News
Insufficient vitamin D supply may increase risk of pneumonia
13 January 2014
A new analysis of US intake survey data indicates that people with vitamin D deficiency may be more likely to have community-acquired pneumonia.
23 June 2010
Long-term reductions in blood homocysteine levels with vitamin B9 (folic acid) and vitamin B12 supplementation may not have beneficial effects on incidence of vascular disease or cancer, suggests a new UK study.
In the randomized controlled trial (‘SEARCH’ study), 12,064 individuals who had previously had heart attacks were allocated to receive either 2 mg vitamin B9 (folic acid) plus 1 mg vitamin B12 daily or placebo for an average of 6.7 years (1). The researchers assessed the effects of homocysteine -lowering with B vitamins on the incidence of vascular (coronary death, second heart attack, or stroke) and non-vascular (cancer) events. The results showed that although B vitamin supplementation reduced homocysteine concentrations by 28% (3.8 micromoles/L), it did not affect mortality and major morbidity. In particular, the researchers found that folic acid supplementation did not increase the risk of cancer, which had been speculated earlier.
One possible explanation for the lack of protective effect from a reduction in homocysteine levels could be that homocysteine is not a valid biomarker for cardiovascular risk, the scientists commented. Elevated homocysteine levels have been linked with increased risk of cardiovascular disease but it is not known yet if this association is causal. It has been shown that blood homocysteine levels are elevated by deficiencies in B vitamins and that supplementation with vitamin B9, B6 and B12 can reduce the concentration of homocysteine.
Consequently, the results of an earlier meta-analysis of prospective studies showed that lower homocysteine levels were associated with an 11% lower risk of coronary heart disease and 19% lower risk of stroke (2). In addition, a subgroup analysis of the ‘HOPE-2’ trial also found a protective effect of B vitamin supplementation (2.5mg folic acid, 50mg B6, and 1mg B12 for 5 years) on stroke (3).
Given that all 12,000 individuals previously had heart attacks, the SEARCH study certainly does not answer the question of whether B vitamins taken over time, and in combination with other healthy lifestyle habits, could help prevent cardiovascular disease, experts commented.
13 January 2014
A new analysis of US intake survey data indicates that people with vitamin D deficiency may be more likely to have community-acquired pneumonia.
1 December 2014
Optimizing vision throughout the lifespan is a public health priority worldwide, not only because of its central importance to quality of life, but also because of the health care costs associated with the loss of vision in an aging population. Oxidative stress is thought to be a key pathogenic mechanism of compromised vision, and the antioxidant properties of some nutrients show the capacity to modulate disease conditions linked to oxidative stress. Considerable evidence has accumulated showing that vitamins A, C, E, beta-carotene and zinc help support vision and may be protective against the development or progression of some common – especially age-related – eye diseases such as age-related macular degeneration and cataracts. In addition, increased intakes of the carotenoids lutein and zeaxanthin and the omega-3 fatty acid docosahexaenoic acid (DHA) – all concentrated in the eye – have been associated consistently with lower likelihood of sight-threatening conditions. There has also been some promising research with B vitamins in age-related eye diseases and with vitamin A and DHA in the rare disease retinitis pigmentosa (see also Key nutrients for healthy vision).
27 February 2015
A new review from Iran suggests that vitamin E supplementation can have significant anti-inflammatory effects.