For years, good bone health and fracture prevention have been associated with calcium and vitamin D. But new government recommendations say that older people have been misled to believe vitamin D and calcium supplements will protect them from fractures. Recent research on vitamin D has drawn the same conclusion as similar research on calcium: natural sources are far more beneficial than supplements.
The sunshine vitamin
Vitamin D is being hyped as a panacea for everything from flu to diabetes because nearly every cell in our bodies puts it to good use. Our primary source of vitamin D comes from exposing bare skin to the sun. When your skin absorbs the sun’s ultraviolet rays, a type of cholesterol is converted to inactive vitamin D3, which is passed into the bloodstream.
Vitamin D’s activation starts in the liver, where it is converted into calcidiol. It then moves to the kidneys, which activate it by turning it into calcitriol, the hormone responsible for health benefits in humans. Vitamin D that is ingested goes through the same process.
Supplements vs. food
Most people don’t get enough of the “sunshine vitamin” through exposure to sunlight or diet. That’s why food manufacturers use vitamin D2 for supplements and to fortify foods such as milk and bread. However, new research conducted by scientists from the University of Surrey in the U.K. clearly showed that vitamin D3, the type of vitamin D found in foods including eggs and oily fish is more effectively converted by the body into calcitriol.
The rise of ergocalciferol
Vitamin D2 was produced in the early 1920s by exposing foods to ultraviolet light. This process was patented and licensed to pharmaceutical companies, which led to the development of a plant-based supplemental vitamin D2 known as ergocalciferol.
Since then, vitamin D2 and vitamin D3 have been officially considered interchangeable. But an analysis by the University of Surrey researchers of 10 separate studies involving over 1,000 people comparing the health benefits of vitamin D2 and D3 shows the body reacts differently to both types and that vitamin D3 is better at raising vitamin D levels in the blood.
Far behind Europe
For years the suitability of vitamin D2, or ergocalciferol, for supplementation or fortification have been questioned. In the 1950s, the most popular vitamin D supplement in Europe was reformulated to replace its vitamin D2 content with vitamin D3. But to this day supplementation and fortification in North America are in the form of vitamin D2.
Your daily dose of vitamin D
Most nutrition experts say that going out into the midday sun for 10 minutes in shorts and a tank top a few times a week will keep you supplied with vitamin D. But that can be difficult for people living above 42 degrees in northern latitude.
Doctors recommend from 600 to 800 IU of vitamin D intake daily. Here’s a list of foods that can give you your daily dose of vitamin D:
- 3½ ounces of cooked salmon: 90 percent of your daily needs
- One can of sardines: 70 percent
- One 5-ounce can of tuna: 80 percent
- One egg: 10 percent