What the heck? Rickets?

SO according to research around 40% of under fives in the UK are in danger of developing rickets!  I find this a terribly high figure. The government are proposing giving free vitamin supplements to all under fives. 
Hey! I know this might be reactionary, but instead of giving out vitamin tablets, why not make sure the Mothers know how to cook a nutritious meal.  After all, there is no excuse for this vitamin deficiency.  In this day and age there really is no excuse for children to develop this condition.  As for the excuse the Mum's interviewed were giving, what right thinking parent allows their child to be using game systems and watching TV for prolonged periods of time, so that they don't have time to "play out" or spend time outside?  For pity's sake.....it's UNDER FIVES that are being said to be in danger, do these parents allow their under fives to set the rules? 
I used to love taking my three out for walks along the canal, down to the village, to the library, to the playground, as they got older we used to go on longer walks to "explore".  Don't get me wrong, they did watch TV, and on a miserable rainy day we liked nothing better than spending the day baking, making things, or even just curling up and watching a good Disney film....but we would do lots of other stuff, even invented silly games that we'd just thought up on the spur of the moment.
So..instead of throwing sticking plaster answers, the government should look at the cause and not the consequences, after all things don't happen without a cause.
Right...I'll get off my soapbox and shut up.