5000 IU of Vitamin D3 Boosts The Body's Ability To Respond To Cardiovascular Stress and Cancer
A daily vitamin D dose of 5,000 IU for 28 days is associated with maintenance of the so-called sympatho-vagal balance, or the interaction between the sympathetic nervous system and the vagus nerve, according to findings published in the International Journal of Cardiology .
Pre-supplementation, an acute stressor was associated with an unfavorable shift in this sympatho-vagal balance, said the researchers.
The data also indicated improvements in cardiac autonomic tone, which refers to the the heart's ability to respond to a stressor and return to normal, said researchers from the University of Calgary, the Libin Cardiovascular Institute of Alberta, and the Alberta Kidney Disease Network.
"To our knowledge, this is the first study investigating the association of vitamin D3 supplementation on cardiac autonomic tone, a potentially modifiable target for risk of sudden arrhythmic death, in humans," they wrote.
"Pre-vitamin D3 supplementation, subjects demonstrated an unfavorable increase in sympatho-vagal balance in response to an acute physiological stressor, whereas post-vitamin D3 supplementation, cardiac autonomic tone was maintained in response to the same stressor, largely driven by restoration of cardioprotective vagal input.
"These novel findings suggest a mechanism by which vitamin D3 supplementation may improve cardiac autonomic function and potentially decrease cardiovascular and risk of sudden arrhythmic death in [high risk] populations."
"In summary, our results suggest that vitamin D3 supplementation improves cardiac autonomic tone in response to an acute stressor in healthy humans. While larger, prospective studies are required to determine the effect of vitamin D3 supplementation on clinical outcomes, optimizing vitamin D levels remains an exciting potential therapeutic target for those populations at high risk of cardiovascular mortality."
Anticancer Effect of Vitamin D
In another study in Anticancer Research, breast cancer patients with high levels of vitamin D in their blood are twice as likely to survive the disease as those with lower levels, new research has suggested.
Researchers at McGill University have previously discovered a molecular basis for the cancer preventive effects of vitamin D, whereby its active form essentially shuts down cancer cells.
The new study, published in Anticancer Research, investigated a possible relationship between vitamin D levels (measured as 25-hydroxyvitamin D) and breast cancer survival rates after previous research suggested that low vitamin D status may be linked to a higher risk of premenopausal breast cancer.
Led by Professor Cedric Garland from the University of California, San Diego School of Medicine, the researchers performed a meta-analysis of five clinical studies, with data from more than, 4,000 breast cancer patients. They found that those with the highest vitamin D status had around twice the survival rate of those with the lowest status.
"The study has implications for including vitamin D as an adjuvant to conventional breast cancer therapy," explained co-author Heather Hofflich.
Research scientist Albert Obrimovich said high vitamin D levels have been correlated with low cancer rates. "We know the correct daily dose of vitamin D3 for adults is approximately 5,000 IU/day, not the 200 IU recommended by the Institute of Medicine and the correct dosage has a direct impact on cancer rates," he stated.
Indeed, Garland recommended that randomised controlled clinical trials to confirm their findings should commence soon - adding that it could be that adding vitamin D into a breast cancer patient's standard care could commence right away, so long as those patients were closely monitored.
"There is no compelling reason to wait for further studies to incorporate vitamin D supplements into standard care regimens since a safe dose of vitamin D needed to achieve high serum levels above 30 nanograms per milliliter has already been established," commented Garland.
Garland and colleagues performed the 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.
When combined, the data included 4,443 breast cancer patients, said the team - who found that women classified in the 'high' serum group had an average level of 30 nanograms per milliliter (ng/ml) of 25-hydroxyvitamin D in their blood, while the 'low' group averaged 17 ng/ml.
The team noted that previous research has found the average vitamin D serum level in patients with breast cancer in the United States to be around 17 ng/ml.
"Higher serum concentrations of 25(OH)D were associated with lower case-fatality rates after diagnosis of breast cancer," explained the researchers. "Specifically, patients in the highest quintile of 25(OH)D had approximately half the death rate from breast cancer as those in the lowest."
Indeed, Garland and his team concluded that a high serum 25(OH)D status is associated with lower mortality from breast cancer.
"Serum 25(OH)D in all patients with breast cancer should be restored to the normal range (30-80 ng/ml), with appropriate monitoring," they wrote - adding that clinical studies should be initiated to confirm that this association was not due to reverse causation.
Mae Chan holds degrees in both physiology and nutritional sciences. She is also blogger and and technology enthusiast with a passion for disseminating information about health.