2016
Increased levels of the protective macular pigment in the fovea of the eye are shown to be positively associated with increased blood serum of lutein, zeaxanthin and DHA in a new human study (1)
24 December 2012
Over 50% of the Korean population above 49 years have low blood vitamin D concentrations increasing the risk of osteoporosis, says a new study from Korea.
In the observational study, the 25-hydroxyvitamin D (25[OH]D) blood concentrations of 1,451 men and 1,870 women aged 49 years and above were analyzed (1). The study results showed that 8.7% of the men and 17.9% of the women had serum 25(OH)D values below 12.1 ng/mL (30nM) and 50.4% resp. 66.3% had values below 20.4 ng/mL (51nM)– vitamin D concentrations defined as insufficient. Furthermore, bone mineral density (BMD) of the participants’ femurs increased until 25(OH)D concentration dropped below
20.4 ng/mL; no significant changes were observed thereafter. Serum 25(OH)D values of 12.1 ng/mL and 20.4 ng/mL were associated with an increased risk of osteoporosis, while a value of 30 ng/mL (75.0 nmol/L) was not. 25(OH)D concentrations varied in relation to the season of the year, being highest in summer and lowest in spring.
The researchers commented that these findings are in line with earlier studies that have found that the Korean population has the lowest absolute concentration of serum 25(OH)D (17.6 ng/mL) compared to populations in other countries from a wide variety of latitudes and that vitamin D inadequacy, defined as serum 25(OH)D concentrations below 30 ng/mL, was highest in Korea with 92% (2). Also in agreement with the new results are earlier observations (3) indicating that adequate serum 25(OH)D concentrations for bone health may be lower than previously suggested. Accordingly, concentrations of 20 ng/mL might be sufficient.
The WHO defines vitamin D insufficiency as a serum 25(OH)D concentration below 20 ng/mL, and concen-trations below 10 ng/mL are considered vitamin D deficient. However, many observational studies suggest that the optimal serum 25(OH)D concentration for bone health is greater than 30 ng/mL and that concen-trations between 30 and 20 ng/mL are considered vitamin D insufficient and those below 20 ng/mL represent deficiency.
10 May 2010
A once-a-year high dose vitamin D supplementation may increase elderly women’s rate of falls and fractures, indicates a new study.
1 January 2014
Cell aging is a complex process in which numerous factors can be involved. Telomeres located at the ends of chromosomes play an important role here – they consist of repetitive DNA sequences and associated proteins (histones) that stabilize the DNA by forming a kind of protective cap. When DNA is copied during cell division, some of the DNA building blocks (nucleotides) at the ends of the chromosomes are not copied, with the result that the telomeres on the newly formed DNA strands get shorter with each cell division. With increasing telomere shortening the cell changes its pattern of gene activation, slows its rate of division, then halts division completely (senescence), and eventually dies (apoptosis). Telomerase, an enz- yme that forms telomeres, counteracts this cell aging process by adding nucleotides that would otherwise be lost to the ends of the new DNA strand. Cell aging and death are thus delayed. Both telomere length and the amount and activity of telomerase, along with other factors, determine how many times cells can divide. Studies have shown that these factors can be positively influenced by micronutrients.