Recent studies show that people who have heart disease and other associated conditions are much more likely to be depressed if their vitamin D levels are low. This information was present at the annual American Heart Association meeting in November of last year.
A second study shows that people how have low vitamin D levels are much more likely to have heart disease or suffer a stroke and die at a younger age than people with adequate levels.
In the first study blood levels of vitamin D were measured in 8,680 people age 50 or older who had been diagnosed with heart disease, stroke, or another type of cardiovascular disease. Vitamin D levels above 30 nanograms per milliliter of blood (ng/mL) were considered normal, levels between 15 and 30 ng/mL were low, and those 15 ng/mL and below were deemed very low. While levels above 30 are considered normal, they are far from optimal. The study did not consider optimal levels of vitamin D, but it should be noted that in order to reap all of the benefits of vitamin D levels should be no lower than 50 ng/mL.
Among those with very low levels of vitamin D, 32 percent were depressed, as were 25 percent of the people with low levels, and 21 percent of those with normal levels. This trend was seen even among individuals with no history of depression. Winter seemed to make the association even clearer. Winter makes it much harder to get enough sun because of two reasons. First, the winter months are colder so when we are outside our skin is covered by our clothes preventing the synthesis of vitamin D. Secondly, during the winter the Northern hemisphere tilts away from the sun. This causes the strength of the sun’s rays reaching the surface of the earth to be lower. As a matter of fact, according to the National Institute of Health, the sun is not even strong enough to produce any vitamin D in latitudes north of Boston from November to March.
In the second study, which looked at 27,686 people age 50 or older with no history of cardiovascular disease, it was found that, compared to individuals with normal levels of the vitamin, people with very low levels of vitamin D were 77 percent more likely to die, 45 percent more likely to develop heart disease, and 78 percent more likely to have a stroke during the study, which lasted for more than a year. They also had double the risk of heart failure.
It is estimated that many of the genes that regulate cardiovascular health are either directly or indirectly affected by vitamin D. We also know that the brain is particularly affected by low levels of vitamin D. The brain is saturated in receptors for the vital nutrient and this may be how low levels are linked to depression.
Vitamin D has been linked to a host of other conditions that include cancer, osteoporosis, diabetes, Alzheimer’s disease, schizophrenia, and some autoimmune disorders. While not all of these may turn out to be caused by low vitamin D levels it is safe to assume there is at least some relationship.
Monitoring levels of vitamin D is a simple thing to do. I routinely measure my patients’ levels and have found that most people are astoundingly low. The current recommendations for adults in the US in terms of adequate vitamin D intake is anywhere from 200-600 IUs per day. They say the “safe” upper limit would be 2,000 IUs per day. These levels are a severe underestimation of what human beings need. I routinely recommend anywhere from 4,000-10,000 IUs per day depending on my patient’s needs and health goals. This is an effective and safe way to raise serum vitamin D. The safe upper limit that is set by the government today is extremely low and scientific research supports that. Below is a quote from the Merck Manual about what it actually takes to produce vitamin D toxicity.
Because synthesis of 1,25(OH)2D (the most active metabolite of vitamin D) is tightly regulated, vitamin D toxicity usually occurs only if excessive doses (prescription or megavitamin) are taken. Vitamin D 1000 μg (40,000 IU)/day produces toxicity within 1 to 4 mo in infants. In adults, taking 1250 μg (50,000 IU)/day for several months can produce toxicity.
So what this is saying is that in infants it takes more than 40,000 IUs daily for 1-4 months and 50,000 IUs in adults over roughly the same time period to produce toxicity. So where did they get the 2,000 IUs recommendation? Very good question. I think it means we must also question the daily allowances of all of the other nutrients we need to function and function optimally. I don’t know about you, but I don’t want to ‘just get by’. I want to feel great and live life to its fullest.
Even if you live in a sunny, warm climate you may not be protected. You may need less supplementation, but I recommend vitamin D for everyone. The research into this vitamin has exploded over the last 5 years and there have been nothing but positive results. If you have a family history of any of the conditions listed in this blog, you would probably benefit from vitamin D supplementation.