Everything You Need to Know About Nzu (Calabash Chalk)

Calabash chalk

Nzu, or calabash chalk is an edible clay that is found mainly in Nigeria and other West African countries. The common name is calabash chalk. However, in Nigeria, most people call it nzu in Igbo. It is also called ndom in Efik/Ibibio and eko in Bini/Edo language.

Although nzu is predominantly eaten by pregnant women as a cure for nausea. Many other people consume it for eating pleasure. This act is known as geophagia (eating of chalk, clay or soil).

Calabash chalk is also consumed outside Nigeria and Africa. You can find it in ethnic stores in the United States, Canada, and the United Kingdom.

Since calabash chalk is so widely consumed, it would be vital that you get to know more about it, especially the health and medical aspect of it.

This in-depth article will discuss the composition of Nzu (calabash chalk), the health benefits of Nzu, and the side effects of Nzu.

You will also find out the answers to questions like, why Pregnant women consume nzu? Is nzu good during pregnancy And can nzu cause miscarriage?

Composition of Calabash Chalk

The major component of calabash chalk is aluminum silicate hydroxide. It also contains an excessive amount of lead. In fact, the amount of lead in food should not exceed 1 mg/kg, but the amount of lead present in calabash chalk has been reported to be between 10–50 mg/kg.

Other substances present in calabash chalk include Aluminum, organic pollutants, silicon, iron, alpha lindane, chromium, arsenic endrin, and endosulfan 11.


Why Pregnant Women take Calabash Chalk

Pregnancy usually comes with nausea and vomiting, so taking calabash chalk helps them to prevent morning sickness and nausea.

Spitting is also very common during pregnancy. Many pregnant women have claimed that eating calabash chalk helped them to stop spitting.

Most pregnant women are lack iron and are anemic. Several studies have shown that people who have a craving for clay are anemic. Since clay is rich in iron, the craving for clay is a way the body is trying to make up for the iron deficiency.

The Real Reason why People Crave Nzu

Although, most people might like to take Nzu for pleasure, some people have a craving for it. Those people have an eating disorder called pica syndrome.

Pica syndrome is that persistent act of eating substances that are not food. Geophagia (eating of soil) is a type of pica syndrome.

Most times, pica syndrome is caused by a deficiency in iron, zinc, or calcium in the body. In pregnant women, anemia, or iron deficiency, may be the reason why pregnant women crave Nzu.

Are there any health benefits of eating Nzu (calabash chalk)?

Health Benefits of Nzu

Honestly, there is little information about the health benefits of Nzu (calabash chalk). However, the only two medically proven health benefits of calabash chalk are:

• Treatment of morning sickness

Nzu or calabash chalk can definitely reduce morning sickness, especially in pregnant women. The taste of the chalk stops nausea.

However, note this. Normal morning sickness causes no harm to a pregnant woman or her baby. Although, Nzu can relieve you of morning sickness, they are other ways to treat morning sickness during pregnancy.

• It supplies some nutrients to the body.

Medical research have suggested that when you crave for calabash chalk, it may mean that your are lacking iron and calcium in your body. Most women usually lack those nutrients during pregnancy. Hence, Nzu health benefits could be to provide such nutrients to the body.

Now, pay attention to this, iron or calcium deficiency is not a medical emergency. It could be bad for health in the long run, but they are many other ways to get calcium and iron if you are deficient. Scientific studies, have shown that calabash chalk on the whole is not a significant source of mineral nutrients.

• It detoxifies the body

Studies may suggest that Nzu may help in detoxifying the body of harmful toxins. It is claimed that they prevent toxins from being absorbed by the body. Hollywood actress, Shailene Woodley backed up those claims backed up those claims, by saying that she learnt about eating clay from an African taxi driver, and that it has helped her health.

Dr. David L. Katz, a nutritionIist and founder of the Prevention Research Center at Yale University, also stated in an interview with ABC News interview with ABC News that clay has detoxifying properties. He said that it is possible that the binding effect of clay would cause it to absorb toxins.


Health Effects of Calabash Chalk (nzu) 

Calabash chalk

1. It harms the digestive system

When geophagic materials like calabash chalk are consumed and enter the digestive system, they can cause harmful effects to the individual.

2. Effect on the Blood

Numerous reports regarding the health risks of consuming calabash also claim that it affects the blood.
It alters the normal concentration of hemoglobin, red blood cell counts and erythrocyte sedimentation rate in the body.

3. Effect on bone and growth development

A medical study by Dr. Moses B. Ekong of the Department of Anatomy, Faculty of Basic Medical Sciences, University of Uyo, Uyo Nigeria and his team of researchers showed that the consumption of calabash chalk might affect bone and growth development.

They investigated the effect of the calabash chalk on bone mineralization and other morphological changes in experimental Wistar rats. They found out that calabash chalk can alter growth rate, and cause de-mineralization in the bone, thus making it damaging to bone growth.
Although this experiment, was carried out on rats, it is suggested that would also be harmful to humans.

4. Other health issues

Many other medical reports have suggested that calabash chalk consumption also causes several gastrointestinal disorders like nausea, ulcers and gastritis.

Calabash chalk caused a lot of histomorphological changes that to the stomach and oesophagus, and that may lead to other pathophysiological conditions.

Don’t forget that calabash chalk contains a huge amount of lead. Excessive lead intake has been linked to gastritis, nausea, ulcers vomiting, and constipation.

Increased lead intake during pregnancy can also affect the babies. It could cause neurological damage to children, reduced IQ and an increased risk of cognitive under development.

5. Addiction

South African health journal, Health-e spoke to several women who ate clay about their habit. They found out that, for many, the desire to eat soil can be a form of stressful addiction.

Many woman reported that they started eating soil as teenagers, others started during pregnancy. Some women are so much addicted to eating clay that they are not able to stop because they feel their food is not complete without clay in it. Thus, the addiction is could be a bad habit and result in the dangers of eating nzu which was mentioned above.

Can Nzu cause miscarriage?

Can Nzu cause miscarriage?

It is possible. A medical study by Jonah Sydney Aprioku and Ezinne Margaret Ogwo-Ude on the toxicity of calabash chalk (Nzu) in pregnant Wistar Rats might have suggested so.

In their experiment, 24 pregnant albino wistar rats were divided into 3 groups, 8 each. Thereafter, one group was orally administered 400mg/kg of calabash chalk, another group was given 800 mg/kg of Calabash chalk, the last group were not given (control group). They were given calabash chalk throughout the 20 days of their gestation.

In their results, most of the rats that were given calabash chalk had miscarriage, abortion and stillbirths. They concluded that Calabash chalk or Nzu is not good for maternal health and pregnancy.


If you ask, is eating Nzu bad for me?, then the answers you will get is yes, it might be.
From this article, you have learnt about the benefits of Nzu and the dangers of eating Nzu.

You should know that all the benefits of eating Nzu, can be gotten by talking to your doctor. In fact, Dr. Mba Sunday, an Obstetrician and Gynecologist at the Enugu State University Teaching hospital advised that pregnant women should consult their doctor, since craving for Nzu is a condition called pica syndrome. If the doctor determines that you are lacking minerals and nutrients, he will suggest that you take supplements or foods which will replenish it.

Please share this informative article and comment below, we want to read them.


Moses, E.B.; et al. (2012). “Effect of Calabash Chalk on the Histomorphology of the Gastro-Oesophageal Tract of Growing Wistar Rats”. The Malaysian Journal of Medical Sciences19 (1): 30–35.

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4 thoughts on “Everything You Need to Know About Nzu (Calabash Chalk)

  1. First of all, this article is well articulated and thank you for taking the time to write on a topic that is crucial and highly appreciated. However, I would add that nzu has little or no benefit having been a victim of its consequences and also a victor in overcoming the addiction. If you check my Facebook “I want to quit eating clay, you will understand that Nzu has zero nutrient and that the grace of God is needed to conquer that demon.

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