Vitamin D: Most people don’t need supplements –

Vitamin D is found in oily fish, red meat, liver, egg yolk and some fortified breakfast cereals and dairy products. It is also manufactured from cholesterol in our skin when skin is exposed to sunlight (specifically ultraviolet B radiation).

For quite some time now, I have been trying to find reliable evidence that vitamin D supplementation is a good idea for the multitude of people for whom it has been recommended.

This topic is once again in the media spotlight following a series of articles recently published in the British Medical Journal.

Although the U.S. Preventive Services Task Force recommends that healthy postmenopausal women should not take calcium and vitamin D supplements to prevent fractures, other guideline groups continue to recommend vitamin D supplements, with or without calcium, to prevent falls or fractures.

However, in a new practice article from researchers in New Zealand, it is reported that they examined the current literature and found that “there is no consistent evidence that vitamin D supplementation or raising 25-hydroxyvitamin D levels improves musculoskeletal outcomes.”

They agree that people who are at high risk of vitamin D deficiency (those who are confined indoors, have very limited sunlight exposure or have severe malabsorption syndromes) should receive counseling about getting exposure to sunlight and having a healthy diet. Then, low-dose vitamin D supplements (400–800 IU per day) may be considered on an individual basis.

They concluded that current evidence does not support the widespread use of vitamin D supplementation to prevent disease.

On the other hand, the United Kingdom’s Scientific Advisory Committee on Nutrition (SACN) recently suggested that adults should consider taking a low-dose vitamin D supplement in autumn and winter.

The SACN reviewed the evidence for musculoskeletal health outcomes with vitamin D and estimated that 10 micrograms (400 IU) per day is the amount of vitamin D needed for 97.5 percent of the population to maintain blood concentrations at or above the level they say is needed to protect musculoskeletal health when exposure to sunshine is minimal.

Unlike the U.S. Preventive Services Task Force, the SACN recommends that those who do not get much sun exposure or have darker skin should consider taking 10 micrograms per day of vitamin D supplement year round, and everyone should consider taking this type of supplement in the fall and winter.

For now, in a review of more than 50 meta-analyses of the data, it appears that there is no or little benefit from taking vitamin D supplements to prevent falls or fractures, and some trials have even reported increased risk of falls and fractures with intermittent use of high-dose vitamin D.

Combined vitamin D and calcium prevented fractures in two trials of severely vitamin D–deficient frail elderly women in residential care, but not in seven trials of community-dwelling people.

Some meta-analyses have reported positive non-skeletal effects of vitamin D supplements, but the evidence was weak. For example, vitamin D deficiency may play a role in the incidence of multiple sclerosis. But, if this is true, it is uncertain whether supplementation will help prevent or treat the disorder.

It important to remember that people should avoid taking too much vitamin D, since this can result in high calcium levels in the blood, weakened bones due to the loss of minerals, soft-tissue calcification and kidney damage.

Although is agreed that vitamin D treatment still has a role in people with proven deficiency or in high-risk groups such as infirm elderly people or high-risk infants, the rest of us should probably avoid taking vitamin D supplement unless better evidence can be produced to show some as yet unproven benefit.

Instead, the focus should be on having a healthy lifestyle, including sunshine, exercise and a variety of real food.

Dr. Terry Gaff is a physician in northeast Indiana. Contact him at or on Facebook. To read past columns and to post comments go to


Write a Reply or Comment:

Your email address will not be published.*