A Cheesy Way to Get Your D

Looking for ways to get more vitamin D into your diet? Eating fortified cheese might be the answer, says a new study in the Journal of Nutrition.

Super D—how much is enough?

Vitamin D has been in the spotlight in recent years, with dozens of studies highlighting its importance in health. Not only is the sunshine vitamin essential for healthy bones, but it also appears that vitamin D can help prevent heart disease, diabetes, autoimmune diseases, and some cancers. People with higher vitamin D levels also fare better after a cancer diagnosis than people who have lower levels.

With the advent of these new studies, some researchers have called into question the cut-off point for what is considered “low” vitamin D levels, saying that a much higher level is actually necessary to prevent disease. These findings have also led some experts to suggest that 400 IU of vitamin D per day is not nearly enough to keep up healthy vitamin D levels, and that a more reasonable daily intake might be around 2,000 IU.

How do you D?

There are two ways to get vitamin D into the body: through diet and by exposing the skin to the sun or other ultraviolet light (from a tanning bed, for example). People living at higher latitudes—like in New England or the UK—simply can’t make enough vitamin D from the sun except during the summer months. If you live south of 35 degrees latitude (around Flagstaff, Arizona), you can get plenty of vitamin D from the sun all year round, provided you don’t slather on the sunscreen or wear sun protective clothing all the time.

There aren’t many foods that naturally contain high levels of vitamin D; fatty fish like salmon and mackerel have a good amount (about 350 IU per 3.5 ounce serving), while a hard boiled egg contains about 20 IU. Otherwise, fortified foods and supplements, including some cod liver oils, are the major non-sunlight sources of vitamin D for most people.

Even with the fortification of milk and other foods, many people still don’t get enough vitamin D to bring their levels into an optimal range. The new study looked at the feasibility of fortifying cheddar cheese as a way to boost vitamin D intake. They compared high- and low-fat versions of vitamin D-fortified cheese, vitamin D supplements, unfortified cheese, and a placebo supplement given to 80 people for eight weeks. The fortified cheeses and the supplement each provided a daily dose of 4,000 IU of vitamin D.

The researchers found that the cheeses and vitamin D supplement all raised vitamin D levels by the same amount, bringing over 90% of the peoples’ vitamin D levels into a healthy range. None of the people complained of side effects related to treatment. “These data demonstrate that vitamin D is equally bioavailable from fortified hard cheeses and supplements, making cheese suitable for vitamin D fortification,” said the team.

Where’s the cheese?

Milk that is processed into cheese, yogurt, and ice cream doesn’t have vitamin D added to it; with the recent rise in interest about the health benefits of vitamin D, though, it shouldn’t be long before vitamin D–fortified cheeses hit the shelves. Until then, look for other vitamin D–fortified foods and enjoy some sockeye salmon for a natural vitamin D boost.

During seasons when the sun is strongest, expose the face, hands, and arms to the sun for about 10 minutes, three times per week to help the body produce vitamin D. Darker skinned people have more UV light-blocking melanin in their skin, and therefore need to be in the sun longer in order to meet their vitamin D needs than someone who is more fair. For those cold, dark winter months, a vitamin D supplement might be necessary. A tolerable upper intake level of 2,000 IU per day has been set by the Food and Nutrition Board, so check with your doctor to see how much vitamin D is right for you.

(J Nutr 2008;138:1365–71)

Kimberly Beauchamp, ND

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