Dangers Of Eating Raw Cassava

[Stephani Kapnick]

KimChin is a registered dietitian and foodie at heart. She works in corporate wellness and provides nutrition counseling in the San Francisco Bay Area. Her passion is connecting with people through food and helping them obtain a balanced life.

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Second, resistant starch has been studied for its ability to improve metabolic health and reduce the risk of obesity and type 2 diabetes. These benefits are likely related to improved blood sugar management, increased feelings of fullness, and reduced appetite (8, 9, 10, 11).

Cassava is a good source of resistant starch, which supports gut health and blood sugar management. It also contains vitamin C, a key micronutrient that can enhance immune function and collagen production.

Regularly consuming cyanogenic glycosides or eating them in high amounts increases the risk of cyanide poisoning. Cyanide poisoning is associated with impaired thyroid and nerve function, paralysis, organ damage, and even death (21, 22).

Processing cassava by peeling, chopping, and cooking it significantly reduces its content of vitamins, minerals, fiber, and resistant starch. Still, cooking the root before consumption is necessary to avoid side effects (24).

Some older studies have found that boiling cassava root retains more nutrients, compared with other cooking methods like roasting or frying. The exception is vitamin C, which is sensitive to heat and easily leaches into water (24).

Cassava is relatively high in calories and must be prepared before eating to avoid adverse health effects. Some highly processed varieties like tapioca are low in important micronutrients but high in calories.

Cassava, an edible tuberous root often made into flour, contains cyanogenic glycosides, which can result in fatal cyanide poisoning if not properly detoxified by soaking, drying, and scraping before being consumed. Acute cassava-associated cyanide poisoning outbreaks are rarely described.

In September 2017, an outbreak of suspected cyanide poisoning, involving 98 cases with two deaths, occurred in western Uganda. Epidemiologic and laboratory investigation identified consumption of a cassava flour dish made from wild cultivars of cassava with high cyanogenic content as the cause of the outbreak.

Informed by findings of this investigation, police in Kasese District confiscated all sacks of cassava flour from retailers where affected families had purchased the product. Health education was conducted in the communities about cyanide poisoning from cassava and the need to adequately process cassava to reduce the cyanide content.

Cassava crops are resistant to drought, pests, and diseases, making cassava invaluable for food security, especially in areas plagued by food shortages (7). Approximately 600 million tropical residents, half of whom live in Africa, rely on cassava as their main food source (8). Acute cyanide poisoning, often with fatal consequences, can occur after eating a large amount of cassava, especially in communities dependent on a monotonous cassava diet (9). Recurrent exposure to nonlethal concentrations through a monotonous cassava-based diet leads to long-term effects, including paralytic diseases such as tropical ataxic neuropathy and konzo, a neurologic disease characterized by sudden onset of irreversible, nonprogressive spastic paralysis (2). In sub-Saharan Africa, particularly Uganda, Tanzania, and the Democratic Republic of the Congo, thousands of persons might have experienced cyanide poisoning from cassava (7,8), but the full extent of the problem remains unknown because reliable data are lacking.

Although wild cassava cultivars have greater yield, higher resistance to pests, and longer storability in the soil than do sweet cultivars, they are bitter, and hence, have a lower market value. In addition, the cyanogenic content of wild cultivars is as high as 2,000 ppm of dry weight (1), 200 times the safe level (

A rapid, semiquantitative, colorimetric test that is free to workers in developing countries can be used by relatively untrained persons to quickly determine the cyanogenic potential of cassava flour (10). Wholesalers and government food inspectors can use this method to routinely measure cyanogenic content of commercial cassava flour. Farmers and consumers in areas that depend upon cassava should be warned about cyanide poisoning caused by eating improperly processed or wild-cultivar cassava, and instructed to strictly adhere to the established processing methods to degrade cyanogenic glycosides.

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If you have heard of boba or bubble tea, then you may be familiar with tapioca. It is also popular in recipes like tapioca pudding. Other foods that contain tapioca include cassava chips and some gluten-free baked goods made with tapioca flour.

While boba milk tea is not a very nutritious drink, the lack of nutrients is not the only disadvantage of eating tapioca. Since it is a concentrated source of starch, there is some controversy surrounding the regular consumption of foods containing tapioca and cassava.

Though it is low in calories and nutrients, there are health benefits of tapioca. However, they are often associated with cassava benefits. Since cassava is a whole food, cassava benefits may outweigh those of tapioca.

One advantage of tapioca is that is is naturally gluten-free. Mayo Clinic recommends tapioca flour in place of wheat flour. This is a convenient alternative for people with Celiac disease, gluten intolerance or other dietary restrictions that exclude gluten. They state it can be used to thicken foods like gravy, soup, sauces and stir-fries.

Tapioca-based foods may also be beneficial for people with digestive issues. According to Cleveland Clinic, tapioca is a low-FODMAP alternative to legumes. This is especially helpful for people with irritable bowel syndrome.

Since resistant starch is extracted from cassava to make tapioca, it is an excellent source of resistant starch. This has further gut health benefits. According to a June 2017 study published in Cellular Physiology and Biochemistry, resistant starch helps regulate the gut microbiota. One of the ways that it helps is by encouraging beneficial bacteria to flourish.

In impoverished regions of sub-Saharan Africa, some villagers need sticks to walk because of neurological damage from the very food that keeps them from starvation - cassava. Toxins in the tuber can cause sudden and irreversible paralysis and, researchers have learned, also undermine cognitive ability even without overt physical symptoms.

This problem has widespread public health implications because cassava, also known as yucca, manioc and tapioca, is a dietary staple for more than 600 million people globally. The cyanide it contains as a chemical defense against herbivores and insects is normally removed by processing through soaking, peeling and drying, but in stressed conditions such as drought, famine and armed conflict, people may eat cassava only partially processed and risk neurological damage.

One country with the highest prevalence of this paralysis is the Democratic Republic of Congo, where the condition is known as konzo and can affect up to 5 percent of people in some villages. A research team decided to investigate the extent of neurological damage from cassava as a first step toward finding interventions to reduce it. Congolese-born U.S. researcher Dr. Desire Tshala-Katumbay of both Oregon Health and Science University and the University of Kinshasa and Dr. Michael Boivin of Michigan State University obtained support from Fogarty's brain disorders program, with additional funding from the NIH's National Institute of Environmental Health Sciences (NIEHS). With Dr. Jean-Jacques Meyembe of the Congo National Institute of Biomedical Research, they conducted a study in the Kahemba district.

The team enrolled preteens from villages with and without konzo and gave them standard cognitive and motor proficiency tests. All children in konzo-harboring villages - even without physical symptoms - showed poorer memory than children from konzo-free villages. Those in konzo villages additionally lagged in visual-spatial aptitude and in mental processing. These results suggest that even without physical manifestations from cassava toxins, some children suffer damage and the overall burden of cassava-related brain impact may have been underestimated. The team is also working on a biomarker to predict deficits in konzo patients and is investigating whether genetic susceptibility or dietary patterns can explain the spate of cases within families.

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