by LuAnne Steininger
Little things make a difference could also be a title for this article. In an effort to keep ourselves in the best physical condition and to keep a positive mental outlook , we must be the “D”etectives in our lives.
In our first wellness article, we looked at “A”ttitude as an important component to good health. We then covered good “B”reathing as a way to reduce stress, followed by a conversation about the constants of “C”hange and “C”hoice. Now we arrive at the letter “D”. Yes, we are our own detectives. As we pay attention internally, we can notice how choosing a positive attitude, breathing deeply and making wise choices can improve our health. We see good results as we make good choices. Now, we begin a conversation about something we cannot see inside our bodies that can have a huge impact on our health, vitamin “D”.
Vitamin D is a fat-soluble vitamin naturally present in very few foods, but is added to others and available as a dietary supplement. It can also be converted in the body after exposure to ultraviolet rays from the sun. It seems remarkable that the wisdom of the bodies' cells knows how to convert sunlight to a vitamin. The major function of vitamin D is to maintain normal blood levels of calcium and phosphorous. If we don't get enough vitamin D severe health consequences can result. Some researchers now suggest that increasing blood serum levels of vitamin D can reduce the risk of developing certain diseases.
The history of the discovery of vitamin D is very interesting. A Roman physician in the 1st and 2nd century AD described bony deformities among infants. In 17th century England, rickets was a common disease. At the turn of the 20th century, rickets was rampant among poor children living in the industrialized and polluted northern cities of the United States. Their small frames showed skeletal deformities such as bowleg or spinal curvature. (A note of clarification is that scurvy is a deficiency disease that results from a lack of vitamin C which leads to general weakness, anemia and gum disease. English sailors were referred to as “limeys” for the lime juice they drank to prevent this disease during long sea voyages).
The chemical structure of vitamin D was determined only about 80 years ago. It is somewhat ironic that this vitamin was classified as a vitamin since the biological active form is a hormone. The liver and kidney help convert vitamin D to its active hormone form. However as it is classified, scientists have determined that it is an important component of health.
What are some food sources of vitamin D?
(Perhaps your grandmother knew cod liver oil was good for you)
| Food | IU (international units) |
|---|---|
| Cod liver oil, 1 tablespoon | 1,360 |
| Cooked salmon, 3.5 ounces | 360 |
| Canned tuna in oil, 3 ounces | 200 |
| Milk, 1 cup | 98 |
| Whole egg | 20 |
| Swiss cheese, 1 ounce | 12 |
How much vitamin D do we need?
The current daily recommended dietary allowance (RDA) varies by age.
| Age | Recommendation IU |
|---|---|
| 0-50 | 200 |
| 51-70 | 400 |
| 71+ | 600 |
Who is at risk of vitamin D deficiency?
- Breastfed infants: human milk alone does not meet recommended requirements;
- Older adults: skin cannot synthesize efficiently and kidneys are less able to convert vitamin D;
- People with limited sun exposure: homebound individuals, people who work indoors, live in northern latitudes or wear protective clothing;
- People with dark skin: reduces the skin's ability to produce vitamin D from sunlight;
- People who cannot absorb dietary fat: associated with medical conditions such as Crohn's disease, cystic fibrosis, celiac disease, surgical removal of part of the stomach or intestine and some forms of liver cancer;
- People who are obese: individuals with a body mass index over 30, vitamin D becomes trapped within the fat and cannot circulate.
Current Issues and Controversies about vitamin D
At the October 2008 American Public Health Association 136th annual meeting in San Diego, researchers Cedric F. Garland, Department of Family and Preventive Medicine, University of California, San Diego, the Mona Calvo, Department of Health and Human Services, the U.S. Food & Drug Administration and others reported on the newest research promoting increased intakes of vitamin D to reduce the risks of chronic disease.
Several scientists have produced a call to action that can be accessed at www.grassrootshealth.org. Their call to action states; evidence indicates that the daily intake of vitamin D should be 2,000 IU/day from all sources and aim for a blood serum level of 25-hydrosyvitamin D of 40-60 ng/ml (nanograms/milliliter).
Always consult with your health care practitioner to develop a custom plan. Be your own “D”etective and live well.
LuAnne Steininger, B.S., Health Education, is the Wellness Coordinator at the Sanford Center for Aging, University of Nevada, Reno. She has worked with people ages 50+ for 20 years and is on the leading edge of the baby boomer generation. This article was written with the help of Rori Lee, graduate research assistant at the Sanford Center for Aging.