Sunshine vitamin essential for pregnant women
Friday December 28th, 2007
Vitamin D deficiency is triggering serious problems in infants, British health officials warned today.
Problems such as seizures and rickets are on the rise because pregnant and breastfeeding women produce less vitamin D in winter months.
A new government warning suggests that as many as one in 100 children in ethnic minority groups may develop rickets, as people with darker skin do not absorb as much sunlight.
Health experts say that during winter people rely on body stores and dietary intake to maintain adequate vitamin D.
"In winter months at latitudes of 52 degrees north (above Birmingham), there is no ultraviolet light of the appropriate wavelength for the body to make vitamin D in the skin," says a department of health press release.
Dr Colin Michie of Ealing Hospital, UK, says: "We are seeing significant numbers of children with vitamin D deficiency. Mothers and babies are simply not getting enough of this important vitamin."
Good dietary sources include oily fish, eggs, fortified cereals and breads, but supplements may be necessary. In England, the NHS's "Healthy Start" scheme provides free vitamins via GPs and health visitors.
Dawn Primarolo, the health minister, said: "The Healthy Start scheme is designed to improve the health of some of our most vulnerable families. We encourage people who are eligible to take advantage of the free vitamins, to minimise the risk of developing vitamin D deficiency and other conditions.
"We particularly encourage women who are pregnant or breastfeeding to take vitamin D, to protect the health and wellbeing of their baby and help them get the best possible start in life."
Experts find genetic clue to overeating
Friday December 28th, 2007
Researchers have identified a protein that may be crucial to overeating and obesity.
Dr Maribel Rios of Tufts University, Boston, USA, and colleagues say the protein - brain-derived neurotrophic factor (BDNF) - regulates appetite and body weight in adult mice.
Knowledge of this process could help unravel the causes of the current obesity epidemic.
The expression of BDNF in two specific brain regions is needed to suppress appetite, explain the team in the Journal of Neuroscience. When the gene is deleted in these two regions, mice eat more and become significantly heavier.
But if the mice have limited access to food, their body weight returns to normal. This suggests that the deletion of the gene does not affect energy expenditure.
Dr Rios explains: "Prior to this study, we knew that the global lack of BDNF and/or its receptor during development leads to overeating and obesity in young mice. However, it remained unclear and controversial whether BDNF mediated satiety in adult animals."
The new findings show that BDNF is necessary in the ventromedial (VMH) and dorsomedial hypothalamus (DMH) of adult animals, for normal energy balance.
"Additionally, because the mice examined in this study were genetically altered in adulthood, we were able to establish that BDNF acts as a satiety signal in the mature brain independently from its putative actions during development of the brain," Dr Rios said.
This might help define critical periods when obesity treatments and interventions would be particularly effective, she hopes, pointing out that many obese humans carry mutations or abnormalities in the BDNF gene or its receptor.
"This is bound to be an important area of obesity research," she concluded.
Unger, T. J. et al. Selective Deletion of Bdnf in the Ventromedial and Dorsomedial Hypothalamus of Adult Mice Results in Hyperphagic Behavior and Obesity. The Journal of Neuroscience, Vol. 27, December 26, 2007, pp. 14265-74.
New fish boost for brain disease
Thursday December 27th, 2007
Fish oil may give patients with Alzheimer's disease exactly what they need, according to new findings.
The oil, widely touted for its health benefits, has long been thought to help patients with the brain disease.
Now a new scientific study suggests why this is so - showing how fish oil directly restores the body's ability to counteract the disease.
The study on laboratory rats, at the University of California, Los Angeles, USA, found that fish oil increases the production of a protein called LR11, which is found in reduced levels in patients. It is also known to destroy that substance that forms the plaques that cause the disease in the brain.
The effect was linked to the omega-3 fat found in fish, known as DHA or docosahexaenoic acid.
Researcher Professor Greg Cole said that fish oil treatment is now being tested on patients with established Alzheimer's disease - although it might be too late to help them much.
He said: "We found that even low doses of DHA increased the levels of LR11 in rat neurons, while dietary DHA increased LR11 in brains of rats or older mice that had been genetically altered to develop Alzheimer's disease."
Progress towards better hay fever medications
Thursday December 27th, 2007
British researchers have made a discovery about the immune system that they think will lead to better allergy treatments.
Dr Carsten Schmidt-Weber, of Imperial College London, UK, and his team hope it could help counteract increasing rates of hay fever and asthma.
The team investigated genes that control the immune system, and how they interact. They found out that allergies are triggered by a mechanism which prevents the immune system from regulating itself properly.
When a gene, known as FOXP3, is blocked, "regulatory T cells" stop being made. These cells are vital for preventing allergic reactions. So if a drug could stop FOXP3 being blocked, the immune system would return to normal.
Details are published on December 27 in the journal PLoS Biology.
"This finding will help us to understand how healthy individuals are able to tolerate allergens and what we need to do to re-induce tolerance in the immune systems of patients with allergies," said Dr Schmidt-Weber.
"We hope that we will soon be able to help not only patients suffering from single allergies, but also those with multiple ones - the atopic patients."
Dr Schmidt-Weber and his colleague Professor Stephen Durham have also been involved in researching the development of new preventative treatments for hay fever.
Professor Durham said: "We know this pill is effective, that it improves quality of life, and reduces the need for treatment."
Patients in general prefer to take a pill rather than have an injection, he believes.
"Popping a pill under the tongue for a few months prior to the grass pollen season would be a much more acceptable form of therapy."
Mantel, P. Y. et al. GATA3-Driven Th2 Responses Inhibit TGF-b1–Induced FOXP3 Expression and the Formation of Regulatory T Cells. PLoS Biology, Vol. 5, December 27, 2007.
Hope for novel anti-cancer drug
Monday December 24th, 2007
A new compound activated by light may offer powerful new treatments for diseases such as ovarian cancer, researchers have reported.
The compound is up to 80 times more powerful than other platinum-based anti-cancer drugs, say Professor Peter Sadler of Warwick University, UK, and colleagues.
It is a light activated "PtIV complex" which is highly stable and non-toxic, when kept in the dark. However, it becomes much less stable and highly toxic to cancer cells when exposed to light.
The team compared it against the current platinum-based anti-cancer drug Cisplatin, and found it is 13 to 80 times more toxic. Using ovarian cancer cells, the researchers found that it can also kill cancer cells that are resistant to cisplatin.
Professor Sadler explains: "Light activation provides its massive toxic power and also allows treatment to be targeted much more accurately against cancer cells."
He says that patients could be treated in the dark, with light directed at the cancer cells alone. In this way, normal cells exposed to the compound would be protected.
In the Proceedings of the National Academy of Science, the team write that the compound "is remarkably stable in the dark", but "rapidly undergoes photoinduced reactions".
"When the compound is photoactivated in cells, it is highly toxic," they write. "It therefore has remarkable properties and is a candidate for use in photoactivated cancer chemotherapy."
It may be particularly effective at treating surface cancers, they explain, adding that it could be used as part of a new type of photoactivated chemotherapy for cancer in a few years time.
Mackay, F. S. et al. A potent cytotoxic photoactivated platinum complex. The Proceedings of the National Academy of Science, published online December 19, 2007.
Dark chocolate's health benefits in doubt
Monday December 24th, 2007
Researchers have delivered bad news to chocoholics - claiming that even dark chocolate may not always contain healthy flavanol chemicals.
These chemicals are found in cocoa and thought to be strong antioxidants. A recent study suggests that dark chocolate rich in flavanols reduces risk factors for atherosclerosis - clogging, narrowing, and hardening of the arteries.
However, the Lancet now warns that not all dark chocolate contains flavanols, and it's impossible to tell from the packaging.
An editorial in the journal states: "Dark chocolate can be deceptive. When chocolate manufacturers make confectionary, the natural cocoa solids can be darkened and the flavanols, which are bitter, removed, so even a dark-looking chocolate can have no flavanol. Consumers are also kept in the dark about the flavanol content of chocolate because manufacturers rarely label their products with this information."
The possible health benefits are offset by the fat, sugar, and calories also contained in dark chocolate, according to the analysis.
"To gain any health benefit," the editorial says, "those who eat a moderate amount of flavanol-rich dark chocolate will have to balance the calories by reducing their intake of other foods - a tricky job for even the most ardent calorie counter."
A calculator may be called for, says the editor, now the holiday season is upon us.
"Some would say that, in terms of food intake, the best and simplest health message would be to stay away from the chocolate and eat a healthy, balanced diet, low in sugar, salt, and fat, and full of fresh fruit and vegetables," the journal states.
"We say: Bah, humbug to that. Pass the chocolates."
Editorial: The devil in the dark chocolate. The Lancet, Vol. 370, December 22/29, 2007, p. 2070.
Flammer, A. J. et al. Dark Chocolate Improves Coronary Vasomotion and Reduces Platelet Reactivity. Circulation, Vol. 116, November 2007, pp. 2376-82.
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