Discussie over vitamine D
Geplaatst: 13 dec 2013, 17:11
Vit D tekort is niet oorzaak, maar een gevolg van kwalen
Limits of Vitamin D Supplements
By NICHOLAS BAKALAR
A large review of studies has found that vitamin D supplements have little or no benefit beyond the low levels required for bone health.
low vitamin D levels are almost surely an effect of these diseases, and not a cause.
The meta-analysis, published in The Lancet Diabetes & Endocrinology, combined data from 290 observational studies and 172 random trials.
All the studies used blood levels of vitamin D to measure outcomes. Dosages varied, but most trials used 800 units or more.
The observational studies generally found an association of lower vitamin D levels with increases in cardiovascular disease, lipid concentrations, glucose levels, weight gain, infectious disease and mood disorders.
But random trials showed little or no effect of vitamin D supplements on any of these problems.
The authors conclude that low vitamin D levels are almost surely an effect of these diseases, and not a cause.
Current guidelines recommend supplements for anyone with a blood level under 30 nanograms per milliliter, but the lead author, Dr. Philippe Autier, said that only at levels of 10 or less would there be a risk to skeletal health.
Less than 10 percent of Americans, he estimates, fall into this category.
Dr. Autier is a researcher at the International Prevention Research Institute in Lyon, France.
“Unfortunately, there is probably no benefit to expect from vitamin D supplementation in normally healthy people,” he said.
Verder lezen:
http://www.thelancet.com/journals/landi ... 7/abstract
Vitamin D status and ill health: a systematic review
Prof Philippe Autier MD a b Corresponding AuthorEmail Address, Prof Mathieu Boniol PhD a b, Cécile Pizot MSc a, Prof Patrick Mullie PhD a c
Summary
Low serum concentrations of 25-hydroxyvitamin D (25[OH]D) have been associated with many non-skeletal disorders. However, whether low 25(OH)D is the cause or result of ill health is not known. We did a systematic search of prospective and intervention studies that assessed the effect of 25(OH)D concentrations on non-skeletal health outcomes in individuals aged 18 years or older. We identified 290 prospective cohort studies (279 on disease occurrence or mortality, and 11 on cancer characteristics or survival), and 172 randomised trials of major health outcomes and of physiological parameters related to disease risk or inflammatory status. Investigators of most prospective studies reported moderate to strong inverse associations between 25(OH)D concentrations and cardiovascular diseases, serum lipid concentrations, inflammation, glucose metabolism disorders, weight gain, infectious diseases, multiple sclerosis, mood disorders, declining cognitive function, impaired physical functioning, and all-cause mortality. High 25(OH)D concentrations were not associated with a lower risk of cancer, except colorectal cancer. Results from intervention studies did not show an effect of vitamin D supplementation on disease occurrence, including colorectal cancer. In 34 intervention studies including 2805 individuals with mean 25(OH)D concentration lower than 50 nmol/L at baseline supplementation with 50 μg per day or more did not show better results. Supplementation in elderly people (mainly women) with 20 μg vitamin D per day seemed to slightly reduce all-cause mortality. The discrepancy between observational and intervention studies suggests that low 25(OH)D is a marker of ill health. Inflammatory processes involved in disease occurrence and clinical course would reduce 25(OH)D, which would explain why low vitamin D status is reported in a wide range of disorders. In elderly people, restoration of vitamin D deficits due to ageing and lifestyle changes induced by ill health could explain why low-dose supplementation leads to slight gains in survival.
Limits of Vitamin D Supplements
By NICHOLAS BAKALAR
A large review of studies has found that vitamin D supplements have little or no benefit beyond the low levels required for bone health.
low vitamin D levels are almost surely an effect of these diseases, and not a cause.
The meta-analysis, published in The Lancet Diabetes & Endocrinology, combined data from 290 observational studies and 172 random trials.
All the studies used blood levels of vitamin D to measure outcomes. Dosages varied, but most trials used 800 units or more.
The observational studies generally found an association of lower vitamin D levels with increases in cardiovascular disease, lipid concentrations, glucose levels, weight gain, infectious disease and mood disorders.
But random trials showed little or no effect of vitamin D supplements on any of these problems.
The authors conclude that low vitamin D levels are almost surely an effect of these diseases, and not a cause.
Current guidelines recommend supplements for anyone with a blood level under 30 nanograms per milliliter, but the lead author, Dr. Philippe Autier, said that only at levels of 10 or less would there be a risk to skeletal health.
Less than 10 percent of Americans, he estimates, fall into this category.
Dr. Autier is a researcher at the International Prevention Research Institute in Lyon, France.
“Unfortunately, there is probably no benefit to expect from vitamin D supplementation in normally healthy people,” he said.
Verder lezen:
http://www.thelancet.com/journals/landi ... 7/abstract
Vitamin D status and ill health: a systematic review
Prof Philippe Autier MD a b Corresponding AuthorEmail Address, Prof Mathieu Boniol PhD a b, Cécile Pizot MSc a, Prof Patrick Mullie PhD a c
Summary
Low serum concentrations of 25-hydroxyvitamin D (25[OH]D) have been associated with many non-skeletal disorders. However, whether low 25(OH)D is the cause or result of ill health is not known. We did a systematic search of prospective and intervention studies that assessed the effect of 25(OH)D concentrations on non-skeletal health outcomes in individuals aged 18 years or older. We identified 290 prospective cohort studies (279 on disease occurrence or mortality, and 11 on cancer characteristics or survival), and 172 randomised trials of major health outcomes and of physiological parameters related to disease risk or inflammatory status. Investigators of most prospective studies reported moderate to strong inverse associations between 25(OH)D concentrations and cardiovascular diseases, serum lipid concentrations, inflammation, glucose metabolism disorders, weight gain, infectious diseases, multiple sclerosis, mood disorders, declining cognitive function, impaired physical functioning, and all-cause mortality. High 25(OH)D concentrations were not associated with a lower risk of cancer, except colorectal cancer. Results from intervention studies did not show an effect of vitamin D supplementation on disease occurrence, including colorectal cancer. In 34 intervention studies including 2805 individuals with mean 25(OH)D concentration lower than 50 nmol/L at baseline supplementation with 50 μg per day or more did not show better results. Supplementation in elderly people (mainly women) with 20 μg vitamin D per day seemed to slightly reduce all-cause mortality. The discrepancy between observational and intervention studies suggests that low 25(OH)D is a marker of ill health. Inflammatory processes involved in disease occurrence and clinical course would reduce 25(OH)D, which would explain why low vitamin D status is reported in a wide range of disorders. In elderly people, restoration of vitamin D deficits due to ageing and lifestyle changes induced by ill health could explain why low-dose supplementation leads to slight gains in survival.