For most people, maintaining the proper caloric intake and eating a balanced diet will generally ensure an adequate intake of all of the necessary vitamins and minerals. This is not necessarily true for aging seniors – especially those who are in their 80s or older. Vitamin deficiency in these folks can occur even when maintaining a proper diet. Older seniors often lack the ability to properly absorb certain vitamins from their food. Or they may have reduced ability to synthesize certain vitamins in their bodies. In other cases, they need larger amounts of a certain vitamin because their bodies don’t utilize it as well as younger people. Vitamin supplementation with minerals is always recommended for the elderly to avoid this problem.
Despite supplementation, there are two vitamins that still might cause problems – sometimes very severe problems. Some researchers consider a deficiency in these vitamins in the elderly to be a malnutrition epidemic that must be addressed with every elder. These two vitamins are vitamin B12 and vitamin D. We discussed vitamin B12 deficiency in a previous article. In this article we will discuss vitamin D deficiency.
Vitamin D is one of four vitamins stored by the liver. Generally, the liver can hold up to a 1 to 4 month supply. Unfortunately, if this vitamin is not replenished through skin exposure to the ultraviolet radiation from the sun or through oral supplementation, stores will decrease and blood levels of the vitamin will plunge. At a certain point, low circulating vitamin D in the bloodstream can result in serious consequences.
Vitamin D deficiency is now recognized as a national pandemic. The major cause of vitamin D deficiency is the lack of exposing the skin to the sun as this is the major source of vitamin D for humans. Historically, humans have worked outside under the sun and those who were exposed most heavily to the sun’s rays have developed pigment in their skin to prevent damage from ultraviolet. Even for those with dark skin, production of vitamin D is not hindered if enough sunlight is absorbed. Those who live in northern latitudes where there is less sun and clothing is required to stay warm, have light skin. This adaptation likely has occurred in order to encourage production of vitamin D through a conversion of 7-dehydrocholesterol in the skin.
Sunlight is the major source of vitamin D for humans. Very few foods naturally contain vitamin D, and foods that are fortified with vitamin D are often inadequate to satisfy either a child's or an adult's vitamin D requirement. The best food source is the flesh of fatty fish such as salmon, tuna and mackerel and fish liver oils. Small amounts of vitamin D are found in beef liver, cheese and egg yolks. Meat contains small amounts of vitamin D, but animal muscle flesh – which is our predominant choice for animal meat – contains almost none. Most of the vitamin D supplied by eating animals is found in the internal organs and mostly in the liver.
Very few Americans spend much time in the sun and in fact the fear of skin cancer causes those who do expose their skin to use sun blockers to take out the ultraviolet rays. Unfortunately, it is ultraviolet that produces vitamin D in the skin. As a result of less sun exposure, many people – young and old – become deficient in vitamin D. Even for those people who occasionally go to the beach or spend some time in the sun, the use of sun blocker inhibits the production of vitamin D. It is impossible to produce vitamin D by exposure to sunlight that comes through window glass. The beta ultraviolet radiation that produces the vitamin in the skin is absorbed by glass. Ironically, the alpha ultraviolet that also causes sunburn or a tan is not absorbed by glass and a person can receive a sunburn or a tan by exposure to sunlight that comes through window glass. In addition, most tanning booths are constructed to produce mostly alpha ultraviolet and very little beta ultraviolet because of the fear of skin cancer and as a result, tanning booths are usually not an alternative source for producing vitamin D.
As a final note, exposure to the sun in the morning hours and afternoon hours produces very little vitamin D. This is because the beta ultraviolet from sunlight that converts cholesterol in the skin into the vitamin form, is mostly absorbed by the atmosphere when the sun is at low angles to the horizon. In fact, in the late fall, winter and early spring in northern latitudes, even at noon time, the sun is so low in the sky that almost no vitamin D can be produced by exposure to the sun.
Aging is also a risk for low levels of vitamin D. The skin of aged adults has a 75% reduced capacity of making vitamin D when compared with younger adults. Obesity also puts one at risk for deficiency. Vitamin D is fat-soluble and is readily taken up by fat cells making it unavailable to the body. Medications such as anti-seizure medications and glucocorticoids and fat malabsorption are also common causes of vitamin D deficiency.
A study of 349 elderly people who had poor muscle strength in their hands, were unable to climb stairs and had recently fallen, found that blood levels of vitamin D were significantly lower compared with the levels in people without these problems. Another study showed that six months of treatment with vitamin D deficient elderly women improve knee strength and walking distance. However, there has been no evidence to suggest that vitamin D supplements improve muscle strength in those with normal vitamin D levels.
In addition to age-related deficiencies mentioned above, vitamin D deficiency in older people can also be attributed to poor absorption by the intestines or impairments in vitamin D metabolism due to liver or kidney disease.
Not only is vitamin D essential to prevent osteopenia, osteoporosis and fractures in adults, but deficiency of the vitamin has been associated with an increased risk of common cancers, adult onset diabetes, coronary heart disease, autoimmune diseases, hypertension and infectious diseases. Advocates of vitamin D supplementation claim that we would have less cancer, fewer autoimmune disorders, less heart disease and less diabetes if people would maintain adequate blood levels of vitamin D.
Numerous studies show that people who live in coastal regions and eat seafood seem to have fewer autoimmune disorders. No one has yet tied this to vitamin D deficiency and more studies are needed. The same health differences are found in people who live at latitudes closer to the equator where ultraviolet sunlight is more plentiful as opposed to people who live in northern latitudes where there is less ultraviolet radiation.
A reevaluation needs to take place of what the adequate intakes of vitamin D should be for children and adults. The literature over the past decade suggests that the Institute of Medicine recommendations in 1997 are inadequate, and some experts suggest that both children and adults should take daily doses of 800–1000 IU vitamin D from supplemental sources when sunlight is unable to provide it. This recommendation, however, has not yet been embraced either by official government or pediatric organizations in the United States, Canada, or Europe for either children or adults.
Recommended levels of 400 IU daily supplementation may be too low. On the other hand, caution must be exercised because in large doses, vitamin D can become toxic. Some researchers suggest that vitamin D supplementation is safe up to 10,000 IU per day, but others would say that over a period of months this could result in toxicity. We are not advocating any particular level of supplementation in this article and readers must decide for themselves or consult with their physicians what is safe for them.
This article has been provided by the National Care Planning Council.