Even with the explosion of research surrounding Vitamin D – as many as one-third to one-half of US adults are Vitamin D deficient . The main reasons individuals become deficient in vitamin D include lack of sun exposure, and limited skin synthesis of this vital nutrient.
What is Vitamin D?
Vitamin D is not technically a vitamin – rather it is classified as a hormone. Specifically, it belongs to the steroid hormone family, and is synthesized from cholesterol. Steroid hormones are most well-known for their ability to directly target and signal DNA—subsequently turning certain genes on while simultaneously turning other genes off.
Vitamin D has a specific receptor that can control the transcription of many genes, such as immunoregulatory genes, cancer genes, anti-inflammatory genes, and even blood pressure-related genes. It is also utilized by smooth muscle cells within the arteries, helping to lower blood pressure. When blood pressure is chronically elevated, scientists and physicians know the risks for cardiovascular disease and stroke skyrocket. A number of small clinical trials have demonstrated Vitamin D’s ability to decrease blood pressure [2,3].
Why aren’t I getting enough?
UVB rays from the sun are necessary for the production of Vitamin D in the skin. Lack of sun exposure, often attributable to seasons, cultural dress or the use of sunscreen, can inhibit Vitamin D production. Renal disease, liver issues, as well as gastrointestinal diseases such as Crohn’s disease can also limit both the conversion of vitamin D into its active form, as well as the dietary absorption of vitamin D .
Now that you understand how Vitamin D works, and why it is so important, here are a few signs that your levels may be too low:
- Suicidal thoughts and depression. While environment, psychological health and genetic factors certainly influence the presence of suicidal thoughts and depression, scientists are discovering that approximately 58% of suicide attempters are deficient in Vitamin D. In addition, these individuals typically display elevated proinflammatory status, and it has been suggested that Vitamin D deficiency may play a role in the increase in neurological inflammation in suicidal patients . With depression, several studies have demonstrated a relationship between severity and risk of depressive symptoms and low vitamin D levels [6,7]. Successful intervention with vitamin D has also been observed, resulting in an improvement in depressive symptoms in overweight adults .
- High blood pressure. While the true cause of most cases of hypertension –or high blood pressure—is unknown, vitamin D has a role in regulating the angiotensin-renin axis signaling that is responsible for hypertension in the smooth muscle cells that line arteries and veins. The kidneys are capable of converting inactive vitamin D into active vitamin D forms, and using it locally to help regulate blood pressure. A number of studies have shown that vitamin D interventions help to reduce blood pressure in adults .
- Your immune system doesn’t seem up to par. Vitamin D is responsible for helping to keep inflammatory immune cells at bay, and encouraging the maturation of naïve cells into regulatory immune cells . Which means your body will be able to produce that delicate balance of immune reaction, but not over-reaction, to a stimulus. Beyond that, certain cells, such as antigen presenting cells, have the ability to convert inactive vitamin D into the active form of vitamin D. Vitamin D signaling in immune cells leads to a decrease in histamine production – that annoying molecule that makes your eyes watery and your nose itchy.
- Osteoporosis or osteopenia, or rickets in children. If your bone health is not the best, making sure your vitamin D level is adequate is essential to help keep a problem from getting worse. In children, bowed legs, or weak, soft bones is a symptom of rickets, and is a direct result of a vitamin D deficiency .
- You have pre-diabetes – or insulin resistance. Vitamin D is related to the auto-immune development of type 1 diabetes, as well as the onset of type 2 diabetes . Vitamin D plays a vital role in the action of insulin, which is dysfunctional in type 2 diabetes .
- You have high cholesterol or high triglyceride levels. A recent study showed that presence of metabolic syndrome as well as hyperlipidemia is associated with decreased vitamin D levels. Adding vitamin D to statin treatment lowered cholesterol levels an additional 10 points lower than just the statin alone. People who were given vitamin D also saw a greater decrease in triglyceride levels as well .
- You have low HDL or “healthy” cholesterol levels. If your HDL – or good cholesterol—levels are too low, studies show that this is independently and significantly related to the vitamin D deficiency .
- Thomas J. Wang, MD; Michael J. Pencina, PhD; Sarah L. Booth, PhD; Paul F. Jacques, DSc; Erik Ingelsson, MD, PhD; Vitamin D Deficiency and Risk of Cardiovascular Disease. Circulation. 2008;117:503-511.
- Lind L, Wengle B, Wide L, Ljunghall S. Reduction of blood pressure during long-term treatment with active vitamin D (alphacalcidol) is dependent on plasma renin activity and calcium status: a double-blind, placebo-controlled study. Am J Hypertens. 1989;2:20 –25.
- Pfeifer M, Begerow B, Minne HW, Nachtigall D, Hansen C. Effects of a short-term vitamin D(3) and calcium supplementation on blood pressure and parathyroid hormone levels in elderly women. J Clin Endocrinol Metab. 2001;86:1633–1637.
- Kurt A. Kennel, MD; Matthew T. Drake, MD, PhD; and Daniel L. Hurley, MD Vitamin D Defciency in Adults: When to Test and How to Treat. Mayo Clin Proc. 2010;85(8):752-758.
- Cécile Grudet, Johan Malmb, Åsa Westrina, Lena Brundind. Suicidal patients are deficient in vitamin D, associated with a pro-inflammatory status in the blood. Psychoneuroendocrinology (2014) 50, 210—219.
- Milaneschi, Y., Hoogendijk, W., Lips, P., Heijboer, A.C., Schoevers, R., van Hemert, A.M., Beekman, A.T., Smit, J.H., Penninx, B.W., 2014. The association between low vitamin D and depressive disorders. Mol. Psychiatry 19, 444—451.
- Milaneschi, Y., Shardell, M., Corsi, A.M., Vazzana, R., Bandinelli, S., Guralnik, J.M., Ferrucci, L., 2010. Serum 25-hydroxyvitamin D and depressive symptoms in older women and men. J. Clin. Endocrinol. Metab. 95, 3225—3233.
- Jorde, R., Sneve, M., Figenschau, Y., Svartberg, J., Waterloo, K., 2008. Effects of vitamin D supplementation on symptoms of depression in overweight and obese subjects: randomized double blind trial. J. Intern. Med. 264, 599—609.
- Kimberly Y.Z. Forrest, Wendy L. Stuhldreher. Prevalence and correlates of vitamin D deficiency in US adults. Nutrition Research 31 (2011) 48–54.
- Chiu KC, Chu A, Go VLW, Saad MF. Hypovitaminosis D is associated with insulin resistance and beta cell dysfunction. Am J Clin Nutr 2004;79:820-5.
- Qin XF, Zhao LS, Chen WR, Yin da W, Wang H. Effects of vitamin D on plasma lipid profiles in statin-treated patients with hypercholesterolemia: A randomized placebo-controlled trial. Clin Nutr. 2015 Apr;34(2):201-6. doi: 10.1016/j.clnu.2014.04.017. Epub 2014 May 2.
- Holick MF. Vitamin D deficiency. N Engl J Med. 2007;357:266-281.
- Tamblyn JA, Hewison M, Wagner CL, Bulmer JN, Kilby MD. Immunological role of vitamin D at the maternal-fetal interface. J Endocrinol. 2015 Mar;224(3):R107-21. doi: 10.1530/JOE-14-0642.