Rickets and the Immune System

Today I have been reading another medical book from the middle of the 20th century.

Diseases of Infancy and Childhood, by Wilfred Sheldon was first published in 1936 and went into at least six editions. Sheldon worked at Great Ormond Street and advised the government on child health.

The section I've been reading is on rickets, a deficiency disease caused by lack of Vitamin D that was common in the past and still crops up occasionally today.

Sheldon knew a thing or two about rickets and how it distorted every part of the growing skeleton in babies and toddlers.

He noted that rickets was more likely to occur in late winter. He was well aware that winter sunshine has no vitamin D generating effect in countries far from the equator. He also believed that food such as milk and eggs had less vitamin D in the winter, which seems very plausible.

He states that breastfed babies are less susceptible to rickets - presumably because many proprietary milks and foods in the past did not have added vitamin D. These days the babies most likely to get rickets are the breastfed babies of mothers whose bodies are low in vitamin D. This can be for dietary reasons (few animal fats) or because the mothers tend not to expose their skin to sunlight. These babies need vitamin D supplements to protect them.

There is a lot of research interest in vitamin D and the immune system these days. We know that there are receptors for the vitamin all over immune cells. You don't have a letterbox if you are not expecting mail.

So it was interesting that Sheldon says:

"Uncomplicated rickets is seldom a fatal condition: its danger lies in weakening the child's resistance to infection, the immediate cause of death being usually broncho-pneumonia or diarrhoea. The prognosis of fevers, particularly measles, whooping cough, and influenza, is made much worse when they are complicated by rickets."

If he was writing today he might have put it differently: a child with very low levels of vitamin D is more susceptible to infections - the function of their immune system is impaired.

There are only 3 ways to get vitamin D. By the action of sun on skin; by eating a diet rich in animal fats - oily fish being the richest source and by taking supplements.

We should wonder whether children today are getting the amount of vitamin D they need. Not much playing outdoors seems to go on and if they do go out on sunny days a layer of sunblock is often applied. Muslim girls do PE with their head, arms and legs covered. The many darker skinned children that live in places where sunshine is in short supply may also be vulnerable because darker skin makes vitamin D more slowly.

And older adults too. They may not spend much time sitting in the sun. Or if they do they are less likely to expose much flesh and older skin makes vitamin D more slowly than young skin.

We all need vitamin D. We don't know yet how much. We are just beginning to find out how it affects the immune system. A bit of sunshine on the skin, in moderation, is probably good for us. Sunburn is not.

I am not a fan of supplements generally. The only one I take, at least in winter, is vitamin D.

A Healthy Glass of Juice?

I'm going to stay with the vitamin C theme and talk about fruit juice. It is a delicious drink, particularly freshly-squeezed orange juice. But it is also a triumph of marketing.

In the Second World War the British Ministry of Food worried, probably unnecessarily, that children would be deficient in vitamin C. Fresh, imported fruit was rare but people did consume quite a lot of vegetables - so their vitamin C consumption was probably fine. But juice drinks were recommended for children as a supplement. Blackcurrants and rosehips were home-grown sources of fruit concentrate. Those of us who grew up in the post war decades remember concentrated orange juice from the NHS clinic. 

Meanwhile the orange growers of Florida were promoting orange juice, and doing so very successfully. OJ, as it became known, became a standard part of the diet in the United States. Every good mom dispensed it liberally. I visited Las Vegas once and it was being doled out to breakfast-buffet-eaters by the pint. As soon as your glass was nearly empty, someone would offer to fill it.

Since then fruit juice in various forms has become a regular feature in most British shopping trolleys. It maintains an image of being a healthy drink, riding on the back of the stellar success of vitamin C. (see previous post)

But is it really healthy?

The recommended daily intake of Vitamin C varies between countries but is always under 100mg. A 250ml glass of vitamin C contains about 120mg of vitamin C, more than our daily requirement. How much is 250ml? It is an American 'cup' or a large wine-glass full. It may contain a few other useful micronutrients but it also contains a lot of sugar.

Every 250ml glass of unsweetened juice contains the equivalent of 8 teaspoonfuls of sugar - similar to non-diet cola. And this of course accounts, in part, for its success. From cradle to grave we adore sweet things. And the more we eat, the more we crave.

Dentists disapprove of regular juice consumption - the sugar encourages decay and the acidity of the juice erodes enamel.

Dietitians are not keen either - they grudgingly allow that a small glass of juice can be counted as one of your "five-a-day". Their recommended serving is 150ml. In other words a small wine glass size. You can't achieve your five-a-day target by drinking 750ml of juice. You can only count one.

Increasing rates of obesity and type 2 diabetes are undoubtedly fuelled by consuming sugar and there is no reason to think that sugar-laden juice is somehow exempt from blame. The fact that it claims to be healthy perhaps makes it more culpable. There is no reason to think juice, in anything other than small quantities, is a good choice if you are trying to eat a healthy diet.

What about "juicing" then? It is quite entertaining, if you have a cheap source of fruit and a user-friendly machine. But is it "healthy"? I suggest that if you have a sick person to look after, one who is not eating well for more than a couple of days, then juicing may have a role - fresh juice offers palatable fluid and calories if calories are a priority.  But the idea that it is otherwise beneficial to health has no foundation.

Milk, water and unsweetened teas are better ways of consuming fluids than any form of sweet drink. Vitamins are better obtained by eating a variety of whole fresh fruit and vegetables. If you want to a citrus-flavoured drink when you have a cold, consider options that don’t contain lots of sugar - fruit or ginger tea bags, sweetened with just a little honey or marmalade.

Vitamin C – A Cure For Colds? Really?

Winter is just around the corner, so I’ll start with the health claim we all know best: vitamin C prevents colds and flu and alleviates the symptoms of these irritating ailments.

There is little evidence to support much of a case for vitamin C supplements, despite the publication of enough research papers to build a small hill.

Cochrane Collaboration scientists, after systematically reviewing all the well-designed studies they could lay their hands on, concluded that there is no evidence that supplements of vitamin C prevent colds. There is, they conclude, a small reduction in the severity and duration of colds in those taking regular supplements.

It is possible, they go on to say, that massive doses (e.g. 8 grams), at the onset of a cold may help symptoms but there are too few trials to be sure. The jury is still out on this and doses of this size can cause diarrhoea. And remember the effects that are found in some (but not all) studies are minor, not curative.

There is some evidence that for those indulging in arduous physical activity – marathons and so on - vitamin C can help to reduce their incidence of colds. So if you are entering a triathlon or climbing a mountain then make sure your diet contains plenty of fruit and veg.

So what are the other facts?

Severe deficiency of vitamin C causes scurvy. This is a disease in which the walls of blood vessels cannot repair themselves. Sufferers eventually die from bleeding (and not, apparently, from infections). So we are certain that vitamin C is essential to the body if it is to carry out repairs. It is also used by cells, including immune cells, but they only seem to need a small amount.

You have to be eating a terrible diet for several weeks to get scurvy – one that contains no fresh food. If you are an Arctic hunter eating plenty of fresh meat you will be fine. If you eat chips and burgers and nothing else, you will not get scurvy. If you ate only cake and sweets you might.

There is circumstantial evidence that people who eat lots of fruit and vegetables tend to be healthier but there is no reason to think that vitamin C is the magic ingredient. When we eat fruit and veg we get a range of benefits and extracting pure vitamins and consuming them as supplements does not seem to be the same thing at all.

So, my conclusion is that we should not be seduced into buying products that claim to have added vitamin C or wasting our money on vitamin C supplements. Spend money on fruit and veg instead and you will get your vitamin C along with the other nutrients.

Here’s the link to the Cochrane article.

http://bit.ly/Xgdysx