Flashcards in Final Deck (148):
What is the definition of fluid?
- Molecules are far enough apart that they can slide past each other
- Conforms to shape of container
- Retains a nearly constant volume independent of pressure
How much fluid is in the human body?
- 60% fluid (decreases as we age) with electrolytes
- In blood (90% water), muscle (75%), bone (25%), fat (10%)
What are intra and extracellular fluids?
- Intracellular fluids: fluid within cells (eg. inside RBC, mucous membrane)
- Extracellular/interstitial/tissue fluid: fluid located outside of cells (eg. blood)
What are the functions of fluids?
1. Dissolve and transport substances
- Carbohydrates, amino acids, water-soluble vitamins, minerals, medications
- Fat-soluble substances are transported with transport proteins (chylomicrons, lipoproteins, albumin)
2. Protect us
- Cerebrospinal fluid cushions brain from damage
- Amniotic fluid protects the developing fetus
- Saliva, tears, and mucus moistens us
- Synovial fluid in joints protect joints from going bone on bone
4. Maintain body temperature at 37 C
- Water keeps us from overheating and dying
- If hot, blood vessels bring up more blood (vasodilation) which evaporates as sweat
5. Involved in chemical reactions
- Hydrolysis: water breaks 2 molecules apart
- Condensation: water is released when 2 molecules are joined
What is water balance?
- State of equillibrium in which fluid intake from water/foods = fluid losses from GI tract, urine, sweat, and other secretions
Where does water intake and loss come from?
- Mainly beverages, 1/4 from foods
- Some released during making triglycerides/peptide bonds + metabolism
Urine, feces, evaporation, sweat, breath, insensible losses (unaware)
How is water intake/loss regulated?
- Hypothalamus receives signals to drink
- High solute concentrations in blood, low blood volume/pressure, dryness in mouth
- Low blood volume/increased solute = thirst centre in brain + saliva secretion is reduced = thirst = blood volume increases when drink
- May get confused with hunger message
- Blood becomes concentrated
- Antidiuretic hormone (ADH) is released
- Tells kidneys to retain water = no urination
What are the fluid recommendations?
AI (no RDA): women need 2.7 L, men 3.7 L
What is dehydration? How is it measured and who is susceptible?
- Excrete more water than take in
- Measured using change in body weight
- Susceptible: infants and children (increased body surface area and metabolic rate), older adults (decreased sensitivity for thirst), athletes (sweat losses)
What is mild, moderate and severe dehydration?
1. 1-2% decrease in body weight
- Loss of appetite, crankiness, headaches, faintness, tiredness, dry eyes and mouth, dark urine
2. Moderate dehydration is loss of 3-5% of body weight
- Sleepiness, nausea, headache, decreased concentration, decreased cognitive functions
3. Severe dehydration is greater than 7%
- 10-20% loss of body weight can cause death
What is overhydration?
- Caused by too much fluid without enough sodium in diet
- Hyponatremia: low sodium per volume
- Swelling of tissues occurs (water moves out of blood vessels into interstitial spaces)
- Can lead to brain swelling, seizures, coma, death
- Rare, usually has kidney disfunction
What are electrolytes? Where are they found?
- Dissolved mineral ions with + or - charge
- Allows water to be drawn in (Na+) or out (K+) of cell/blood vessels
- Found in all foods (potassium, sodium, calcium)
What do electrolytes do? What are symptoms of not enough and how is it caused?
- Regulate fluid balance through osmosis
- Allows nerves to work
- Allows muscles to contract
- Imbalance = poor appetite, muscle cramps, confusion, irregular heartbeat
- Can occur due to kidney disease, vomiting, diarrhea, sweating, IV fed hospital patients
How are electrolyte levels in blood regulated?
- Controlled by kidneys
- Decrease in blood pressure due to low electrolytes = kidneys release enzyme renin = converts angiotensin I to II = secretion of aldosterone, increasing sodium retention + constriction of blood vessels = pull in water = reestablish blood pressure
What is sodium for? What are high sodium foods?
- Required for nerve signals, fluid balance, blood pressure (increase), nutrient transport
- High sodium foods: dill pickle, cured ham, tomato juice, canned cream-style corn, canned tomato soup, salted potato chips and saltine crackers
What are the recommendations for sodium? What are the risks and the process for this risk?
- Most Canadians consume more sodium (2400 mg/day) than UL (2300 mg/day)
- Increases risk of hypertension
- High sodium intake = increases blood sodium levels = fluid retention = increase in blood volume and pressure
Most individuals: kidneys excrete sodium, water follows = normal pressure
Salt-sensitive individuals: slow sodium excretion OR sodium prevents dilation of blood vessels = high blood pressure persists
What is hypertension? What are the process?
- 20% of Canadians have hypertension
- 70% of those over 80 (elasticity decreases with age)
- 20% of people with hypertension do not know
- Higher risk for heart attacks, stroke and kidney disease
- Causes include genetics, age, family history, lifestyle factors
What are vitamins and minerals?
- Vitamins: organic molecules (C) our body needs to function
- Minerals: inorganic molecules (metals) our body needs to function
- Do not provide us with energy, but necessary
What are water soluble vitamins? How are they absorbed and transported?
- B vitamins or vitamin C
- Some absorption in stomach
- Transported into intestinal cells using facilitated diffusion or active transport
- Transported in body bound to blood proteins
- If too much, excreted in urine
- In natural form, do not build up
What are fat soluble vitamins? How are they absorbed and transported?
- Vitamins A, D, E, and K
- Require dietary fat for absorption
- In stomach, digestion occurs and some niacin is absorbed
- Gallbladder releases bile to emulsify fat
- Absorbed into intestinal cells in small-intestine through simple diffusion (micelles) and packaged into active chylomicrons which enter lymph before passing through blood to liver
- Transported in body as lipoproteins or bound to transport proteins
- Stored in fat in body, accumulation can be dangerous
What is fortification and enrichment?
1. Fortification: process of adding nutrients to food
- Examples: table salt with iodine (thyroid), milk with vitamin D (rickets), grains with thiamin, riboflavin, niacin, iron, and folic acid
2. Enrichment: adding nutrients back to foods that were lost in processing
- Flour, “white flour”, “enriched flour”, or “enriched white flour” is enriched (mandatory) with thiamin (B1), niacin (B3), folic acid (B9), and iron
What are the B vitamins? What do they do?
- B1 (thiamin), B2 (riboflavin), B3 (niacin), B5 (panththenic acid), B6 (pyridoxine), B7 (biotin), B9 (folate or folic acid), B12 (cobalamin)
- Conenzyme vitamins that help enzymes function
- Involved in energy production (burning carbohydrates, fat protein)
- Involved in energy metabolism
- Vitamin combines with chemical group to form functional coenzyme
- Functional coenzyme combines with incomplete enzyme to form active enzyme
What is B1? What are its functions, sources and RDA?
- Needed to burn glucose for energy
- Needed for carbohydrate and protein metabolism (converts amino acid or glucose to acetyl CoA)
- Found in whole grains, pork, yeast extract, nuts, legumes, flaxseeds
- RDA: 1.1 mg/day for women and 1.2 mg/day for men
What is Beriberi? Why does it occur, what are the consequences?
- Profound weakness
- Lack of thiamin
- Most commonly occurs due to alcoholism (damages GI cells, decrease absorption)
- Causes lethargy, fatigue, depression, cardiovascular problems
- Nerve damage: dementia, confusion, memory loss
- Became common in Asia when white rice was introduced
What is B9? Where is it found and RDA?
- Found in lentils, asparagus, spaghetti, liver, spinach, brussel sprouts, romaine lettuce, avocado
- RDA: 400 mcg/day
- DFE: dietary folate equivalents
- 1 mm of folate from food = ½ mm of folate from vitamin/fortified foods
What is folic acid? What are the consequences and where is it found?
- Synthetic form used to fortify foods in Canada
- White flour, corn meal, pasta, infant formula, cereals, instant breakfasts, meal replacements, supplements
- 2 x DFE
- Less handled in the body and not as water-soluble
- Neural tube defects decreased since food fortification of folate, however increase in colon cancer
What is the function of B9? What are the consequences of not enough?
- DNA synthesis (with B12) and metabolism of some amino acids
- Neural tube defects in pregnancy or anemia (RBC is affected)
- Defects in brain are fatal, those of spinal cord result in paralysis
- Low folate intake is associated with increase risk of heart disease
What is B12? Where is it found, how is it absorbed and what does it do?
- Found almost exclusively in animals (yeast)
- Absorbed in small intestine bound to intrinsic factor (helper chemical produced by parietal cells)
- Required for myelin sheath, DNA, red cell production (hemoglobin)
- Deficiency can cause low red cells, white cells or platelets, neurological and psychiatric symptoms, anemia
Absorption affected by genetics (transport proteins), GI health (celiac disease or IBD is at high risk), alcohol, or medications:
- Metformin (for diabetics)
- Proton pump inhibitors (to lower stomach acid)
- Oral contraceptives
- Cholesterol medications
What is vitamin C? Where is it found? How is it destroyed?
- Major water soluble antioxidant
- Donates electrons to free radicals
- Helps to protect DNA, lipids, cells and tissues from damage
- Found in oranges, kiwis, strawberries, cantaloupe, broccoli, tomato
- Supports the immune system
- Coenzyme required to make collagen (connective tissue), bile acids, neurotransmitters, thyroid and steroid hormones
- Destroyed at high temperatures (>190 C)
- Boiling, steaming, roasting or stir-frying is OK, but baking may
What is scurvy?
- Occur after 3 months with little or no vitamin C
- Bleeding gums, loose teeth, easy bleeding, impaired wound healing, swelling, bone pain, diarrhea
What is oxidation?
- We need oxygen to burn energy
- During energy metabolism, this oxygen sometimes forms free radicals (reactive oxygen molecules) which is unstable
- Phospholipids (cell membrane), LDL and proteins can be oxidized
- More oxidation over long-term increases risk for progression or degenerative diseases such as heart disease, cancer, diabetes, arthritis, cataracts, kidney disease, Alzheimer’s and Parkinson’s disease
What are the recommendations for vitamin C?
- Infants (0-6 months): 40 mg/day for males (AI) and 40 mg/day for females (AI)
- Children (4-8 years): 25 and 25
- Adolescents (14-18): 75 and 65
- Adults (19+): 90 and 75
- Smokers (19+): 90 and 75
- Some people may need more than RDAs
- You can get increase in kidney stone risk or diarrhea if too much
Where is vitamin A found? What are the forms?
- Found preformed in animal products (milk, eggs, meat, cheese, butter, LIVER) or supplements or in precursor form from plant foods
- Preformed = retinoids (retinol, retinal, retinoic acid)
- Precursors = carotenoids (eg. beta-carotene)
- Strongly colored red-orange pigment
- Found in mango, papaya, sweet potato, pumpkins
- Our body converts to retinoid
- Too much may increase risk of certain cancers
What are the functions of vitamin A?
- Conversion required with vitamin A as cofactor
- If not, cannot go forwards in cycle of eyesight and block recycling of rhodopsin and alteration in vision function
2. Cell differentiation
- Vitamin A ensures young stem cells turn into the right cell
3. Maintenance of epithelial tissue (skin, lining of eyes, digestive tract, lungs)
- Ensures that epithelial cells differentiate properly
- Signs of deficiency include bumps on back of arms or changes in skin in eye
- Vitamin A in vulnerable populations can reduce morality and blindness
- Regulates cell differentiation for development of embryo and growth of child
- Excess can be toxic to fetus and cause miscarriages or malformations
5. Protect against free radicals
- Beta-carotene is antioxidant
- May prevent cancer, heart disease, macular dengeration, cataracts and others
What are the recommendations of vitamin A?
- RAE: retinol activity equivalent
- How much retinol would precursor be equal to if 100% converted
- RDA: 900 RAE or ug/day for men and 700 RAE for women
- UL of preformed vitamin A is 3000 ug/day (RAE = 10000 IU)
- Builds up in the body
- Preformed vitamin A can be toxic if too much
- Vitamin A medications (eg. retin A, accutane) can cause serious side effects
How does vitamin A deficiency come about and what does it result in? Discuss zinc.
- Can be caused by insufficient intake of vitamin A, fat (fat-soluble vitamin), protein (transport) or zinc
- Results in night blindness, poor growth, or xerophthalmia (dry eyes)
- Zinc: necessary for transporting vitamin A in blood, required for retinol to be converted to retinal (rhodopsin; eye protein that abosbrs light)
- Deficiency is associated with decreased release of vitamin A from liver
What occurs if you have too much vitamin A?
- Loss of appetite
- Blurred vision
- Pain, nausea
- Liver and other organ damage
- Birth defects in the babies of pregnant women
- Cleft lips, eye defects, cleft palates, etc.
What are the forms of vitamin E, where is it found and what is the RDA?
- Tocopherol and tocotrienol forms
- Alpha-tocopherol: form absorbed by human body (active form)
- Powerful antioxidant properties
- Found in plant oils, nuts, seeds, leafy green vegetables
- RDA is 15 mg/day
What is the function of vitamin E?
- Vitamin C donates electrons back to vitamin E to recycle it so it can be used to repair another lipid environment
What are tips for utilizing vitamin E to the max?
- Vitamin E can be destroyed by oxygen, light, heat (don't fry oils) = more potential for free radical formation
- Keep oils in dark, cool place
- Vulnerable PUFAs in coloured bottles
- The more unsaturated fatty acids (PUFA), the easier oxidized
- This is why saturated fat/trans fat have longer shelf life, old fish smells rancid, frying in oil with high heat can smell bad
- Need antioxidants like vitamin E to protect those fats
Discuss vitamin E toxicity.
- Occurs with synthetic forms of vitamin E, not food
- Doses would have to be huge
- UL: 1000 mg/day
- 1 mg = 1.1 IU
- Causes nausea, upset stomach
Discuss vitamin E deficiency.
- Due to low intake or fat malabsorption or low fat intake
- Nerve damage: impaired vision, speech, movement, leg cramp (myelin sheath needs fat)
- Hemolytic anemia: breaking blood cells (membranes made of lipids)
Discuss low intake of vitamin E (how it comes about, consequences).
- Majority of North Americans have low vitamin E levels
- Consequences: greater risk of heart disease (oxidized LDL = plaque)
- Eating lower quality fat
- Low fat diet
- Cooking methods of frying in oil
What is the link between cardiovascular disease and vitamin E?
Vitamin E reduces:
- Inflammation of blood vessels, lead to plaque flaking off
- Stickiness or clumping of platelets within blood vessels
- Oxidation of LDL cholesterol
However, no evidence to suggest would help us even though deficient
What is vitamin D, the forms and sources?
- “Sunshine vitamin”
- Conditionally essential: we can make it ourselves
- Produced in skin by exposure to UV light
- Occurs as cholecalciferol-vitamin D3 or calcitrol (active form, 1,25-dihydroxyl vitamin D3)
- Food sources include fatty fish, liver, egg yolks (contain cholecalciferol)
- Farmed salmon has less vitamin D than wild
- Most come from fortified beverages (milk, soy/almond milk, orange juice)
How is vitamin D synthesized?
1. Vitamin D from diet and from synthesis in skin is inactive until chemically altered in liver and then in kidney
- Type of cholesterol involved in creating vitamin D is 7-dehydrocholesterol
- 7-dehydrocholesterol in skin with sun = cholecalciferol (vitamin D3)
2. Liver: hydroxy group (OH) added to form 25-hydroxy vitamin D3 (calcidiol) which circulates in blood
3. Kidney: another OH added to form active 1,25-dihydroxy vitamin D3 (calcitrol)
4. Low levels of active vitamin D stimulate calcium absorption from the intestine
- Higher levels act with parathyroid hormone (PTH) at bone to increase bone breakdown and at kidney to increase calcium retention
- Blood calcium and phosphorus are maintained at levels that support bone mineralization
What are the benefits of vitamin D?
1. Bone health
- Maintain good levels of calcium and phosphorus in blood by PTH
- Helps absorb, retain and regulate levels of calcium
2. Mental health
- Vitamin D is associated with pathology of cognition and mental illness
- Associated with therapeutic effect for autoimmune diseases
4. Role in cancer prevention
- Prevent cell mutation and inhibit cancerous cell proliferation
- Increase cystatin D, which possesses antitumor and antimetastatic properties
5. Immune system
- Help body fight viruses/infections
How gets less vitamin D absorption?
- People with darker skin
- People who live far from equator (North)
- Elderly (fewer vitamin D making compounds in skin)
- People who wear sunscreen or cover all skin
- People who work inside from 10am to 3pm
What are vitamin D recommendations?
- RDA for men and women up to 70 years of age is 600 IU/day or 15 ug/day
- RDA for 70+: 800 IU/day or 20 ug/day
- UL for those over 9 years: 4000 IU/day or 100 ug/day
- Studies haven’t been able to show vitamin D to help, so RDAs are moderate
What is vitamin D toxicity? Mention hypercalcemia.
- Not possible from sun exposure
- Rarely from supplements
- Vitamin D alters % of calcium absorbed from gut
- Hypercalcemia: high blood calcium levels
- Calcium is deposited in organs or excreted through kidneys (stones)
- Excess is stored in fat deposits and liver
What is vitamin D deficiency?
Vitamin D affects calcium levels
1. Rickets (wrickken)
- Common in children in cities in which pollution blocked sun
2. Osteomalacia: in adults, soft bones
- Unchanged total bone mass (altered ratio)
- Symptoms include poor mineralization, bowed legs, bone pain, muscle aches and weakness
- Most common in older adults
- Low calcium, vitamin D, phosphorus, and magnesium and low levels of exercise over time
- Loss of bone mass, become more porous
- Deterioration of bone tissue, increase in bone fragility
- Decreased mineral content does not necessarily change integrity of bone matrix (strength)
- May cause pain, disfigurement, low self-esteem, fear of falling, and loss of mobility (skeletal structure is altered)
- Altered ratio between matrix and mineral
- AND less matrix and mineral
What is the function of bones and the nutrients that play a role in bone health?
1. Structure and support for organs, and body segments
- Protection of brain and internal organs
- Muscle support for movement
2. Metabolic processes
- Mineral storage
- Production of blood cells in bone marrow
- Major roles: vitamin D, calcium, phosphorus
- Minor roles: magnesium, vitamin K/A, protein, fluoride, zinc
Discuss changes in bone over time and the factors.
1. Childhood and adolescence: bones grow in size
2. 20-30 years old: peak bone mass
- Having high peak bone mass may protect against osteoporosis
3. Adulthood: bone mass levels out
- Stays stable with exercise
- May lose bone slowly after 35
4. 50+: bone mass declines significantly
Factors: medications, diet, exercise
- Women have accelerated bone loss after menopause because estrogen is involved in maintaining bone mass
- Zinc supplementation can reverse bone loss
- High calcium foods can block zinc absorption
What is bone remodelling?
- Body constantly breaks down and builds up bones to keep them strong
- Bone resorption: breakdown of bone by osteoclasts (bone cells)
- Bone formation: formation of bone by osteoblasts (Bone cells)
- As you grow when younger, osteoblasts work faster; you gain bone
- As you age, osteoclasts work faster; you lose bone
How is bone health measured?
- Done with dual energy x-ray absorptiometry (DEXA)
- Measures bone mineral density (BMD)
- Bone mineral content (g)/bone area (cm2)
- Monitors changes over time
- Used to diagnose osteoporosis
Discuss gender and bones.
Women have higher risk of osteoporosis than men:
- Lower peak bone mass
- Longer life expectancy
- Post-menopausal bone loss due to low estrogen levels
What is vitamin K, its functions and recommendations?
- Coenzyme needed for production of blood-clotting protein prothrombin and other blood-clotting factors
- Blood-clotting factors are activated with vitamin K (formation of fibrin from fibrinogen)
- Men: 120 ug/day
- Women: 90 ug/day
What are the forms of vitamin K?
1. Phylloquinone (K1)
- Found in plants (green leafy veggies, kale, spinach, kiwi, soybean oil, olive oil)
- Primary form in diet
- Participates in blood clotting
2. Menaquinones (K2)
- Found in fish oils and meat (butter, lard, animal-based food)
- Synthesized in large intestine by bacteria or supplements
- Involved in Ca transport and can improve bone density
What are the major and trace minerals?
Major minerals: you need more than 100 mg/day
- Calcium, phosphorus, and magnesium
Trace elements: you need less than 100 mg/day
- Iron, zinc, copper, selenium, iodine
What are the functions of minerals?
1. Structural roles
- Calcium, magnesium, phosphorus, and fluoride are needed for bone structure
2. Regulatory roles
- Iodine is used to make thyroid hormones
- Iron is needed for oxygen transport in red blood cells
- Many minerals are needed as cofactors for enzymes (eg. zinc)
What is the composition of bone?
- Hydroxyapatite (calcium and phosphorus crystals) is bone mineral
35% organic substances:
- Collagen (a fibrous protein)
What is calcium, and where is it found? How much is absorbed?
- Most abundant mineral in body (1-2% of body weight)
- Found in milk, fortified foods, fish with bones, tofu, nuts and seeds, dark green veggies (kale, bok choy, chard, broccoli)
- Only 25% of calcium in foods is absorbed
- Less if you have low vitamin D (10%)
What are the functions of calcium?
1. Strong bones
- 99% of calcium stored in bones and teeth
- Critical part of hydroxyapaptite crystals
- Provide strength to bones
- 1% of calcium in blood as electrolyte
- Muscle contraction, blood clotting, nerve signal transmissions, blood pressure regulation
How is calcium regulated in the body?
Body controls blood calcium levels closely
1. High blood calcium (medication or illness) = signal to thyroid to produce calcitonin = inhibit calcium release from bone
- Too much calcium: body stops absorbing it
- Kidneys excrete in urine
- Can be deposited in soft tissue = calcification of heart, blood vessels and kidneys (more likely if supplement)
2. Low blood calcium = parathyroid glands = parathyroid hormone = stimulates calcium release from bone + calcium reabsorbed by kidney + activates vitamin D (increase calcium absorption)
- Blood level test does not reflect dietary intake
- Not enough calcium: blood calcium will be stable but bones will weaken over time
What are the recommendations for calcium? What blocks calcium?
- 13-18: 1300 mg/day for men, 1300 mg/day for women
- 19-50: 1000, 1000
- 51-70: 1000, 1200
- 70+: 1200, 1200
- Spread calcium throughout day
- Intestines can only absorb 30% worth of calcium at a time
- Oxalates (green vegetables), phylates (whole grains and legumes) and tannins (tea) decrease absorption
- Broccoli and especially spinach isn’t absorbed as well as kale, milk and yogurt
- Avoid taking zinc, iron, or magnesium supplement as calcium will block absorption of these
- Don’t take with multivitamin
- When taking a supplement, choose calcium citrate or malate
- Calcium carbonate (Tums) is cheapest
- Taken with food = increased absorption
Where is phosphorus found?
- 85% phosphorus is found in bones and teeth
- Part of hydroxyapatite crystals along with calcium
- Found in almost everything we eat
- Foods highest in phosphorus is high protein foods (milk, cheese, legumes, egg, meats)
- Added to baked goods, cheese and carbonated beverages
- About 60-70% absorbed from typical diet
What is the function of calcium?
- Cell membranes (in phospholipids)
- Energy metabolism (ATP, creatine)
- Activates enzyme in metabolic reactions
- Important for DNA and RNA
- Cell signaling (electrolyte)
- Acid-base balance (helps regulate pH within cells)
What is calcium deficiency?
- Usually not caused by low dietary intake but medical condition
- Low energy diet, low protein diet, poor absorption due to improper functioning of GI tract
Most common in:
- Premature infants
- Elderly (low stomach acid to break down nutrients)
Discuss the interaction between phosphorous and calcium.
- High phosphorus, low calcium diet can interfere with calcium absorption
- Like calcium, phosphorus intake doesn’t affect blood levels
- Tight regulation by mechanisms
Where is magnesium found?
- Found in most foods, so acute deficiencies are rare
- Best sources: whole grains, leafy green vegetables, nuts, seeds and beans
- In reality, North America has deficient soil so we are inadequate in magnesium
What are the functions of magnesium?
- 50-60% of our body’s magnesium is in the bone
- Influences hydroxyapatite formation
- Regulates the transport of calcium and potassium ions across cell membrane
2. Cofactor for over 300 enzymes
- Required for necessary chemical reactions
- Enzymes control energy production, building DNA and proteins, blood pressure and regulation (high magnesium = lower blood pressure) and muscle contractions
Discuss too much or too little magnesium.
- Too much = supplements
- Diarrhea, nausea, cramping
- Acute deficiencies are rare
- Low intakes are associated to increase risk of osteoporosis, type 2 diabetes, high blood pressure and migraines
What are the forms of iron?
- In meat, poultry, fish, and seafood
- The best absorbed form of iron
- Component of hemoglobin (4 hemes) and myoglobin (1 heme)
2. Non-heme iron
- Found in beans, lentils, grains (whole wheat, brown rice), dried fruits, vegetables (spinach and broccoli), fortified cereals
- Difficult to absorb
- Take with vitamin C and meat products to enhance absorption
- Calcium (can also inhibit heme iron), phytates (in whole grains, beans, legumes, nuts, seeds), tannins (tea) and fibre can inhibit absorption
- You can also increase iron content of your food using a cast iron pot and an iron fish.
What is hemoglobin and its functions?
- Found in red blood cells
- Transports oxygen to body cells
- Carries carbon dioxide away from cells for elimination by lungs
- 70% of body’s iron is in the form of hemoglobin
- Iron binds oxygen molecules to hemoglobin
- Hemoglobin carries iron and oxygen everywhere in the body
- Your body cannot make hemoglobin without iron
- Your body cannot transport oxygen without iron
What is myoglobin and its functions?
- Found in enzymes that are needed to metabolize energy from CHO, fat and protein (eg. cytochromes in ETC)
- Essential for energy production
- Transports oxygen within skeletal and heart muscles
- Enhances the amount of oxygen available for use in muscle contraction
What is cyanide and what does it do?
- Poison found in hydrogen cyanide gas (smoke from fire), cyanide salts in metal polishing materials, certain insecticides and seeds (eg. apples)
- Binds to iron in cytochromes and stops cells from using oxygen
- Results in death
How is iron regulated in the body?
- Controlled at intestine
- Iron enters mucosal cells of small intestine from food
1. Found in iron storage protein mucosal ferritin
- Excreted in feces when mucosal cells die
2. Picked up by iron transport protein transferrin
- Transported in blood to liver, bones and other body tissues
How is iron stored?
- Excess iron that is transported out of mucosal cells can be stored in protein ferritin (not mucosal)
- Stored in liver, spleen, and bone marrow
- Available to human at later time
- When ferritin concentrations in liver become high, some are converted to hemosiderin (iron-storage protein complex in cells) = not available
How is iron lost?
- Not readily excreted
- When RBC die, iron is removed and transported back to the bodies’ tissues
- Most loss comes from blood loss in healthy individuals
- Some iron is also lost through shedding of cells from intestine, skin and urinary tract
What are the recommendations for iron?
- Women (19-50): 18 mg/day
- Menstruation = loss of blood
- Men (over 19) and postmenopausal women: 8 mg/day
- Pregnant women: 27 mg/day
- Expansion of red blood cell mass and transfer of increasing amounts of iron to fetus and placental structures
Increase in oxygen consumption by mother and fetus
- Vegetarians and vegans: plant sources are less bioavailable
- Men and post-menopausal women: 14 mg/day
- Menstrating women: 32 mg/day
What are the components of blood?
1. Plasma - 55%
- Fluid compartment of blood
- Water with electrolytes, minerals, vitamins and other solutes
2. Red blood cells (erythrocytes) - 45%
3. White blood cells
- Part of immune system
- With platelets, makes up less than 1% of blood volume
- Blood clotting
What are the functions of blood?
- Transport oxygen and nutrients
- Removes waste products
- Blood clotting factors (platelets)
- Immune system (white blood cells)
What is healthy blood?
- Transport everything efficiently
- Unhealthy blood doesn’t transport oxygen and/or nutrients well (often due to problems with red blood cells)
What are red blood cells? Link to iron.
- Contains hemoglobin (binds oxygen and delivers to cells)
- Oxygen transport doesn’t happen if too few red blood cells (low hemoglobin) or damaged red blood cells
- Too few red blood cells = iron deficiency anemia
What is iron deficiency?
- Too little iron/hemoglobin
- Adequate: good stores, good circulation, good hemoglobin
- Stage 1: low iron stores (ferritin)
- Symptoms may appear
- Stage 2: low circulating iron (low serum iron) and low red cell indices (MCH, MCV)
- Stage 3: low hemoglobin
- Stores are depleted
- Insufficient iron to maintain total hemoglobin in sample of blood
- Iron deficiency anemia: microcytic anemia
- Tired, pale skin, low immune function, brain fog, lack of concentration, depression
What is PICA?
- Compulsion to eat nonfood items
- Strange symptom related to iron deficiency
Discuss iron worldwide.
- Most widespread nutrient deficiency
- Price and availability of food sources
- Malaria and parasites increase iron needs
- Women and children in lower resource countries are at risk
- Poor pregnancy outcome for mothers and children
- Impaired physical and cognitive development
- Poor immune function for children
Discuss iron research.
- Iron deficiency alters metabolism, neurotransmission, myelination and gene and protein profiles
- Infants with iron-deficiency anemia are at risk for poorer cognitive, motor, social-emotional and neurophysiologic development
- Improvement in serum ferritin was associated with 500-700% improvement in cognitive performance
- Improvement to hemoglobin was related to improved speed in completing cognitive tasks
- Iron deficiency decreases athletic performance and impairs immune function, and increases risk for mental illness
- Iron deficiency may protect against malaria infection and morality
Discuss excess in iron.
- Can’t be caused by foods
- Accidental overdose due to supplements common in children under 6
- Stomach pain, dizziness, confusion, rapid heart beat, organ damage
What is the most abundant intracellular trace element?
What are the functions of zinc?
1. Required for enzymes important for:
- Carbohydrate metabolism
- DNA and RNA synthesis
2. Helps regulate:
- Immune function
- Sexual maturation
- Bone development
- Cell division (tissue growth and repair)
3. Structural role in specific transcription factors
- Finger-like structures called zinc fingers allow nuclear protein receptors that bind to vitamin A, D, and hormones interact with regulatory region of gene and affects gene expression
*People with down syndrome need for zinc as produce more superoxide dismutase which needs zinc
How is zinc regulated?
Low zinc → more zinc moves from lumen into mucosal cells + from vesicles into cytosol → little metallothionein is synthesized → more zinc enters blood circulation
High zinc → less zinc moves from lumen into mucosal cells → more metalloinein is produced → binds zinc to stop more from going into blood
What are the recommendations for zinc?
- Men (19+): 11 mg (mixed) or up to 17 (vegan)
- Women (19+): 9 and up to 12
- Canadians are not meeting zinc requirements
What are the sources of zinc?
- Best sources are in animal products (red meats, organ meat, fish and seafood)
- Better absorbed than plant sources
- Calcium and phytates reduce bioavailability
- Breakfast cereals fortified with zinc are often taken with milk
What are the symptoms of zinc deficiency?
- Growth retardation
- Loss of appetite
- Impaired immune function
- Delayed sexual maturity
- Taste aversion
Who is at risk for zinc deficiency?
- Those with GI diseases (poor absorption)
- Pregnant or breastfeeding women (higher requirements)
- Alcoholics (decreased absorption)
- Vegans and vegetarians (dereased bioavailability)
- Children and adolescents (increased requirements due to growth and development)
- Elderly persons (decreased intake and decreased absorption)
- People on medications (decreased absorption, increased losses)
What are the consequences of zinc deficiency?
- Retarded growth
- Mental lethargy
- Skin changes (eczema, acne)
- Night blindness
- Impaired immune system, slow wound healing
- Impaired brain function, brain fog, ADHD, depression
- Omega-3 more superior for depression
- GI infections, diarrhea
What are symptoms of zinc toxicity?
- Mostly due to high supplement intake
- Nausea and vomiting
- Loss of appetite
- Abdominal cramps
Discuss the link between zinc and the common cold.
- Not well understood
- Prolonged intake of zinc lozenges can lead to side effects (bad taste, nausea)
- Zinc administered within 24 hours of onset of symptoms reduces duration of symptoms
What are the sources of copper?
- Richest sources are organ meats (liver, kidney) and copper water pipes
- Also found in seafood, nuts and seeds, whole-grain breads, cereals and chocolate
- 30-40% of copper of typical diet is absorbed
- Affected by presence of other minerals in diet
Discuss factors affecting copper absorption.
- High levels of zinc → synthesis of metallothionein → preferentially binds copper and limits absorption
- Phytates (inhibit zinc) increase absorption and utilization of copper
- Copper absorption is reduced by large intakes of iron, manganese, molybdenum, and vitamin C
What is ceruoloplasmin?
- Major copper-carrying protein in blood (more than 95%)
- Plays a role in iron metabolism as enzyme
- Converts Fe2+ (ferrous iron) into Fe3+ (ferric iron)
- Assists in association of only ferric iron with transferrin (main transport protein for iron)
What are the functions of copper?
- Iron and lipid metabolism
- Connective tissue synthesis
- Maintenance of herat muscle
- Blood clotting
- Functioning of immune and central nervous system
- Synthesis of neurotransmitters norepinephrine and dopamine
Discuss elevated copper and high Cu/Zn ratio.
- Elevated copper levels and lead = GI effects in short term + possible liver effects in the long term
- High Cu/Zn (Cu is stronger) ratio will affect medical conditions and cognitive development
- Negative correlation betwen Cu/Zn and educational attainment
- Linked with multiple-mortality in elderly (serum Cu rises with age; Zn important for bone, muscles and immune system)
- Lower bone mineral density, measures of speed and strength and muscle mass
Where is manganese found and what does it do?
- Best sources are whole grains and nuts
- Also found in fruits and vegetables
Enzymes that require manganese are involved in:
- Amino acid, carbohydrate, and cholesterol metabolism
- Urea synthesis
- Cartilage formation
- Antioxidant effects
Where is selenium found? Discuss selenium in the diet.
- Found in seafood, kidney, liver, brazil nuts, and eggs
- Grains and seeds may be good sources as well
- We are needing our needs but variable
- Breakfast cereals made from Ontario wheat contains less selenium
- Baked goods and cereals are consumed daily in large amounts and are 51% of selenium intake
What are the functions of selenium?
- Functions through association with proteins called selenoproteins
- Some selenoproteins (eg. glutathione peroxidase) are antioxidants
- Spares vitamin E as neutralizes free radicals once produced
- Needed for synthesis of thyroid hormones
What are the recommendations of selenium?
- RDA is 55 ug/day
- Based on the amount needed to maximize the activity of the enzyme glutathione peroxidase in the blood
Discuss selenium deficiency.
- Symptoms include muscular discomfort and weakness
- Keshan disease
Where is iodine found?
- Iodine content in food varies depending on soil
- Found in seawater (seafood and plants grown near sea are high in iodine)
- In Canada, most of iodine comes from ionized table salt (not pink himalayan or sea salt, not salt found in processed foods
- 400 mcg/tsp of table salt
Why do we need iodine?
- Needed for synthesis of thyroid hormones
- Necessary for metabolism
- More than ½ of body’s iodine is located in thyroid gland
- Essential compoennt of thyroid hormones
- Thyroxine (T4 has 4 iodines) and triiodothyronine (T3) made from amino acid tyrosine
- Thyroid hormones promote protein synthesis and regulate basal metabolic rate, growth and development
What are iodine recommendations?
- RDA: 150 ug/day
- Based on amount needed to maintain normal iodine levels in thyroid gland
- Higher in pregnancy to account for amount of iodine needed by fetus and during lactation to account for amount secreted in milk production
- RDA = ⅓-½ tsp iodized table salt/day
What does iodine deficiency do? What are symptoms?
- Enlarged thyroid gland (goiter)
- Reduces production of thyroid hormones → constipation, brain fog, cold intolerance, fatigue, depression
- Excess hormone (too much iodine) → depression, diarrhea, trembles, weight loss
- Metabolic rates slow with insufficient hormones → fatigue, weight gain
Where can fluoride be found? How is it absorbed? What is the AI, deficiency and toxicity symptoms?
- About 80-90% of ingested fluoride is absorbed
- Absorption decreased with calcium
- Present in small amounts in almost all soil, water, plants and animals
- Richest sources are fluoridated water, tea, and marine fish consumed with bones
- Most of Canadians’ fluoride comes from toothpaste and fluoride added to water
- Fluoride content in food can be significantly increased when prepared with fluorided with water
- AI is 0.05 mg/kg/day for everyone 6+ months
- Deficiency → tooth cavities
- Toxicity → fluorosis (stained, pitted teeth), crippling (skeletal fluorosis), changes in kidney function, nerve/muscle damage
How should you prevent food outbreak?
1. Wash hands and clean surfaces
- Wash hands and countertops with warm, soapy water
2. Don’t cross contaminate foods
3. Cook to proper temperatures
- Heat will destroy most harmful microorganisms
- Use meat thermometer
- Reheat to 75 degrees
- Eggs shouldn’t be eaten raw
4. Refrigerate properly
- Fridge should be at 4 degrees
- Freezers should be -18 degrees
5. Store foods properly
- Cold foods at 4 degrees or less
- Hot foods at more than 60 degrees
- Food should be thawed not at room temperature
- Produce should be stored in fridge
- Meats should be frozen if not used within 2 days
- Pasta = 3-5 days
- Cooked beef, poutry, pork, vegetables, soup and stew = 3-4 days
- Stuffing or meat in gravy = 1-2 days
- Applied to crops to prevent plant disease and insect infestations
- Can spread into water supplies and soil
- Types of pesticides that can be used + amount of residue are regulated
Discuss antibiotics and hormones.
- Antibiotics are given to animals to prevent disease
- Hormones are given to animals to increase growth
- Health Canada regulates the use of antibiotics and hormones in Canada
- Fecal contamination, raw eggs/meat (poultry)
- Nausea, abdominal pain, diarrhea, headache, fever
- Onset: 6-48 hours
- Duration: 1-2 days
Discuss escherichia coli.
- Fecal contamination, undercooked ground beef
- Abdominal pain, bloody diarrhea, kidney failure
- Onset: 5-48 hours
- Duration: 3 days - 2+ weeks
- E.coli O157:H7 can contaminate meat after slaughter and live in intestines of healthy cattle (needs to be cooked to 71 degrees, high risk with ground)
Discuss clostridium botulinum.
- Deadliest bacterial foodborne toxin
- Blocks nerve function = abdominal pain, vomiting, double vision, dizziness, paralysis, respiratory failure
- Found in low acid foods (potatoes, stew), in anaerobic environments (canned foods), honey
- Infant botulism: ingest spores, shouldn’t eat unpasteurized honey before 1 years old
What are the benefits of physical activity?
1. Decreases chronic conditions
- Obesity: decreases fat mass, maintains lean body mass
- Cardiovascular disease: strengthens heart, improves blood lipids, slows athlerosclerosis, maintains healthy blood pressure
- Type 2 diabetes: enhances insulin sensitivity, helps with weight control
2. Bone and joint health
- Strengthens bones and joints
- Prevents osteoporosis
3. Mental health
- Improves stress management and reduces anxiety levels
4. Helps pregnancy
- Maintain mom’s fitness and muscle tone
- Control weight gain
- Decreased risk of caesarean birth
- Shorter labour, and improved post-natal recovery
What are the recommendations for physical activity?
- Adults (18-64): at least 150 minutes of moderate-vigorous intensity aerobic physical activity per week, in bouts of 10 minutes or more
- Beneficial to add muscle and bone strengthening activities using major muscle groups at least 2 days per week
What are the 3 characteristics of a good exercise regime?
1. Aerobic activity
- Greatest effect on cardiovascular health
- Breathe harder and heart beat faster
2. Strength training
- Exercises to improve strength and improve muscle/bone health
- 2 days per week is recommended
- Includes weight training, but yoga, pilates, push-ups, etc.
3. Exercises for balance and flexibility
- Should be done 3-4 times per week
- Stretching, yoga, tai chi
When do people stick to exercise regime?
- They start slowly and work their way up
- They have people to be active with
- It’s fun!
- They have a variety of activities they enjoy
- Record their progress
- Listen to their bodies
- Don’t hurt yourself!
Discuss energy needs in athletes.
- Duration, frequency and intensity of exercise
- Males need more energy due to larger body size
- The bigger the body and more lean mass, the more energy needed
- Most people do not do well on a diet and exercising (loss of muscle, risk of fatigue or injury, prolonged recovery)
- If too much or too little energy = weight loss/gain, loss in performance
Discuss unhealthy weights in athletes.
- Emphasis on weight: gymnastics, diving, dance, boxing, wrestling
- Low energy, low performance, dehydration
Female Athlete Triad:
- Disordered eating
- Ammenorrhea (absense of menstruation, not enough fat to maintain fat mass to produce hormones)
- Osteoporosis (estrogen levels are linked to bone mass)
Discuss carbohydrate needs in athletes.
- AMDRs: 45-65% of energy
- Strength: >55%
- Endurance: >60%
- Complex carbohydrates should be primary source of CHO (eg. starches, whole grains)
- Simple carbohydrates from fruit/dairy/processed foods spike insulin (store sugar as fat)
- High carb diets increase glycogen stores (liver, muscles, source of energy during exercise, increases performance)
- Eat throughout the day rather than suddenly
- Before = improves performance, after = replenishes glycogen storage
- May be needed during activity for activities lasting more than 1 hour
How much carbs should you eat according to type of exercise?
- Rest/light activity: mostly fatty acids
- 3-5 g/kg
- Moderate activity: fatty acids + glucose
- 5-7 g/kg/d
- High intensity activity: all glucose (glycogen)
- 6-10 g/kg/d
What is hitting the wall?
Sudden fatigue and loss of energy that happens when glycogen stores run out
What is carbohydrate loading?
- Process of planning your training and CHO intake to maximize glycogen stores
- Can double glycogen stores (enhance performance)
- In a few days before event, decrease training time and increase carb intake
- Use less, store more = more glycogen
- Some people feel ill (bloated, diarrhea)
What are fat needs for athletes and why?
- 20-25% of kcal
- Low in saturated and no trans fat
Needed for storage of energy for activity and proper hormone balance
- Lower sex hormone levels
- Stunted growth
- Slow sexual maturation
- Poor bone health
What are protein needs of athletes? Discuss sources and studies.
- Sources: low fat/low sodium animal-based sources, legumes, nuts
- The general population needs 0.8 g/kg body weight
- Endurance athletes need 1.2-1.4 g/kg body weight
- Strength athletes need 1.2-1.7 g/kg body weight
- Athletes require a little more protein
- To build and maintain muscle mass
- To provide protein for enzymes and other body proteins
- To provide energy
- Can usually get it from food alone
- Vegan athletes
- Adolescent athlets
- Low body weights aiming for weight category
- No increases in performance and muscle mss with protein powders/drinks
- Tiny benefit for body builders
- Muscle growth is stimulated by exercise not protein
- Whey supplements increased muscle mass more than soy and carbohydrate supplements
- Skim milk powder is cheaper, dissolved easily, tastes better and has ½ amount of protein per scoop as protein supplement
What are stress fractures and what can you do?
- Overuse injuries
- Fatigued muscle transfers stress ovelroad to bon
- May be compounded by low bone mineral density
- Increase energy intake as well as calcium, zinc, and vitamin D intake to appropriate levels
Discuss iron and sports anemia in athletes.
- Athletes need more as involved in energy and RBC production
- Females have poorer iron status than males due to menstruation and poor diet
- Supplementation may be needed
Sports anemia: decrease in hemoglobin concentration
- Occurs early in training or when training intensity increases
- Blood volume increases, hemoglobin apperas to be low
- Does not impair oxygen delivery, performance
- Does not require iron supplementation
Why might supplementation be needed for athletes?
- Disordered eating
- Habitually restricting intake to maintain a certain body weight
- Has specific micronutrient deficiency or is at risk
What is creatine?
- Body and diet each produces 1 g/day naturally
- Only proven benefits for repeated bouts of high intensity exercises lasting more than 30 seconds
- Effects of creatine diminish as length of time spent exercising increases
- May improve physical performance, growth of skeletal muscle, recovery from injury
- Stored in muscles; interacts with phosphate to allow ADP to be converted to ATP for muscle contraction
- Benefits not consistently reported in all athletes (diet, race, supplementation protocol)
- May slightly raise creatinine levels but no sustained negative effect
What is L-Carnitine?
- Amino acid-like molecule produced by lysine and methionine
- Enhances fat utilization as energy (beta oxidation) instead of glucose during exercise
- Spares glycogen stores, delay hitting the wall (endurance training)
What are medium-chain triglycerides (MCT)?
- Increases free fatty acids in blood = increases use of free fatty acids instead of glucose for energy
- Increases endurance, spares glycogen, and enhances performance
What is caffeine for athletes?
- Enhances performance and endurance during prolonged exhaustice exercise
- Enhances alertness and reduces fatigue
What can insufficient hydration cause in athletes?
- Heat exhaustion: dizziness from standing in the heat
- Heat cramps: cramps that happen several hours after intense heat workuts
- Heat stroke: high body temperature due to working out in the heat (serious!)
What is a good fluid regime for athletes?
1. Before exercise
- 500 mL 2-3 hours before
- 250 mL 10-20 minutes before
2. During exercise
- 180-360 mL every 10-20 minutes
- For prolonged workouts, add electrolytes
3. After exercise
- At least 500 mL for every pound of weight loss
- Add electrolytes
Discuss electrolytes for athletes.
- When sweating, lose sodium (hyponatremia)
- If you are doing an intense workout for MORE than 60 minutes, you should replace your lost electrolytes AS WELL AS your fluid
- Drink sports drinks, milk, diluted fruit juice, oral rehydration solution
What is the optimal blood pressure?
- Optimal blood pressure is 120/80
- Systolic: heart contract (120-140)
- Diastolic: heart releases (70-90)
- With high blood pressure, systolic > 140 mm Hg and diastolic > 90 mm Hg
How is hypertension treated?
- Sodium-to-potassium ratio appears to be more strongly associated with blood pressure than either electrolyte alone
- Supplementation of potassium increases excretion of sodium
- Magnesium and fatty fish oils can also help regulate blood pressure
- DASH diet is recommended to treat hypertension
- More fruits and vegetables (K to draw water out of vessels), low in saturated fat, lots oh whole grains, legumes and pulses, low-fat dairy and meat, low sodium foods
- 30-60 minutes of physical activity most days
Where are the B vitamins found?
- Grains (B1, B2, B3, B6)
- Vegetables and fruit (B2, B6, folate)
- Milk and milk products (B2, B12)
- Meats (B1, B2, B3, B6, B12, folate)
What is Wernicke-Korsakoff syndrome? How is it caused?
- Inflammation or brain (memory disturbances, confusion)
- Caused by profound thiamin deficiency and inflammation of brain (low quality diet)
Discuss calcium and heart health.
- Calcium supplements without vitamin D is associated with increased risk of myocardial infarction
- High total calcium intake was associated with decreased atherosclerosis over long term (without supplements)