Bad to the Bone! Are you at risk for Vitamin D and Calcium Deficiency?

Vitamin D deficiency is one of the most common deficiencies worldwide and in the United States.  Approximately 1 billion people worldwide are Vitamin D deficient, while about 50% of the US population has Vitamin D insufficiency.

Vitamin D is the only vitamin that is also considered a hormone.  It can be made in the skin when exposed to sunlight.   The amount of sunlight needed is dependent on geographical location.  Populations that live in year-round cooler temperatures means less sun exposure to the skin.  Even in a warm and sunny climate like Central Texas, people that work and play indoors or wear full clothing and sunscreen may not have adequate exposure to the sun.   Vitamin D production is also limited by the amount of melanin in the skin (This is the pigment that determines skin color).  The more melanin in the skin or the darker the skin, the less Vitamin D will be produced with exposure to the sun.  On average, it can take 20-40 minutes of sun exposure per day to produce adequate Vitamin D. 

In addition to sun exposure, Vitamin D is added to fortified foods and beverages such as dairy products including milk, yogurt, cheese, and butter.  These foods are also good sources of calcium.  Other foods such as egg yolks, flounder, cod, sardines, mushrooms, and beef liver are also good sources of Vitamin D.

While Vitamin D plays a role in the nervous system and immune function, the most important function of Vitamin D is for healthy bones and muscles.  Vitamin D helps calcium stay in our bones and teeth.   Vitamin D deficiency is often linked to bone fractures and tooth loss.  Without enough Vitamin D, calcium will not be well regulated in the body.

Low levels of Vitamin D and calcium can lead to conditions called osteopenia and osteoporosis, which are generally seen in adulthood.  Both osteopenia and osteoporosis are diagnosed with a bone density test, which is an easy and painless medical test.  These bone loss disorders occur when calcium has leached out of the bone, or possibly there was never an adequate supply there in the first place.  Calcium is best absorbed during childhood and adolescence when the bone is still growing, and calcium absorption is at its highest.

Having low intakes of Vitamin D and calcium during adolescence can further increase the risks for bone loss later in life, especially when Vitamin D rich beverages, such as milk, are replaced by sodas, which is high in phosphorus.   Phosphorus can limit calcium absorption.

Phosphorus is an important mineral in the diet and needed for multitudes of biochemical pathways in the body, however, because of food additives found in sodas and even packaged bakery products, it is easy to consume more phosphorus than calcium consumed (Other food sources of phosphorus include edamame, mushrooms, potatoes, rice, cereals, milk, meats, beans, and eggs).  Ideally, calcium and phosphorus would be consumed at a 1:1 ratio.  It is estimated that the average American consumes a calcium to phosphorus more like 1:3 because of the vast variety of foods naturally containing phosphorus and the addition of phosphoric acid in processed foods to maintain extended freshness.  This unbalanced ratio creates an undesirable absorption situation where less calcium is absorbed.  In addition, calcium is found in a lesser variety of foods (listed above).

During adolescence, calcium is absorbed in the bone like a water into a dry sponge, but sometime in late teens to early 20s, that sponge becomes resistant to absorbing calcium and continues to decrease.  Complicating matters even more for females is pregnancy and breastfeeding.  Calcium intake during pregnancy is vital for both mom and baby.  If mom is not consuming adequate dietary calcium, the calcium will be leached from mom's bones and teeth to meet the needs of the baby.  Prenatal vitamins generally contain 100% RDI for iron and minimal amounts of calcium.  This is because iron deficiency is the most common and acute deficiency during pregnancy.  Calcium is not added at the full recommended dose in prenatal vitamins because it will inhibit the iron absorption.  The best alternative is to take the prenatal vitamin (or if you are not pregnant and take a multivitamin/multi-mineral supplement) at one end of the day and a calcium supplement at the opposite.  For example, if dairy products are consumed at breakfast, the calcium supplement would be best in the morning, and the iron containing supplement with the evening meal when consuming protein rich foods, to reduce and chance of interaction.

In cases where Vitamin D and calcium rich food intakes are low or not tolerated, Vitamin D and calcium can be supplemented easily with traditional dietary supplements or newer versions, such as calcium chews fortified with Vitamin D.  The calcium chews are often preferred to traditional supplements, as the chocolate or caramel chew is pleasant and delivers the same dose contained in the more traditional supplements.

Vitamin D and calcium intake are important for bone health.  Lots of Americans are at risk for deficiency.  If you have limited intakes of foods rich in these nutrients, talk to your provider and get screened for deficiency.   Your bones and teeth will thank you!