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

Health Advice from your Home Doctor

In the days before the NHS, when the British had to pay for a consultation, "home doctor" books seem to have been quite popular. I've been whiling away a chilly afternoon by dipping into one that was published in 1935. It contains a great deal advice on how to keep healthy. 

On alcohol consumption readers were advised thus:

"The counsel of perfection would be that of complete abstention from alcoholic liquor." The author though, obviously feels this is unrealistic and without explaining why he deems it unhealthy to consume too much liquor, goes on to recommend a sensible daily consumption:

"A glass of beer, light wine or claret at the middle-day meal is quite reasonable, but it is wise to eschew spirits, port, sherry etc" ... A sherry between 6 and 7 pm (the cocktail hour) is preferable to a "spirituous" cocktail "and with the evening meal, a glass or two of white wine, claret or burgundy may be taken as routine" ... "A glass of whisky and soda last thing at night may round off the day, and the average man has had all he wants in the way of alcoholic stimulant for twenty-four hours."

Sounds like a fair bit to me - five drinks a day - but it rather sounds as if this is what the author consumed routinely. So it must be alright.

On tobacco he starts by saying: "It is at least doubtful whether the habit often does any really very great harm," - an interesting sentence that reveals his conflicted feelings. We know that the majority of doctors smoked in the mid 20th century because in the huge study of the effects of smoking, conducted on a large group of British doctors, only 17% were lifelong non-smokers. He goes on to list a number of forms of possible harm caused by the habit: irritation and inflammation of the airways, smokers cough ("too well known to require description"), irregular heart beat, colitis, gastritis, constipation and a form of blindness.

On the subject of exercise the good doctor is cautious, recommending a brisk, 15 minute walk, out of doors, every day, ensuring that one's breathing is deep, head is thrown back and arms are swinging naturally. This is seen as primarily beneficial to the lungs and the reader is reminded: "It almost goes without saying that smoking should not be considered during such a walk."

He cautions against launching into team sports without prior conditioning and recommends that that such activities do not combine well with alcohol or smoking. Running meets with cautious approval but "Except in rare cases, men of over thirty-five years of age should not partake in competitive athletics."

It is notable that the tone of the book is of one middle class gentleman, advising another. Women are considered when specific female problems are dealt with, such as the menopause. Female readers are warned against the habitual consumption of brandy, whisky, gin or aspirin and: "Emotionalism is to be avoided."

There are many pages devoted to areas of life into which health professionals would never dream of venturing today, such as the time of day to take a hot (but not overly hot) bath. The evening is deemed the appropriate time, with perhaps a cold dip in the morning.

There are pages given over to the kind of clothing appropriate for the maintenance of health. Wool next to the skin is strongly recommended but not "old, washed and felted woollen garments" which are, apparently, "a common source of colds." Undergarments made from other fabrics are given cautious approval. Tight collars are mentioned, which "certainly hide that Adam's Apple, but they do impede a free flow of blood between the head and the heart".

He ends the section on clothing with the following: "It should be remembered that to be well dressed is to be inconspicuously dressed, and some of the various freaks and vagaries of attire one so often sees in some individuals are quite unnecessary and usually a sign of exaggerated self-importance." 

The only place that science informed health advice of the 1930s was the diet because it had recently revealed the existence of the key nutrients, so the importance of having a balanced diet was understood. 

We sometimes gripe today about ever-changing recommendations about diet or the consumption of alcohol, so it is interesting to look back and notice how much has changed since the childhood of today's great-grandparents. Long gone are the days when doctors thought that colds were caused by woolly undergarments that had seen better days and the time when they had no idea that smoking caused lung cancer and cardiovascular disease.

Thanks to a great deal of careful scientific enquiry, we all have much better knowledge about the factors that affect health than anyone could have dreamed of in 1935. The official health advice we receive is not perfect, but it is no longer based on firmly held opinions and nothing more.

The Modern Home Doctor, published by the Daily Express in 1935 and written by "members of the Medical Profession".

Doll R, Hill AB. (1954). "The mortality of doctors in relation to their smoking habits". BMJ 328 (7455): 1529.

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