Vitamin D Deficiency and Seasonal Depression

March 4, 2022
Couple dancing

Vitamin D is well known for its important role in the formation of healthy bones, immune function, and cell growth; however, vitamin D is now gaining popularity for its potential aid in preventing seasonal affective disorder and other mood disorders. Seasonal affective disorder is described as “major depressive episodes that follow a seasonal pattern” and occurs typically in the seasons with shorter periods of sunlight and colder days. The most common season related to higher reported occurrences of seasonal affective disorder is winter. Vitamin D is thought to be a contributor to seasonal affective disorder because serum vitamin D levels tend to be lower when people have less exposure to sunlight and clinical studies have found that vitamin D levels are lower in depressed individuals. Vitamin D levels have been shown to affect the amount of serotonin and dopamine (happy hormones) produced in the central nervous system. Lower levels of vitamin D means less production of those feel-good hormones.

While the correlation between lower serum vitamin D levels and seasonal depression exists, it is important to note that there are many causes of depression such as chemical imbalances and other brain disfunctions as well as a wide range of severity for mood disorders. Vitamin D has not been proven effective in the prevention, treatment, or symptom management of moderate and severe mood disorders. However, in mild cases, vitamin D supplementation has shown promise as a treatment and prevention option. In mild cases of seasonal depression, vitamin D supplementation demonstrates improvements in daily mood, fatigue, and other symptoms.

The studies relating vitamin D deficiency and depression are not perfect, but they do demonstrate a potential relationship, which is why it is important to ask your health care provider about checking your serum 25-hydroxy vitamin D [25 (OH) D] levels if you are concerned. A level of 30-60 ng/dL is considered adequate, while insufficiency is defined as a level of 21-29 ng/dL. Vitamin D deficiency is classified as a serum level of 25 (OH) D of 20 ng/dL or less. Vitamin D insufficiency and deficiency are both common and treatable. Some studies indicate that between 30-50% of children and adults are at risk of developing vitamin D deficiency or already are deficient in vitamin D.

If you find that you are insufficient or deficient in vitamin D, the best way to achieve optimal serum vitamin D levels is through a combination of dietary intake of vitamin D, sun exposure, and supplementation. Currently, the recommended daily allowance (RDA) for vitamin D is 600 IU of vitamin D per day for children and adults ages 1 to 70 years old. For adults over 70 years old, the RDA is 800 IU per day. However, if you are deficient in vitamin D the recommended daily intake is closer to 1,000-2,000 IU per day. Vitamin D is generally recognized as safe, however, vitamin D toxicity can occur when taking extreme high doses. The tolerable upper limit for vitamin D is currently set at 4,000 IU per day; however, higher doses may be used at the discretion of your health care provider. Vitamin D also has the potential to interact with medications, so it is important to talk with your doctor before beginning supplementation.

Tips for avoiding vitamin D deficiency:

  • Get outside for 10-30 minutes per day. Enjoy some sunshine by going on a walk, taking your kids/dog to the park, going for a bike ride, etc.
  • Eat a variety of vitamin D rich foods. Incorporate some of the foods listed below into your diet, including fortified milks, cereals, and juices.
  • Take a Vitamin D3 supplement. Most vitamin D supplements come in 500-1,000 IU capsules. By taking 1,000-2,000 IU per day, you can ensure that your body is getting enough vitamin D even on days when you don’t go outside or eat enough vitamin D rich foods.

Dietary sources of vitamin D include:

  • Soy milk
  • Mushrooms
  • Egg yolks
  • Butter
  • Oily fish
  • Fortified milk, cereal, and juice

There are many factors that increase your risk for seasonal depression and other mood disorders but getting enough vitamin D is one easy way to potentially help reduce that risk. More studies need to be done on the effectiveness of vitamin D as a treatment for depression, however, it currently has a lot of promise as a natural remedy.  

This nutrition tip was provided by Kayla Jimerson, RD at St. Francis Hospital.


  1. Parker GB, Brotchie H, Graham RK. Vitamin D and depression. J Affect Disord. 2017 Jan 15;208:56-61. doi: 10.1016/j.jad.2016.08.082. Epub 2016 Oct 11. PMID: 27750060.
  2. Stewart AE, Roecklein KA, Tanner S, Kimlin MG. Possible contributions of skin pigmentation and vitamin D in a polyfactorial model of seasonal affective disorder. Med Hypotheses. 2014 Nov;83(5):517-25. doi: 10.1016/j.mehy.2014.09.010. Epub 2014 Sep 18. PMID: 25270233.
  3. Holick MF, Chen TC. Vitamin D deficiency: a worldwide problem with health consequences. Am J Clin Nutr. 2008 Apr;87(4):1080S-6S. doi: 10.1093/ajcn/87.4.1080S. PMID: 18400738.
  4. Holick MF. Sunlight, UV Radiation, Vitamin D, and Skin Cancer: How Much Sunlight Do We Need? Adv Exp Med Biol. 2020;1268:19-36. doi: 10.1007/978-3-030-46227-7_2. PMID: 32918212.
  5. Robien K, Oppeneer SJ, Kelly JA, Hamilton-Reeves JM. Drug-vitamin D interactions: a systematic review of the literature. Nutr Clin Pract. 2013;28(2):194-208. doi:10.1177/0884533612467824
  6. Vitamin D; Fact Sheet for Health Professionals. Updated August 17, 2021. National Institute of Health.
  7. Kaviani M, Nikooyeh B, Zand H, Yaghmaei P, Neyestani TR. Effects of vitamin D supplementation on depression and some involved neurotransmitters. J Affect Disord. 2020 May 15;269:28-35. doi: 10.1016/j.jad.2020.03.029. Epub 2020 Mar 13. PMID: 32217340.