Fat soluble vitamins: A, D, E, and K

Vitamin D deficiency 1. An estimated ___ percent of Americans have low blood levels of vitamin D. 2. List four factors that contribute to vitamin D deficiency. 3. A vitamin D deficiency subsequently causes a _____ deficiency.

1. 16 2.Dark skin, breastfeeding without supplementation, lack of sunlight, not consuming fortified milk 3. calcium Vitamin D deficiency in adolescents may prevent reaching peak bone mass.

Diseases associated with vitamin D deficiency 1) Osteomalacia 2) Osteoporosis 3) Rickets 4) The elderly

1. Affects adults, poor mineralization causes soft, brittle bones 2. Fractures often result from calcium loss from bones 3. Affects children, causes bones to bend 4. Reduced ability to activate and make vitamin D

Fat-soluble vitamins differ from water-soluble vitamins in that: 1. They require ____ for digestion and absorption. 2. They travel through the _____ system. 3. Excesses are ______ in the liver and adipose tissues. 4. They are not readily ______. This increases risk of _______

1. Bile 2. Lymphatic 3. Stored 4. Excreted; toxicity

Free radicals: 1. Free radicals contain one or more unpaired _____. 2. The body does/does not produce free radicals. 3. _______ neutralize free radicals. This prevents ____ stress.

1. Electron 2. Does 3. Antioxidants; oxidative Environmental factors including pollution generate free radicals. Antioxidants don't become free radicals.

Vitamin K deficiency 1. Primary deficiency 2.Secondary deficiency 3. Infants

1. Inadequate dietary intake. Is rare 2. Antibiotics kill off vitamin K-producing bacteria; If bile production fails 3. Sterile gut, no vitamin K-producing bacteria Intestinal bacteria produce vitamin K. In newborns, it takes weeks to establish those bacteria. A vitamin K shot is given at birth.

Vitamin K sources 1. Explain the non-food source of vitamin K and comment on its sufficiency. 2. List three food sources of vitamin K.

1. Synthesized by intestinal bacteria. However, amount is insufficient to meet needs, and bioavailability is limited. 2. Leafy greens including kale and spinach. Fruits such as avocado and kiwi. Vegetable oils.

Vitamin A roles in the body: 1. Retinal 2. Retinol 3. Retinoic acid

1. active in vision 2. Supports reproduction and is the major transport and storage form 3. Regulates cell differentiation, growth, and embryonic development

Vitamin E recommendations: 1. The RDA is based on the ______- _______ form only. 2. Vitamin E is widespread in foods. Much of dietary vitamin E comes from _____ oils or foods containing them. 3. Vitamin E is destroyed by _____ and heat, therefore fresh foods are preferable sources.

1. alpha-tocopherol 2. vegetables 3. oxidation Vegetable oils, margarine, seeds, and nuts are good sources of vitamin E.

Vitamin D's role in the body 1. The active form of vitamin D is a ______. 2. Vitamin D is essential for making and maintaining ____. Vitamin D assists in the absorption of calcium and _____. 3. In brain and nerve cells, vitamin D may protect against ________ (2 words).

1. hormone 2. bones; phosphorus 3. cognitive decline Vitamin D may also regulate adipose cells to influence obesity development. Research shows vitamin D may be protective against heart disease, inflammation, brain disorders, type 2 diabetes, and more.

Keratinization 1. Epithelial cells of the skin change shape and secrete the protein _____. As a result, skin becomes ____ and scaly. 2. In the GI tract, ____ cells diminish. This limits the secretion of _____. This impedes _____ and absorption, often worsening malnutrition.

1. keratin; dry 2. goblet; mucus; digestion Keratin is the hard, inflexible protein commonly found in nails and hair. Keratinization increases the risk of infection of the respiratory tract, GI tract, urinary tract, vagina, and inner ear.

Vitamin D recommendations: 1. There are few food sources of vitamin D, list them. 2. The recommendations for vitamin D may be too high/too low. 3. Toxicity can/cannot occur from sun exposure.

1. oily fish, egg yolks, fortified milk 2. too low 3. cannot Meeting recommendations are difficult without sunlight, supplementation, or fortification. Vitamin D production varies with skin color, latitude, season, and time of day.

Vitamin A and cell differentiation: 1. Epithelial cells on the outside of the body form ____. They also line the inside of the body, forming ______(2 words). 2. Goblet cells synthesize and secrete _____.

1. skin; mucous membranes 2. mucous

Vitamin D 1. Vitamin D is/is not an essential nutrient. Explain. 2. Vitamin D requires two hydroxylation reactions to occur for it to become ______. 3. These reactions occur first in the _____, then in the ____.

1.Is not. The body can synthesize vitamin D via exposure to sunlight from a precursor the body makes from cholesterol. 2. activated 3.liver,kidney

Defending against heart disease

Oxidized LDL scenario - Accelerate formation of artery-clogging plaques - Additional changes in arterial walls • Vitamin E - Protect against hypertension and heart disease - Defends against LDL oxidation • Vitamin C - Protect against LDL oxidation • Unclear if supplements provide same benefit as food

Vitamin A and Beta-Carotene

Recommendations - Expressed as retinol activity equivalents (RAE) - International Units (IU) • Food sources - Animal sources - Plant sources - Golden rice and biofortified food

Vitamin A's role in reproduction and growth

Sperm development • Normal fetal development • Growth of children - Bone remodeling • Antioxidant - Beta-carotene

The fat soluble vitamins: A summary

Toxicities are possible • Functions of fat-soluble vitamins together - Vitamins E and A § Oxidation, absorption, and storage - Vitamins A, D, and K § Bone growth and remodeling - Vitamins E and K § Blood clotting

Vit A in selected foods

cornflakes, fortified; broccoli; carrots; tomato juice; beef liver; sweet potato; mango

Vitamin D Most sunscreens reduce the synthesis of vitamin D

true: Exposing hands, face, and arms on a clear summer day for 5 to 10 minutes two to three times a week is often sufficient.

Defending against cancer

• Damage to cellular DNA - Antioxidants may protect DNA from this damage - Inverse relationship with vegetable intake • Healthy diet with abundant fruits and vegetables - Protect against certain types of cancer • Vitamin E - Supplement cautions

Vitamin A toxicity

• Develops when binding proteins are loaded - Vitamin A is free to damage cells • Concentrated amounts of preformed vitamin A - From animal sources, fortified foods, supplements - Children most vulnerable • UL for preformed vitamin A • Bone and birth defects • No effect on acne

Foods, supplements, or both?

• Dietary strategies for preventing heart disease - Use unsaturated instead of saturated or trans fats - Select foods rich in omega-3 fatty acids - Diet high in fruits, vegetables, nuts, and whole grains, and low in refined grain products • Supplement use - Research outcome: provides no benefit § May increase risk → prooxidants

Free radicals damage

• Free radical attacks - Occasionally helpful - Most cause damage • Contribute to cell damage, disease progression, and aging - PUFAs in lipoproteins and membranes - Alter DNA, RNA, and proteins - Elicit inflammatory response

Vitamin A deficiency

• Large problem in developing countries • Vitamin A status - Adequacy of stores, 90 percent in liver - Protein status • Consequences of deficiency - Risk of infectious diseases - Night blindness and blindness § Treatment - Death

Vitamin E toxicity

• Liver regulates vitamin E concentrations - Toxicity is rare • UL is 65 times greater than RDA for adults • Extremely high doses of vitamin E - May interfere with blood-clotting of vitamin K activity § Hemorrhage

Vitamin A and vision

• Maintains clear cornea • Converts light energy to nerve impulses in the retina - Photosensitive cells contain rhodopsin • Repeated small losses of retinal - Need for replenishment

Vitamin D toxicity

• Most likely of the vitamins to have toxic effects - Supplements • Raises blood calcium concentrations - Forms stones in soft tissues § Kidneys - May harden blood vessels § Can cause death

Vitamin K toxicity

• Not common - No adverse effects with high intakes • No UL • High doses can reduce effectiveness of anticoagulant drugs - Consistent intake of vitamin K is best

Free radicals and disease

• Oxidative stress causative factor in: - Reduced cognitive performance, cancer, heart disease, arthritis, cataracts, diabetes • Body's natural defenses and repair systems - Not 100 percent effective - Less effective with age

Vitamin K

• Primary action: blood clotting - Prothrombin • Metabolism of bone proteins - Osteocalcin § Low bone density • Other possible roles of vitamin K in the body

Vitamin E deficiency

• Primary deficiency is rare • Secondary deficiency - Fat malabsorption, e.g., cystic fibrosis • Effects of deficiency - Red blood cells split as PUFAs become oxidized § Erythrocyte hemolysis - Neuromuscular dysfunction - Vitamin E treatment

Defending against free radicals

• System of enzymes against oxidants - Uses copper, selenium, manganese, and zinc • Antioxidant vitamins - Vitamin E § Defends body lipids - Beta-carotene § Defends lipid membranes - Vitamin C § Protects skin and blood fluid

Vitamin E

• Two subgroups: tocopherols and tocotrienols - Each contains four members: alpha, beta, gamma, and delta § Position of methyl group - Only alpha-tocopherol maintained in the body • Antioxidant - Stops chain reaction of free radicals § Protects cells and their membranes o Prevents oxidation of poly unsaturated fatty acids (PUFAs) § Heart disease and protection of LDLs

Vitamin A and Beta-Carotene

• Vitamin A - First fat-soluble vitamin recognized - Precursor: beta-carotene • Three different forms - Retinol, retinal, and retinoic acid § Conversion to other forms • Absorption and conversion - Beta-carotene