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beyond 4 weeks and there is considerable evidence of its many adverse effects including decreased appetite, insomnia, headaches, stomach aches, drowsiness, anxiety, irritability, and dizziness. Sinn, N. and Bryan, J. Effect of Supplementation with Polyunsaturated Fatty Acids and Micronutrients on Learning and Behavior Problems Associated

with Child Behavioral

ADHD.

Journal

of

Developmental

&

Pediatrics, 2007,Vol. 28, April, pp. 82-91

Schachter, HM, et al. How Efficacious and Safe Short-acting Methylphenidate for the Treatment

is of

Attention-deficit Adolescents?

Disorder Canadian

in Children and Medical Association

Journal, 2001, Vol. 165, November 27, pp. 1475-88.

MORE POSITIVE RESEARCH RESULTS FOR VITAMIN D

In a milieu that is very strongly against supplements, at least within mainstream medicine, with papers appearing very frequently that report either null results, it is refreshing to observe the rapid progress that vitamin D is making as an established hero in preventive medicine, especially since aside from sun exposure, supplementation is the only practical answer to achieving and maintaining a healthy and desirable vitamin D status. Advice to obtain more vitamin D by sun exposure of course is in direct conflict with the recommendation to severely limit sun exposure and utilize sunscreens to reduce the risk of skin cancer.

VITAMIN D SUPPLEMENTATION AND TOTAL MORTALITY There are those who believe that total or all-cause mortality is the only really important endpoint for studies of benefit. If an intervention does not cause one to live longer, why bother? However, this is not a universally shared belief and in addition, mortality studies generally must be both large and relatively long-term to yield statistically significant results. This problem can be overcome with a meta-analysis even if all or most of the included studies failed to achieve statistical significance. With the enlarged cohort obtained by combining studies, statistically significant results may be forthcoming. This is the case in the study by Autier and Gandini recently reported in the Archives of Internal Medicine. The researchers identified 18 trials for the analysis which included over 57,000 participants and a total of 4777 deaths from any cause. Daily vitamin D supplement doses ranged from 300 to 2000 IU. When the studies were stratified into two groups according to high vs. low statistical power, the nine with high power yielded a significant 8% reduction in mortality associated with vitamin D supplementation. The low power group failed to give statistical significant benefit, and for the nine high- powered studies, individually they all failed to achieve statistically significant evidence of benefit. Nevertheless, it was concluded that ordinary doses of vitamin D appeared to be associated with a

decrease in mortality rates.

Only 8 studies reported 25-hydroxyvitamin D levels at baseline and during the study. In the intervention

groups, 7 out of 8 studies found hydroxyvitamin D levels below 50

mean 25- nmol/L at

baseline, represent

levels that are considered by some to

a

deficiency.

Supplementation

brought

the means nmol/L but

up to where most were near or above 50 only 2 out of 8 studies achieved a mean

value

of

over

100

nmol/L.

This

meta-analysis

did

not

permit

examining

the

question

of

the

impact

of

dose

on

mortality.

Nor

were

the

results

stratified

by

major causes of death. The authors also that the results based on this very large indicate the absence of adverse effects from

remark cohort vitamin

D supplementation at the doses which were between 400 and 800

involved, IU/day.

most

of

In an accompanying editorial, Edward Giovannucci from Harvard comments that the studies in question, which had a range of follow-up from 6 months to 7 years, may have underestimated the potential benefit from vitamin D supplementation since it was not possible to examine the impact of this vitamin on the incidence and development of a variety of diseases. He also points out that questions raised by the meta-analysis include the possibility of even a greater reduction of mortality if higher intakes of vitamin D were employed, if compliance was improved, if higher levels of 25- hydroxyvitamin D were achieved, and if the duration

of supplementation were longer. Autier, P. and Grandini, S. Vitamin D Supplementation and Total Mortality. Archives of Internal Medicine, 2007, Vol. 167, No. 16, pp. 1730-7. Giovannucci, E. Can Vitamin D Reduce Mortality? Ibid, pp. 1709-10

ARE HIGH DOSES OF VITAMIN D SAFE? Kimball et al have recently reported on a study done in Toronto, Canada that addresses this question in the context of using very high doses of vitamin D for the treatment of multiple sclerosis (MS). During a 12-week period, 12 patients in an active phase of MS were given 1200 mg/day of calcium and

International Health News

November 2007

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