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Tag: Vitamin D

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Excerpts from an article by Jane Brody in the NY Times:

Beating Back the Risk of Diabetes

This year, nearly two million American adults and more than 5,000 children and adolescents will learn they have a potentially devastating, life-shortening, yet largely preventable disease: Type 2 diabetes. They will join 29.1 million Americans who already have diabetes.

Diabetes and its complications are responsible for nearly 200,000 deaths a year; the fatality rate among affected adults is 50 percent higher than among similar people without diabetes. Alarmingly, recent studies even have linked diabetes to an increased risk of dementia and Alzheimer's disease. Even people with above-average blood glucose levels, but not diabetes, have an elevated risk.

The Diabetes Prevention Program study, conducted among about 3,800 people who had pre-diabetes, found that moderate weight loss — an average of 12 pounds —  reduced the odds of progression to diabetes by nearly 50 percent.

An excellent discussion of what is known about the effect on diabetes of various foods and supplements appeared recently in Nutrition Action Healthletter at cspinet.org/iceberg.pdf. Some highlights:

Carbohydrates - breads, grains, cereals, sugary drinks and sweets of all kinds — are most problematic for people with diabetes or at risk of developing it. Carbohydrates are eventually metabolized to glucose, which raises the body’s demand for insulin. Consume less of them in general, and choose whole-grain versions whenever possible.

If you must have sweet drinks, select artificially sweetened ones. In two huge studies of nurses and other health professionals who were followed for 22 years, those who drank one or more sugary soft drinks a day had about a 30 percent higher risk of developing diabetes than those who rarely drank them, even after their weight was taken into account.

But there’s good news about coffee. Two or three cups of coffee (but not tea) a day, with or without caffeine, have been consistently linked to a lower risk of Type 2 diabetes. 

For protein, limit consumption of red meat, especially processed meats like sausages, hot dogs and luncheon meats, which are linked to a higher diabetes risk. Instead, choose fish, lean poultry (skinless and not fried), beans and nuts. Low-fat dairy products, including yogurt, and even fatty ones may lower the risk of diabetes; the reason is unclear.

Most protective are green, leafy vegetables — spinach, chard, kale, collards, mustard greens and even lettuce — as well as cruciferous vegetables like cabbage, broccoli and cauliflower. But all vegetables are good and should fill at least two-thirds of your dinner plate.

The nutrients magnesium and vitamin D are also potentially protective. In fact, the preventive value of leafy greens, whole grains, beans and nuts may lie in their high magnesium content. In a well-designed clinical trial of 32 overweight people with insulin resistance, the prelude to diabetes, blood glucose levels and insulin sensitivity improved in those who took a daily magnesium supplement for six months. Don’t go overboard: More than 350 milligrams of magnesium daily can cause diarrhea. 

Vitamin D, long known to be crucial to healthy bones, may also be helpful. In one study of 92 overweight or obese adults with prediabetes, those who took a supplement of 2,000 international units of vitamin D daily had better function of the pancreatic cells that produce insulin..

Of course, how much you weigh and what you eat are not the only concerns. Regular, preferably daily, physical exercise is a vital component of any prevention and treatment program for Type 2 diabetes, or most any chronic ailment. Weight loss can reduce diabetes risk by about 50 percent, but adding exercise to that can lower the odds by 70 percent, compared with people who remain overweight and inactive, according to a study that followed nearly 85,000 female nurses for 16 years. Women who were active for seven or more hours weekly had half the risk of developing diabetes as did women who exercised only a half-hour a week.

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Two new studies find problems when vitamin D levels are low. From Science Daily:

Low vitamin D levels linked to increased risks after noncardiac surgery

Patients with low blood levels of vitamin D are at increased risk of death and serious complications after noncardiac surgery, suggests a study. The researchers analyzed the relationship between vitamin D level and surgical outcomes in approximately 3,500 patients who underwent operations other than heart surgery between 2005 and 2011. Only patients who had available data on vitamin D levels around the time of surgery -- from three months before to one month afterward -- were included in the study.

Most patients did not meet the recommended 25-hydroxyvitamin D concentration of greater than 30 nanograms per milliliter (ng/mL). The median vitamin D level was 23.5 ng/mL -- more than 60 percent of patients were in the range of vitamin D insufficiency (10 to 30 ng/mL). Nearly 20 percent had vitamin D deficiency (less than 10 ng/mL).

"Higher vitamin D concentrations were associated with decreased odds of in-hospital mortality/morbidity," the researchers write. For each 5 ng/mL increase in 25-hydroxyvitamin D level, the combined risk of death, cardiovascular events, or serious infections decreased by seven percent.

From Science Daily:

Vitamin D deficiency may reduce pregnancy rate in women undergoing IVF

Women with a vitamin D deficiency were nearly half as likely to conceive through in vitro fertilization (IVF) as women who had sufficient levels of the vitamin, according to a new study. Long known for its role in bone health, vitamin D is a steroid hormone that is emerging as a factor in fertility.

Women who had sufficient levels of vitamin D were nearly twice as likely to conceive as their counterparts with vitamin D deficiency. Since women with sufficient levels of the hormone were more likely to produce top-quality embryos, researchers theorized vitamin D was involved in the production of quality eggs in the ovaries as well as the successful implantation of embryos in the uterus.

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Yes, going out in the sunshine for a while is a good way to get vitamin D. From Science Daily:

Link between vitamin D, dementia risk confirmed

Vitamin D deficiency is associated with a substantially increased risk of dementia and Alzheimer's disease in older people, according to the most robust study of its kind ever conducted. An international team found that study participants who were severely vitamin D deficient were more than twice as likely to develop dementia and Alzheimer's disease.

The team studied elderly Americans who took part in the Cardiovascular Health Study. They discovered that adults in the study who were moderately deficient in vitamin D had a 53 per cent increased risk of developing dementia of any kind, and the risk increased to 125 per cent in those who were severely deficient.

Similar results were recorded for Alzheimer's disease, with the moderately deficient group 69 per cent more likely to develop this type of dementia, jumping to a 122 per cent increased risk for those severely deficient.

The study was part-funded by the Alzheimer's Association, and is published in Neurology, the medical journal of the American Academy of Neurology. It looked at 1,658 adults aged 65 and over, who were able to walk unaided and were free from dementia, cardiovascular disease and stroke at the start of the study. The participants were then followed for six years to investigate who went on to develop Alzheimer's disease and other forms of dementia.... Previous research established that people with low vitamin D levels are more likely to go on to experience cognitive problems, but this study confirms that this translates into a substantial increase in the risk of Alzheimer's disease and dementia.

Vitamin D comes from three main sources -- exposure of skin to sunlight, foods such as oily fish, and supplements. Older people's skin can be less efficient at converting sunlight into virVitamin D, making them more likely to be deficient and reliant on other sources. In many countries the amount of UVB radiation in winter is too low to allow vitamin D production.

The study also found evidence that there is a threshold level of Vitamin D circulating in the bloodstream below which the risk of developing dementia and Alzheimer's disease increases. The team had previously hypothesized that this might lie in the region of 25-50 nmol/L, and their new findings confirm that vitamin D levels above 50 nmol/L are most strongly associated with good brain health....During this hottest of summers, hitting the beach for just 15 minutes of sunshine is enough to boost your vitamin D levels. 

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Another study finding risks from too low vitamin D levels. From Science Daily:

Lower vitamin D level in blood linked to higher premature death rate

Researchers at the University of California, San Diego School of Medicine have found that persons with lower blood levels of vitamin D were twice as likely to die prematurely as people with higher blood levels of vitamin D.

The finding, published in the June 12 issue of American Journal of Public Health, was based on a systematic review of 32 previous studies that included analyses of vitamin D, blood levels and human mortality rates. The specific variant of vitamin D assessed was 25-hydroxyvitamin D, the primary form found in blood.

This new finding is based on the association of low vitamin D with risk of premature death from all causes, not just bone diseases."

Garland said the blood level amount of vitamin D associated with about half of the death rate was 30 ng/ml. He noted that two-thirds of the U.S. population has an estimated blood vitamin D level below 30 ng/ml."This study should give the medical community and public substantial reassurance that vitamin D is safe when used in appropriate doses up to 4,000 International Units (IU) per day," said Heather Hofflich, DO, professor in the UC San Diego School of Medicine's Department of Medicine.

The average age when the blood was drawn in this study was 55 years; the average length of follow-up was nine years. The study included residents of 14 countries, including the United States, and data from 566,583 participants.

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Two studies published in the British Medical Journal (BMJ) looked at Vitamin D. From NY Times:

Low Vitamin D Levels Linked to Disease in Two Big Studies

People with low vitamin D levels are more likely to die from cancer and heart disease and to suffer from other illnesses, scientists reported in two large studies published on Tuesday.

The new research suggests strongly that blood levels of vitamin D are a good barometer of overall health. But it does not resolve the question of whether low levels are a cause of disease or simply an indicator of behaviors that contribute to poor health, like a sedentary lifestyle, smoking and a diet heavy in processed and unhealthful foods.

Nicknamed the sunshine nutrient, vitamin D is produced in the body when the skin is exposed to sunlight. It can be obtained from a small assortment of foods, including fish, eggs, fortified dairy products and organ meats, and vegetables like mushrooms and kale. And blood levels of it can be lowered by smoking, obesity, and inflammation.

Vitamin D helps the body absorb calcium and is an important part of the immune system. Receptors for the vitamin and related enzymes are found throughout cells and tissues of the body, suggesting it may be vital to many physiological functions, said Dr. Oscar H. Franco, a professor of preventive medicine at Erasmus Medical Center in the Netherlands and an author of one of the new studies, which appeared in the journal BMJ.

The two studies were meta-analyses that included data on more than a million people. They included observational findings on the relationship between disease and blood levels of vitamin D. The researchers also reviewed evidence from randomized controlled trials — the gold standard in scientific research — that assessed whether taking vitamin D daily was beneficial.

Dr. Franco and his co-authors — a team of scientists at Harvard, Oxford and other universities — found persuasive evidence that vitamin D protects against major diseases. Adults with lower levels of the vitamin in their systems had a 35 percent increased risk of death from heart disease, 14 percent greater likelihood of death from cancer, and a greater mortality risk overall.

When the researchers looked at supplement use, they found no benefit to taking vitamin D2. But middle-aged and older adults who took another form, vitamin D3 — which is the type found in fish and dairy products and produced in response to sunlight — had an 11 percent reduction in mortality from all causes, compared to adults who did not. In the United States and Europe, it is estimated that more than two-thirds of the population is deficient in vitamin D. In their paper, Dr. Franco and his colleagues calculated that roughly 13 percent of all deaths in the United States, and 9 percent in Europe, could be attributed to low vitamin D levels.

In the second study, also published in BMJ, a team of researchers at Stanford and several universities in Europe presented a more nuanced view of vitamin D.

They concluded there was “suggestive evidence” that high vitamin D levels protect against diabetes, stroke, hypertension and a host of other illnesses. But they also said there was no “highly convincing” evidence that vitamin D pills affected any of the outcomes they examined.

Dr. Theodoratou was not alone in suggesting people hold off on taking vitamin D supplements for now. Even though Dr. Franco found them to be beneficial, he said that more research was needed to show what levels are best. Instead of taking pills, people could improve their vitamin D levels with an adequate diet and 30 minutes of sunlight twice a week, he said.

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Two studies about Vitamin D. From Science Daily:

Vitamin D increases breast cancer patient survival, study shows

Breast cancer patients with high levels of vitamin D in their blood are twice as likely to survive the disease as women with low levels of this nutrient, report University of California, San Diego School of Medicine researchers in the March issue of Anticancer Research.

In previous studies, Cedric F. Garland, DrPH, professor in the Department of Family and Preventive Medicine, showed that low vitamin D levels were linked to a high risk of premenopausal breast cancer. That finding, he said, prompted him to question the relationship between 25-hydroxyvitamin D -- a metabolite produced by the body from the ingestion of vitamin D -- and breast cancer survival rates.

Garland and colleagues performed a statistical analysis of five studies of 25-hydroxyvitamin D obtained at the time of patient diagnosis and their follow-up for an average of nine years. Combined, the studies included 4,443 breast cancer patients.

Women in the high serum group had an average level of 30 nanograms per milliliter (ng/ml) of 25-hydroxyvitamin D in their blood. The low group averaged 17 ng/ml. The average level in patients with breast cancer in the United States is 17 ng/ml.

A 2011 meta-analysis by Garland and colleagues estimated that a serum level of 50 ng/ml is associated with 50 percent lower risk of breast cancer. While there are some variations in absorption, those who consume 4,000 International Units (IU) per day of vitamin D from food or a supplement normally would reach a serum level of 50 ng/ml. 

From Science Daily:

Vitamin D deficiency may compromise immune function

Older individuals who are vitamin D deficient also tend to have compromised immune function, according to new research accepted for publication in the Endocrine Society's Journal of Clinical Endocrinology & Metabolism (JCEM).

"Our data suggest vitamin D may be involved in maintaining the health of the immune system as well as the skeletal system," said one of the study's authors, Mary Ward, PhD, of the University of Ulster in Coleraine, U.K.

The observational study of 957 Irish adults who were at least 60 years old examined vitamin D levels as well as biomarkers of inflammation. Participants who were vitamin D deficient were more likely to have high levels of these biomarkers, which are linked to cardiovascular disease and inflammatory conditions such as multiple sclerosis and rheumatoid arthritis.