Is Nzu or Ulo Safe in Pregnancy? Risks of Eating Clay, Heavy Metals & Baby Brain Development or Autism Risk

Is Nzu Safe in Pregnancy? Clay Eating Risks, Lead Exposure & Baby Brain Development

If you are pregnant and craving nzu (kaolin), ulo, or bentonite clay, you may be wondering:

 “Is it actually safe for me and my baby?”

Many women experience these cravings during pregnancy.

However, medical research shows that eating clay may expose your baby to harmful heavy metals like lead and arsenic, which can affect brain development and long-term health.

[Start Here for Autism Support in Nigeria]

In this article, you will learn:

• The hidden risks of eating nzu or ulo
• How it can affect your baby’s brain
• The possible link to developmental delay and autism
• Safer alternatives you can use

What Is Nzu, Ulo, and Bentonite Clay?

Nzu and ulo are natural clays commonly consumed during pregnancy, especially to reduce nausea.

Because they are sourced from the earth, they may contain toxic substances, including:

• Lead
• Arsenic
• Cadmium

Studies analysing edible clay have found significant contamination with heavy metals, particularly in kaolin (nzu) (1).

Why Eating Clay in Pregnancy Can Be Dangerous

When you eat clay during pregnancy:

• Heavy metals enter your bloodstream
• They cross the placenta
• They reach your baby’s developing brain

This exposure can interfere with normal fetal development.

These toxins can affect your baby’s brain development early. Learn more about [autism risk factors during pregnancy]

Effects on Your Baby’s Brain Development

Your baby’s brain develops rapidly during pregnancy. Toxic metals can:

• Disrupt brain cell formation
• Affect nerve connections
• Interfere with learning and memory

Research shows that prenatal exposure to heavy metals is linked to:

• Reduced IQ
• Learning difficulties

• Behavioral problems (2,5)

  You can also read about the [early signs of autism in toddlers] to know what to watch for as your child grows.

Developmental Delay and Learning Problems

Children exposed to lead and arsenic before birth may develop:

• Speech delay
• Poor attention span
• Learning difficulties

Studies have found strong associations between environmental metal exposure and intellectual disability (4).

Not sure what is normal? See our guide on [developmental milestones in babies and toddlers]

Is There a Link Between Nzu and Autism?

This is an important question.

Current evidence suggests:

Heavy metals do not directly cause autism

However, they can:

• Increase the risk of neurodevelopmental disorders
• Affect brain development in vulnerable children
• Contribute to developmental delays

Research has shown associations between prenatal exposure to toxic metals and autism-related outcomes (7).

 This means your baby’s brain development could be affected in ways that influence behaviour and learning.

If you are concerned, here is a detailed explanation of [what causes autism in children]

Other Pregnancy Risks of Eating Nzu or Ulo

Consuming clay has also been linked to:

• Low birth weight
• Premature birth
• Poor fetal growth (2)

These complications can further affect your child’s development.

“Natural” Does Not Mean Safe

It is easy to assume nzu is safe because it is natural.

However, health reports warn that bentonite clay may contain unsafe levels of lead, which can harm:

• The brain
• The kidneys
• The nervous system (8)

Why You Crave Nzu During Pregnancy

Craving non-food substances is called pica.

It may be caused by:

• Iron deficiency
• Mineral deficiencies
• Hormonal changes

 The craving is real-but eating clay is not the solution.

You can also download our [free guide: 5 common foods worsening autism symptoms]

Safe Alternatives to Manage Cravings

Instead of eating nzu or ulo, you can:

• Take iron supplements (if prescribed)
• Use safe nausea remedies (e.g. ginger)
• Eat small, frequent meals
• Speak to your doctor

What You Should Do Now

If you are currently eating nzu:

•  Stop as soon as possible
•  Speak to a healthcare professional
•  Check your iron levels

Early action can protect your baby’s development.

If you need personalised support, you can [book a consultation with a certified autism specialist]

Conclusion

 It is safest to avoid nzu, ulo, and any clay products during pregnancy

Because they may expose your baby to lead and arsenic, which can affect:

• Brain development
• Learning ability
• Behaviour

Need Personalised Guidance?

If you are worried about:

• Your pregnancy nutrition
• Your child’s development
• Early signs of autism

Getting expert guidance early can make a significant difference. Book a consultation today for personalised support tailored to your child.

 References 

Umar NB, et al. Essential minerals and heavy metals in edible clay. FUDMA Records of Chemical Sciences. 2024.

https://scholar.google.com/scholar?q=heavy+metals+in+edible+clay+kaolin…

Zhang Y, et al. Prenatal exposure to heavy metals and adverse birth outcomes. PubMed. 2024.

 https://pubmed.ncbi.nlm.nih.gov/?term=prenatal+exposure+heavy+metals+ad…

Karimi P, et al. Toxic metal exposure and neural tube defects. PubMed.

 https://pubmed.ncbi.nlm.nih.gov/?term=toxic+metals+neural+tube+defects+…

McDermott S, et al. Soil metal exposure and intellectual disability. Dev Med Child Neurol.

https://pubmed.ncbi.nlm.nih.gov/?term=soil+metal+exposure+intellectual+…

Review of heavy metals and neurodevelopment. PMC.

 https://www.ncbi.nlm.nih.gov/pmc/?term=heavy+metals+neurodevelopment+re…

Meta-analysis of cadmium exposure and child IQ. PubMed.

https://pubmed.ncbi.nlm.nih.gov/?term=cadmium+exposure+child+IQ+meta+an…

Prenatal metal exposure and autism-related outcomes. PMC.

https://www.ncbi.nlm.nih.gov/pmc/?term=prenatal+metal+exposure+autism

Clinical safety concerns on bentonite clay exposure. Medical safety summaries.

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