Why I’m interested in Vitamin D supplementation.

I recently came across some interesting research, emphasising how important vitamin D is for fighting viral infections. This led me to ask my patients if they supplement vitamin D during the Autumn/Winter, and I was surprised how many do not, inspiring me to write this blog. As an osteopath I’m interested in my patients lifestyle and health as a whole: age, occupation, activities, prescribed medication, previous injuries/surgery. Finding out about my patients as individuals, and understanding their history, helps me to assess what may have predisposed their injury/disease. I am then able make suggestions how to improve their overall future health, wellbeing and prevent injury reoccurrence.

What is Vitamin D?

Vitamin D is known as the sunshine vitamin. It is both a nutrient and a hormone that is produced in the body. There are 3 common ways vitamin D is produced/enters the body:

• The sun’s ultraviolet energy turns a chemical in our skin into vitamin D
• Food – Few food sources are naturally rich in vitamin D, it can be found in fish, fish oils, certain mushrooms and fortified types of dairy and milk.
• D2 and D3 nutritional supplements. (5)

The Public Health England, National Diet and Nutrition Survey shows that around 1 in 6 adults in the UK has low levels of vitamin D in their blood (1)

What is the function of vitamin D?

Vitamin D promotes calcium absorption, and maintains bodily calcium and phosphate levels, enabling bone mineralisation, growth and remodelling (these processes take place throughout life). Without sufficient vitamin D bones can become thin and brittle. Together with calcium, vitamin D helps protect older adults from osteoporosis. Research has found vitamin D to have other important roles in the body, including reducing inflammation, supporting muscle and immune function. (6)

The UK Government advise everyone to consider taking a daily vitamin D supplement during the autumn and winter. This includes pregnant women (2,8)

Who’s at risk of vitamin D deficiency?

Many people have insufficient vitamin D levels because they live in places similar to the U.K., where sunlight is limited in winter, or because they have limited sun exposure due to being inside much of the time. People with darker skin tend to have lower blood levels of vitamin D because their skin pigment (melanin) acts like a shade, reducing the production of vitamin D. Deficiencies are also common in people with intestinal disorders that limit absorption of fat and those with kidney or liver diseases. Advancing age is also linked to an increased risk of vitamin D deficiency. (3) (5)

Vitamin D helps regulate the amount of calcium and phosphate in the body. These nutrients are needed to keep bones, teeth and muscles healthy (2)

Vitamin D deficiency and the musculoskeletal system.

During vitamin D insufficiency, muscle function and physical function can be impaired before clinical or biochemical signs of bone disease are apparent. An increased risk of falls in the elderly with low vitamin D levels has been documented in several studies and randomised controlled trials. It is well known that severe deficiency causes rickets (in children), osteoporosis and osteomalacia (‘softening of the bones’) in adults. Symptoms of vitamin D deficiency can include tingling/numbness in hands and feet, as well as aching muscles and bones. (7)

As a safe, widely available, and being affordable, Vitamin D may help to reduce the severity of the COVID-19 pandemic (4)

Vitamin D deficiency and the immune system.

A recent large-scale US study investigated the association between vitamin D₃ and D₂ supplementation in veterans, and the probability of COVID-19 infection and COVID-19 infection ending in mortality within 30-days. The results showed supplementation of Vitamin D3 and D2 reduced infection by 20% and 28% respectively. There was a 33% reduced mortality rate within 30 days of covid-19 infection in veterans supplemented in D3. Black veterans received greatest association of covid-19 risk reduction. (4)

Vitamin D insufficiency and deficiency affect approximately half of the US population, with increased rates in people with darker skin, reduced sun exposure, people living in higher latitudes in the winter, nursing home residents, and healthcare workers. Populations with low levels of Vitamin D have also experienced higher rates of COVID-19 (4)

What is the difference between D2 and D3?

Both are naturally occurring forms that are produced with help from the sun’s ultraviolet-B (UVB) rays. D2 is produced in plants and fungi and D3 in animals and humans. (5)

It’s thought that low vitamin D in pregnancy can lead to a greater risk of complications for the mother, including pre-eclampsia, diabetes, premature birth, and low birthweight. Babies born with vitamin D deficiency have a greater risk of developing rickets and serious allergies (8)

Vitamin D supplementation

There is major disagreement about the optimal vitamin D supplement dose. The UK Scientific Advisory Committee for Nutrition has set the lowest level for defining sufficiency (10 ng/ml or 25 nmol/L) of any national advisory body or scientific society and recommends supplementation with 10 micrograms (400 IU) per day.

A report by The Royal College of Physicians, within The Clinical Medicine Journal, concluded “The current UK SACN threshold for vitamin D sufficiency of 25 nmol/L 25(OH)D is set too low and is not supported by evidence. A higher threshold of 50 nmol/L is supported by the evidence and is safely achievable by supplementation with at least 800 IU per day (20 micrograms per day). Since vitamin D is widely sold in 1,000 IU capsules, and it is universally agreed that doses up to 4,000 IU per day are safe, then a recommendation of 800–1,000 IU per day (20–25 micrograms per day) for all adults would be safe and sufficient and should be urgently promoted.” (9)

Blog wrote by Lee Clarke BOst (Hons) published November 2022

References

(1) British Nutrition Foundation survey reveals 49% adults unaware of UK government guidelines for Vitamin D (no date) British Nutrition Foundation. Available at: https://www.nutrition.org.uk/news/2021/british-nutrition-foundation-survey-reveals-49-adults-unaware-of-uk-government-guidelines-for-vitamin-d/ (Accessed: November 26, 2022).

(2) Vitamin D (2020) NHS choices. NHS. Available at: https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-d/ (Accessed:November 26, 2022)

(3) Vitamin D and your health: Breaking old rules, raising new hopes (2021) Harvard Health. Available at: https://www.health.harvard.edu/staying-healthy/vitamin-d-and-your-health-breaking-old-rules-raising-new-hopes (Accessed: November 26, 2022).

(4) Gibbons, J.B. et al. (2022) “Association between vitamin D supplementation and covid-19 infection and mortality,” Scientific Reports, 12(1).

(5) Vitamin D (2022) The Nutrition Source. Harvard Health. Available at: https://www.hsph.harvard.edu/nutritionsource/vitamin-d/#:~:text=The%20best%20sources%20are%20the,high%20amounts%20of%20ultraviolet%20light (Accessed: November 26, 2022).

(6) Office of dietary supplements – vitamin D (2022) NIH Office of Dietary Supplements. U.S. Department of Health and Human Services. Available at: https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/ (Accessed: November 26, 2022).

(7) Rejnmark, L. (2010) “Effects of vitamin D on muscle function and performance: A review of evidence from randomized controlled trials,” Therapeutic Advances in Chronic Disease, 2(1), pp. 25–37.

(8) Clinical team. (2021) How much vitamin D should you take during pregnancy?, LloydsPharmacy. LloydsPharmacy. Available at: https://lloydspharmacy.com/blogs/vitamins-and-supplement-advice/vitamin-d-and-pregnancy (Accessed: November 26, 2022).

(9) Griffin, G. et al. (2020) “Preventing vitamin D deficiency during the COVID-19 pandemic: UK definitions of vitamin D sufficiency and recommended supplement dose are set too low,” Clinical Medicine, 21(1). Available at: https://doi.org/10.7861/clinmed.2020-0858.