Calcium and vitamin D (further thoughts)

Richard pointed out (in an e-mail) that I had claimed that there were no very good vegetable sources of calcium, and that the only serious alternative to milk was the fish where you eat the bones and all. What I said there had been based on rather popular and inexact reports on the internet, so I promised to check out some facts.

Here (from Denise Mortimore The Complete Illustrated Guide to Vitamins and Minerals) are some figures for quantities of dietary calcium in mg/100g (this is just a selection from a longer list of course, but the top ones are the important ones):

Kelp 1,093
Cheddar cheese 750
Sesame seeds 700
Sardines with bones 550
Dried figs 280
almonds 234
watercress 220
plain yogurt 200
pilchards 105
whole milk 103
cabbage 57
brown rice 32

So what I said was not quite accurate. Kelp is a very good source (but you would probably have to go out of your way to get that in even quite small quantities on a daily or weekly basis. It's not part of an ordinary popular diet available in schools and homes, in the way the milk, cheese and sardines are). Sesame seeds are also a good source, but again not so regular in our local produce. My concern is that one ought to be able to get adequate nutrients from a non-fussy seasonal diet based on local produce. And in that respect, the normal way of securing a calcium intake in this part of the world, where traditional meadow pasture is available, is from dairy products.

As regards vitamin D, in mcg/100g

Cod liver oil 212.5
Herring and kipper 22.4
canned salmon 12.5
eggs 1.6
butter 0.8
liver 0.8
cheddar cheese 0.3
whole milk 0.03
and a trace in dark green leafy vegetables.

Looking at this list, you might think that the butter, milk and cheese was a rather less effective way to get this vital nutrient than the herring and the cod liver oil. But the fact is that a good spread of butter on your bread twice or three times a day and some creamy milk on your breakfast cereal is likely to ensure that you have that smidgeon of a regular daily intake that is needed to add to the glimmer of sunshine that catches the edges of your ear lobes and (on a warm day) the backs of your hands on your way to work. Of course if you have a kipper or a boiled egg for breakfast every day, this will be quite helpful too, and might make up for the fact that we're giving up foreign holidays in sunny places because of the carbon emissions. Instead we can make up for it by going on a brave English holiday, with plenty of walks in the hills to get above the clouds, and staying somewhere where they serve The Traditional English Breakfast.