By Dr. Mercola
Vitamin D research has repeatedly shown that vitamin D can improve a number of brain disorders, including depression and dementia—the most devastating form of which is Alzheimer's disease.
Vitamin D receptors appear in a wide variety of brain tissue early in the fetal development, and activated vitamin D receptors increase nerve growth in your brain.
Researchers believe that optimal vitamin D levels may enhance the amount of important chemicals in your brain and protect brain cells by increasing the effectiveness of the glial cells in nursing damaged neurons back to health.
Vitamin D may also exert some of its beneficial effects on your brain through its anti-inflammatory and immune-boosting properties.
Vitamin D Deficiency Drastically Raises Your Risk for Dementia
According to one recent study,1 , 2 seniors who have low vitamin D levels may double their risk of dementia and Alzheimer's disease. Specifically, compared to those with vitamin D levels in the normal range:
- Those with low levels had a 53 percent increased risk for dementia, and a 70 percent higher risk of Alzheimer's
- Severely deficient individuals had a 125 percent higher risk for dementia and 120 percent higher risk for Alzheimer's
As noted by the authors: "This adds to the ongoing debate about the role of vitamin D in nonskeletal conditions."
The Link Between Depression and Dementia
Other recent research has found links between depression and dementia, and between vitamin D deficiency and depression. One eight-year-long study3 from Rush University Medical Center found that higher levels of depression translated into greater risk for dementia later on.
The severity of the depression was also linked to the speed of memory decline—the worse the depression, the faster the decline in memory. According to lead researcher Robert S. Wilson:
"These findings are exciting because they suggest depression truly is a risk factor for dementia, and if we can target and prevent or treat depression and causes of stress we may have the potential to help people maintain their thinking and memory abilities into old age."
Studies4 point to the fact that low vitamin D levels also predispose you to depression, so the links between vitamin D, dementia, and depression indeed appear to be quite real.
In essence, vitamin D deficiency raises your risk of both depression and dementia, so the fact that depressed individuals have a higher risk of dementia then becomes rather logical—but the root of the problem is likely to be a lack of vitamin D, not depression in and of itself.
Vitamin D Deficiency Predisposes You to Depression
In one previous study, seniors with the lowest levels of vitamin D were found to be 11 times more prone to be depressed than those who had normal levels. More recent research was discussed in a Times Online article:5
"The Amsterdam research, which tracked over 1,200 people aged 65 to 95, showed that blood vitamin D levels were 14 percent lower in individuals with major and minor depression compared with non-depressed participants.
A study in the United States indicated that vitamin D deficiency occurred more often in certain people, including African-Americans, city dwellers, the obese, and those suffering from depression.
People with vitamin D levels below 20 ng/mL had an 85 percent increased risk of depression compared to those with vitamin D levels greater than 30 ng/mL" [Emphasis mine]
Vitamin D deficiency has long been associated with Seasonal Affective Disorder6 (SAD), and in 2007, researchers noted that vitamin D deficiency is associated with depression and fibromyalgia.7
A double-blind randomized trial8 published in 2008 also concluded that: "It appears to be a relation between serum levels of 25(OH)D and symptoms of depression. Supplementation with high doses of vitamin D seems to ameliorate these symptoms indicating a possible causal relationship."
Vitamin D May Reduce Depression and Diabetic Pain
Vitamin D supplementation has been found to reduce both depression and diabetic pain.9, 10 Here, researchers assessed how vitamin D supplementation affected women with type 2 diabetes who were also diagnosed with depression.
At the outset of the study, 61 percent of participants reported neuropathic pain (shooting or burning pain in their legs and feet); 74 percent reported numbness and tingling in their extremities. The participants were given 50,000 IUs of vitamin D2 once a week for six months. At follow-up, both depression and pain scores had improved.
According to lead researcher Todd Doyle, Ph.D., vitamin D supplementation "is a promising treatment for both pain and depression in type 2 diabetes." However, I would note that you'd probably get even better results using vitamin D3 rather than prescription D2. In fact, previous research suggests vitamin D2 might do more harm than good in the long term.
Optimizing Your Vitamin D Also Reduces Your Risk of Diabetes, New Study Suggests
Bringing the focus of this article full circle is research showing that vitamin D may also play a role in type 2 diabetes; so now we have a number of cross-links between vitamin D and dementia, depression, and diabetes. One Indian study found that vitamin D and calcium supplementation in combination with exercise can aid prediabetic individuals by preventing the progression into full blown diabetes.
Since exercise is one of the most effective ways to improve your insulin and leptin sensitivity, this certainly makes sense, and may make it more difficult to ascertain which of the two factors—vitamin D or exercise—had the greatest impact. Either way, both are part and parcel of diabetes prevention, so the results still speak to the power of simple lifestyle modifications. As noted by Nephrology News:11
"Vitamin D deficiency has been linked to prediabetes, which is a blood glucose, or sugar, level that is too high but not high enough to be considered diabetes. It is unclear, however, if bringing low vitamin D blood levels to normal through supplementation will affect progression to diabetes.
In the new study, every unit increase in vitamin D level after supplementation of the vitamin decreased the risk of progression to diabetes by eight percent... 'Without healthy lifestyle changes, nothing works to prevent diabetes in at-risk individuals,' said the lead author, Deep Dutta, MD, DM... 'However, our results are encouraging because the addition of vitamin D and calcium supplements is easy and low in cost.'" [Emphasis mine]
Here, a vitamin D level below 30 ng/ml was considered insufficient. All participants in the study were prediabetic. The treatment group received a once-weekly dose of 60,000 IUs of vitamin D3, along with 1,250 milligrams (mg) of calcium carbonate daily, for eight weeks. A second group received only the calcium supplement. Both groups were advised to get 30 minutes of daily exercise. More than two years worth of follow-up revealed that:
- Just under 11 percent of those receiving both vitamin D3 and calcium became diabetic, while 26.5 percent of the calcium-only group developed diabetes
- Blood sugar levels normalized in over twice as many of those in the vitamin D/calcium group, compared to the calcium-only group (41.8 percent versus 20.4 percent respectively)
US Seniors Are at Particular Risk for ALL of These Problems
As noted in a recent MedicineNet article,12 60 percent of seniors seen in emergency rooms (ER) across the US are either malnourished or at risk for malnutrition—despite 95 percent of them having primary care physicians, and 96 percent having health insurance, and being otherwise mentally competent. Those most likely to be malnourished were seniors who:
- Suffered from depression
- Lived in assisted-living facilities
- Had trouble swallowing or chewing due to issues with their dentures or dental pain
- Had difficulty shopping for groceries
Vitamin D sufficiency is important both when it comes to preventing depression and pain, but a vast majority of seniors are also vitamin D deficient. So here again we see how a vicious cycle can be set into motion by vitamin D deficiency.
How to Optimize Your Vitamin D Level
When it comes to vitamin D, you want to be in the "optimal" range, not the "normal" one. Based on the evaluation of healthy populations that get plenty of natural sun exposure, the optimal range for general health appears to be somewhere between 50 and 70 ng/ml.
As for HOW to optimize your vitamin D levels, I firmly believe that sensible sun exposure is the best way. There's a smartphone app called DMinder (dminder.info) that will tell you how much UV radiation you're getting and how many IUs of vitamin D you're making based on your local weather conditions (reported from the weather service) and other individual parameters such as your skin tone and age. It will also tell you when to get out of the sun, to protect yourself from sunburn.
If you can't get enough sunshine, then a safe tanning bed would be your next best option. Most tanning equipment use magnetic ballasts to generate light. These magnetic ballasts are well known sources of EMF fields that can contribute to cancer. If you hear a loud buzzing noise while in a tanning bed, it has a magnetic ballast system. I strongly recommend you avoid these types of beds and restrict your use of tanning beds to those that use electronic ballasts.
If your circumstances don't allow you to access the sun or a safe tanning bed, then you really only have one option left, and that is to take a vitamin D supplement. GrassrootsHealth has a helpful chart showing the average adult dose required to reach healthy vitamin D levels based upon your measured starting point. Many experts agree that 35 IUs of vitamin D per pound of body weight could be used as an estimate for your ideal dose.
The Vitamin D Council aims to raise awareness among the general public on the growing vitamin D deficiency pandemic and the benefits of sun exposure. They are currently at the end of fund drive but there is still time to participate. Your support will allow them to increase their efforts in reducing the burden of vitamin D deficiency and begin the many exciting projects they have lined up.
If You Opt for Oral Vitamin D, Remember Vitamin K2
Keep in mind that if you opt for a vitamin D supplement, you also need to take vitamin K2. The biological role of vitamin K2 is to help move calcium into the proper areas in your body, such as your bones and teeth. It also helps remove calcium from areas where it shouldn't be, such as in your arteries and soft tissues. Vitamin K2 deficiency is actually what produces the consequences similar to vitamin D toxicity, which includes inappropriate calcification that can lead to hardening of your arteries.
The reason for this is, when you take vitamin D, your body creates more vitamin K2-dependent proteins that move calcium around in your body. Without vitamin K2, those proteins remain inactivated, so the benefits of those proteins remain unrealized. So remember, if you take supplemental vitamin D, you're creating an increased demand for K2. Together, these two nutrients help strengthen your bones and improve your heart health.
Test Your Levels at Least Once a Year—Even if You're Healthy
I recommend testing your vitamin D level at least once a year, in the middle of the winter when your level would be at its lowest. This will give you an idea of the extent of your insufficiency. Ideally, you'd want to get your level tested several times a year, at regular intervals, to ensure you're continuously staying within the ideal range. Once you know your pattern and can comfortably predict that you will not fall below 60 ng/ml, then it would be fine to shift to annual testing.
I believe vitamin D testing should be at the top of virtually everyone's list—but especially pregnant women and cancer patients. It's important to remember that optimal vitamin D levels appear to offer powerful PREVENTION of a whole host of chronic diseases, so please, do not wait for a problem to appear before addressing your vitamin D status.
The D*Action Project by GrassrootsHealth is one cost effective solution. To participate, simply purchase the D*Action Measurement Kit and follow the registration instructions included. (Please note that 100 percent of the proceeds from the kits go to fund the research project. I do not charge a single dime as a distributor of the test kits.)
As a participant, you agree to test your vitamin D levels twice a year during a five-year study, and share your health status to demonstrate the public health impact of this nutrient. There is a $65 fee every six months for your sponsorship of this research project, which includes a test kit to be used at home, and electronic reports on your ongoing progress. You will get a follow up email every six months reminding you "it's time for your next test and health survey."