Data analysed by digital healthcare company Forth With Life revealed 74 per cent of UK adults aged 25 and over “hover in the lower quarter of the normal vitamin D range or below”.
The data also showed 27 per cent fell below the normal range.
By age group, 76 per cent of those aged 25 to 34 and 45 to 54 showed the biggest lack of vitamin D.
This was followed by 73 per cent of those aged 35 to 44 and 71 per cent of 55 to 65 year olds.
By gender, 77 per cent of women showed inadequate vitamin D levels, versus 72 per cent of men.
According to Forth With Life, the normal range for vitamin D is between 50 and 175 nmol/L. Levels above 75 nmol/L are advised for optimum health.
The main source of vitamin D is sunlight, but despite 2018 seeing one of the hottest summers on record in the UK, the data suggests people are still not getting enough.
“This year will go down as one of the sunniest summers on record for the UK, but this still may not be enough for the population’s vitamin D levels to be at their peak,” said Forth With Life.
“Health professionals have stated that we need six hours of sunshine per month to produce enough vitamin D.”
“However, increasing cloud cover during the summer months and extensive rainfall have reduced the total number of sunshine hours in the UK to four hours less per month since the mid-1990s.”
People who receive less exposure to the sun include those who conceal their skin with clothing and those who spend little time outdoors.
Being overweight can also limit the amount of vitamin D taken in by the body as fat cells tend to hang on to it, according to the healthcare firm.
It’s important to ensure the body gets enough vitamin D, as a lack of the vitamin can lead to health complications such as poor muscular strength, depression, fatigue and in severe cases, rickets or osteomalacia.
Aside from sunlight, it’s possible to obtain vitamin D from some foods such as oily fish, beef liver, cheese and egg yolks.
Some foods such as certain dairy products, orange juice, soy milk and cereals are also fortified with vitamin D.
During the winter when there is less sunlight, UK health officials advise all adults take a vitamin D supplement to get the required amount.
“The UK population needs to be aware of the importance of vitamin D and what their levels are,” said Forth With Life Founder Sarah Bolt.
“Almost three-quarters of Forth’s customers are in the bottom quartile (50 to 81.25 nmol/l) or below, averaging 72 nmol/L. The data gives a worrying insight into the state of the wider UK population’s vitamin D levels.”
“Knowing your vitamin D levels can give you a real clue about how your body is functioning, particularly as deficiency can have so many side effects including depression, fatigue and, in severe cases, rickets.”
“Gaining an insight and understanding of your body’s key biomarkers, such as vitamin D, will help individuals to make informed decisions about their lifestyle and protect their future health.”