Large Scale Study Verifies That Low Vitamin D Levels Are Linked To Depression
In the absence of vitamin D, many diseases increase by 1000 percent, especially in the winter months. Low levels of the sunshine vitamin is liked with significant cognitive impairment and widespread chronic pain. According to a recent Finnish population study, higher vitamin D levels have a lower risk of depression according to results from over 5000 people.
Previous data has shown in the International Archives of Medicine that people with vitamin D deficiency are at an 85 percent increased risk of having current depressive episodes, compared with people with sufficient levels.
The study used data from Finland's national Health 2000 Survey, amounting to 5371 individuals aged 30--79 years of whom 354 were diagnosed with depressive disorder and 222 with anxiety disorder.
Individuals with higher serum 25(OH)D concentrations showed a reduced risk of depression, according to the study published in the British Journal of Nutrition. However, the same could not be said for anxiety which is successfully treated with a range of natural remedies.
"These results support the hypothesis that higher serum 25(OH)D concentrations protect against depression even after adjustment for a large number of socio-demographic, lifestyle and metabolic factors," wrote the researchers from the National Institute for Health and Welfare in Helsinki.
The population attributable fraction (PAF) - the proportion of cases that can be attributed to one or more risk factors -- was 19% for depression when serum vitamin D concentrations were at least 50 nanomoles/litre (nmol/l). This means raising serum levels above 50 nmol/l could have avoided about 19% of the depression cases in the study, the researchers said.
The key findings
The results found a weaker association amongst the participants over 59 years -- although they said this could be explained by a greater prevalence of both depression and low vitamin D in the younger participants.
Meanwhile, the link between higher vitamin D and a lower depression risk was seen in particular for those who were divorced, had an unhealthier diet or lifestyle or had a metabolic syndrome.
If such a causal relationship was established, this could mean vitamin D's protection against depression was especially strong for individuals with poor socio-economic status, lifestyle choices and metabolic health.
They also found individuals free from chronic diseases or anxiety disorder demonstrated a stronger association than those suffering from these conditions.
Who has the highest?
Those with the highest vitamin D levels were more likely to be older, married or cohabiting, more educated and without economic problems compared to those with lower levels.
This group had a healthier lifestyle since they were leaner, more active in their leisure time, smoked less and consumed less alcohol. They ate better and got more vitamin D from their diet and supplements, according to the food intakes recorded by the participants.
This higher level group also had better metabolic health in terms of blood pressure, triglyceride, glucose and cholesterol levels. They also perceived their health to be better.
Public saving potential
The researchers said the findings could have big public spending implications -- with Finland currently spending about 1 billion on depression per year.
Epidemiological evidence of this link had previously been scarce, they said, and large-scale prospective studies were now needed to confirm the relationship.
How Much Vitamin D Do You Need for Your Best Health?
The optimal range is somewhere between 50 and 60 ng/ml (125 to 150 nmol/l). To convert ng/ml to nmol/l, simply multiply by 2.5.
Unfortunately, the only way to know where you're at is to ask your doctor to include 25 (OH) D, also known as 25-hydroxy D, with your blood work during your next checkup. Some labs test for 1,25 hydroxy D, which isn't as accurate a marker of your vitamin D status as 25 hydroxy D, so be sure to specifically ask for 25 hydroxy D.
You want your 25 hydroxy D level to be at least 30 ng/ml (75 nmol/l), but again, based on the research that I have reviewed, mainly that of Dr. Michael Holick, the optimal range appears to be 50 to 60 ng/ml. Some prominent physicians and vitamin D experts feel that one can go even higher, even up to 80 ng/ml. But my suggestion is to err on the side of caution and aim to be in the 50 to 60 range.
The 50 to 60 range is based on numerous studies that show strong relationships between these levels and reduced risk of a wide variety of chronic diseases and increased lifespan. This range is also based on the 25 hydroxy D levels of healthy people living in areas of the world (tropical and subtropical regions) where it's quite common to receive more than enough sunlight exposure to ensure regular vitamin D production.
But here's an important point that you want to keep in mind: When sunlight creates vitamin D in a healthy person and that person's 25 hydroxy D is in the optimal range, that person is almost certainly benefiting from other natural compounds that are generated with sunlight exposure. Dr. Holick calls these other compounds "photo products," and he and his team are currently researching the makeup and benefits of these photo products.
Put another way, establishing optimal vitamin D status mainly via healthy sunlight exposure may provide more health benefits than establishing optimal vitamin D status mainly via foods and supplements. Correct usage of foods and supplements only gives you the right amount of vitamin D - they don't generate the photo products that sunlight does.
At the same time, it's worth remembering that even responsible exposure to sunlight comes with some undesirable effects, like premature aging of skin and possibly increased risk of non-melanoma skin cancers, depending on your history of sunlight exposure.
So it's too early to say which is more desirable between getting vitamin D mainly from sunlight vs. mainly from foods and supplements.
What we do know for sure is that keeping your 25 hydroxy D level somewhere between 50 and 60 ng/ml, possibly even up to 65 ng/ml can significantly decrease your risk of all types of disease and increase your lifespan. And a wise approach is likely getting vitamin D from a combination of responsible sunlight exposure and foods and supplements that come with vitamin D.
Vitamin D is best obtained by sunlight, but if pursuing supplementation, look for high quality vitamin D3 cholecalciferol and stay away from those with dangerous preservatives such as potassium sorbate.