Cassava Flour: Ins and Outs for the Health Conscious

Cassava flour is gaining popularity among the gluten-free, but there are health concerns to consider, especially for pregnant women and children.

What is Cassava Flour?  Is Cassava Flour Safe?

Cassava Paleo in a nutshell

Key points.

Cassava flour is flour made from the ground roots of the cassava plant.  It is also sometimes called “Yucca flour.”  Yucca, as we know it in the Southwest is not the same plant that is used to make cassava flour.  Cassava is a major food in parts of Africa and in tropical regions.  It grows well in poor soil and difficult conditions that would kill other crops.  It seems to be growing in popularity (or at least marketing) among followers of the paleo diet, which excludes grains.  Diets high in cassava are problematic for several reasons. Consumption of cassava releases cyanide.  Cyanide can cause a lot of oxidative damage.  This includes damage to neurons.  Eating a lot of cassava can lead to a neurological disease called Konzo.   The body has defense mechanisms against cyanide.  It metabolizes it to thiocyanate, which is much less toxic, but can still cause problems.   Thiocyanate can contribute to hypothyroidism. Thiocyanate interferes with the body’s ability to use iodine.  Iodine is needed to make thyroid hormones. Thyroid hormones are important for controlling metabolic rate and for brain development.  Not having enough thyroid hormone is dangerous during pregnancy and infancy because it can lead to low IQ, reading disabilities and attention deficit hyperactivity (ADHD) types of behavioral problems.

Tell me more about Konzo and Cassava Flour.

Konzo is a debilitating disease that occurs when people eat high in poorly processed cassava.  Signs of Konzo include spastic gait, need for support while walking, or complete inability to walk.   They may also show exaggerated knee and ankle jerk reflexes.  These are, of course, signs of nerve damage.Konzo usually shows up in people who have had nothing to eat but cassava.  The amount of cyanide in cassava varies according to the variety.  There are different varieties of cassava, like there are different varieties of apple.  Plant scientists have been working to develop less toxic cassava varieties.  Cyanide levels can also be reduced by processing and cooking.   Having nothing to eat but cassava is most likely to happen to people who are living in crisis and turmoil, conditions where processing and cooking cassava may be less than ideal.  While konzo is extremely unlikely to show up in someone living under reasonable conditions, the possibility of lesser forms of nerve injury should be considered.  This would be especially true for pregnant women and infants.  Nerve insult that occurs early in development can have life-long impact in the form of reduced IQ and/or behavioral issues. Consider something like lead, the metal.  Even tiny exposures during fetal development can be harmful.   Cassava may follow the same pattern (Bumoko et al. 2014).  The potential for cyanide to harm neurons is something to consider.  Even if it is only “a little.”

Anything else regarding Cassava Paleo concerns?

Just a bit.  There is also evidence that a cassava diet will make diabetes worse, possibly by damaging the pancreas.  This is from an animal study.

What is good about Cassava Flour?

Cassava flour may be a choice for people with celiac disease.  It should also be safe if it is properly processed and if a varied, healthy diet is followed otherwise.  Increased spending on Cassava Flour might also help the economies of developing countries that export cassava.

Andrea B. Kirk, PhD
Boivin, M., Okitundu, D., Makila-Mabe Bumoko, G., Sombo, M., Mumba, D., Tylleskar, T., Page, C., Tamfum Muyembe, J., & Tshala-Katumbay, D. (2013). Neuropsychological Effects of Konzo: A Neuromotor Disease Associated With Poorly Processed Cassava PEDIATRICS, 131 (4) DOI: 10.1542/peds.2012-3011

Bumoko GM, Sombo MT, Okitundu LD, Mumba DN, Kazadi KT, Tamfum-Muyembe JJ, Lasarev MR, Boivin MJ, Banea JP, & Tshala-Katumbay DD (2014). Determinants of cognitive performance in children relying on cyanogenic cassava as staple food. Metabolic brain disease, 29 (2), 359-66 PMID: 24481810

Nunn PB, Lyddiard JR, & Christopher Perera KP (2011). Brain glutathione as a target for aetiological factors in neurolathyrism and konzo. Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association, 49 (3), 662-7 PMID: 20816718

Yessoufou A, Ategbo JM, Girard A, Prost J, Dramane KL, Moutairou K, Hichami A, & Khan NA (2006). Cassava-enriched diet is not diabetogenic rather it aggravates diabetes in rats. Fundamental & clinical pharmacology, 20 (6), 579-86 PMID: 17109651