“Vitamin D” Continuing our stroll through the fat- soluble vitamins…

Uniqueness of Vitamin D “Unique because the body can synthesize all it needs from sunlight.” So, technically, we may not need vitamin D from our food. However, “2/3 of Americans don’t get enough.” How can that be?

Let’s take a closer look at D. What foods do we find D added to? Milk…why? “One of a number of nutrients that regulate blood calcium and phosphorus.” Therefore, D helps with bone integrity.

“Vitamin D works at three body sites to replenish blood calcium.” 1. the skeleton (Ca warehouse) 2. digestive tract (food) 3. kidneys (recycle Ca)

Another way D is unique… “Vitamin D also acts like a hormone.” What does this mean? Hormone = compound made by one organ that acts on other organs D affects over 30 body tissues! Hair follicles to repro cells, to immune system

“Vitamin D Deficiencies” The most obvious sign occurs in early life: rickets. “Rickets = children develop bowed legs because bones can’t hold their growing weight”

Other symptoms “Also beaded ribs and protruding chests.” Some areas of the world: more than half children have it Rare in U.S.

Rickets As early as the 1700’s, doctors knew to treat it with cod-liver oil…rich in D. More than 100 years later, Polish physician linked sunlight exposure with curing it.

How can we prevent it? American Academy of Pediatrics recommends 400 IU/day until adulthood Why might it be a greater problem for teens? No milk/more time spent indoors: can cost you bone strength later!

Osteomalacia In adults: soft, brittle, or deformed bones Can also cause painful joints and muscles in elderly patients

“Osteoporosis” “Loss of calcium from bones” fractures common

Can you get too much D? “Most potentially toxic vitamin” Why? “Raises blood calcium, which can collect in tissues, forming stones or hardening blood vessels.” Kidney stones, etc. Most common in infants and elderly

Why is it most common in people of African or Hispanic descent? UV rays shine on cholesterol compound in skin, form D precursor. People who move north from sunnier places with lots of skin pigment don’t get enough UV.

But what about skin cancer? We must find a happy medium between too much and too little. Fair-skinned people only need 5 min. w/out sunscreen or with. Dark-skinned people need up to 3 hours! (They can still get cancer)

“Food Sources” “Salmon, milk, tuna” Some cereals and yogurts are fortified, check the label. “Must be eaten with calcium in order to matter.” They work together!

New Research Recent research suggests that wintertime vitamin D deficiency might have a connection to S.A.D. Seasonal Affective Disorder, the winter blues.