Calcium and Vitamin D - The Disappearing Micronutrients

Calcium and vitamin D are so critical for human health and yet these micronutrients are slowly disappearing from Western diets.  This is largely due to a reduction in consumption of animal products, either because of dietary preferences or due to digestion challenges.  It is widely known that calcium and vitamin D are critical for building healthy bones, yet they do so much more to maintain health.

 

Calcium is by far the most abundant mineral in the body of which 99% is stored in the bones and teeth.  Did you know that almost the entire adult human skeleton is rebuilt every ten years?  This is because our bones are in a constant state of formation and dissolution.  The remaining 1% is found in the fluids that bathe and fill the cells in the body.  This reservoir of calcium is critical for nerve cell transmission, blood pressure maintenance, blood clotting and muscle contraction (and therefore, the heartbeat).  In addition, calcium enables secretion of hormones, digestive enzymes, and neurotransmitters.  Studies are emerging to suggest that calcium deficiency is associated with a number of major illnesses including high blood pressure, colon cancer, and diabetes. 

 

Obtaining dietary calcium outside of dairy products is not as hard as you may think.  Significant quantities may be found in tofu, green vegetables such as broccoli, kale and collard greens, figs, oranges, sardines, canned salmon, almonds and white beans.  The Daily Recommended Intake (DRI) for calcium is 1000 to 1200 mg per day.

 

While calcium is a critical dietary component, vitamin D (theoretically) is not.  This is because with exposure to sunlight your body can make all the vitamin D it needs.  UV light converts a cholesterol-like compound to a vitamin D precursor which is then converted to vitamin D in the liver and kidneys.  Unfortunately, blood level of this vitamin have been declining due to lack of sun exposure and due to the rising obesity epidemic.  Since vitamin D is a fat soluble vitamin it is easily trapped in fat cells and thus, less available in the blood where it functions to regulate blood calcium, and thereby maintain bone integrity.  Once activated by light vitamin D also functions as a hormone.  In this capacity it affects how cells grow, multiply and specialize.  Not only is vitamin D deficiency a risk factor for osteoporosis but nascent research suggests a correlation with many diseases including macular degeneration, cardiovascular disease, some cancers, respiratory infections and multiple sclerosis.  

 

Dietary sources of vitamin D include cod liver oil, sardines, salmon, mackerel, tuna and fortified foods like milk, orange juice and cereals.  Recommended intake for those between the ages of 19 and 70 is 15 micrograms per day.  Have your blood tested for vitamin D deficiency at your yearly physical.  You may need to take a supplement of 1000-5000 IUs per day.  However, since this vitamin is the most potentially toxic among vitamins it should only be taken on an as-needed basis.  Vitamin D intoxication raises the concentration of blood calcium, which can then collect in soft tissues leading to a decline in kidney and heart function.