A major new study led by the University of Surrey has found that people with severe vitamin D deficiency had a 33 per cent higher rate of hospitalisation with respiratory tract infections, including bronchitis and pneumonia, compared with those who had sufficient levels.
Vitamin D is commonly known as the sunshine vitamin because our bodies produce it when our skin is exposed to sunlight. However, during autumn and winter in the UK, there is not enough because the sun's UVB rays are not strong enough.
The largest study of its kind analysed NHS data from 36,258 UK Biobank participants. Researchers also found that for every 10nmol/L increase in vitamin D levels, the rate of hospitalisation with a respiratory tract infection was 4 per cent lower.
The study identified an association between vitamin D levels and hospitalisation.
Aimee Benbow, Head Nutritionist at vitamin company Viridian Nutrition, said: “A 33 per cent higher rate of hospitalisation is a significant finding, particularly when vitamin D deficiency remains so common in the UK.
“Respiratory infections such as bronchitis and pneumonia can be extremely serious, especially for older people. Although this study shows an association rather than cause and effect, it adds to the growing evidence around the importance of vitamin D status and immune health.
“With almost one in four teenagers and nearly one in five adults aged 19 to 64 having low vitamin D levels, this is something we need to take seriously.”
How many of us have low vitamin D?
During winter, low vitamin D status rises to 31 per cent among adults aged 19 to 64 and 36 per cent among children aged 11 to 18, according to seasonal analysis of National Diet and Nutrition Survey data.
Clinically studied vitamin D3
A separate randomised controlled clinical trial by the University of Surrey used Viridian Nutrition’s Vitamin D3.
135 WOMEN. took part across high and low latitude locations
15 MICROGRAMS or 600IU of Viridian Vitamin D3 was taken daily
12 WEEKS was the length of the clinical trial
Significantly increased vitamin D3
Viridian Vitamin D3 significantly increased vitamin D levels compared with placebo, regardless of location and exposure to sunlight
Prevented deficiency
Everyone taking Viridian Vitamin D3 had sufficient vitamin D levels at the end of the study, even though 18 per cent had been deficient at the beginning. The published study was conducted by Marcela Mendes at the University of Surrey alongside Professor Susan Lanham New, Professor of Human Nutrition and a former member of the Scientific Advisory Committee on Nutrition Vitamin D Working Group.
Your own pocket of sunshine
From 1 September to 31 October 2026, customers who buy Viridian Vitamin D3 2000IU 150 capsules from a participating independent health store will receive a complimentary sunshine umbrella worth £25. The offer is available while stocks last. Find out more here.
The Viridian Vitamin D Range
• Vitamin D3 400IU, 30 capsules, £7.55,
• Vitamin D3 2000IU, 150 capsules, £38.55, with free
sunshine umbrella
• Vitamin D3 2000IU Spray, 20ml, £23.55
• Viridikid Liquid Vitamin D3 Drops 400IU, 30ml, £10.15
• Vitamin D3 and K2 Liquid, 50ml, £24.85, 90 capsules, £31.85
Viridian Nutrition offers a complete spectrum of 12 vitamin D products across a multitude of sizes and formats, including daily maintenance and high potency capsules, liquids, drops and sprays, products for babies and children, and formulations combining vitamin D3 with vitamin K2 or calcium for all individual requirements. Prices range from £4.95 to £38.55.
Viridian’s vegan Vitamin D3 is sourced from lichen and is available in capsules, liquids and sprays, with options for adults, children and the whole family.
Every Viridian product is formulated by nutritionists using active ingredients with no unnecessary artificial fillers or binders.
Additional information
The latest National Diet and Nutrition Survey figures cover 2019 to 2023. Low vitamin D status is defined as a blood concentration below 25nmol/L. www.gov.uk/government/statistics/national-diet-and-nutrition-survey-2019-to-2023/national-diet-and-nutrition-survey-2019-to-2023-report
The University of Surrey respiratory study analysed data from 36,258 UK Biobank participants. Severe vitamin D deficiency was defined as below 15nmol/L and sufficient vitamin D status as at least 75nmol/L. www.surrey.ac.uk/news/low-vitamin-d-levels-shown-raise-risk-hospitalisation-potentially-fatal-respiratory-tract-infections
The respiratory study was observational. It identified an association and did not prove that vitamin D deficiency causes respiratory infections or that supplementation prevents hospitalisation.
The information contained in this article is not intended to treat, diagnose or replace the advice of a health practitioner. Please consult a qualified health practitioner if you have a pre-existing health condition or are currently taking medication. Food supplements should not be used as a substitute for a varied and balanced diet.
