Current guidance on the intake of vitamin D has been turned “on its head” following new research revealing that vitamin D3 is twice as effective as vitamin D2 in raising levels of the nutrient in the body.
The findings of the study, carried out by UK researchers, has prompted a call for a change to official guidance around Vitamin D, with a number of governments currently advising that the two forms of vitamin D are equivalent and can be used to equal effect.
Lead author Dr Laura Tripkovic from the University of Surrey, said: “The importance of vitamin D in our bodies is not to be underestimated, but living in the UK it is very difficult to get sufficient levels of it from its natural source, the sun, so we know it has to be supplemented through our diet.
“However, our findings show that vitamin D3 is twice as effective as D2 in raising vitamin D levels in the body, which turns current thinking about the two types of vitamin D on its head.”
The study marked the first of its kind evaluating the benefits of vitamin D2, produced by plants, and D3, derived from animal products, in low doses of food.
The findings suggest people who aim to consume more D3 through eating fish, eggs or taking supplements will be twice as likely to raise their vitamin D levels compared to those only consuming vitamin D2 rich-foods such as mushrooms, fortified bread or D2 containing supplements.
Researchers examined the vitamin D levels of 335 South Asian and white European women over two consecutive winter periods, a time when the nutrient is known to be lacking in the body. The women were split into five groups, with each group receiving either a placebo, a juice containing vitamin D2 or D3 and a biscuit with D2 or D3.
The researchers found that vitamin D3 was twice as effective in raising levels of the vitamin in the body than its counterpart D2.
Vitamin D levels in women who received vitamin D3 via juice or a biscuit increased by 75% and 74% respectively. Meanwhile, those given D2 saw an increase of 33% and 34% over the course of the 12-week intervention.
The research also found that levels of both vitamin D2 and D3 rose as a result of both food and acidic beverages such as juice - which were found to be equally as effective.
Those who received the placebo experienced a 25% reduction in the vitamin over the same period.
Findings contradict current guidance
The findings contradict current guidance given by government bodies, say the team. For example, the US National Institute of Health says the two forms of vitamin D are equivalent and can be used to equal effect. Meanwhile,
Furthermore, recent figures from Public Health England revealed that more than one in five people in the UK have low levels of vitamin D and has increased intake of the vitamins to 10 micrograms a day for everyone aged four and older.
As well as having an impact on public health policy, the findings could have implications for the retail sector.
In recent years, retailers have added vitamin D2 to their products in the belief that it will help a person fulfil their daily intake.
“This is a very exciting discovery which will revolutionise how the health and retail sector views vitamin D," said Professor Susan Lanham-New, head of the Department of Nutritional Sciences at the University of Surrey. “Vitamin D deficiency is a serious matter, but this will help people make a more informed choice about what they can eat or drink to raise their levels through their diet.”