Health implications of Eating Ulo and Nzu(Geophagy)

The act of eating soil in the form of Ulo and Nzu is a common practice in West African and more especially among pregnant women and children. It is known as geophagy which is defined as a deliberate or abnormal
practice of eating soil or its substance (clay
or chalk) for reasons or benefits yet not fully

Both Ulo (brown clay) and Nzu(white clay) are obtained from clay and have salty taste, while ulo is usually flat and taste like dust, Nzu may be in form of power or moulded round. Nzu is also known as calabash chalk,  La craie, Argile, Mabele or calabar stone.

Why geophagy 

People engage in geophagia for a variety of reasons including religious beliefs, medicinal purposes, or as part of a regular diet (1). It is believed to supplements the diets with
essential nutrients or to treats disorders such
as diarrhea, swollen legs and absorbs
dangerous toxins. Ulo and Nzu is usually eaten by pregnant women as a remedy for morning sickness. Geophagy is an additive behavior, such that once you start it’s always difficult to stop.

Possible health Benefits of Geophagy

Supply of micronutrients.

The soil supply the body with micronutrients which may otherwise be lacking in conventional foods. Several studies show that geophagy is often associated with anaemia. 2 So perhaps eating iron-rich soil is an instinctive attempt to remedy iron deficiency, as we tend to crave for those things we lack in the body.

Enhance  Fetal Development

Traditionally,  Nzu is believed to ensure fetal development and help women in giving birth to beautiful babies. Cooper, 2000. Studies has shown that geophagy  can help increase nutrient absorption, which is important during early pregnancy and the childhood years for growth. 3

Detoxifying Effects

Nzu and ulu help detoxify the body by binding to toxins and pathogens thereby preventing them from being absorbed. Studies has also shown that clay can strengthen the stomach lining or act as barrier, thereby stopping the entrance of viruses and bacteria.

In studies on rabbits and rats, researchers found that clay in the intestines can act as a barrier, stopping the entrance of viruses and bacteria. 4

Treat stomach disorder

Clay can be used to treat stomach disorders because it’s very good at binding to things which help calm gastric pains. Clay has a soothing effect on the stomach and also help to combat heartburn because of its ability to influence the pH of the stomach acid.

Risk factors

Presence of lead

A research carried out by UK’s food standard agency, showed that Nzu contain high level of lead. Exposure to high levels of lead by pregnant and breast feeding women poses a risk to the mental development of the unborn child and breast fed infant. 5

Interfere with bioavailability of micronutrients.

The presence of lead in clay interferes with bioavailability of micronutrients leading to micronutrient deficiency. Lead occupies similar niches with iron in the human body and so competes with iron for absorption in the gut and uptake within the body 6. Lead also reduces the production of red blood cells (erythropoiesis), their size (microcytic anemia) and their lifespan 7.

Contamination with pathogens

Geophagy can act as a pathway for  ingestion of  pathogens which could result in the development of  soil born diseases. A research conducted by  ogomaka (2015) showed that those who eat clay could be more prone to worm infestation than those who do not eat earth due to poor handling and exposure to the environment by the dealers.


Due to the health risks geophagy pose to the unborn babies, their mothers and other adults, it will be wise if consumption of Nzu and ulu be reduced if it not stopped completely . The recommendation to stop completely may be  difficult to implement, because addictive behaviour cannot be changed overnight.


Cooper, D.W.(2000).Clay Eating Parrot s, Parrot Magazine 36.

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