And another one about milk

I realise, after reading some more technical stuff, that what I wrote about the nutritional value of milk yesterday is a little bit misleading. We ought to distinguish more clearly between the importance of vitamin D and the importance of calcium. And, of course, both of these are distinct from the nutritional value of milk in terms of energy and protein (which was part of my point yesterday). So let's talk about vitamin D and calcium now.

Vitamin D is vital for the regulation of calcium. It not only supplies calcium to our bones when it can (so it's vital for growing bones), but it causes us to remove calcium from our bones if there is not enough calcium in the diet for our normal day to day needs. That's why you get osteoporosis or osteomalacia in adult life, if there isn't enough calcium in the diet.

As you'll see from the links I gave yesterday, they've discovered (and are discovering) that vitamin D and the hormones it generates are also important for a whole lot of other things in adult life, including prevention of colon cancer, autoimmune diseases, regulation of cholesterol and various other things.

As well as vitamin D you need the calcium so that the Vitamin D can do its job, keeping the right amount of calcium in your blood stream, and not taking it out of your bones to do so.

Where does milk come in then? Well it's not just a good source of protein and energy (as I mentioned yesterday, vital for diets in places where you can't grow strong grain rich in protein) but it's also a very good source of calcium. So in order to avoid serious bone problems, people need to be consuming a good deal of milk. There are no very good vegetable sources of calcium. The only alternative to milk is the kind of fish where you eat the bones, such as sardines and whitebait. The nutritional authorities suggest that for an adult you need this much every day: one glass of milk (200 mls), one small pot of yogurt, and a 40 gram portion of hard cheese. Anything less than that and you're at risk of calcium deficiency.

The other contribution is in respect of the vitamin D. The best sources of vitamin D are either sunbathing, or neat cod liver oil. If we work indoors and cover ourselves up with lots of clothes we tend to get not enough exposure to the sun (especially during the winter, when the days are too short and the sun barely gets above the horizon, let alone into the city streets). One way of getting more vitamin D, besides cod liver oil, is from the fats in milk products. Vitamin D is a fat-soluble vitamin, and there tends to be some vitamin D in the milk and the butter from cows and goats and other grazing animals, because the cows stand out in the sunshine all day (well if there is some sunshine they get some of it). This means that even if we work indoors and wear lots of clothes in the winter, we can secure a bit of vitamin D from the milk we drink and the butter, cheese and whole-milk yogurt we eat, because the cow has been getting a better chance to make vitamin D and pass it on in the milk. The milk is creamier in the summer and has more vitamin D then, but even in the winter we can get some from a good glass of creamy milk or a decent spread of butter.

Of course, if you use semi-skimmed milk you'll cut out most of the valuable fat soluble nutrients, including the vitamin D, and all of it if you drink skimmed milk. That's one of the reasons why it's vital that children have full cream milk all through the time when their bones are growing, but actually, given how hard it is to get vitamin D if you're not working outdoors all year. I'd say it's not just children who should be on the look out for damage caused by lack of vitamin D. We may be building up problems in the form of cancer, bad cholesterol management and bone disease, for our old age, even middle age. The myth that semi-skimmed milk is better for you than whole milk needs to be challenged. It's only better for you if you need to avoid fats for some reason, but not if your diet is deficient in all the things it's likely to be deficient in, given the refined and processed foods raised on poor quality soil that most people are eating most of the time in Britain.

Despite a lot of misleading propaganda against dairy products, being put out by Vegan organisations, it isn't actually true that dairy products increase cholesterol problems. Most of the instructions about reducing animal fats in the diet ignore the evidence that dairy fats don't actually seem to be implicated (hard hydrogenated fats may be bad, and so may the kind of fat that comes in meat products and oily chips, but even this is not really securely proven). In fact if you think about why the results are not clear on any of these issues, and think about the fact that they're still only just discovering how the "essential fatty acids" and agents like vitamin D control our metabolism, you'll see that the chances are that when you cut out the dairy products, and especially the fats in dairy products, you cut out the very vitamins and hormones that the body needs in order to regulate its handling of fats and cholesterol. It's long been known that the capacity to manage cholesterol is related to hormones. It's time to stop blaming the fats in the diet and start working out why a healthy body with good hormones turns into an unhealthy one that starts depositing fat in its arteries. The answer to that may be in the diet, but it's going to be in the effect the diet has on the hormones, not in the simple issue of how much animal fat is provided in the daily diet. It's perfectly possible that we need to eat dairy products precisely in order to avoid problems with metabolising fats... For instance dairy products contain monounsaturates (these are kinds of fat that occur in olive oil, and some studies seem to think they help to lower cholesterol in the blood: personally I suspect that most of these studies are still jumping to conclusions by looking at correlations and drawing false conclusions about what the explanatory factors are, but there we are).

Here is a site which explains the enormous extent of the contribution to adequate nutrition in our society made by milk products.