The new report, released today by the American Academy of Pediatrics (AAP), says children should be consuming 400 International Units (IUs) of the vitamin per day.
This is a massive leap from the 200 IUs previously recommended by AAP, and essentially means that millions of children will need to take vitamin D supplements.
The move follows repeated calls in scientific and public circles for a hike in recommended consumption levels in light of research indicating the protective effects that vitamin D may have against conditions such as diabetes, heart disease and cancer.
The vitamin is produced in the body on exposure to sunlight, but increasing vitamin D levels via sunlight or supplements has been a source of ongoing debate.
In the US, where over 1.5 million people are diagnosed with skin cancer every year, experts are pushing supplements, claiming recommendations for sun exposure are "highly irresponsible".
Another push for supplements comes from the fact that intakes are low from dietary sources coupled with a lack of sunshine in northern climates, has led to estimates that as much as 60 per cent of northern populations may be vitamin D deficient.
In adults, vitamin D deficiency may precipitate or exacerbate osteopenia, osteoporosis, muscle weakness, fractures, common cancers, autoimmune diseases, infectious diseases and cardiovascular diseases.
Dietary Reference Intakes
Although the AAP report is sure to have a major impact on the supplement landscape in the short-term, it is ultimately the federal government that sets recommended intake levels for vitamins and nutrients, based on advice from the National Academy of Sciences' Institute of Medicine (IOM).
IOM’s latest vitamin D review, conducted in 1997, recommends that children and adults up to age 50 should consume 200 IUs per day – equivalent to 5μg. Adults aged between 51 and 70 should have an intake of 400 IUs (10 μg), and adults aged 71 and over should consume 600 IUs (15 μg).
A spokesperson for IOM confirmed to NutraIngredients-USA.com this morning that the group is preparing to conduct its own review of vitamin D intakes.
“We are currently in discussions with federal agencies in the US and Canada. IOM is ready and willing to undertake a new analysis, it’s just a matter of getting the go-ahead and the funding,” said Christine Stencel.
She said IOM’s review is expected to take place “in the not too distant future”.
Vitamin D precursors
Vitamin D refers to two biologically inactive precursors - D3, also known as cholecalciferol, and D2, also known as ergocalciferol. Both D3 and D2 precursors are hydroxylated in the liver and kidneys to form 25- hydroxyvitamin D (25(OH)D), the non-active 'storage' form, and 1,25-dihydroxyvitamin D (1,25(OH)2D), the biologically active form that is tightly controlled by the body.
There is growing evidence that 1,25(OH)2D has anticancer effects, but the discovery that non-kidney cells can also hydroxylate 25(OH)D had profound implications, implying that higher 25(OH)D levels could protect against cancer in the local sites.
Calls to increase the current recommendations of 200 IU per day for children and adults up to 50 years of age for vitamin D up to 800 - 1000 IU vitamin D3, have become more frequent in both scientific and public circles.
Tolerable upper intakes
A review of the science conducted by the supplements trade group Council for Responsible Nutrition (CRN) in January last year reported that the tolerable upper intake level for oral vitamin D3 should be increased five-fold.
Currently, the tolerable upper intake level (UL) in Europe and the US is set at 2000 International Units (IU), equivalent to 50 μg per day. However, recent research, particularly from clinical trials, suggests that this should be raised. The CRN scientists state that this could be raised to 10,000 IU (250 μg per day).