Chapter 13

Roles of vitamin K

-Activation of many of the proteins involved in blood clotting, including prothrombin -When any of the clotting factors are missing hemorrhagic disease results -Vitamin K however is not always the cause of hemorrhage, other possible causes include hemophilia -Hemophilia: a hereditary disease caused by a genetic defect which has no relation to vitamin K -participates in the metabolism of bone proteins (ex. Osteocalcin) -Without vitamin K, abnormal proteins that are unable to bind to minerals are produced. -This results in decreased bone density

Osteomalacia

-Adult form of rickets -A bone disease characterized by softening of the bones -Symptoms include bending of the spine and legs -Women who have had multiple pregnancies and lactation with very little sunlight high at risk

Canadian Cancer Society statement on Vitamin D

-Adults in Canada - 1000 IU supplement/day fall & winter -1000 IU supplement all year for adults who are over 50, have dark skin, don't go outside often and those who wear clothing that covers most of their skin -No change to the Sunsense guidelines: SPF 15 or higher, SPF 30 if you work or spend a lot of time outdoors.

Magnesium deficiency

-Although Canadians appear to eat less than the recommended, deficiency symptoms are rare - may be due to hard water -May occur in alcohol abuse, protein malnutrition, kidney disorders, prolonged vomiting and diarrhea -May cause impaired central nervous system activity, hallucinations

Vitamin D toxicity

-Among the most likely of the vitamins to have toxic effects when consumed in excess -Excess from supplements raises the concentration of blood calcium which can -Result in precipitate forming in soft tissue ex. kidney stones -Calcification may also harden the arteries -No risk of excess from the sun

Magnesium

-Barely qualifies as a major mineral because of its small amount in the body -1/2 of the body's magnesium is in the bones, majority of remaining is in muscles and soft tissues, 1% is in extracellular fluid -Significant sources are legumes, nuts, seeds, whole grains, dark green vegetables, seafood, chocolate and cocoa

Major minerals in a 60kg body

-Calcium 1150 grams -Phosphorus 600 grams -Potassium 210 grams -Sulfur 150 grams Sodium 90 grams -Chloride 90 grams Magnesium 30 grams

Body's handling of minerals

-Can greatly differ between minerals -Potassium is easily absorbed, transported freely and excreted readily by the kidneys -Calcium requires a carrier for transportation and absorption -Some minerals can be toxic in very high levels -Have varying bioavailability in food -Binders can combine with nutrients, absorption is prevented -Phytates are primarily in legumes and grains -Oxylates found in rhubarb and spinach

Fluoride toxicity

-Can result in fluorosis -Discolouration and pitting of tooth enamel caused by excess fluoride during tooth development -Only occurs during tooth development and cannot be reversed -To prevent should supervise toddlers and ensure that they don't swallow toothpaste -Use supplements only if prescribed by a doctor

Health Canada statement

-Canadians over 50 -400 IU supplement/day

Calcium toxicity

-Constipation -Increased risk of urinary stones and kidney dysfunciton -Interference with absorption with other minerals

Blood

-Continually moving -Deliver of nutrients -Removal of waste products -Only takes about one minute for blood pumped from the blood to circulate the body -5 to 5.5 litres of blood in average person

Vitamin D recommendations

-DRI committee set recommendations based on not receiving any from the sun, recommendations have recently been increased -Food sources are fortified milk, butter, margarine, egg yolks, liver, fatty fish -Vegans require sunlight or fortified foods

Vitamin D deficiency

-Factors which contribute to vitamin D deficiency include dark skin, breastfeeding without supplementation, lack of sunlight -Not using fortified milk With vitamin D deficiency, production of calbindin (a protein that binds calcium in the intestinal cells) slows, leaving bones under supplied with calcium -A vitamin D deficiency creates a calcium deficiency - increasing risk of osteoporosis -Common in the elderly because capacity of skin, liver, and kidneys decline, drink little milk, spend more time indoors

Fluoride

-Fluoride is present in almost all soils, water supplies, plants and animals -Only a trace of fluoride occurs in the human body, but the crystalline deposits are important to bones and teeth -During mineralization of bones and teeth, calcium and phosphorus form crystals called hydroxyapatite. -Fluoride replaces the OH of the hydroxyapatite forming fluorapatite which makes bones stronger and teeth more resistant to decay -Drinking water is often fluoridated -Sources are fluoridated water, seafood, and tea

Vitamin D other roles

-Immune system -Brain and nervous system -Pancreas skin, muscle and cartilage -Reproductive organs -Vitamin D enhances or suppresses the activity of genes that regulate cell growth -Vitamin D may protect against tuberculosis, inflammation, multiple sclerosis, macular degeneration, hypertension, and some cancers -Evidence does not support taking supplements above correcting deficiencies

Nutrient interactions

-Interactions can affect absorption, metabolism and excretion -Sodium and calcium have interactions when sodium intake is high causing both to be excreted -Phosphorus binds magnesium in the GI tract therefore magnesium absorption is limited when phosphate intake is high

Trace minerals in a 60kg body

-Iron 2.4 g Zinc 2.0 g Copper 0.09 g Manganese 0.02 g Iodine 0.02 g Selenium 0.02 g

Vitamin K toxicity

-Is not common - No established UL -High doses of vitamin K can interfere with some anticoagulation drugs -Those on certain anticoagulant drugs should eat vitamin K foods in moderation and keep amounts constant

Roles of magnesium

-Major roles is to act as a catalyst for energy metabolism -Bone health -Acts along with calcium in muscle contraction and blood clotting -Supports normal functioning of the immune system -Prevents dental carries by holding calcium to the enamel of the teeth

Roles of vitamin D

-Member of the bone making and maintenance team -Helps to maintain blood concentrations of calcium and phosphorus -Vitamin D raises blood concentrations of these minerals in three ways ( enhancing their absorption from the GI tract when the diet is sufficient, enhancing their reabsorption by the kidneys when the diet is insufficient, enhancing mobilization from the bones into the blood when the diet is insufficent)

Calcium

-Most abundant mineral in the body -Roles are mineralization of bones and teeth, muscle contraction, nerve function, blood clotting, blood pressure -Deficiency leads to stunted growth, bone loss (osteoporosis) -Sources are milk, fish with bones, calcium set tofu, greens and legumes, fortified milk products

Vitamin K

-Phylloquinone (natural form); menadione (synthetic form) -Can be produced by bacteria in the GI tract, it is then absorbed and stored in the liver -Vitamin K gets its name from Danish word "koagulation" -GI tract only synthesizes about half the required amount Significant sources are liver, green leafy vegetables and cabbage-type vegetables, milk, canola oil

Vitamin K deficiency

-Primary deficiency is rare -Secondary deficiency -Can occur with fat malabsorption, -Can occur when drugs disrupt synthesis -Antibiotics can kill the vitamin K producing bacteria in GI tract. -Newborns receive a dose of vitamin K because of a newborns sterile GI tract

Magnesium toxicity

-Rare, but can be fatal -Only occurs with supplements or salts -Symptoms are diarrhea, alkalosis, dehydration

Phosphorus

-Second most abundant mineral in the body (behind calcium) -85% of it is found combined with calcium in bones and teeth to strengthen bones -Phosphoric acid is part of buffer system in cells -Part of DNA and RNA which necessary for all growth -Necessary for activation of many enzymes and B vitamins -Phospholipids are in the phosphate group -Significant sources are meat, milk, fish, poultry, eggs

Rickets

-Still affects many children world wide -Prevalence is extremely high in Mongolia, Tibet, and Neitherlands -Found in Canada in Northern Territories and those breastfed without Vit D. -Deficiency symptoms are inadequate calcification of bones, bowed legs (bones bend under body weight), enlargement of the ends of long bones, deformities of the ribs, delayed closing of the fontanel thus rapid enlargement of the head, lax muscles

Osteoporosis Canada statement

-With osteoporosis or at high risk -800 IU -2000 IU supplement daily regardless of age -Doses above that level may be prescribed by a doctor -No osteoporosis under 50: supplements of 400 - 1000 IU daily -Over 50: supplements of 800 - 2000 IU daily

Osteoporosis

Inadequate vitamin D production or inadequate Vitamin D intake provides opportunity for calcium to be leached from bones, and fractures can result

Vitamin D

Other name is Calciferol -Nonessential nutrient -Body can make it from sunlight -Precursor comes from cholesterol (converted by UV light, then activated through a reaction in the liver, then in the kidneys) -Both vitamin D2 (plant food) and D3 (animal food) must be activated -Hormone -Has a carrier protein that transports it to its target organs like the intestines, the kidneys and the bones which respond by making minerals avialble