The Value of Vitamins

It all started with the important discovery of vitamin deficiency diseases like scurvy, pellagra and rickets and now it's become a huge industry. You can hardly venture onto public transport without seeing adverts for supplements on railway stations, in tube trains or on the backs of buses. Anyone would think vitamins and minerals were to the body what oil is to the engine of a car - a simple top up and smooth running is assured.

It's very hard for the average consumer to make informed decisions in this area - the products sound tempting and "everyone's" taking them, so they must be good, mustn't they?

Doctors tend to be conservative on the subject - "you only need vitamins if you have a vitamin deficiency disease" would be their traditional position statement.

"Nutritionists" are far more liberal. They believe that vitamins not only prevent diseases but can also "heal" all manner of ills. They recommend a vitamin (or six) for every ailment. As if that extra oil in the car could mend a broken engine part. They tend to be overly eager to support their beliefs by citing  evidence from experiments involving cells and mice.

In the middle ground we have the lucrative supplement industry with a vested interest in convincing us that we need supplements and so getting us to part with our money.

So what's the scientific take on all this?

Evidence cannot convince the scientific community unless it involves a large group of humans (not genetically modified mice), taking vitamins over a long period of time, with a "blind" comparison group taking placebos. Only then can you check whether the supplements are safe and whether any positive effects result. Such trials are, of course, very expensive and are consequently rather rare. Such studies that do exist have sometimes shown no benefit, or even demonstrated harm to those who take vitamin supplements for long periods.

In summary - the better quality evidence has generally been "disappointing" inasmuch as it has failed to show that supplements reduce your chances of avoiding colds or cancers, or that they increase your chances of living longer. Vitamins cure vitamin deficiency diseases, but evidence that they are curative in other areas is very flimsy indeed.

The other problem for consumers is that vitamins are very lightly regulated. In Europe, now, you cannot even hint on packaging that a food has an active health benefit. There are only a few examples that are approved by the European Food Standards Agency (notably oats and the cholesterol-lowering products such as Benecol margarine). Food packaging is still allowed to bear words like "fortified with Vitamin A" or "a source of vitamin C" as long as they contain minimum amounts of the relevant nutrient.

Where food supplements are concerned, as long as they are not actually toxic or contaminated and as long as they make their claims in qualified terms such as "may help support a healthy immune system" they are very lightly regulated. In other words there is not a lot of consumer protection.

Cochrane systematic reviews are a good place to look if you want to check the best evidence about supplements. A new book has been published which goes into more myth-busting detail and it looks like interesting reading.

http://www.thecochranelibrary.com/view/0/index.html

http://www.guardian.co.uk/lifeandstyle/2013/jun/07/vitamins-stop-taking-the-pills?INTCMP=SRCH

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.

Infant Feeding, Past and Present

I have in front of me a tattered book entitled Modern Methods of Feeding in Infancy and Childhood. It was first published in 1926 and was still selling well in 1941. It was written by two doctors and aimed at trainee nurses and doctors. It is fascinating to flick through and discover a bit more about the lives of mothers and babies in the not so distant past.

Then, as now, breastfeeding was strongly recommended with several advantages to the baby:

It is the perfect food for human babies; it contains immune bodies "which help the child in its early struggle for existence";  the child "thrives better and has good motions, a good digestion and sleeps well; "it is five times less likely to die during the first year of life" and it is better off being" thrown into the company of its mother" than being cared for by "some disinterested person".

In case this message needs emphasising the authors remark on the first page: "In the first six months of life the mortality is largely among those who are artificially fed."

Breastfeeding contraindications are few: open tuberculosis in the mother is the only complete prohibition while mothers with syphillis are advised to breastfeed, as the baby will already be infected. Mothers with malignant diseases and insanity should, the authors say, be encouraged to breastfeed if at all possible but the doctor should make the decision.

Regular feeding times should be strictly adhered to, using either a three or four-hourly schedule.

For those mothers who opted for artificial feeding (i.e. bottle feeding), and for those who were weaning, there was a wide range of options - tinned evaporated milk, sweetened condensed milk, fresh milk, dried milk and a few peculiar mixtures. Virol and Milk, for instance, contained: malt extract, eggs, marrow fat and red bone marrow, along with "salts of lime" iron and dried milk. 

Fresh milk could not be relied on as being safe at that time. Since 1922 there had been attempts to improve the safety of milk, but this was still a work in progress. Of course raw milk would still be a dangerous food today, even though hygiene in the cowshed has improved a great deal. 

The authors recommend that fresh milk for a baby should be from a "mixed herd" and not a single animal. Their reasoning is that if this single cow was diseased it was likely to prove detrimental to the child.

Smoking in excess while breastfeeding is discouraged as "it has a definite toxic effects on the infant." But the authors go on to say: "It is claimed that up to seven cigarettes a day can be smoked without upsetting the infant."

Then, as now some mothers made their own weaning foods. Strained broth made from bones, vegetables and a range of other ingredients (e.g. the occasional piece of liver) is strongly recommended.

There was much concern about rickets and giving babies cod liver oil was strongly advised. There were a number of alternative Vitamin D preparations available at this time, including Radiostoleum, RadioMalt and Viosterol. These names might sound strange today but they were intended to convey that the product was prepared in a scientific way. In the pre-Hiroshima years, radiation was viewed as an entirely beneficial product of science. We are still encouraged today to buy supposedly beneficial products with sciency sounding brand names and ingredients, dreamed up during meetings of the marketing department.

Many things were very different then. The amount of serious disease in the mothers for instance. This was the period just before the invention of antibiotics when infant and young adult mortality were still high. Powdered milk production had not been standardised. It is also interesting that, despite the scientific approach in the book, the physiology of breastfeeding was not fully understood and putting the newborn to the breast in the first six hours is seen as undesirable.

The French have a saying: "Plus ca change, plus c'est la meme chose" - the more it changes, the more it stays the same. So apart from sciency marketing and brand names what's the same? Breastfeeding is still, of course, much better for babies, despite the improvements made in commercial baby milks. There has, it seems, been a recent swing back to putting babies on schedules. And there is, again concern about vitamin D levels. This week the Royal College of Paediatrics and Child Health have been highlighting the fact that there are worrying levels of vitamin D deficiency in the British population and that rickets is again on the rise. We now know that vitamin D plays many roles within the body and that deficiency can predispose people to a range of diseases.

When one of the Royal Colleges is sufficiently alarmed to urge us to give babies vitamin supplements, we should all take it very seriously.

http://www.rcpch.ac.uk/news/rcpch-launches-vitamin-d-campaign

Modern Methods of Feeding in Infancy and Childhood, Paterson and Smith, Constable, 1926 and still reprinting the seventh edition in 1941.