It is estimated that up to 80% of adults in the US, or the western world in general are deficient in Vitamin D for some or all of the time.  This number rises to 90% in infants and very young children.  In many countries, doctors and pediatricians recommend that babies are given Vitamin D drops to boost their Vitamin D intake and in winter months, most adults would benefit from a boost in their Vitamin D.

Why?  First, and most importantly, particularly if you are pregnant or have a baby, Vitamin D aids the absorption of calcium which is imperative for healthy bone development.  A serious Vitamin D deficiency can lead to rickets.  Among other effects, in the long term it can also impair the effectiveness of the immune system allowing a myriad of other diseases to gain a foothold in your body.  Rickets used to be a serious health problem right up until the 1960s, but in recent years it has returned.  Many commentators lay the blame on the success of those trying to protect us from skin cancer who advocate the use of UV barriers, sun creams etc. particularly on infants and small children.  They act to screen out the UV rays, but in the process, they make our skin unable to produce Vitamin D, so even if we are in the sun, with sun cream on, we won’t produce Vitamin D.

Research, mostly in Australia has concluded that mushrooms can, indeed, make vitamin D, in much the same way that humans do when exposed to the sun, but there are several subtle differences which I will discuss later.  Even supermarket or shop bought mushrooms will produce vitamin D if placed in direct sunshine for an hour once purchased.  To maximize the effect the mushrooms should be laid outside on a tray (not behind a window), gill side up.  After an hour’s exposure to the sunlight the mushrooms will produce vitamin D.  Studies suggest that 85% of this is retained after 5 minutes frying or 8 days in the fridge.

So, are mushrooms the answer to all our Vitamin D problems?  Perhaps not.  Research has shown that mushrooms make Vitamin D2, rather than Vitamin D3 which is what the human body produces naturally.  Vitamin D2 does not last as long in the body as vitamin D3 so an extremely regular supply of either would be fine to meet daily requirements, but vitamin D3 is more likely to meet your long term requirements if Vitamin D is not available every day.  There are some commentators who actively suggest that Vitamin D2 is bad for you and that the ‘great mushroom rumour’ is put about by those who sell or market mushrooms.

I am not an expert, but it seems to me, that a diet with Vitamin D enriched mushrooms can’t be a bad thing, unless, like everything else in life, it is taken to excess.