Every day after lunch, I take my little container of vitamin D spray and squirt some under my tongue. Apparently, thatâs a highly effective way of getting vitamin D into the bloodstream; and itâs an inherent part of my daily routine I wouldnât be without. Iâm irritatingly prone to coughs, colds and bugs, so the main reason I take vitamin D is to help regulate my immune system (and the benefits for my bones, teeth and muscles arenât to be sniffed at, either).
But Iâve now learned that vitamin D could be helping more than my physical health. It could (emphasis on âcouldâ!) be helping my (often debilitating) anxiety, too. As Neurotherapist and Naturopath Alexa Ryan says: âThere is a strong link between vitamin D deficiency and anxiety.â
But, of course, thereâs always more to the story. What exactly counts as a âvitamin D deficiencyâ? Is this link definite, or is further research needed? And can a vitamin D deficiency be linked to any other aspects of our mental health?
These are all crucial questions. So weâve asked experts to cover all this â and more â below.

What exactly is a vitamin D deficiency?
âVery simply, a âvitamin D deficiencyâ is when the body lacks an adequate amount of this essential nutrient,â says Dr. Brynna Connor, MD, Healthcare Ambassador at NorthWestPharmacy.com. âVitamin D is a fat-soluble vitamin that plays an integral role in the bodyâs ability to maintain stable levels of calcium and phosphate (which are both crucial for various physiological functions), as well as bone health, immune system function and neuromuscular activity.
âTypically, a vitamin D deficiency is defined by the levels of 25-hydroxyvitamin D (25(OH)D),â Connor continues. This highly complicated wording is also known as calcidiol, which is âthe major circulating form of vitamin D in the body and how doctors determine someoneâs vitamin D statusâ. Connor also provided a helpful list of the vitamin D ranges (though these can vary depending on the individual and other factors):
- Deficient: < 30 ng/mL
- Insufficient: 30â50 ng/mL
- Sufficient: > 50 ng/mL
âVitamin D deficiency can result from inadequate sun exposure, poor dietary intake, malabsorption syndromes, chronic kidney or liver disease, and/or certain medications,â Connor concludes.

Whatâs the link between vitamin D and anxiety?
For starters, itâs not quite as simple as âTake vitamin D and your anxiety will disappear!â. As ever, thereâs no silver bullet.
âWhile there is evidence to support a link between vitamin D deficiency and anxiety, itâs important to note that it appears to be one of correlation, not causation,â explains Connor: âMeaning, yes, thereâs a relationship between the two, but vitamin D deficiency doesnât directly cause anxiety.
âThis link is due to vitamin Dâs role in the physiological processes, particularly neurotransmitter regulation and inflammation,â Connor continues. âVitamin D receptors are found in areas of the brain involved in mood regulation, such as the hippocampus and prefrontal cortex. Vitamin D may also influence serotonin synthesis, which plays a key role in anxiety and depression. Vitamin D also has anti-inflammatory properties, and chronic, low-grade inflammation, which can result from deficiency, has been linked to several anxiety disorders like depression, anxiety, schizophrenia and seasonal affective disorder (SAD).â
So there you have it; low levels of vitamin D could play a role in anxiety levels, not to mention depression and other mental health difficulties. But, as Connor added: âWe need more high-quality randomized controlled trials to confirm causation and determine whether supplementation significantly reduces anxiety symptoms.â
If youâre reading an article on the Vitals blog, weâd hazard a guess that youâre in possession of a uterus. In which case, you may be wondering: âWhat about hormones? Could a vitamin D deficiency be impacting how I feel at certain times of the month?â To which weâd answer: Very possibly; particularly when it comes to PMDD (pre-menstrual dysphoric disorder).

Whatâs the link between vitamin D deficiency and PMDD?
âA vitamin D deficiency may exacerbate the mental health symptoms of PMS,â says Yvette Hill, Registered Dietician Nutritionist at www.yvettehill.com. âWhile the research on the more severe [PMDD] is sparse, a vitamin D deficiency may also worsen symptoms here as well.â
âEmerging research suggests that vitamin D deficiency may worsen PMDD symptoms for a few reasons, including the hormonal interaction between vitamin D, estrogen and progesterone, both of which are integral to the menstrual cycle, and may influence mood symptoms in PMDD,â says Connor.
âThe inflammatory pathways may also play a factor, as, similar to anxiety, PMDD may involve elevated inflammatory markers. Since vitamin D has anti-inflammatory effects, deficiency might contribute to a pro-inflammatory state that can exacerbate mood swings and irritability,â Connor continues. âFinally, vitamin D can potentially impact serotonin production, which is especially relevant in PMDD, as serotonergic dysregulation (the imbalance or malfunction of the serotonin system in the body, primarily affecting the brain and nervous system) is a known characteristic.â
So there you have it. A vitamin D deficiency can be linked to not only heightened anxiety, but also to increased PMDD mental health symptoms.
But whatâs the answer? Weâve dwelled on the negative side of things â but how can we move things on to a more positive note?

What should I do if Iâm vitamin D deficient?
âFor someone who thinks they have a vitamin D deficiency and struggles with anxiety/depression/PMDD, they should first ask their doctor for a blood test (specifically one called 25-Hydroxyvitamin D), as it tells us exactly how low your levels are, and helps guide what treatment you need),â says Connor.
Then, if you are deficient, there are a number of things you can do to get your levels up to where you need them to be.
Ryan emphasises the importance of vitamin D testing and subsequent supplementation (if needed). âDosage should be individualised,â she says; but, as a starting point, the NHS indicates that âchildren from the age of 1 year and adults need 10 micrograms of vitamin D a day.â Ryan adds that, during low sunlight months or seasons (October to early March in the UK) â especially in regions that experience extreme sunlight deprivation â supplementation is especially key. âAlso, vitamin D is a fat-soluble nutrient, meaning it should be taken with foods that contain healthy fats to ensure absorption,â Ryan concludes.
âItâs important to note that you should never self-dose with high quantities of vitamin D without medical advice/guidance, as too much vitamin D can be detrimental to your health,â warns Connor. On that note, the NHS states: âDo not take more than 100 micrograms (4,000 IU) of vitamin D a dayâ.
It doesnât all have to be about supplements, though; Connor adds: âGetting additional sun can also be an option; making sure not to burn or tan! Just short, regular exposure can be beneficial.â (Please wear SPF, thoughâŚ)
Ultimately, if youâre curious or concerned about your vitamin D levels at all, book an appointment with your doctor and ask to get your vitamin D levels tested. You never know; it could be as simple as an under-the-tongue daily spray. And we canât resist the opportunity to let you know that Dayeâs Hormone Test tests for Vitamin D, tooâŚ



