vitamin D

Vitamin D study sheds light on immune system effects

April 17, 2019

Science Daily/University of Edinburgh

Scientists have uncovered fresh insights into how vitamin D affects the immune system and might influence susceptibility to diseases such as multiple sclerosis.

 

Vitamin D is produced by the body in response to sunlight and is often lauded for its health benefits. Researchers found it also affects key cells of the immune system.

 

This discovery might explain how vitamin D regulates immune reactions that have been implicated in autoimmune diseases such as MS.

 

The University of Edinburgh team focused on how vitamin D affects a mechanism in the body's immune system -- dendritic cells' ability to activate T cells.

 

In healthy people, T cells play a crucial role in helping to fight infections. In people with autoimmune diseases, however, they can start to attack the body's own tissues.

 

By studying cells from mice and people, the researchers found vitamin D caused dendritic cells to produce more of a molecule called CD31 on their surface and that this hindered the activation of T cells.

 

The team observed how CD31 prevented the two cell types from making a stable contact -- an essential part of the activation process -- and the resulting immune reaction was far reduced.

 

Researchers say the findings shed light on how vitamin D deficiency may regulate the immune system and influence susceptibility to autoimmune diseases.

 

The study, published in Frontiers in Immunology, was funded by the Medical Research Council, Biotechnology and Biological Sciences Research Council, Natural Environment Research Council and Wellcome.

 

Professor Richard Mellanby, of the University of Edinburgh's Centre for Inflammation Research, said: "Low vitamin D status has long being implicated as a significant risk factor for the development of several autoimmune diseases. Our study reveals one way in which vitamin D metabolites can dramatically influence the immune system."

https://www.sciencedaily.com/releases/2019/04/190417111440.htm

Vitamin D supplements may promote weight loss in obese children

September 27, 2018

Science Daily/European Society for Paediatric Endocrinology

Vitamin D supplements may promote weight loss and reduce risk factors for future heart and metabolic disease in overweight and obese children, according to new research. These findings indicate that simple vitamin D supplementation may be part of an effective strategy to tackle childhood obesity and reduce the risk of serious health problems, such as heart disease, in adulthood.

 

Obesity in childhood and adolescence represents a major health problem worldwide, which leads to the development of expensive, serious and debilitating complications, including heart disease and diabetes, in later life. Although vitamin D deficiency is typically associated with impaired bone health, in recent years it has been increasingly linked with increased body fat accumulation and obesity, with the precise nature of this relationship currently under intense investigation by researchers. However, the effect of vitamin D supplementation on the weight and health of obese children and adolescents had not yet been investigated.

 

In this study, Dr. Christos Giannios, Professor Evangelia Charmandari and colleagues at the University of Athens Medical School and the 'Aghia Sophia' Children's Hospital in Athens, assessed 232 obese children and adolescents over 12 months, with 117 randomly assigned to receive vitamin D supplementation, in accordance with the Endocrine Society's guidelines on treatment and prevention of deficiency. Levels of vitamin D, body fat, and blood markers of liver function and heart health were assessed at the start of the study and 12 months later. The study reported that children given vitamin D supplements had significantly lower body mass index, body fat and improved cholesterol levels after 12 months of supplementation.

 

"These findings suggest that simple vitamin D supplementation may reduce the risk of overweight and obese children developing serious heart and metabolic complications in later life," says lead researcher Prof Charmandari.

 

The team now plan to investigate the effects of vitamin D supplementation on the health of obese children and adolescents that already have unhealthy conditions, such as high blood pressure, high blood glucose and high cholesterol, all of which increase the risk of heart disease, stroke and diabetes.

 

Prof Charmandari cautions, "Although these initial findings indicate that vitamin D could be used in the treatment of obesity, there remains a lack of evidence on the safety and long-term effects of supplementation, particularly if there is no vitamin D deficiency. However, if your child is overweight or obese I recommend that you consult your primary care physician for advice, and consider having their vitamin D levels tested."

https://www.sciencedaily.com/releases/2018/09/180927215656.htm

Vitamin D levels in the blood linked to cardiorespiratory fitness

October 30, 2018

Science Daily/European Society of Cardiology

Vitamin D levels in the blood are linked to cardiorespiratory fitness, according to a study published today in the European Journal of Preventive Cardiology, a publication of the European Society of Cardiology (ESC).

 

"Our study shows that higher levels of vitamin D are associated with better exercise capacity," said Dr Amr Marawan, assistant professor of internal medicine, Virginia Commonwealth University, Virginia, US. "We also know from previous research that vitamin D has positive effects on the heart and bones. Make sure your vitamin D levels are normal to high. You can do this with diet, supplements, and a sensible amount of sun exposure."

 

It is well established that vitamin D is important for healthy bones, but there is increasing evidence that it plays a role in other areas of the body including the heart and muscles.

 

Cardiorespiratory fitness, a reliable surrogate for physical fitness, is the ability of the heart and lungs to supply oxygen to the muscles during exercise. It is best measured as the maximal oxygen consumption during exercise, referred to as VO2 max. People with higher cardiorespiratory fitness are healthier and live longer.

 

This study investigated whether people with higher levels of vitamin D in the blood have improved cardiorespiratory fitness. The study was conducted in a representative sample of the US population aged 20-49 years using the National Health and Nutrition Survey (NHANES) in 2001-2004. Data was collected on serum vitamin D and VO2 max. Participants were divided into quartiles of vitamin D levels.

 

Of 1,995 participants, 45% were women, 49% were white, 13% had hypertension, and 4% had diabetes. Participants in the top quartile of vitamin D had a 4.3-fold higher cardiorespiratory fitness than those in the bottom quartile. The link remained significant, with a 2.9-fold strength, after adjusting for factors that could influence the association such as age, sex, race, body mass index, smoking, hypertension, and diabetes.

 

Dr Marawan said: "The relationship between higher vitamin D levels and better exercise capacity holds in men and women, across the young and middle age groups, across ethnicities, regardless of body mass index or smoking status, and whether or not participants have hypertension or diabetes."

 

Each 10 nmol/L increase in vitamin D was associated with a statistically significant 0.78 mL/kg/min increase in VO2 max. "This suggests that there is a dose response relationship, with each rise in vitamin D associated with a rise in exercise capacity," said Dr Marawan.

 

Dr Marawan noted that this was an observational study and it cannot be concluded that vitamin D improves exercise capacity. But he added: "The association was strong, incremental, and consistent across groups. This suggests that there is a robust connection and provides further impetus for having adequate vitamin D levels, which is particularly challenging in cold, cloudy places where people are less exposed to the sun."

 

On the other hand, Vitamin D toxicity can lead to excess calcium in the blood, which can cause nausea, vomiting, and weakness. "It is not the case that the more vitamin D, the better," said Dr Marawan. "Toxicity is caused by megadoses of supplements rather than diet or sun exposure, so caution is needed when taking tablets."

 

Regarding further research, Dr Marawan said: "We know the optimum vitamin D levels for healthy bones but studies are required to determine how much the heart needs to function at its best. Randomised controlled trials should be conducted to examine the impact of differing amounts of vitamin D supplements on cardiorespiratory fitness. From a public health perspective, research should look into whether supplementing food products with vitamin D provides additional benefits beyond bone health."

https://www.sciencedaily.com/releases/2018/10/181030091449.htm

Low vitamin D levels, depression linked in young women

March 18, 2015

Science Daily/Oregon State University

There is a relationship between low levels of vitamin D and depression in otherwise healthy young women, a new study shows.

 

OSU researchers found that young women with lower levels of vitamin D were more likely to have clinically significant depressive symptoms over the course of a five-week study, lead author David Kerr said. The results were consistent even when researchers took into account other possible explanations, such as time of year, exercise and time spent outside.

 

"Depression has multiple, powerful causes and if vitamin D is part of the picture, it is just a small part," said Kerr, an associate professor in the School of Psychological Science at OSU. "But given how many people are affected by depression, any little inroad we can find could have an important impact on public health."

 

The findings were published recently in the journal Psychiatry Research. Co-authors are Sarina Saturn of the School of Psychological Science; Balz Frei and Adrian Gombart of OSU's Linus Pauling Institute; David Zava of ZRT Laboratory and Walter Piper, a former OSU student now at New York University.

 

Vitamin D is an essential nutrient for bone health and muscle function. Deficiency has been associated with impaired immune function, some forms of cancer and cardiovascular disease, said Gombart, an associate professor of biochemistry and biophysics, principal investigator with the Linus Pauling Institute and international expert on vitamin D and the immune response.

 

People create their own vitamin D when their skin is exposed to sunlight. When sun is scarce in the winter, people can take a supplement, but vitamin D also is found in some foods, including milk that is fortified with it, Gombart said. The recommended daily allowance of vitamin D is 600 IU per day. There is no established level of vitamin D sufficiency for mental health.

 

The new study was prompted in part because there is a widely held belief that vitamin D and depression are connected, but there is not actually much scientific research out there to support the belief, Kerr said.

 

"I think people hear that vitamin D and depression can change with the seasons, so it is natural for them to assume the two are connected," he said.

 

According to Kerr and his colleagues, a lot of past research has actually found no association between the two, but much of that research has been based on much older adults or special medical populations.

 

Kerr's study focused on young women in the Pacific Northwest because they are at risk of both depression and vitamin D insufficiency. Past research found that 25 percent of American women experience clinical depression at some point in their lives, compared to 16 percent of men, for example.

 

OSU researchers recruited 185 college students, all women ages 18-25, to participate in the study at different times during the school year. Vitamin D levels were measured from blood samples and participants completed a depression symptom survey each week for five weeks.

 

Many women in the study had vitamin D levels considered insufficient for good health, and the rates were much higher among women of color, with 61 percent of women of color recording insufficient levels, compared to 35 percent of other women. In addition, more than a third of the participants reported clinically significant depressive symptoms each week over the course of the study.

 

"It may surprise people that so many apparently healthy young women are experiencing these health risks," Kerr said.

 

As expected, the women's vitamin D levels depended on the time of year, with levels dropping during the fall, at their lowest in winter, and rising in the spring. Depression did not show as a clear pattern, prompting Kerr to conclude that links between vitamin D deficiency and seasonal depression should be studied in larger groups of at-risk individuals.

 

Researchers say the study does not conclusively show that low vitamin D levels cause depression. A clinical trial examining whether vitamin D supplements might help prevent or relieve depression is the logical next step to understanding the link between the two, Kerr said.

 

OSU researchers already have begun a follow-up study on vitamin D deficiency in women of color. In the meantime, researchers encourage those at risk of vitamin D deficiency to speak with their doctor about taking a supplement.

 

"Vitamin D supplements are inexpensive and readily available." Kerr said. "They certainly shouldn't be considered as alternatives to the treatments known to be effective for depression, but they are good for overall health."

http://www.sciencedaily.com/releases/2015/03/150318145501.htm

Fewer indications of ADHD in children whose mothers took vitamin D during pregnancy

October 7, 2016

Science Daily/University of Southern Denmark Faculty of Health Sciences
Children of mothers who took vitamin D during pregnancy with resultant high levels of the vitamin in the umbilical blood have fewer symptoms of ADHD at the age of 2½ years.

These were the findings in a new study from the Odense Child Cohort just published in The Australia & New Zealand Journal of Psychiatry.

 "And for every 10 nmol/L increase in the vitamin D concentration in umbilical blood, the risk of a being among the 10% highest score on the ADHD symptom scale fell by 11%," explains one of the study's initiators, Professor Niels Bilenberg.

1,233 children from Odense Municipality were monitored in the study. Vitamin D was measured in umbilical blood, and mothers completed the Child Behavior Checklist (CBCL) when their child was 2½ years old. The CBCL questionnaire can be used to identify early symptoms of ADHD, even though an ADHD diagnosis cannot be made at that age.

"And the trend was clear: those mothers who had taken vitamin D, and had a vitamin D level (25OHD) in their umbilical blood over 25 nmol/L, had children with lower ADHD scores," continues Bilenberg. "This was after we had corrected for other factors that could explain the link, such as the mother's age, smoking, alcohol, obesity, education, number of children, psychiatric disease in the parents, child's sex, age and seasonal variation."

The link between vitamin D and early ADHD symptoms has not been described before, and has therefore attracted attention.

"We were very surprised that the link was so clear," say two of the study's other authors, medical students Jens Bull Aaby and Mats Mossin, "as there was no previous awareness that this link could be identified at such an early age. It's impossible to say with which children will develop ADHD later on, but it will be interesting to further follow up those children who were at the highest end versus the normal range of the ADHD scale."

The study offers no explanation as to how vitamin D can protect against ADHD, but other studies have shown that vitamin D plays an important role in the early development of the brain.

"We had an idea about it," says Aaby, "but we cannot say with certainty that vitamin D protects against early symptoms of ADHD. Our study only indicates that there is a link that we cannot explain in any other way."

Facts: Odense Børnekohorte is a joint study between Odense University Hospital, the Psychiatric Service of the Region of Southern Denmark, Odense Municipality, and the University of Southern Denmark. In the study, 2,500 mothers and their children are being monitored from early pregnancy to the child's 18th birthday. The children are now 3-5 years old and a number of follow-up studies are planned.

Science Daily/SOURCE :https://www.sciencedaily.com/releases/2016/10/161007105202.htm

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