Is tofu a high calcium food?

This is a frequently asked question, especially from new vegans and/or vegetarians monitoring the intake of vitamins and minerals in their eating regime. And, as is often the case with such questions, there is no easy answer.

Tofu is a magical creation from three basic ingredients: soybeans and water (to make soy milk) and a coagulant used to set (or coagulate) the protein in the soy milk to result in tofu. The calcium content is derived directly from the coagulant and, while tofu is generally regarded as a high calcium food, the levels of calcium are dependent on the quality of coagulant used.

A truly superior kind of coagulant – in every way – is naturally occurring calcium sulfate (CaS04) in the form of crushed rock known popularly as gypsum. This is also the form of coagulant used by the traditional custodians of tofu, the Chinese.

Earth Source Foods uses gypsum in all our tofus in keeping with our ethos for excellence and our respect for the origins of this unique Asian food. That is, except for one type of tofu: SILKEN.

Given that SILKEN tofu is a Japanese form of tofu, we’ve followed the lead of thousands of years of Japanese tradition and use nigari (a concentrated solution of various salts remaining after the crystallisation of salt from seawater) as the coagulant instead – but only to create the creamy consistency of this special variety of tofu. In all of our other tofus, we use gypsum.*

Philip Anderson from Earth Source Foods’ gypsum supplier, Calsocorp – a microbusiness importing and supplying bulk calcium sulfate and calcium carbonate minerals to the food industry – came to food by way of the building industry. Having completed a degree in Engineering, he worked as a research and production engineer with plasterboard. Gypsum is used to make Plaster of Paris, which is then used to make plasterboard. Who would’ve thought gypsum could be such a versatile mineral?

About 25 years ago, Philip says food regulations were changed and none of the gypsums available in Australia met the new purity requirements.

“The Australian food industry had to use Calcium Sulfate imported from the US or Europe,” admits Philip. “I wanted the independence of running my own business so I developed the technology to purify Australian gypsums to meet the food regulations. I also found an alternative source of a pure grade of gypsum in Southeast Asia. Unfortunately, it is cheaper to import calcium sulfate than it is to process Australian gypsum so I have been importing it for over 20 years.”

“The pure calcium sulfate that I supply to my customers, such as Earth Source Foods, contains 23 percent calcium and over 18 percent sulfur,” further explains Philip. “I just Googled the composition of the human body, and we have 1.5 percent calcium in us and 0.3 percent sulfur. Calcium is essential for strong bones and sulfur is essential for many of the biological processes in our bodies, including being a critical part of the insulin hormone.”

It’s no secret that we need calcium to survive. And, while milk is celebrated as a high source of calcium, for those of us on a plant-based/vegan diet, dairy is definitely not a viable alternative. So, we’re pleased to say – along with plenty of green leafy vegetables and fortified cereals – good quality tofu might be the food to give you that little extra calcium boost.

* We've tested the calcium content of our FIRM tofu at 140mg per 100g.

Click here more information on how Earth Source Foods tofu is produced.