The impact of dephytinization on iron absorption from a meat analog based on soy protein and chickpea farinata: a randomized study in young women

Summary description of the study

The aim of this study is to investigate the effect of dephytinization (breakdown of phytic acid) on iron absorption in young women with non-anemic iron deficiency. We hypothesize that iron absorption from plant-based meals prepared with dephytinized soy protein concentrate (SPC) or chickpea flour will be higher compared to the corresponding meals without dephytinization. The experimental phase will last 45 days. During the study, each participant will consume assigned meals. These will be randomly distributed and taken on days 1–2, 8–9, 23–24, and 30–31 both in the morning and at noon. A total of 16 meals are planned. The test meal consists of a soy-based meat analog product with or without dephytinization or farinata with or without dephytinization, served with a vegetable sauce and 150 ml of water. Participants will only be informed of the exact composition and order of the test meals at the end of the study. Each meal contains approximately 4.2 mg of iron. Of this, 20% of the total iron will be in the form of isotopic markers (either ⁵⁷Fe or ⁵⁸Fe) as FeSO₄. On days 1, 23, and 45, a blood sample will be taken to perform iron isotope analyses as well as measurements of iron status and inflammatory markers. The study will be conducted at the Laboratory of Nutrition and Metabolic Epigenetics at ETH Zurich.

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Intervention under investigation

Specifically, we plan to measure iron availability from 4 standardized test treatments enriched with equivalent amounts of iron(II) sulfate (FeSO4), as described below:

1. Meat substitute prepared with dephytinized soy protein concentrate.

2. Meat substitute prepared with soy protein concentrate.

3. Farinata prepared with dephytinized chickpea flour.

4. Farinata prepared with chickpea flour.

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Disease under investigation

A shift to more plant-based, protein-rich foods as meat substitutes requires an assessment of their nutritional value, as meat provides important nutrients such as iron. Iron from animal foods (heme iron) is particularly well absorbed by the body (15–40%), while iron from plant foods (non-heme iron) is less efficiently utilized. Additionally, there are substances like phytic acid that block iron absorption in the gut. Phytic acid is a natural substance found in many plant foods such as legumes, grains, and nuts. It binds minerals like iron, zinc, and calcium, making them inaccessible for absorption in the gut. Therefore, a reduction in phytic acid may promote human iron absorption. Iron deficiency anemia (IDA) is one of the leading causes of lost healthy years of life worldwide, particularly among women. This is often due to a diet low in iron or the difficulty of the body to utilize the iron in food. A plant-based diet can increase the risk of iron deficiency if no measures are taken to enhance iron bioavailability. Studies show that plant-based meat alternatives often contain little iron and a lot of phytic acid. To improve iron absorption, the ratio of phytic acid to iron should be as low as possible (below 1, preferably below 0.4). There are methods to reduce the phytic acid content, such as grinding, using enzymes (phytase), or adding grains that contain natural phytase. Phytase breaks down phytic acid and makes iron more available. This study investigates how well the body can absorb iron from soy meat substitutes and chickpea pancakes (farinata) – each with and without phytic acid breakdown. The aim is to measure the effect of this treatment on iron absorption and to assess whether such foods can serve as favorable and effective plant-based alternatives to meat.

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Sponsor

Swiss National Science Foundation (SNSF)

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Name of the authorising ethics committee (for multicentre studies, only the lead committee)

Ethics Committee Zurich

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Date of authorisation

04.02.2025

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Results of the trial