The mistake many people make with vitamin D – it could have consequences
During the winter months, when there is less sunlight, many people seek vitamin D supplements.
According to official recommendations from the British government, it is recommended to take a daily vitamin D supplement during the autumn and winter, especially from October to early March. The reason is simple: the body produces vitamin D when the skin is exposed to the sun, and at that time of year there is often not enough sunlight.
Recommended doses and the risk of overdose
The recommended daily dose for children over one year old and adults is 10 micrograms, while for infants up to one year old it is 8.5 to 10 micrograms. Experts warn that these doses should not be exceeded. Taking excessive amounts of vitamin D for a long time can lead to the accumulation of calcium in the body, or hypercalcemia, which can weaken bones and put a strain on the kidneys and heart.
A 2019 study found that high doses of vitamin D in adults did not provide additional benefits for bone density compared to moderate doses, and in some cases, the results were worse.
Dr. JoAnn E. Manson of Harvard Medical School pointed out that compared with more modest daily doses, no improvement in bone density was observed at higher doses, and similar findings have been reported in other randomized studies with very high doses.
The difference between vitamin D2 and D3
In addition to dosage, the form of vitamin D you take is also important. You'll most often find vitamin D2, or ergocalciferol, and vitamin D3, or cholecalciferol. D2 is found in plants and mushrooms, while D3 is present in animal foods, such as fatty fish. D3 is also the form that the body naturally produces when exposed to sunlight, so it's generally considered a more effective choice in the form of a dietary supplement.
Research: D2 may lower D3 levels in the body
Scientists have also warned that vitamin D2 supplements can lower vitamin D3 levels in the body. A study published in the journal Nutrition Reviews analyzed data from several studies and concluded that taking D2 was associated with lower levels of D3 in some cases compared to control groups, Klankosova.tv reports.
Emily Brown from the University of Surrey said vitamin D supplements are particularly important between October and March, when the body in the UK finds it harder to produce vitamin D from sunlight. She added that the results suggest that, depending on personal circumstances, D3 may be a more beneficial choice for most people than D2.
Vitamin D3 is also often associated with supporting normal immune function. So it's a good idea to check that a supplement contains vitamin D3 rather than D2, unless you're choosing a vegan option, which is more likely to be in the form of D2.
