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The very latest on vitamin D

Summer’s here, the sun is (mostly) out and, when it comes to warmer weather, it’s natural for Vitamin D to be at the forefront of everyone’s mind. Research on this ever-important vitamin is constantly revealing more and more about its uses. Read on to find a snapshot of some of the more interesting studies published in the first half of 2022...


Vitamin D, as you probably know, produced when the skin is exposed to UV light which gave rise to its nickname ‘the sunshine vitamin’. We know that our short days and murky skies in winter are likely to cause a deficiency and so banking as much in the natural light of summer makes sense. 

At the height of the pandemic, we published two related blogs about this most important of vitamins. The first highlighted just how Vitamin D is created and what its known functions are; the second focussed on the role of Vitamin D in the immune response (both adaptive and innate) and in particular its response to the Covid 19 virus.  

Over the past few months, there has been a succession of new and interesting research into Vitamin D and with science moving all the time, we know that practitioners can often find it difficult to keep up with this latest in evidence.

Here then we bring you a round-up of the latest research into Vitamin D, all from studies published in the first half of 2022.

Index finger prick Vitamin D test

The majority of FDX tests test for Vitamin D3 (25 OH). We also offer an excellent stand-alone Vitamin D test in our Index range of at-home finger-prick tests. A low-cost way of assessing a client’s Vitamin D status with results you can trust.

Vitamin D and stroke/dementia

The links between Vitamin D and cognitive function were further supported by an observational study published in The American Journal of Clinical Nutrition in April. The study analysed almost 300,000 patients from the UK Biobank examining the impact of low levels of Vitamin D and the risk of dementia and stroke. It found that lower levels of Vitamin D were associated with lower brain volumes and therefore an increased risk of both dementia and stroke. The research team found that as much as 17% of dementia cases could be prevented by increasing the population to normal Vitamin D levels. (1)

High-dose vitamin D in the treatment of SARS-CoV-2

Vitamin D’s potential positive role in the battle against Covid-19 was further highlighted by a May study in PLOS MEDCINE. The study assessed the 14-day survival rates of an at a group of at-risk older adults when administered with a single oral high dose of cholecalciferol (vitamin D3) with 72 hours of diagnosis. The early high dose was found to improve overall mortality but the effect was no longer observed after 28 days leading the researchers to conclude that subsequent supplementation after the initial high dose might be required. The single oral high dose administered in the study was 400,000 IU. (2)

Vitamin D and skin pigmentation

Further proof of low levels of Vitamin D in those with darker skin comes in the form of a study published in the May edition of the Journal of Pediatric Healthcare. The University of Houston College of Nursing study looked at the Vitamin D results of 119 ethnically diverse children aged 12 t0 18 and found that 61% of otherwise healthy Black and Hispanic children had low Vitamin D levels and that levels dropped with age. (3)

Vitamin D and miscarriage

Vitamin D deficiency is very common and women in pregnancy are more likely to be deficient, which is why Vitamin D is part of the NHS’s free Healthy Start vitamins for women in pregnancy and children up to their first birthday. A study published in the journal Fertility & Sterility in June shows that women with low Vitamin D levels are at a significantly increased risk of miscarriage. The study, conducted by Tommy’s National Centre for Miscarriage Research and led by a team from the University of Birmingham performed a systematic review and meta-analysis of studies investigating the association between maternal Vitamin D status and miscarriage and/or Vitamin D treatment and miscarriage. While they found there was a link between deficiency/insufficiency and miscarriage, they concluded that: “Whether preconception treatment of Vitamin D deficiency protects against pregnancy loss in women at risk of miscarriage remains unknown.” (4) 

Vitamin D, whey protein, muscle mass and strength

For those looking to increase strength and muscle mass, combining Vitamin D supplementation with whey protein may be the way forward, according a study published in Nutrients in May 2022. Researchers in China performed a randomised control trial on 42 untrained males aged between 18 and 24 and split them into three groups. One received 25g whey protein and 4000 IU Vitamin D3 before bedtime, another received the same supplementation on waking up, while a third were given a maltodextrin placebo. It concluded that the two supplementation groups increased muscle mass over the placebo group following a six-week training programme. (5)

Vitamin D and cardio-metabolic risk in the elderly

A study published in June 2022’s Diabetology & Metabolic Syndrome suggests that Vitamin D supplementation could improve insulin concentration and dyslipidemia in the elderly. The systematic review and meta-analysis of clinical trials by a team at the University of Tehran identified 4409 studies, of which 12 trials met inclusion criteria. (6)

Vitamin D and type 2 diabetes

With both vitamin D deficiency and type 2 diabetes on the rise in the northern hemisphere, it’s long been hypothesised there may be a link between the two. Given vitamin D is required for healthy levels of insulin secretion, the theory is that a lack of it could put people at risk but also worsen insulin resistance in people who have type 2 diabetes. In a study published in the BMJ in May 2022, researchers in Japan spent six years conducting a double blinded, multicentre, randomised, placebo controlled trial with 1256 participants who were split into a placebo group and another receiving a daily 0.75 μg supplement of the vitamin D analog  eldecalcitol. The group taking eldecalcitol showed a 13% decrease in their risk of developing type 2 diabetes, but the researchers found it was not significant. (7) However, another study published in the Pakistan Journal of Pharmaceutical Sciences also in May showed that Vitamin D supplementation of 16 weeks reduced fasting blood glucose and HbA1C significantly in Vitamin D deficient Type 2 diabetes. The researchers from the University of Karachi assessed 52 patients with pre-trial Vitamin D levels <30 ng/ml. The intervention consisted of 50,000 IU of orally administered Vitamin D3 once a week. (8)


1. Navale SS, Mulugeta A, Zhou A, Llewellyn DJ, Hyppönen E. Vitamin D and brain health: an observational and Mendelian randomization study. Am J Clin Nutr [Internet]. 2022 Apr 22 [cited 2022 Jun 30]; Available from: https://academic.oup.com/ajcn/advance-article/doi/10.1093/ajcn/nqac107/6572356 

2. Annweiler C, Beaudenon M, Gautier J, et al. High-dose versus standard-dose vitamin D supplementation in older adults with COVID-19 (COVIT-TRIAL): A multicenter, open-label, randomized controlled superiority trial. Cannegieter SC, editor. PLoS Med [Internet]. 2022 May 31 [cited 2022 Jun 30];19(5):e1003999. Available from: https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1003999 

3. Varghese SB, Benoit J, McIntyre T. Vitamin D Levels in Ethnic Minority Adolescents in Primary Care. J Pediatr Heal Care [Internet]. 2022 May [cited 2022 Jun 30]; Available from: https://pubmed.ncbi.nlm.nih.gov/35654708/ 

4. Tamblyn JA, Pilarski NSP, Markland AD, et al. Vitamin D and miscarriage: a systematic review and meta-analysis. Fertil Steril [Internet]. 2022 May 27 [cited 2022 Jun 30];118(1). Available from: https://pubmed.ncbi.nlm.nih.gov/35637024/ 

5. Chen Y, Liang Y, Guo H, Meng K, Qiu J, Benardot D. Muscle-Related Effect of Whey Protein and Vitamin D3 Supplementation Provided before or after Bedtime in Males Undergoing Resistance Training. Nutrients [Internet]. 2022 May 30 [cited 2022 Jun 30];14(11):2289. Available from: https://pubmed.ncbi.nlm.nih.gov/35684089/ 

6. Qorbani M, Zarei M, Moradi Y, et al. Effect of vitamin D supplementation on cardiac-metabolic risk factors in elderly: a systematic review and meta-analysis of clinical trials. Diabetol Metab Syndr [Internet]. 2022 Dec 25 [cited 2022 Jun 30];14(1):88. Available from: https://pubmed.ncbi.nlm.nih.gov/35752843/ 

7. Kawahara T, Suzuki G, Mizuno S, et al. Effect of active vitamin D treatment on development of type 2 diabetes: DPVD randomised controlled trial in Japanese population. BMJ [Internet]. 2022 May 25 [cited 2022 Jun 30];377:e066222. Available from: https://www.bmj.com/content/377/bmj-2021-066222 

8. Abbas Rizvi SQ, Ikram R, Sarfaraz S, Munawwar R. Beneficial effects of oral vitamin D supplementation in diabetes mellitus type II patients – a clinical study in Karachi. Pak J Pharm Sci [Internet]. 2022 May [cited 2022 Jul 12];35(3):845–50. Available from: https://pubmed.ncbi.nlm.nih.gov/35791486/