It is common to believe that you can't mix dairy products (calcium) and iron-rich foods in a meal. Many have heard that calcium in dairy products can reduce how much iron the body can absorb. In this blog post, Elin finds out how this actually works.
It is true that calcium can affect iron absorption, especially when it comes to iron from plant sources (non-heme iron), when iron absorption can be reduced by up to 40–60%. When it comes to iron from animal sources (heme iron), the inhibitory effect is much smaller, only around 10–20%.
But! The good news is that the inhibitory effect appears to be only temporary. For children (and adults) who eat a varied diet, iron levels are not affected over time, even if they occasionally eat iron-rich foods along with milk and dairy products. The body adapts and makes sure to get the iron when it needs it.
This means that even though calcium appears to inhibit iron absorption to some extent in specific meals, it does not affect iron status over the long term, especially not with a balanced diet.
What does the Food and Drug Administration say?
The Swedish National Food Agency recommends that you do not give pure milk as a drink or large amounts of yoghurt and filbert to children under 1 year of age. This is because babies don't eat much food and should therefore not be fed iron-poor foods (such as yogurt), as iron is so important at that age. Dairy products such as cream and crème fraiche are perfectly fine in cooking (where it's more the saturated fat that you need to think about trying to keep down).
Why do I serve yogurt with something rich in iron?
When I have served yogurt to my children when they are under 1 year old, I have almost always served it with something rich in iron, e.g.For example, mixed whole wheat bread, pumpkin seeds and/or apricot puree and preferably with something rich in vitamin C. I have done this so that they get both iron and calcium in the meal, even though some of the iron absorption may be inhibited. But this way the yoghurt does not compete with iron-rich food in the same way because the yoghurt meal then contains iron.
What about foods, such as porridge and gruel, that are fortified with both calcium and iron?
These products are made so that the added calcium and iron work optimally together. Many such products also contain vitamin C, which helps the body absorb iron.
Promote iron absorption!
Do you want to optimize iron absorption? Serve iron-rich foods with vitamin C-rich fruits and vegetables, such as bell peppers or oranges. This is especially important when it comes to non-heme iron. Vitamin C reduces the iron to a form that is easier for the body to absorb.
Recipes with good sources of iron
In short,
It's perfectly okay to combine iron-rich foods and dairy products occasionally. You don't need to be afraid of it. If your child has difficulty eating a varied diet or has low iron status, there may be a point in separating dairy products from iron-rich foods during the day, especially if it is non-heme iron. But in general, you can, for example, serve yogurt with wholemeal bread or make a smoothie with both milk and pumpkin seeds (the smoothie also contains vitamin C, which promotes iron absorption!).
Sources, read more here:
- Abioye, AI, Okuneye, TA, Odesanya, A.-MO, Adisa, O., Abioye, AI, Soipe, AI, Ismail, KA, Yang, JF, Fasehun, L.-K., & Omotayo, MO (2020). Effect of calcium intake on iron absorption and hematologic status: A systematic review and dose-response meta-analysis of randomized trials and case-cross-over studies. withRxiv.
- Armah, CN, Sharp, P., Mellon, FA, Pariagh, S., Lund, EK, & Dainty, JR (2015). Iron Bioavailability: Enhancers and Inhibitors. SpringerLink.
- Reddy, M. B., & Cook, J. D. (2023). The effect of calcium on iron absorption in humans: An update on current findings. ResearchGate.
- Abioye, AI, Okuneye, TA, Odesanya, A.-MO, Adisa, O., Abioye, AI, Soipe, AI, Ismail, KA, Yang, JF, Fasehun, L.-K., & Omotayo, MO (2020). Effect of calcium intake on iron absorption and hematologic status: A systematic review and dose-response meta-analysis of randomized trials and case-cross-over studies. withRxiv.
- Armah, CN, Sharp, P., Mellon, FA, Pariagh, S., Lund, EK, & Dainty, JR (2015). Iron Bioavailability: Enhancers and Inhibitors. SpringerLink.
- Reddy, M. B., & Cook, J. D. (2023). The effect of calcium on iron absorption in humans: An update on current findings. ResearchGate.
- Hallberg, L., Brune, M., & Rossander, L. (1991). The role of vitamin C in iron absorption. International Journal for Vitamin and Nutrition Research, 61(1), 103–110.
- Cook, JD, Dassenko, SA, & Whittaker, P. (1991). Calcium supplementation: effect on iron absorption. American Journal of Clinical Nutrition, 53(1), 106–111.
- Heaney, RP, & Weaver, CM (1993). Calcium and iron absorption: is there an interaction? American Journal of Clinical Nutrition, 57(4), 595–596.
- Hurrell, RF, Reddy, MB, Juillerat, MA, & Cook, JD (1989). Calcium fortification and iron absorption: a synergistic inhibitory effect. American Journal of Clinical Nutrition, 49(2), 546-552.
/Elin Oresten
Lic. nutritionist and founder of Knatteplock.
