What can high-vitamin D foods do for you?

  • Help prevent a growing list of chronic diseases, including type 2 diabetes, heart disease, hypertension, osteoporisis, breast cancer, colon cancer, and ovarian cancer
  • Help keep your bones and teeth strong and healthy
  • Regulate the growth and activity of your cells
  • Reduce inflammation

What events can indicate a need for more foods rich in vitamin D?

  • Bone pain and/or soft bones
  • Frequent bone fractures
  • Bone deformities or growth retardation in children
  • Lack of exposure to sunlight for any reason, including geography, use of sunscreen, or wearing of protective clothing
Concentrated food sources of vitamin D include salmon, sardines, shrimp, milk, cod, and eggs.
Sockeye salmon are an exceptionally rich source of vitamin D: a 4-ounce serving of baked or broiled sockeye salmon provides 739.37 IU of vitamin D. The same 4-ounce serving of chinook salmon, another excellent source of vitamin D, supplies 411 IU.

Why are sockeye salmon even more richly endowed with vitamin D than other salmon species? Because zooplankton constitute so much of their diet, and zooplankton-along with phytoplankton-are the key sources of vitamin D in the marine food chain. The zooplankton eaten by salmon are tiny marine animals, such as larval-stage crustaceans, while the phytoplankton eaten by salmon are small, plant-like marine organisms.

Both types of minuscule sea life create lots of vitamin D from sunlight, and zooplankton feed on phytoplankton, building up their vitamin D content to even higher levels.

Unlike most other fish and salmon species (except chum), sockeye feed largely on zooplankton through all stages of life. Chinook, on the other hand, feast on insects and sideswimmers when young, then consume a variety of fish, especially smelt and ciscoes, a type of lake herring, as they mature.
 

What are current public health recommendations for vitamin D?

In 1997, the National Academy of Sciences established the following Adequate Intake (AI) levels for vitamin D:

  • Infants and children: 5 micrograms
  • Teenagers: 5 micrograms
  • Adults up to 50 years of age: 5 micrograms
  • Adults 51-70 years: 10 micrograms
  • Adults above 70 years: 15 micrograms
  • Pregnant and lactating women: 5 micrograms
Since the establishment of these vitamin D recommendations in 1997, over 3,000 research studies involving vitamin D have been published in top level science journals. Many of these studies suggest that significantly higher levels of vitamin D may be essential for certain groups of people. These groups include persons living in more northern geographical areas, for example, residents in the Pacific Northwest or New England in the United States; obese persons; persons getting very little sunlight due to indoor jobs or personal habits, including constant use of sunscreen; and persons with naturally darker skin. Individuals in these categories are likely to require at least 1,000 IU per day, an amount significantly higher than the 200-600 IU levels listed above.

A review study (one that summarizes the evidence from a number of other studies) published in the July 2006 issue of the American Journal of Clinical Nutrition found that the currently recommended daily intakes of 200 and 600 IU of vitamin D for younger and older adults, respectively, were insufficient to provide the blood levels of vitamin D needed for bone mineral density, lower-extremity function, dental health, and to lessen risk of falls, fractures, and colorectal cancer.

Adequate blood levels of vitamin D to provide for these health needs begin at 75 nmol/L. Blood levels of vitamin D between 90 and 100 nmol/L are optimal. A daily intake for all adults of >/=1000 IU vitamin D (cholecalciferol)/d is needed to bring vitamin D concentrations in no less than 50% of the population up to 75 nmol/L.

If you are concerned about your vitamin D status, ask your doctor to check your blood levels of 25(OH)D3. The major circulating form of vitamin D in the blood, this form of the vitamin is the true barometer of vitamin D status.