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I wonder if there are any benefits to eat earth. What I mean by earth is the topsoil that is sometimes on vegetable (I eat organic vegetables and some of them like spinach are full of topsoil).

I found this article (a study about why people, in certain culture, eat earth) but it doesn't clearly answer my question as it's about clay and not topsoil. Topsoil has a highest concentration of organic matter than clay.

I wonder if we can digest the soil nutrient (Phosphorus, Potassium, Calcium, Magnesium, Manganese, Zinc, Copper) just as we would if there were coming from vegetable and fruits.

What are the other pros and cons of eating earth (soil)? (I am aware of the cons about parasite and bacteria but my question is not about these risks. It's about nutritive value of earth.)

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The article (a PDF can be found here) suggests that this happens neither for feeding reasons (to get your belly filled, when anything else is available) nor that this is done for supplemental reasons.

They suggest that this happens more for protective reasons. In the abstract they write:

Our results indicate that human geophagy is best explained as providing protection from dietary chemicals, parasites, and pathogens, whereas animal geophagy may involve both micronutrient acquisition and protection.

In the paper they give a few examples for this. First the earth eaten is usually digged up from deeper layers of the ground and sometimes even cooked. Then they bring in the example of people, which eat soil, when they have gastrointestinal problems as a kind of medicine to calm down the problems.

In my opinion there is not much nutritional value in eating soil. Organic compounds can usually not be metabolized (for example we don't have the possibility to break down cellulose). I am not sure, if we can get minerals from clay into our body, since a lot of them is present in soil as unsoluble minerals.

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Thanks a lot Chris! You wrote "I am not sure, if we can get minerals from clay into our body, since a lot of them is present in soil as unsoluble minerals." Is it the same for topsoil ? Are its minerals also present as unsoluble minerals ? –  Arone Mar 6 '14 at 6:32
In the topsoil probably not (though I haven't found any data on that yet) since a lot of the minerals is set free from organic matter. But it also gets washed away with rain if it is soluble. –  Chris Mar 6 '14 at 11:05

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