Tuesday, July 14, 2015

Vitamin D in Mushrooms

I work for the mushroom industry in Australia and very recently we did something not yet done anywhere else that I know of. I arranged a collection of retail mushrooms from a range of stores in five capital cities and had them sent to the National Measurement Institute in Melbourne for analysis of their vitamin D content.

First, I should say that mushrooms are the only non-animal food to naturally produce vitamin D. Just like you, they do it in response to exposure to a source of UV light (eg sunlight). Mushrooms labeled “Vitamin D Mushrooms” have at least the daily needs of D in a serve (10 mcg), because they are exposed to UV light post-harvest.

What surprised me is that regular retail mushrooms have 20-25% of your daily D needs. I suspect that they are producing D from the UV bandwidth in the fluorescent lights in-store.

Table. Vitamin D content of store-bought button mushrooms (100g)
Vitamin D mcg/100 g serve
Regular retail mushrooms (sliced & whole)
Cooked regular mushrooms
Regular mushrooms after 1 hr in the winter sun
Vitamin D labelled mushrooms
Cooked Vitamin D labelled mushrooms
Source: National Measurement Institute

Following the strict protocol set by Food Standards Australia New Zealand, the resulting data was placed on their website. From there you can download the report.

It is winter in the southern hemisphere as I write and about half the population in Australia and New Zealand (and probably Argentina, Chile and South Africa) will be vitamin D deficient. Mushrooms can be part of the solution.