Soft fruit - healthy or hazardous?

Berries are often promoted as a healthy food and grabbing a punnet of blueberries may seem a darn sight easier than giving up smoking, cutting down on alcohol or taking daily exercise. Or indeed, easier than cutting down your total intake of fats and sugars. But of course it’s your entire dietary mix that matters, not whether or not you eat berries.

Fresh berries are expensive because they are so perishable but packets of cheaper frozen berries have now become widely available. These are advocated for all kinds of “healthy recipes” in magazines and cookery books. They are also used by manufacturers to decorate ready-made frozen desserts such as cheesecakes.

There have been two examples in the news recently of serious illnesses being contracted from eating frozen berries.

In Sweden three elderly people died from norovirus, contracted from eating a frozen dessert that contained berries of Serbian origin in  And in Australia, earlier this year, there were several cases of Hepatitis A, linked to frozen berries imported from China. 

Hepatitis A is linked to faecal contamination of food and norovirus can also be spread in this way.

If we were to give the EU berry farmers the benefit of the doubt, we would envisage their fields and packing areas equipped with fragrant portable toilets and well-equipped hand washing facilities. We might confidently envisage that their staff induction sessions include training on the importance of hand hygiene. Whether or not all farmers reach these high standards I cannot say. If we let our imaginations travel further afield then we might be less optimistic about hygiene in berry fields and processing plants. 

Berries are delicious and if you have a garden, growing your own soft fruit is a great way to use it. Fresh soft fruit  should be washed – but of course you can’t scrub a raspberry. As for imported frozen berries, they can potentially do you more harm than good. My advice is to avoid all uncooked berries if your immune system is compromised. And for everyone else, treat frozen berries as a cooking ingredient that needs to be thoroughly cooked before eating.

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

Souvenir Supplements - the Perfect Gift?

In Sydney airport transfer lounge, 20 hours of flying behind me and another three ahead, I cast a bleary eye over the souvenir shops. Their shelves hold aboriginal art, expensive clothing items and a wide selection of souvenir food supplements. Gone are the days when you bring home tea towels or a fridge magnet for your mum. The on-trend global traveller is more likely to say: "I'm back darling, and I've brought you something that's supposed to be really good for arthritis!"

I imagine that the product development for these supplements probably goes like this: you identify a plentiful resource like kangaroos or sheep placentas and brainstorm how you could turn them into an income stream. Having honed in on the plan of selling supplements to the gullible you then make up some marketing blurb that includes a random selection of unspecific "things it must be good for" such as boosting your immune system/ reducing inflammation/ improving mobility of joints/ rebalancing energy/ restoring vitality/ boosting sexual performance and so on. Make sure you list the scientific analysis so you have some scientific words to put on the label. Throw in a few random "facts" and then commission your packaging.

Here are three examples from down under.

Colostrum

This interesting liquid is produced by mammalian mothers in the first few days after giving birth - the perfect food for their own particular species of newborn. Mouse colostrum is ideal for newborn mice while elephant colostrum is tailored to the needs of elephant babies.

Colostrum is very high in protein - much higher than true milk. Those who keep milk-producing animals sometimes use colostrum to cook a special dish. Just mix colostrum with some sugar and bake at a low heat. The result will apparently be a lot like egg custard. You couldn't do this with milk because its protein levels are much lower.

A significant proportion of the proteins in colostrum consist of antibodies (immunoglobulins). This download from the mother's immune system helps to protect the baby from infection until it can develop its own set of immunities to the microbes in its environment. Cow antibodies will protect against cow diseases and the kind of bacteria encountered every day in pastures and the milking parlour. Calves that are deprived of cow colostrum tend not to thrive - they seem to need it to prime their intestines. But why should the benefits of colostrum to newborn calves translate into health benefits for the adults of another species?  Adult humans don't need protecting against bovine diseases. And even if they did, why should we expect that these complex molecules would survive pasteurisation, drying, packaging and digestion by a human stomach? Is there in fact any evidence that consuming cow colostrum has any benefits to human health?

The website of the "Institute of Colostrum Research" seemed to be a promising place to find the answers to these questions. But alas no - not a single link to research could I find.

The Centre for Nutritional Research, also keen on (selling) colostrum is also long on supposition and short on research.

Lamb Placenta Extract

Many animals eat their placentas. I remember once watching my son's pet gerbil giving birth to a large litter and as each one emerged she grabbed the placenta in her front paws and nibbled it, in exactly the same way that she ate sunflower seeds. This was certainly a way of reclaiming some of the nutritional resources, such as iron, that she had devoted to pregnancy. I don't think sheep tend to eat their placentas and I can imagine that people scratching a marginal existence by herding might well scoop them up and make them into a nutritious casserole. But what on earth are pills made from sheep placentas supposed to do for your health other than perhaps act as an iron supplement? Somehow pass on the joie de vivre of a lamb?

The marketing takes a broad-brush approach and mentions things like growth hormones and the wonderful health of the sheep used in production. It's good for all kinds of things, honestly - "rejuventating your organic tissue" for example. I particularly liked the nugget of "information" that sheep's placentas have been used as medicine by the British royal family for 1400 years. Must be good stuff then.

Kangaroo Extract.

The marketing for this emphasises the vigour and sexual potency of the male kangaroo, conjuring up visions of great-grandad leaping from his wheelchair and doing a pogo dance around the lounge while singing a Rolf Harris medley and casting a flirtatious eye at the care staff. Why kangaroo extract should be any more revitalising than, say, beef extract, is not at all clear. But there are large segments of world population that believe in the "law of similars". The law that dictates that if a rhino horn reminds you of an erect penis then extract of rhino horn is bound to do wonders for the flagging erection. If you could distill the essence of a big bouncy virile 'roo, why would it not have a beneficial effect on the aging male? You know it makes sense.

This one may also play to the jokey present market.  "Didn't know what to get you dad but you've been looking a bit tired lately so I got you some Kangaroo extract."

The trouble is that these products, with their vague, "natural" marketing messages, feed into two main belief systems. One is the oriental medicine trade that greedily slaughters wild animals in the interests of producing tonics and impotence cures. Only today I read about the seizure of a large cargo of dead anteaters (pangolins) destined for this market. Endangered plants can also be plundered and rare habitats damaged. There may be plenty of 'roos but I doubt that pangolins are an inexhaustible resource.

The other is the western belief that any natural product extracted from plants or animals is not only health-inducing but somehow superior to modern medicine. It is an alluring idea, but alas, it is just not true, however much we would like it to be. Why should we care? Firstly because some people turn down conventional treatment for serious diseases, believing supplements can cure them. And secondly because people who are not well educated in scientific scepticism are tricked into spending their scarce funds on these products.

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. 

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