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| Vitamins A, D, E, K; share common characteristics but are chemically unique; broken down by bile and dietary lipids and absorbed mostly in the small intestine; stored in the body; |
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| complex organic compound; micronutrient; cannot be synthesized by the body (or make enough of it to maintain); not a source of energy, vitamins participate in the chemical reactions that break down glucose, fatty acids, and proteins |
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| vitamins are not metabolize by cells for energy; vitamins help with the breaking down on carbs, fats, and protein (coenzymes) |
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vitamin precursors that do not function in the body until converted to active forms
ex. beta-carotene is a precursor to vitamin A |
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| found in food that are usable by the body without chemical transformation |
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| most absorption occurs in the small intestine; absorption is not always 100% efficient; absorption tends to increase in times when the vitamin in more needed (ex. pregnancy, infancy, developmental stages, etc.) |
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| Factors that affect absorption of vitamins |
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Definition
| physiological need from the body (according to age and gender), how the food was prepared (raw vs. cooked), synthetic versus non-synthetic vs. processed foods, the combination of foods you ate, etc. |
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| natural sources (plants, animals, fungi, bacteria), synthetic (made in a lab by chemists, synthesize by microbes), enrichment, and fortification |
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| family of compounds; retinol and other forms vitamin A only found in animal foods |
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| provitamin; vitamin A precursor; the body can use beta-carotene to make vitamin A |
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| a dietary compound with a similar structure to retinoids (forms of vitamin A); some can be converted into vitamin A for the body to use |
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| Beta-carotene to retinol ratio |
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Definition
| 12 mcg of beta-carotene = 1 mcg of retinol in the body |
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| gene expression, vision, maintenance of the body lining and skin (crucial for epithelial cells), reproduction |
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| can reduce fertility (epithelial cells); dry eye (xerophthalmia); hard, scaly, bumpy skin (keratinization) |
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| Lutein, zeaxanthin, and lycopene |
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Definition
| other carotenoids; the body does not covert them into vitamin A; function as antioxidant in the human body |
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| since vitamin A is stored in the liver, excess vitamin with cause damage to the liver; caused by excessive consumption of preformed vitamin A (usually supplements) |
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an agent that causes birth defects
ex. access vitamin A (which is why pregnant women should not take vitamin A supplements) |
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| the "sunshine" vitamin; not widespread in food |
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| How the body makes vitamin D |
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Definition
1. skin is exposed to UV
2. Uv radiation converts a cholesterol-derived substance into vitamin D3 (inactive)
3. Vitamin D3 is then released into the blood and finds its way to the liver
4. the liver converts vitamin D3 into 25OH Vitamin D3 and then releases it back into the blood stream
5. 25OH vitamin D3 finds its way to the kidneys and the kidneys then covert it into the active form we call vitamin D |
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| necessary for the production and maintenance of healthy bones; stimulates epithelial cells of the small intestine aiding in the absorption of calcium and phosphorus; reducing risk of cancer since vitamin D is involved in controlling cell growth |
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| small fluctuations in blood calcium levels with have serious consequences (medical emergencies); if there is a drop in blood calcium, vitamin and PTH signal bones to release calcium (PTH stimulates the kidneys to increase vitamin D production and decrease the elimination of calcium in the urine) |
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| Rickets in babies and kids; osteomalacia in adults: symptoms are diffuse bone pain, increased risk of bone fracture, and muscle weakness; leading to osteoporosis |
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| Factors affect vitamin D synthesis |
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Definition
| Air pollution, light exposure, geography, clothing, season, sunscreen, skin color, time of day |
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| excess vitamin D can cause the small intestine to absorb too much calcium from foods and the mineral then is deposited in soft tissues, including the kidneys, heart, and blood vessel |
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| family of compounds; eight forms of vitamin E; easily destroyed by cooking; major fat-soluble antioxidant found in cells; added to food to prevent oxidation |
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Definition
| when an atom or molecule gains one or more electrons, it has been reduced and is more negative, when an atom or molecules loses one or more electron, it has been oxidized and has become more positive |
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| responsible for the synthesis of blood-clotting factors in the blood; 10% of our vitamin K is synthesized by bacteria in the large intestine and the rest comes from our diet (mostly leafy greens) |
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deficiency occurs in some infants because newborns have sterile large intestine and it takes weeks to build up bacteria capable of synthesizing vitamin K
newborns are given a single does of vitamin K at birth |
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