As a vegan, I intend to use tofu as my main source of protein, iron and calcium. Therefore, I am concerned about bioavailability (i.e. absorption divided by intake) of iron and calcium in tofu.

As far as I know, there're two kinds of tofu, divided by a difference in their production process:

  • Those treated with CaSO4, known in US/UK as "calcium-set tofu", and in China as "southern tofu".
  • Those treated with MgCl2 (among other substances), known in US/UK as "traditional tofu" (not sure), and in China as "northern tofu".

These two kinds vary greatly in calcium content: roughly 300+mg/100g for the former, and 100+mg/100g for the latter. [1]

There had been studies on the iron bioavailability in tofu ([2]).

There had also been studies on the calcium bioavailabity in calcium-set tofu ([3],[4]), which give us some good news (that calcium-set tofu is not even defeated by milk).

However, I hadn't found any infomation on the calcium bioavailabity in traditional tofu. So, could you share your relevant experiences, or point out some relevant studies?

UPD: Luckily I've found ways to get around this problem, so answer to this question doesn't matter much to me now.

I'll post links to another paper that I found quite useful, in case it can help somebody: [5], [6]

The paper is about mineral content in all kinds of common soy products in China, and it's written in Chinese.

  • Excellent question with science-based links! Thank you! May 21, 2021 at 1:04
  • 1
    Could you summarize what you decided to get around that problem? Jun 3, 2021 at 12:24
  • @T.C.Proctor nothing interesting ... It's just that I found a store that sells certain soy products that are based on CaSO4 tofu.
    – inverse
    Jun 8, 2021 at 3:46

1 Answer 1


Doesn't that paper also say tofu products have from 300-3000 ppb lead? And at most 0.6mg per gram of Calcium, which seems very far off from the claim of 300mg/100g by a factor of five.

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