Foods rich in vitamin D include fish and fish liver oils…and small amounts are also found in beef liver, cheese, and egg yolks. These foods have the advantage of providing vitamin D3 (cholecalciferol), which is known to be more effective than the vitamin D2 found in some fortified foods.
The US National Institute of Health lists the nutritional values of foods rich in vitamin D as follows:
- Cod liver oil (1 tablespoon): 1340 IU
- Sockeye salmon (3 oz. cooked): 794 IU
- Mackerel (3 oz. cooked): 388 IU
- Tuna (3 oz. canned in water and drained): 154 IU
- Milk (1 cup fortified): 115-124 IU
- Orange juice (1 cup fortified): 100 IU
Unless we’re eating salmon every day, it’s hard to reach the 1,000 IU daily of vitamin D recommended for adults by the Canadian Cancer Society; the 2000 IU recommended by Dr. Michael Holick (author of UV Advantage); or the 5,000 IU recommended by the Vitamin D Council, only from foods rich in vitamin D.
IS COD LIVER OIL THE SOLUTION?
Cod liver oil certainly seems to hold the most promise of the vitamin D-rich foods, but there are several factors to consider before choosing it as your vitamin D program:
- Vitamin D is not well absorbed without supplemental vitamins
- Cod liver oils vary significantly in the amount of vitamin D they provide.
- Several tablespoons a day may be necessary to maintain recommended blood levels of the vitamin
Complementary Vitamins
The Vitamin D Council advises that a variety of vitamins and minerals are needed to help the body use vitamin D properly. These include:
- magnesium
- zinc
- vitamin K2
- boron
- genestein
- a small amount of vitamin A
Magnesium is the most important of these supplementary factors, but it is rarely included with cod liver oil. Taking cod liver oil (or increasing vitamin D through supplements) might actually worsen an underlying magnesium deficiency… already common throughout North America.
cod liver oil brands
Most brands of cod liver oil go through a process that removes all naturally occurring vitamins, including vitamin D…although some manufacturers do add vitamins to the final product. Unheated cod liver oil, fermented and produced using a filtering process that retains the natural vitamins, is highly recommended. But the most popular brands provide only 400 IU of vitamin D per teaspoon (the equivalent of 1,200 IU per tablespoon), which is well below recommended levels. During the winter months in the northern regions (north of Boston, Rome, and Beijing) several tablespoons would be needed each day to maintain adequate blood levels, and additional magnesium would be needed to facilitate absorption.
Many brands of cod liver oil have the benefit of providing EPA and DHA acids (which are valuable to the brain and nervous system), but few provide the highest dosage recommended by a growing number of vitamin D experts. manufacturers argue that their oils provide more absorbable nutrients due to the high vitamin A content… this is highly disputed as vitamin A deficiency is rare in developed countries. In fact, too much vitamin A can be toxic and is particularly dangerous during pregnancy.
A good bone-strengthening supplement is an excellent addition to a diet of foods rich in vitamin D. A higher-quality supplement will not only provide additional vitamin D3, but also the magnesium and vitamin K needed to aid absorption. Although cod liver oil is one of the foods rich in vitamin D…it may not provide as much absorbable vitamin D as expected, while providing false assurance that intake is adequate.
For more information on bone-building supplements that provide vitamin D, as well as magnesium and vitamin K needed for absorption… visit http://osteoporosis-vitamins.com/osteoporosis-treatment-guidelines.html