Zinc fortification and how well zinc is absorbed
What it found
Zinc deficiency is common worldwide, and fortifying staple foods with zinc can help, but how much zinc the body actually absorbs depends on the whole diet.
The paper reviews ways to measure this and current fortification trends.
What they found
Studies in people
Phytate reduces zinc absorption
Phytate, found in grains, legumes, seeds and nuts, binds zinc and reduces how much is absorbed. In children, breaking down phytate in fortified millet porridge increased zinc absorption by 68% to 86%.
Protein helps zinc absorption
Dietary protein increases zinc absorption regardless of the protein source. Adding animal protein, which lacks phytate, readily boosts zinc absorption from the whole meal.
Plasma zinc is not a good marker
Plasma zinc levels naturally vary by 18% to 22% over a day, similar to the peak response from zinc supplements. Zinc taken with food causes only a small change in plasma zinc, and when zinc intake is low the body conserves zinc, keeping plasma levels steady.
Functional biomarkers show promise
Some biomarkers like DNA strand breaks, immune markers, and fatty acid levels respond to small changes in zinc intake even when plasma zinc does not. For example, 20 mg zinc daily for 17 days reduced DNA strand breaks in Ethiopian women, and 4 mg zinc daily for 60 days from fortified milk improved immune markers in elderly adults.
Zinc amino acid complexes
Zinc bound to amino acids or peptides may be absorbed better than inorganic zinc salts. In humans, a 20 mg dose of zinc histidine complex gave a greater serum zinc response than zinc sulfate, and 15 mg zinc bisglycinate gave a greater response than zinc gluconate.
Studies in people and animals
Biofortification works well
Zinc from biofortified crops is absorbed as well as from post-harvest fortified foods. Biofortification targets for Africa could reduce the risk of zinc deficiency 10-fold.
What the authors conclude
“Zinc deficiency is the most common micronutrient deficiency in the world.”
Also in their conclusions
- They propose that future fortification strategies should be based on dietary intakes, predicted impacts on absorbed zinc, and expanded use of functional biomarkers.
- They advise that large-scale human studies should include an assessment of health outcomes.
- They say that improved strategies for assessing the impact of zinc fortification are essential to alleviate zinc deficiency worldwide.
How it was done
Zinc deficiency is widespread and is the most common nutritional problem worldwide. The authors wanted to review how fortification strategies can be improved by considering zinc absorption and utilization.
The authors reviewed studies on zinc absorption, biomarkers of zinc status, and different fortification approaches including zinc salts, biofortification, and food-to-food fortification. They examined data from human tracer studies, animal studies, and cell models.
What it can’t tell you
- Many recent fortification studies did not include adequate controls, so changes in health cannot be conclusively attributed to zinc fortification.
- The lack of sensitive biomarkers means the impact of fortifying foods with zinc on zinc status is hard to assess.
- Animal and cell studies cannot show what happens in people.
Who paid
- Conflicts
- The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.
- Authors work at
- University of California, USA
The paper
- Title
- Zinc Fortification: Current Trends and Strategies
- Type
- ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
- Evidence
- Studies in people · animals · lab
- Summarised from
- Full text
- Cite
- Hall AG, King JC (2022). Zinc Fortification: Current Trends and Strategies. Nutrients. doi:10.3390/nu14193895Free full textPubMed 36235548DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error