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Vitamin D
What is it? Overview Usage Side Effects and Warnings

Vitamin D Usage

Written by FoundHealth.


Effect of Vitamin D on Depression

Wrongly termed a vitamin, vitamin D is actually what is known as a precursor hormone. The metabolic product of vitamin D, the hormone calcitriol, affects the key biological functions of over 2000...

Read more about Depression and Vitamin D.

Effect of Vitamin D on Hypertension

Vitamin D plays a number of roles in the body, some of which are just now being discovered and confirmed. Its exact role in preventing or treating hypertension is not immediately clear. One...

Read more about Hypertension and Vitamin D.

Therapeutic Uses

Without question, if you are concerned about osteoporosis , you should take calcium and vitamin D. The combination appears to help prevent bone loss. 1 This is true even if you are taking other treatments for osteoporosis; after all, you can't build bone without calcium, and you can't properly absorb and utilize calcium without adequate intake of vitamin D. Interestingly, vitamin D may also help prevent the falls that lead to osteoporotic fractures .

Other uses of vitamin D are less well documented.

Some evidence suggests that getting adequate vitamin D may help prevent cancer of the breast, colon, pancreas, prostate, and skin, but the research on this question has yielded mixed results. 2 One study suggests that combined use of calcium plus vitamin D, but not either supplement separately, can help reduce risk of colon cancer. 3 However, an extremely large study involving over 36,000 post-menopausal women found that supplementing the diet with 1,000 mg of calcium plus 400 IU of vitamin D daily did not lower the risk of breast cancer over a period of 7 years. 4 Based on the results of this placebo-controlled study, there does not appear to be a connection between vitamin D and breast cancer risk.

Weak evidence hints that adequate vitamin D intake might reduce the risk of hypertension 5 and diabetes . 6 7 A very large randomized, placebo-controlled trial of over 36,000 postmenopausal women found daily supplementation with 1,000 mg of calcium plus 400 IU of vitamin D did not reduce or prevent hypertension during 7 years of follow-up. These results are possibly limited by non-study calcium use. 8 One preliminary study suggests that supplementation with vitamin D and calcium may be helpful for women with polycystic ovary syndrome. 9 A meta-analysis (formal statistical review) of published studies found some evidence that use of vitamin D at recommended levels may reduce overall mortality. 10 This article suggested, but did not attempt to establish, just how vitamin D might accomplish this.

Vitamin D is sometimes mentioned as a treatment for psoriasis . However, this recommendation is based on Danish studies using calcipotriol, a variation of vitamin D 3 that is used externally (applied to the skin). 11 Calcipotriol does not affect your body's absorption of calcium, so it is a very different substance from the vitamin D you can purchase at a store.

It has been suggested that since vitamin D levels in the body drop in the wintertime, vitamin D supplements might be helpful for seasonal affective disorder ("winter blues"). A small double-blind, placebo-controlled trial conducted during winter on 44 people found that vitamin D supplements produced improvements in various measures of mood. 12 However, a double-blind, placebo-controlled study of 2,217 women over 70 failed to find benefit. 13 It has been hypothesized that light therapy (used successfully for SAD) works by raising vitamin D levels, but there is some evidence that this is not the case. 14 Vitamin D supplements also do notappear to help enhance growth in healthy children. 15


  1. Dawson-Hughes B, Harris SS, Krall EA, et al. Effect of calcium and vitamin D supplementation on bone density in men and women 65 years of age or older. N Engl J Med. 1997;337:670-676.
  2. Garland FC, Garland CF, Gorham ED, Young JF. Geographic variation in breast cancer mortality in the United States: a hypothesis involving exposure to solar radiation. Prev Med. 19(6):614-22.
  3. Grau MV, Baron JA, Sandler RS, Haile RW, Beach ML, Church TR, Heber D. Vitamin D, calcium supplementation, and colorectal adenomas: results of a randomized trial. J Natl Cancer Inst. 95(23):1765-71.
  4. Chlebowski RT, Johnson KC, Kooperberg C, Pettinger M, Wactawski-Wende J, Rohan T, Rossouw J, Lane D, O'Sullivan MJ, Yasmeen S, Hiatt RA, Shikany JM, Vitolins M, Khandekar J, Hubbell FA, Women's Health Initiative Investigators. Calcium plus vitamin D supplementation and the risk of breast cancer. J Natl Cancer Inst. 100(22):1581-91.
  5. Rostand SG. Ultraviolet light may contribute to geographic and racial blood pressure differences. Hypertension. 30(2 Pt 1):150-6.
  6. Hyppönen E, Läärä E, Reunanen A, Järvelin MR, Virtanen SM. Intake of vitamin D and risk of type 1 diabetes: a birth-cohort study. Lancet. 358(9292):1500-3.
  7. The EURODIAB Substudy 2 Study Group. Vitamin D supplement in early childhood and risk for Type I (insulin-dependent) diabetes mellitus. Diabetologia. 1999;42:51-54.
  8. Margolis KL, Ray RM, Van Horn L, Manson JE, Allison MA, Black HR, Beresford SA, Connelly SA, Curb JD, Grimm RH Jr, Kotchen TA, Kuller LH, Wassertheil-Smoller S, Thomson CA, Torner JC, Women's Health Initiative Investigators. Effect of calcium and vitamin D supplementation on blood pressure: the Women's Health Initiative Randomized Trial. Hypertension. 52(5):847-55.
  9. Thys-Jacobs S, Donovan D, Papadopoulos A, Sarrel P, Bilezikian JP. Vitamin D and calcium dysregulation in the polycystic ovarian syndrome. Steroids. 64(6):430-5.
  10. Autier P, Gandini S. Vitamin D supplementation and total mortality: a meta-analysis of randomized controlled trials. Arch Intern Med. 167(16):1730-7.
  11. Kragballe K. Vitamin D3 analogues in psoriasis. Dermatologica. 180(2):110-1.
  12. Lansdowne AT, Provost SC. Vitamin D3 enhances mood in healthy subjects during winter. Psychopharmacology (Berl). 135(4):319-23.
  13. Dumville JC, Miles JN, Porthouse J, et al. Can vitamin D supplementation prevent winter-time blues? A randomised trial among older women. J Nutr Health Aging. 2006;10:151-153.
  14. Partonen T, Vakkuri O, Lamberg-Allardt C, Lonnqvist J. Effects of bright light on sleepiness, melatonin, and 25-hydroxyvitamin D(3) in winter seasonal affective disorder. Biol Psychiatry. 39(10):865-72.
  15. Schou AJ, Heuck C, Wolthers OD. A randomized, controlled lower leg growth study of vitamin D supplementation to healthy children during the winter season. Ann Hum Biol. 30(2):214-9.


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