The Claim

Soy foods contain substantial amounts of iron and zinc, but molar ratios of phytic acid to iron greater than 8 and phytic acid to zinc greater than 15 indicate reduced mineral bioavailability under in vitro conditions.

Source: In vitro DIAAS of Swiss soybean cultivars using the INFOGEST model: Increase in protein quality from soybean to soymilk and tofu.

What the research says

Roughly balanced

Support and challenge are close. The picture may shift as more studies come in.

Supports
6score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

How it works
1 study reviewed
In plain English

Soy foods contain iron and zinc, but high levels of phytic acid relative to these minerals reduce their absorption in laboratory tests.

See the scientific wording

Soy foods contain substantial amounts of iron and zinc, but molar ratios of phytic acid to iron (PA/Fe > 8) and phytic acid to zinc (PA/Zn > 15) suggest a high likelihood of reduced mineral bioavailability under in vitro conditions.

Why this might work

Phytic acid binds tightly to iron and zinc in the gut, forming insoluble complexes that the body cannot absorb, so these minerals pass through the digestive tract without entering the bloodstream.

Verified mechanismbased on 1 study

What the research says

1 study
  1. Study: In vitro DIAAS of Swiss soybean cultivars using the INFOGEST model: Increase in protein quality from soybean to soymilk and tofu.

    Soy has lots of iron and zinc, but it also has a compound called phytic acid that stops your body from absorbing those minerals well — and this study found exactly that in lab tests.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

Fit Body Science verdict — we translate health claims into clear verdicts backed by peer-reviewed research.

Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.