava becomes a major part of the diet, repeated consumption of inadequately processed roots can become a much more serious public-health concern.

 

CYANIDE POISONING: WHEN A STAPLE FOOD BECOMES DANGEROUS

When a person consumes enough cyanogenic compounds from inadequately processed cassava to release a toxic amount of cyanide, acute cyanide poisoning can occur.

The illness can develop rapidly.

A person may experience dizziness, headache, confusion, nausea, vomiting, stomach pain, diarrhoea, rapid breathing, weakness, difficulty breathing or seizures. Severe poisoning can cause loss of consciousness, coma and death.

This is much more serious than an ordinary stomach upset.

Cyanide can interfere with cellular energy production, preventing cells from using oxygen normally. When exposure is severe, the brain, heart and other vital organs can be affected.

The severity depends on the amount of cyanide exposure and other factors that influence how the body handles the toxin.

If several people become suddenly ill after eating the same cassava-based food, particularly if they develop severe weakness, confusion, breathing difficulty, seizures, collapse or loss of consciousness, a serious foodborne poisoning event should be considered and urgent medical attention should be sought.

Documented outbreaks and poisoning events have demonstrated that inadequately processed high-cyanogenic cassava can produce serious cyanide exposure. WHO identifies improperly prepared cassava as an important potential source of acute cyanide intoxication.

No one should wait at home for severe symptoms such as seizures, difficulty breathing, collapse or loss of consciousness to disappear.

These are medical emergencies.

But acute cyanide poisoning is not the only neurological concern associated with cassava cyanogen exposure.

There is another disease that has been documented in cassava-dependent populations in parts of sub-Saharan Africa.

It is called konzo.

 

KONZO: THE NEUROLOGICAL DISEASE THAT CAN CAUSE PERMANENT PARALYSIS

Konzo is a distinct neurological disease that has been documented mainly in parts of sub-Saharan Africa.

Its most characteristic feature is sudden-onset, symmetrical spastic weakness of the legs, known as spastic paraparesis. In more severe cases, the arms can also become affected. The neurological impairment is typically permanent and non-progressive, although the severity and functional impact vary between affected people.

This can have devastating consequences.

A person may develop serious difficulty walking and may be left with lifelong physical disability.

Konzo has been reported particularly among children and women of childbearing age in affected populations. Outbreaks have been documented in several sub-Saharan African countries, including the Democratic Republic of the Congo, Mozambique, Tanzania, Central African Republic, Angola, Cameroon and Zambia.

The disease has repeatedly been associated with chronic dietary reliance on inadequately processed cyanogenic cassava. Research has also identified high dietary cyanogen exposure, food insecurity and inadequate protein or other nutritional factors among the wider circumstances associated with outbreaks.

However, scientific accuracy is essential.

It would be wrong to tell people that eating one plate of fufu, gari, konkonte or akyɛkɛ automatically causes konzo.

That is not what the evidence shows.

Konzo is a complex neurological disease, and its exact biological mechanism remains incompletely understood. The available evidence consistently links konzo outbreaks with chronic consumption of inadequately processed cyanogenic cassava, but nutritional deficiencies and other factors may also contribute. WHO specifically notes that interpretation of the association is complicated by underlying protein and nutrient deficiencies in affected populations.

This distinction is important because it prevents unnecessary fear while preserving the real public-health warning.

The evidence shows a consistent association between konzo and chronic consumption of inadequately processed cyanogenic cassava, particularly in settings where people depend heavily on cassava and are nutritionally vulnerable.

Konzo can result in permanent neurological disability, and there is currently no established treatment that reliably reverses the neurological impairment once it has become established.

That makes prevention extremely important.

 

WHO IS MOST AT RISK AND HOW CAN CASSAVA-RELATED ILLNESS BE PREVENTED?

The risk is not the same in every cassava-eating population.

Concern is greatest when several factors come together: cassava with high cyanogenic potential, inadequate processing, frequent or heavy consumption and dependence on cassava as a major source of dietary energy.

Risk can become particularly serious during food shortages, droughts or other difficult conditions when households may have less water available for processing or may shorten traditional processing methods to obtain food more quickly.

This pattern has been observed during konzo outbreaks.

In one documented outbreak in drought-affected Tanzania, food shortages led to heavy reliance on bitter cassava and shortened processing, resulting in high cyanide exposure among affected people.

Nutrition also matters.

Cassava is primarily an energy-rich starchy food and does not provide a complete source of dietary protein. In populations heavily dependent on cassava, inadequate intake of protein and other nutrients can add to nutritional vulnerability. Research on konzo has repeatedly identified nutritional factors as part of the wider risk picture.

Prevention therefore begins with proper cassava processing.

Cassava should be processed according to the particular food being prepared. Appropriate processing may include peeling, grating or crushing, soaking, fermentation, pressing, drying and adequate heating. The objective is to reduce cyanogenic compounds sufficiently before the food is consumed.

Food processors should avoid shortening essential processing stages simply to save time.

Households should also avoid consuming cassava products that have not undergone the processing normally required for that particular food.

Dietary diversity is another important part of reducing nutritional vulnerability.

Cassava can be an important staple, but it should not be the only major source of food where other nutritious foods are available. Including appropriate sources of protein, vegetables, fruits and other nutrient-rich foods can help improve the overall nutritional quality of the diet.

Food hygiene also matters.

Reducing cyanogenic compounds is not the only food-safety concern. Poor drying, storage and handling can introduce other hazards, including microbial contamination.

The key message is straightforward:

Do not fear cassava.

Process it properly.

And if someone develops severe weakness, confusion, difficulty breathing, seizures, collapse or loss of consciousness after eating cassava or a cassava-based meal, urgent medical assessment is required.

 

THE MESSAGE EVERY CASSAVA-EATING HOUSEHOLD SHOULD REMEMBER

Cassava has fed generations of Ghanaians.

It remains an important crop for food, livelihoods and food security, and it appears in some of the country's most familiar meals.

The purpose of understanding cassava toxicity is therefore not to frighten people away from fufu, gari, konkonte, akyɛkɛ or other cassava foods.

The message is much simpler:

Respect the processing.

Cassava naturally contains cyanogenic glycosides. When cassava containing significant levels of these compounds is inadequately processed, cyanide exposure can become dangerous and can cause acute poisoning.

Long-term consumption of inadequately processed cyanogenic cassava has also been consistently associated with konzo, a neurological disease characterised by symmetrical spastic paralysis that can be permanent and irreversible.

But this does not mean that every cassava meal is dangerous.

It does not mean that everyone who eats fufu, gari, konkonte or akyɛkɛ will develop konzo.

And it does not mean that cassava should be removed from the Ghanaian diet.

It means that the way cassava is processed matters.

So the next time you sit down to eat fufu, gari, konkonte, akyɛkɛ, agbelima, agbelikaklo, yakeyake, boiled cassava, roasted cassava, cassava flour or another cassava product, remember that food safety begins long before the food reaches your plate.

The important question is not simply:

"Is this cassava?"

The more important question is:

"Was this cassava properly processed?"

Cassava does not need to be feared.

It needs to be respected.

Because sometimes, the difference between a familiar staple food and a serious health hazard is not the food itself.

It is what happens to the food before it reaches your plate.