Sunday, January 26, 2014
Why taking vitamin D is 'pointless': Review finds taking supplement does little to prevent chronic disease or early death
Good for Rickets but not much else
Scientists claim there is no evidence to support taking vitamin D supplements to stave off chronic disease and early death - and results of several multi-million dollar trials currently under way are unlikely to alter this view.
A new review examines existing evidence from 40 randomised controlled trials - the gold standard for proving cause and effect - and concludes that vitamin D supplementation does not prevent heart attacks, strokes, cancer, or bone fractures in the general population by more than 15 per cent.
In fact, vitamin D supplements probably provide little, if any, health benefit, according to the study published in The Lancet Diabetes & Endocrinology journal.
In Britain, the supplements market is worth £700 million a year - a growth of 16 per cent in five years - and the most popular pills are multi-vitamins and fish oils, which contain vitamin D.
Some scientists assumed vitamin D, which is produced naturally by exposure to sunlight, could protect against disease because patients with cancer, heart disease or Alzheimer’s, or who died prematurely, often had very low levels of the nutrient.
However, evidence from some trials suggests that rather than vitamin D deficiency leading to disease, these illnesses stop the body from producing vitamin D - so sufferers have lower levels.
Last month, a review of 462 studies involving more than a million adults said a lack of vitamin D was not a trigger for many common illnesses.
In the latest study, Dr Mark Bolland of the University of Auckland, New Zealand, and colleagues used several types of review of existing studies, including a ‘futility analysis’, to predict whether future research results might sway existing evidence.
The results of their study suggest the effect of vitamin D, taken with or without calcium, on heart attacks, strokes, cancer, and total fracture lies below a ‘futility threshold’.
This means there would be no point in taking supplements as it would have little effect on health outcomes.
For hip fractures, the results of some trials even suggested an increased risk with vitamin D supplementation.
The authors’ analysis of whether vitamin D supplementation can reduce death rates by five per cent or more was inconclusive.
Professor Karl Michaëlsson, of Uppsala University in Sweden, writing in a Lancet commentary, said: ‘Without stringent indications - i.e. supplementing those without true vitamin D insufficiency - there is a legitimate fear that vitamin D supplementation might actually cause net harm.’
Two months ago the chief medical officer, Dame Sally Davies, called for free vitamins to be given to children after it emerged that a quarter of youngsters are short of vitamin D. Presently it is only available on prescription to under fives from low income families.
In addition, pregnant women and those who are breastfeeding are advised to take one vitamin D tablet a day - which they can get on prescription - to ensure their baby’s bones are healthy.
Dr Carrie Ruxton from the Health Supplements Information Service, said three quarters of Britons have vitamin D intakes which are below the recommended level, with children and older people at particular risk.’
She said: ‘Rickets, once thought to have largely disappeared in the UK, has returned, in particular among children of Asian and African descent who have darker skins, but the disease is also seen in Causasian children usually in areas of urban deprivation.
She said the new review did not look at vitamin D’s role in bone health, instead focusing on chronic conditions such as cancer.
She added: ‘Vitamin D supplements are not intended for treating any disease conditions, and it is disappointing this review did not address the essential role of vitamin D in bone and musculoskeletal health.
‘In the light of the findings that 75 per cent of the British population have below recommended intakes of vitamin D and that vitamin D is essential for bone health as well as a number of other physiological functions, consideration should be given to everyone taking a vitamin D supplement all year round.
Lingonberries 'halt the effects of high-fat diet' (?)
This is only a rodent study with the mice fed huge amounts of the stuff so generalizability is very weak. Nonetheless, many sub-arctic people have very little in the way of fresh fruit and veg. available but do have the very hardy lingonberrries available. That such people stay healthy has been attributed to their consumption of lingonberries. So they are clearly nutritionally valuable
Everyone dreams of being able to eat chocolate and pizza all day without putting on a pound. Now researchers could have found a simple way of making this dream a reality. Scientists in Sweden found eating lingonberries could prevent weight gain in people with a high-fat diet.
The researchers, at Lund University, discovered the berries almost completely prevent weight gain in mice fed a high-fat diet.
They discovered the Scandinavian berries – which are sometimes known as cowberries in the UK - also lower blood sugar levels and cholesterol.
The research team conducted their study using a type of mouse that easily stores fat and, therefore, can be regarded as a model for humans who are overweight and at risk of diabetes.
Some of the mice were fed a low-fat diet, while the majority of the animals were fed a diet high in fat. They were then divided into groups, where all except a control group were fed a type of berry – lingonberry, bilberry, raspberry, crowberry, blackberry, prune, blackcurrant or acai berry.
When the mice were compared after three months, it could be observed that the lingonberry group had by far the best results.
The mice that had eaten lingonberries had not put on more weight than the mice that had eaten a low-fat diet - and their blood sugar and insulin readings were also similar to those of the ‘low-fat’ mice.
Their cholesterol levels and levels of fat in the liver were also lower than those of the animals who received a high-fat diet without any berries.
However, according to the Lund University researchers, people should not see the findings as an excuse to eat an unhealthy diet.
Lovisa Heyman told MailOnline: 'While the findings in mice are exciting, it should absolutely not be interpreted as a license to eat an unhealthy diet as long as you add lingonberries! 'But we certainly hope to investigate if lingonberries could be part of dietary strategies to prevent obesity also in humans.'
This is the first study of this kind using lingonberries.
‘That is probably because lingonberries are mainly eaten in Scandinavia. At international conferences, I always have to start by explaining what they are, and showing the audience a jar of them,’ said Ms Heyman, a PhD student in Experimental Medical Science.
Blackcurrants and bilberries also produced good effects, although not as pronounced as the lingonberries.
The acai berries, on the other hand, came last, although they had actually been included in the study for the opposite reason – the researchers wanted to see how well the Nordic berries would do in comparison with the Brazilian ‘super berry’.
‘Instead, the opposite happened. In our study, the acai berries led to weight gain and higher levels of fat in the liver,’ said Karin Berger, diabetes researcher at Lund University.
The good results from lingonberries may be due to their polyphenol content, according to the researchers.
The team will now continue to work on understanding the molecular mechanisms involved in the effect of lingonberries. They will also see whether the effect can be observed in humans.
‘Up to 20 per cent of our mice’s diet was lingonberries. It isn’t realistic for humans to eat such a high proportion.
‘However, the goal is not to produce such dramatic effects as in the “high-fat” mice, but rather to prevent obesity and diabetes by supplementing a more normal diet with berries,’ said Dr Berger.
However, the Lund researchers do not recommend people start eating large quantities of lingonberry jam. Boiling the berries can affect their nutrient content and jam contains a lot of sugar. Frozen lingonberries on cereal or in a smoothie are considerably better.
‘If anyone wonders – yes, we now eat lingonberries on a regular basis,’ said Ms Heyman.
Lingonberries are edible fruit that are native to forests and tundra in northern Europe and North America. They are very popular in Sweden and are commercially cultivated in some parts of the U.S. They are most commonly used in jams, compotes, juices, smoothies and syrups.
In the UK, they are not normally available in supermarkets but can be bought from IKEA and some specialist stores
Posted by jonjayray at 12:11 AM