The mounting evidence surrounding the vital role of vitamin D in supporting the health of the nation throughout this global pandemic has been widely reported by the media. Having personally championed vitamin D for over ten years, I want to cut through the noise and bring you everything you need to know about this essential vitamin and its importance for our health.
There are ever-growing demands being made for a formal government announcement on the role vitamin D supplementation can play in our drive to improve immunity. Although the evidence is compelling, confusion remains regarding who will benefit from supplementation and how much we should be taking.
Here, I discuss the key points that we should all know when it comes to vitamin D and how it can play a vital role in our body’s ability to better resist disease.
Vitamin D and COVID-19
Recently, Labour MP Catherine West submitted a written question to Parliament asking whether patients in hospitals were tested for their vitamin D levels, and if an assessment had been made on whether vitamin D deficiencies had been impacted by the COVID-19 lockdown.
While an answer is still ‘being prepared’ to this question, the Conservative Peer Lord Blencathra has also urged the future inquiry into COVID-19 to investigate why vitamin D appears to be a factor in the pandemic.
More political voices continue to be raised, which has encouraged Public Health England (PHE) to begin a rapid review of recent evidence surrounding vitamin D and the prevention of acute respiratory tract infections.
The review, which has a specific focus on the prevention and treatment of COVID-19, is expected to be considered by the Scientific Advisory Committee on Nutrition (SACN) at its next meeting.
One thing we can agree on, is that the importance of vitamin D levels within our society has never been of greater importance as now:
- Vitamin D plays an important role in immune response, with a growing number of clinical studies specifically linking a deficiency to a decline in immune response for respiratory viral infections
- The ‘lockdown’ has denied vital natural vitamin D production at a time when we would normally be building levels, after an annual vitamin D starvation since October.
There are now two large-scale clinical trials operating within the international scientific community to investigate the efficacy of vitamin D against COVID-19, with the most recent being announced on 3 April.
Data from an analysis of 212 people with lab-confirmed COVID-19 – and for whom there were serum 25(OH)D levels (how vitamin D is measured within our blood) available – revealed that 96% of patients with only mild symptoms had optimal levels of vitamin D.
It is unknown whether optimal vitamin D supplementation could be used as an acute treatment to COVID-19, but this is asking the wrong question
What’s more, researchers from Trinity College Dublin and Technical University Dublin, have recently published results that directly link vitamin D levels to enhanced resistance to respiratory infections, or certainly limit the severity of the illness.
It is unknown whether optimal vitamin D supplementation could be used as an acute treatment to COVID-19, but this is asking the wrong question.
The key to optimal protection, certainly in the first instance, is to ensure our bodies are as robust as possible and can resist and better manage the unpleasant, and in some cases fatal, experience of viral infections.
Vitamin D and the BAME community
It has been repeatedly reported that a disproportionately high number of individuals who are from black, Asian and minority ethnic (BAME) communities have died from COVID-19.
Comparing the blood samples of 1,300 adults on the UK Biobank health-monitoring programme (of which 580 tested positive for COVID-19), a new study found that vitamin D levels among white people were around 53% higher than among people of BAME backgrounds.
Deficiency is prevalent in people with darker skin due to a natural barrier (known as melanin) towards the UVB rays needed to penetrate the skin. Melanin is the term used for a group of natural pigments that affect how light or dark your skin colour is; the more melanin you have, the darker your skin colour.
Melanin competes with vitamin D in the skin for UVB absorption, meaning that darker skin types allow less UVB to enter the skin and consequently produce less vitamin D. This may be useful for high UVB exposure nearer the equator, but it is problematic for those in the northern hemisphere.
Furthermore, people of healthy weight had 25% more vitamin D than those who were overweight, suggesting that people who are overweight and have darker skin tones, could be at greater risk of catching the disease. These findings may also help to explain disproportionate levels of infection among the BAME community.
The need for tailored supplementation
Scientific writer and nutritionist Ben Brown ND recently reminded us that a 400iu dose (as recommended by PHE) ‘is inadequate to raise blood levels to sufficiency in deficient, vulnerable people and it is arguable that a deliberate failure to acknowledge potential benefit related to COVID-19 not only misses, but dismisses an important opportunity to improve public health’.
The concept of elevating vitamin D levels naturally is simple. As we expose ourselves to the sun, our bodies generate vitamin D. The more skin we expose, the greater our level of production.
A small child will expose a lower surface area of skin and require less exposure to the sun, than an adult male – a child will produce less vitamin D, as they require less.
It is during this exposure that melanin is produced within the skin, to reduce vitamin D conversion. The more melanin we produce, the slower our vitamin D conversion becomes.
Considering the latest research, along with a decade of testing and supplementation that we have carried out at BetterYou, the evidence suggests that a supplementation dosage related to body mass is required, instead of a single dosage level for all.
It is because of this research that, as a rule of thumb, a daily maintenance dosage of 25mcg (1000iu) of vitamin D for every 25kg of body weight is advisable. 400iu is a suitable maintenance dosage for an infant or toddler, but for an adult woman living in the UK we should be recommending 2000iu, and for an average male 3000iu.
One thing we can agree on, is that the importance of vitamin D levels within our society has never been of greater importance as now
This is for maintenance dosages only. To reverse a deficiency, supplementation should be based upon specific blood level status, and a brief period of double or triple this level may be required.
It is incredibly difficult to eat your way out of a vitamin D deficiency, so it is reasonable to surmise that many of us may be existing with sub-optimal levels of this essential vitamin.
Crucially, baseline vitamin D levels should be acquired to determine how much supplementation is needed. You can easily do this using a simple home test kit, however, in the absence of test results the above maintenance dosage calculation is a sensible one to follow.
A healthy debate exists when it comes to the optimum blood level for vitamin D. The official measurement for insufficient serum levels is under 50nmol/L, and for deficient it is under 25nmol/L. However, there is no guidance for what would be considered optimal.
Garland and Baggerly conducted a review of disease incidence and associated vitamin D levels, which clearly illustrated an optimal serum level would be between 100 to 150nmol/L (40 to 60ng/ml). A level which has been suggested to provide optimum defence against associated auto-immune diseases.
In conclusion, there is no convenient cause and effect, and no ‘quick fix’ solution for COVID-19. There is however enough evidence to suggest that vitamin D has an indirect benefit, as it plays a powerful role in our immune health and resistance to auto-immune diseases.