By Maylin Rodriguez-PaezVitamin D, along with diet and exercise, has emerged as one of the most important preventive factors in human health. Life Extension has been talking about the need for more vitamin research for years … and it seems mainstream medicine is finally listening. Vitamin D blood testing is at last becoming an integral part of yearly physical exams. Thank goodness.
Studies since the 1990s have clearly shown a link between low vitamin D and many conditions including heart attacks, diabetes, multiple sclerosis, strokes, and even cancer.1-5 Interestingly, vitamin D deficiency seems to be linked to depression as well.
Research Linking Vitamin D with DepressionA significant number of studies have recently looked into the question of whether or not low vitamin D can precipitate depression. Most depression experts believe there is a link, given the fact that every cell in the human body, including brain cells, has a vitamin D receptor. That means that this important vitamin plays a role in the normal to even optimal functioning of all cells.
In one study, Dutch researchers measured vitamin D levels in over 1,000 individuals aged 65 to 95. Of the total group, 26 were suffering from major depression and 169 from minor depression. They discovered that vitamin D blood levels were 14% lower in depressed subjects than non-depressed subjects.6
Similar findings were seen in another study involving more than 12,000 people. Participants with lower levels of vitamin D were more likely to experience depressive symptoms.7 These studies lead to the following question: What is it about vitamin D that makes us feel happy?
Vitamin D is a “Feel Good” Neurotransmitter BoosterIt turns out that vitamin D supports serotonin and dopamine production. Serotonin and dopamine are integral to our feelings of happiness. Most antidepressant medications work by modulating serotonin and dopamine activity in the brain.
In a fascinating study, scientists discovered how sunlight directly influenced serotonin production. Blood samples were taken from 101 men during exposure to different amounts of sunlight. Serotonin metabolites were highest when men were exposed to the brightest sunlight.8 This makes sense when you remember that vitamin D is produced in the skin when exposed to the sunlight.
In another study, investigators injected mice with radioactively labeled vitamin D and found that it concentrated in adrenal cells. They discovered that in cultured adrenal cells vitamin D increased the expression of tyrosine hydroxylase, which is the rate limiting enzyme responsible for dopamine production.9
Does Your Body Make Enough Vitamin D?Vitamin D is the only vitamin that can be made by the skin upon sun exposure. However, during the winter it becomes increasingly difficult to make enough.10 The days are shorter and people avoid going outdoors because it’s too cold.
Here’s an interesting fact: If you live above the 34th parallel your body won’t make vitamin D during the winter months.11 The following map shows where the line crosses the United States. If you live above the line, there’s no D for you when you need it most — during the cold and flu season.
D2 or D3? That's the QuestionLife Extension’s own research shows that it may take between 5,000 to 10,000 IU of supplemental vitamin D daily to bring individuals to optimal blood levels (50–80 ng/ml). Before you start supplementing with vitamin D, you should ask your doctor to perform a 25-hydroxy vitamin D test (or order one yourself). This will measure the amount of Vitamin D that circulates in your bloodstream, and it can pinpoint a deficiency.
Please note: Vitamin D is found in two main forms: vitamin D2 (from plants) and D3 (from animals). There is a growing concern that vitamin D2 is not as good or as absorbable as vitamin D3.
The truth is that our bodies have the capacity to convert both D2 and D3 into the active form of vitamin D. A study conducted by Boston University School of Medicine found that 1,000 IU of vitamin D2 daily was as effective as 1,000 IU of vitamin D3 in maintaining serum vitamin D levels.
However, there is research showing that higher dosages of vitamin D3 are better absorbed. Whatever form you decide to use, follow up with a vitamin D blood test to ensure you obtain optimal levels.
For thousands of years, the sun has represented happiness and life. Until recently, we didn’t know exactly how the sun influenced our mood. Now we know that vitamin D is the missing link in this age-old mystery.
Have you had your vitamin D blood level checked? If not, do it right away!
- Int J Epidemiol. 1990 Sep;19(3):559-63.
- Arch Intern Med. 2007 Jun 11;167(11):1159-65.
- Proc Soc Exp Biol Med. 1997 Oct;216(1):21-7.
- Nutr Metab Cardiovasc Dis. 2005 Jun;15(3):188-97.
- Cancer Causes Control. 2005 Mar;16(2):83-95.
- Arch Gen Psychiatry. 2008 May;65(5):508-12.
- Mayo Clin Proc. 2011 Nov;86(11):1050-5
- Lancet. 2002 Dec 7;360(9348):1840-2.
- Brain Res Mol Brain Res. 1996 Feb;36(1):193-6.
- J Clin Endocrinol Metab. 1988 Aug;67(2):373-8.
- Khalsa, Soram. Vitamin D Revolution. Hay House Publishing, 2009.
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