The Dangers of Vitamin D
A new study by the University of Copenhagen is turning advice about Vitamin D on its head. Results of the study, focusing on the association between death (all causes) and vitamin D levels, showed that too much vitamin D could be as harmful to health as too little.
The study took information from almost a quarter of a million Danish residents, a task that was only possible due to the massive archive of patient data held by the Danes in a centralized database. Regardless of the actual cause of death, the study looked at the level of vitamin D as measured by the concentration of 25-hydroxyvitamin (OH) D in the blood. They found that the lowest death rates were in patients with 50-60 nmols per liter. Both above and below this range, they found a significant increase in mortality.
How Much Vitamin D is Recommended for Maximum Health Benefits?
These findings contradict the rash advice given by some that you cannot have too much vitamin D. As with most things in life, moderation is the key. Leader of the study, Darshana Durup, explained that as expected there was a higher mortality in people with low levels of vitamin D, but the surprise was that those with a high level of vitamin D also had a higher mortality rate.
The study showed that in cases where the blood had less than 10 nmol/L, mortality was 2.31 times higher than those who had the optimal level of 50 nmol/L. It also showed that in those with more than 140 nmol/L of vitamin D, mortality was 1.42 times more likely.
How to Reach and Maintain Optimal Levels of Vitamin D
To clarify just how much vitamin D is recommended as a supplement, in 2010 the Food and Nutrition Board of the Institute of Medicine set the recommended daily allowance (RDA) at 600 IU for those under the age of 70 and 800IU for those over 70. They also set the Tolerable Upper Intake Limit at 4,000 IU per day, at which point it may have the potential to be dangerous, ie. toxic to the body. The only way to accurately assess your vitamin D levels is with a blood test showing the 25 (HO) D levels in your blood.
People who are taking supplements such as vitamin D, calcium with D and multivitamins should check their total daily intake of vitamin D, but they are unlikely to exceed sensible limits. The added complication is that those who spend times outdoors in sunshine may have sufficient levels of naturally produced vitamin D in their blood before they take any supplement.
In most cases there is no reason to panic and stop taking vitamin D supplements as it was only when serum concentrations of 25 (OH) D reached 140 nmol/L in the study that it was considered a danger to health. It was estimated that this would only be reached in someone taking around 4800IU per day, which is far above safe recommended levels.
In conclusion, Vitamin D is absolutely essential to the body, not only for healthy bones, but also for a strong immune system and reducing the risk of heart disease, cancer and diabetes. While the alarmist headlines may suggest stopping taking vitamin D altogether, health advice remains the same – that taking vitamin D within the recommended guidelines seems to indicate a lower mortality rate and a long and healthy life.