A team of researchers from Tanzania and the United States has launched an important study looking at how much vitamin B12 pregnant women really need. The trial, carried out at the Ifakara Health Institute (IHI) in Bagamoyo, is the first of its kind in sub-Saharan Africa to use a controlled feeding approach.

Why does it matter?

Vitamin B12 is often called a “hidden nutrient” — you don’t hear about it as much as iron or folic acid, but it plays a vital role in pregnancy. It supports both the mother’s health and the baby’s development, especially the brain and nervous system.

However, doctors and nutritionists still don’t know the best daily dose for pregnant women. Too little can cause deficiency, but the exact amount needed to keep mothers and babies healthy is not well understood. That’s why this study is so important: it could help shape nutrition guidelines in Tanzania and beyond.

Key reasons this matters:

• B12 supports healthy brain and nervous system development in babies.
• Deficiency during pregnancy can lead to serious complications.
• There’s little data on B12 needs for African populations, making this trial groundbreaking.

The study in focus

The trial involves 40 pregnant women and 10 non-pregnant women. Participants are divided into groups to test different daily doses of vitamin B12. For four weeks, women in the study will receive carefully controlled meals while their blood vitamin B12 levels closely monitored. Pregnant participants will also be checked again after giving birth.

This approach will help scientists see how the body absorbs and uses vitamin B12 during pregnancy, and whether higher doses are more effective.

A collaborative effort

Dr. Omar Lweno of the Ifakara Health Institute is the lead author. He worked alongside colleague at Ifakara, Dr. Honorati Masanja. The last author, Dr. Emily R. Smith from George Washington University, also played a key leadership role.

But this is not just about two institutions — it’s a wide collaboration, also involving Muhimbili University of Health and Allied Sciences (Tanzania); University of California, University of Maryland Baltimore, Inova Health System, and Pennsylvania State University (USA).

Together, these scientists bring diverse expertise to answer one crucial question: what is the optimal dose of vitamin B12 for pregnant women in Africa?

Looking ahead

While this first trial is small, it sets the stage for larger studies. The findings could influence global nutrition policies, ensuring that mothers and babies in Africa — and elsewhere — get the right support during pregnancy.

The work is made possible through funding from the Gates Foundation.

Read the research article here.