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Risk of iodine deficiency in vegan diets highlighted by data on customer shopping habits

by Faith Pring, University of Nottingham

milk - Credit Pixabay CC0 public domain.jpg

Switching to alternative milk and removing seafood from your diet could lead to an iodine deficiency, which may have a negative impact on long-term health, a new study shows.


These new findings clearly illustrate how switching to 'plant-based' alternatives to dairy milk can seriously increase the risks for essential nutrient deficiencies - particularly of iodine, and Vitamin B12.

Switching from dairy to plant-based milk reduced average weekly iodine intake of 4/5 customers - and for almost 2/3, the drop was major. (Iodine intake fell by 75% in 20% of the sample, and by 25-75% in a further 45%).

Similar reductions were also seen for Vitamiin B12.

Both iodine and B12 are vital for brain health at any age - but for women of childbearing age these findings are of particular concern, as:
  • Either iodine deficiency or Vitamin B12 deficiency during pregnancy can irreversibly impair brain development in the unborn child
Knowledgeable vegans should be well aware of the need to supplement with Vitamin B12 (or to get recommended amounts from fortified foods).

By contrast, the risks of iodine deficiency are much less well known - and these apply not just to vegans, but to anyone who doesn't eat the recommended 2 portions per week of fish and seafood (the main natural source of iodine), and who also avoids real milk and dairy products.

For details of this research (which is open-access) please see:

Watch FAB's recent event which provides vegan-friendly solutions for ensuring adequate levels of brain-critical nutrients:

For a FAB article explaining the critical importance of iodine during pregnancy, see:

And for further information, please see the following lists of articles, which are regularly updated.

26 Jan 2024 - University of Nottingham


Switching to alternative milk and removing seafood from your diet could lead to an iodine deficiency, which may have a negative impact on long-term health, a new study shows.

Using anonymized data from more than 10,000 Co-Op shoppers, a team of academics, led by Dr. John Harvey from Nottingham University Business School, analyzed their shopping habits to find out whether switching to alternative milk products could lead to various health issues.

Led by N/Lab at the University of Nottingham, the team identified regular Co-op loyalty card shoppers that did a 'big shop' at the Co-op in order to increase visibility of their whole diet and find the customers that made a switch to dairy alternatives. The work is published in the journal Scientific Reports.

Average weekly iodine levels of grocery purchases were calculated and analyzed to examine any reduction that resulted from the transition to plant-based milk.

The effects of the dietary transition on other key nutritional components of dairy milk, including calcium, vitamin B12 and saturated fat, some of which were fortified in plant-based milk, were also analyzed to compare the impacts of transition on other nutritional elements.

The primary sample to be analyzed consists of 10,626 frequent customers who met the inclusion criteria, and who purchased milk for at least four weeks before the transition point and plant-based milk for at least four weeks after the transition.

More than 81% of the customers analyzed decreased their average weekly intake of iodine once they switched to plant-based milk. Of those individuals, approximately 14% experienced a decrease of less than 25%, but around 20% experienced a severe iodine reduction of more than 75%.

The remaining 45% of the individuals experienced a drop between 25% and 75%. Similar results were observed for calcium and vitamin B12.

In contrast, more than 71% of consumers showed a positive reduction in their weekly intake of saturated fat, with about 23% reducing over 50% of their weekly intake.

With the increasingly popular "Veganuary" currently underway, the team behind the study are keen to encourage people to pay attention to their iodine consumption when suddenly changing their diet.

Dr. John Harvey, from Nottingham University Business School, said, "Every year we see a growing number of people experimenting with plant-based foods as part of their diet. There are many good reasons to consider such a transition.

"But our study demonstrates that if you are considering replacing milk in your diet, it is particularly important to consider whether you're getting sufficient iodine from other sources. Many alternative milks are not fortified with iodine, so check the back of the packet. If your preferred sources aren't fortified, consider incorporating iodised salt into your diet instead.

Dr. Simon Welham, assistant professor in nutritional science, added,

"We are particularly concerned about the iodine intakes among women of childbearing age, as embarking on pregnancy with too little iodine can permanently damage the developing baby. I would reiterate John's point regarding the need to check the labels to ensure iodine is present, particularly for plant-based milk alternatives."