What are they? What do they do? “The Vitamins” What are they? What do they do?

History Early 20th century miracle cure? Seemingly miraculous cures by adding a vitamin to a diet! Following decades: learned to isolate vitamins, assess deficiencies

What is a vitamin? “Vitamin = an essential, noncaloric, organic nutrient needed in tiny amounts” Although small in quantity, they are vital for our health! Some were given letters and numbers when discovered. (Vit A was first, then B, and C)

Vitamin Precursors “Some vitamins occur as precursors, aka provitamins.” “These can be transformed into vitamins by the body.” So it’s important to look at these in food as well as complete vitamins, like C.

“Two Classes” “1. Fat-soluble vitamins: dissolve in fat” This quality determines many of the vitamin’s characteristics. “travel in blood, can build up in tissues.” “We may be deficient if we have fat malabsorption.”

“2. water-soluble: absorbed directly into bloodstream.” “Not stored; excess is excreted in urine” This means that they are less toxic; we urinate out the extra.

“The Fat-Soluble Vitamins” So let’s start with the fat-soluble ones. “Vitamins A, D, E, and K” So why are they fat-soluble? “Found in the fats and oils of foods, cannot dissolve in water.”

Why does that matter? “Because they are stored, we don’t need to eat them every day.” If we eat enough of them on average, our body will store the extra for times when we’re not consuming them.

That’s not always a good thing! “This means they can also reach toxic levels.” If we consume too much supplements, especially of A and D, we can overdose. Let’s take a look at A first, then D.

“Vitamin A” First one to be discovered, hence the A. “Beta-carotene is its’ precursor.” So we need to consider our intake from both the vitamin and the precursor.

Where do we find it? “Found in animal products, especially liver and fish oil.” Also milk, eggs, butter, because it has been added. Too much liver can be toxic! Inuits know not to eat polar bear livers; they have accumulated the A from the whole fish they have eaten!

“Beta-Carotene Sources” “carrots, sweet potatoes, spinach, apricots.” The beta-carotene gives them their bright colors.

What do these vitamins do? “Vitamin A:” “Regulates genes” by turning them on and off at the right times. Heard of retinol?

“Sustains normal eyesight” Carrots, anyone? Vit A is a part of rhodopsin, the pigment in the eye that is sensitive to light. Night blindness is often caused by vit A deficiency.

Vitamin A Toxicity We rarely see this because of food (just liver)…mostly because of supplements or fortified foods. Nausea Vomiting and diarrhea Joint pain/loss of coordination Liver damage Stunted growth

Can really add up from fortified foods and supplements!

Who needs to be especially careful? Expectant mothers (can damage spinal cord; need prenatal vitamins) Children who over-eat vitamin chewables/gummies Misinformed acne sufferers Don’t exceed 3,000 micrograms a day! Rely on food, not supplements

Continuing our stroll through the fat-soluble vitamins… “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? Think about it.

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)

“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!

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

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 10-30 with. Dark-skinned people need up to 3 hours! (They can still get cancer, though)

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

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