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Nutrition Final Review.docx

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University of Guelph
NUTR 1010
Andrea Buchholz

Nutrition Final: Review Week 8: Caffeine and Alcohol The most commonly consumed beverages worldwide are: 1. Water 2. Tea 3. Coffee The most commonly consumed beverages in Canada are: 1. Water 2. Coffee 3. Tea Daily coffee consumption varies across the country -Ontario: average amount -British Columbia: Average amount -Atlantic Canada: Least amount -Quebec: The most Caffeine -Most commonly consumed drug worldwide -Natural component of tea leaves, coffee beans, cocoa beans, and >60 other plants -Caffeine content highly variable, therefore caffeine content of resulting teas, coffees and chocolates also variable -Central nervous system stimulant (feel alert & energized) After we consume caffeine -Reaches peak blood concentration within 30-60 minutes of digestion -Half-life of 4-6 hours -I.e., half of the caffeine consumed is still in the body after 4-6 hours -Within this time frame (i.e., 30 minutes to 6 hours or so) Many of us feel the physical effects of caffeine -Vary from person to person -Nervousness, irritability, restlessness, insomnia, headaches, heart palpitations -Caffeine dependency is possible (withdrawal symptoms) -Tolerance with repeated use -E.g., caffeine increases blood pressure for ~ 3 hours in those not used to consuming it; but not in regular coffee drinkers Caffeine and Bone Health -Caffeine decreases absorption of calcium -Caffeine increases urinary calcium -Therefore, excess intake can lead to bone loss -Those who consume caffeine AND have low calcium intakes are at higher risk of poor bone health Caffeine during pregnancy -Caffeine crosses the placenta, so if mom drinks caffeine, so does the baby -Some evidence that caffeine increases risk of low birth weight and preterm birth -Recommendation for caffeine consumption during pregnancy same as for non- pregnant women Caffeine Recommendation -Women of childbearing age <300mg per day -All other adults <400 mg per day Coffee In addition to caffeine, coffee also contains: -Cafestol and kahweol (oily compounds in coffee beans extracted from ground coffee during breaking, but are mostly removed by paper filters) -Increase LDL-Cholesterol -Several kinds of antioxidants (undergo extensive metabolism—health benefits uncertain) Long-term health effects of coffee -Coffee consumption appears to decrease risk of Type 2 diabetes, Parkinson’s disease, colorectal cancer, and liver disease BUT -Coffee consumption appears to increase risk of cardiovascular disease, poor bone health Factors, which complicate our understanding of coffee-health relationship -Coffee drinkers differ from non-coffee drinkers -More likely to smoke, drink alcohol, have less healthy lifestyles (diet, exercise) -Health effects depend on the volume of coffee consumed and the concentration of constituents (i.e., type of coffee bean, growing conditions, etc.) Tea All teas come from the plant Camellia sinensis -Black tea (tea leaves are picked, oxidized/fermented, and dried) -Green tea (tea leaves are picked, steamed, and dried [not oxidized]) -Oolong tea (tea leaves are picked, withered in the sun, and partially oxidized Tea Consumption Type % Of tea produced and Popular in consumed worldwide Black 76-78% Europe, North America, North Africa Green 20-22% Throughout Asia Oolong <2% China, Taiwan Tea is rich in:  Catechins o These are antioxidants o Highest concentrations in green tea, followed by black tea, and then oolong  L-Theanine o An amino acid derivative o Has a calming effect o Helps strengthen the immune system Positive health effects of tea -Increases antioxidant status -Decreases risk of heart disease (>3 cups per day) -Decreased atherosclerosis by protection health of blood vessels -Increase bone density -Help prevent dental cavities (tea is naturally fluoridated) -Green tea may help with weight control -Small increase (5%) in energy expenditure BUT, health effects of tea are inconsistent -The “dose” of tea required to see effects ranges from 1-6 cups/d Catechin content depends on: -Geographical location, growing conditions -How the leaves are processed prior to drying -Type of tea (blended, decaf, instant) -Preparation (amount used, steeping time, whether tea is stirred and how many times, and whether the tea bag is squeezed) Tea drinkers differ from non-tea drinkers -Tea drinkers may make different lifestyle choices than non-tea drinkers -E.g., tea drinkers are 55% more likely to make healthy choices when choosing a restaurant Herbal Tea -Not technically tea: it doesn’t come from camellia sinensis; contains no caffeine or catechins Alcohol What is alcohol? -Alcohol of alcoholic beverages is ethanol -2 carbon molecule with an OH group -A toxin – our body has to detoxify it -Alcohol can be burned fro energy (7 kcals/g), but it is not a macronutrient Fermentation of sugar creates alcohol -Yeast or bacteria break down sugar into alcohol (specifically, ethanol) Alcohol is found in: -Wine -Beer -Vodka, scotch, rum, tequila, whiskey How is wine made? -Grapes are crushed -The pulp fermented with yeast (1-2 weeks) -Secondary fermentation/aging – Wine is stored in casks (often oak) to slowly ferment and mature (3-6 months) How is beer made? -Malted barley, water, yeast, and hops -Malting: barley is soaked in water until the grain germinates, then the grain is dried -During germination starch turns into maltose -Yeast ferments the maltose to alcohol (2-4 weeks) -Hops (a flower) adds flavor What is a ‘moderate’ alcohol intake? -Women: <10 drinks per week, with no mare than 2 drinks in one day -Men: <15 drinks per week, with no more than 3 drinks in one day One standard drink= 1 serving of pure alcohol= 15 grams—1/2 oz. Binge Drinking -Binge drinking is more than 5 drinks in a short time for a man or more than 4 drinks in a short time for a woman. -Evidence of fatty liver can be seen after only 3 days of binge drinking How do we metabolize alcohol? ADH System  Most of the alcohol we consume is absorbed whole from the small intestine o From the small intestine, alcohol travels to the liver o In liver, alcohol is metabolized by alcohol dehydrogenase (ADH) o We also have some ADH in stomach o Together, ADH in stomach and liver metabolizes ~80% of alcohol consumed o Women have less ADH than men What happens to alcohol in the liver? -ADH metabolizes alcohol (i.e., removed hydrogen’s – H’s) -Eventually, we are left with acetyl CoA Acetyl CoA -2 carbon compound produced from macronutrient and alcohol metabolism -When produced from macronutrient metabolism, acetyl CoA enters TCA (tricarboxylic acid) cycle produces energy -When produced from alcohol metabolism, it’s a different story:  Acetyl CoA does not enter TCA cycle  Instead, the acetyl CoA from alcohol metabolism is converted to fatty acids MEOS System -Microsomal ethanol oxidizing system (Found in the liver, takes over when the ADH system is saturated) -Like the ADH system, MEOS converts alcohol to acetyl CoA (Again, acetyl CoA used for fatty acid synthesis) -10% of alcohol consumed is metabolized this way -This pathway is especially important for long term, heavy drinkers (explains the alcohol tolerance of people who abuse alcohol) The remaining 10% is excreted through lungs and urine -Hence, the Breathalyzer test How quickly do we metabolize alcohol? -Varies from person to person -On average, 1 standard drink per hour is metabolized -Alcohol waiting to be metabolized is in the blood and raises blood alcohol levels Health Effects The Good: -Moderate consumption of 1-2 drinks of beer or wine/day associated w/ health benefits -Cardiovascular disease: moderate drinkers have a 20-40% lower risk because it increases HDL levels, decreases blood pressure, and prevents clots -Lower risk of Type 2 diabetes: alcohol may improve insulin sensitivity -Small amount of wine before meal helps stimulate appetite -Red wine is especially beneficial: promotes bone health, particularly in older women/ helps with mental function (decreased risk of Alzheimer’s) What’s so special about red wine? -Contains resveratrol, an antioxidant (possible role in cancer prevention, reduces oxidized LDL-Cholesterol) -However, concentration of resveratrol varies b/w types of grapes and growing seasons Also consider that Wine-drinkers also tend to have good diets (high in fiber, fruits, vegetables, fish, and herbs) so while alcohol does confer health benefits, some of the benefits may also be related to lifestyle. The Bad -Acute effects: associated with motor vehicle accidents, falls, suicides, homicide, and drowning -Chronic alcohol abuse: ~80g alcohol/d (~5-6 drinks/d) for >10y, affects virtually every organ, contributes to 5 of the 10 leading causes of death Cirrhosis -Most cases caused by alcohol abuse -Develops in 15-20% of cases of alcoholism -Compounded by poor nutritional status Alcohol abuse and nutrition -Positive energy balance (abdominal fat distribution) Leads to numerous deficiencies (protein, vitamins, minerals). Here’s how: -Displacement effect (i.e., people who abuse alcohol usually consume alcohol as a substitute for other nutrients, not in addition to) -Alcohol can damage the absorptive cells in GI tract malabsorption excretion -Particular risk for folate, vitamin B1 (thiamin) deficiency Alcohol and Pregnancy -Alcohol crosses the placenta and accumulates in fetal blood -Can cause Fetal Alcohol Spectrum Disorder, a range of disorders caused by alcohol intake during pregnancy:  Growth deficiency  Learning difficulties  Behavioral problems  Physical deformities Week 9: Bone Health Bones -Bones are dynamic, living organs -Have many important roles in the body -Important to maintain healthy bones Functions of bones Structure and Support Metabolic Processes  Structural support for organs and  Storage reservoir for minerals body segments  Protects vital organs  Production of blood cells in bone marrow  Muscle support for movement Bone Structure -65% minerals Provides hardness (calcium and phosphorus) -35% organic substances Provide strength and flexibility (collagen: a fibrous protein) -Minerals form tiny crystals (hydroxyapatite), which cluster around collagen fibers Nutrients Involved in Bone Health -Major Roles: Calcium, vitamin D, and phosphorus -Minor Roles: Magnesium, vitamin K, vitamin A, and fluoride Bone Development Growth: -Determines bone size -Begins in womb -Continues until early childhood Modeling: -Determines bone shape -Longitudinal growth -Continues until early adulthood Remodeling: -Maintains bone integrity -Recycling -Bone resorption and formation -Adulthood Process of Bone Remodeling  Bone Resorption o Osteoclasts break down bone o Secretes enzymes and acids to erode bone surface o Minerals released into blood stream  Bone Formation o Formation of bone by osteoblasts o Build collagen matrix Peak Bone Mass -Highest amount attained during the years of normal bone growth -Achieved by the 3 decade of life -Important for osteoporosis prevention Influenced by: -Genetics -Nutrition -Physical Activity -Disease -Drugs Assessing Bone Health  Dual energy x-ray absorptiometry o Measures bone mineral density (BMD) o Bone mineral content (g)/bone area (cm2) = BMD (g/cm2) o Monitors changes in BMD o Determines risk of osteoporosis o Comparison of BMD values o T-score BMD Values in Adults Compares your BMD to average peak BMD of a 30-year-old healthy adult of similar gender and race. Osteopenia Osteoporosis -Most prevalent bone disease in North America -Low bone mass and deterioration of bone tissue -Bone is porous and thinner compared to a healthy individual -Bone is weak = decreased ability to bear weight -Increased bone fragility -Increased fracture risk Risk Factors of Osteoporosis -Modifiable: nutrient deficiencies, sedentary lifestyles, smoking, low body weight, alcohol abuse, repeated falls, hormone deficiencies, medications -Non-Modifiable: age, gender, ethnicity, fracture history, and family history Age as a Risk Factor  Risk increases as we age o BMD decreases gradually with age o Imbalance in bone remodeling o Resorption occurs ore rapidly than formation Gender as a risk factor  Women higher risk than men o Lower peak bone mass o Longer life expectancy o Hormonal changes o Estrogen promotes bone formation o Low estrogen levels, as occurs during menopause, causes increased bone resorption and decreases bone formation Calcium -Most abundant mineral in our body (makes up 2% of our body weight) -99% of Ca in our body found in bones and teeth (part of the structure of bones (hydroxyapatite crystals), providing strength and rigidity -Ca Bank, helping maintain blood Ca levels What about the other 1% of Ca in our body?  This 1% acts as an electrolyte; it is the active form of calcium (found in blood, soft tissues)  What does this mean? o Helps transmit nerve impulses o Helps muscles contract (contraction occurs when Ca flows into muscle cells) o Initiates blood clotting o Helps maintain healthy blood pressure o Our body controls blood Ca VERY TIGHTLY Normal blood Ca: 2.20-2.58 mmol/L  If blood Ca exceeds 2.58: o Hypercalcemia: loss of appetite, nausea, fatigue, muscle weakness, restlessness, confusion, Ca deposit in soft tissues  To avoid high blood levels, Ca is: o Deposited from blood into bones o Excreted by kidneys (more Ca lost in urine) o Decreased absorption from GI tract  The end result is a decrease in blood Ca back to normal With an adequate intake of calcium-rich food, blood calcium remains normal. With a dietary deficiency, blood calcium still remains normal. BECAUSE: Ca is released from bones Take away message: Blood calcium levels stay the same regardless of intake. How much Ca should we consume? -RDA for 19 to 50 year old adults is 1000 mg/d How much Ca are Canadians actually consuming? -Women: 793 mg/d -Men: 931 mg/d Sources of Calcium -Milk and milk products -Milk Alternatives and fortified foods (e.g., calcium fortified orange juice, soy milk) -Fish eaten with bones -Tofu (set in calcium) -Some nuts (almonds) and seeds (sesame) -Dark green veggies (kale, bok choy, broccoli) Bioavailability -The degree to which our bodies can absorb and use any given nutrient -Bioavailability of Ca is ~30% for many adults o I.e., most of us absorb and use ~30% of the Ca we consume o But, this value changes because: -Age: e.g., infants, children can absorb >60% of Ca -Requirements: e.g., pregnant women can absorb ~50% of Ca -Dietary factors: Phytates (e.g., in whole grains), oxalates (e.g., in spinach), tannins (in tea) decrease Ca absorption -How much we consume: i.e., when diet is high in Ca, absorption decreases; when diet is poor in Ca, absorption increases -Source of Ca Best source of calcium = Kale You need 3 cups of cooked broccoli (6 servings) to get as much calcium as 1 cup of milk Getting the most out of the Ca in your diet  Spread Ca intake throughout the day o Our bodies can absorb only so much Ca in one sitting  Phytates, oxylates, and tannins decrease absorption  Avoid taking zinc, iron, or magnesium supplements when eating a source of Ca o Competition for absorption Note for vegans and other dairy-free people  Good dairy-free sources o Milk alternatives (soy, rice, or almond milk) o High calcium leafy greens (kale, bok choy) o Tofu (set in calcium) o Almonds  Choose several of these foods daily What happens if we consume too much Ca?  Eating more does not change blood levels of Ca  When you have enough, your body stops absorbing it o The extra comes out in the feces o Dietary Ca does not lead to toxicity  Supplemental Ca does not lead to mineral imbalances o Ca interferes w/absorption of other minerals What happens if we consume too little Ca? -Eating less does not change blood levels of Ca -No short-term symptoms of inadequacy -Long-term consequence is osteoporosis  Because osteoclasts break down bone to release bone Ca into blood  I.e., we make a Ca withdrawal from our bones What should we know about calcium supplements?  Amount- you cant absorb more than ~500mg at a time  Form of supplement – how bioavailable is the Ca? o Most supplements are about 30% bioavailable o Calcium citrate malate is slightly more bioavailable (35%) o Calcium carbonate is the cheapest (TUMS) Maximizing Calcium Supplement Bioavailability  Avoid taking calcium with a multivitamin/ mineral supplement (interfere with iron, magnesium, and phosphorus absorption)  Take Calcium supplement with food (increases bioavailability)  Take small amounts throughout the day to maximize absorption Vitamin D  A fat-soluble vitamin  Like other fat-soluble vitamins, we store excess amounts in liver and body fat  Unlike other nutrients: o Does not need to come from diet o That is, vitamin D is conditionally essential  Active form of Vitamin D is a hormone (Calcitriol)  Calcitriol exerts its functions after binding to vitamin D receptor (VDR) on cell surfaces Functions of vitamin D  Helps regulate blood Ca levels o Increase dietary Ca absorption from small intestine o Signals kidneys to decrease the excretion of calcium in urine o Stimulates osteoclasts (bone-breaking cells) to release Ca from the bones  Also helps the process by which Ca and phosphorus (a mineral) are crystalized o Contributes to bone health How much vitamin D should we consume?  Major source is exposure to sunlight  If sun exposure is adequate, don’t need to consume any vitamin D o E.g., sunny climates close to equator, like Southern U.S. and Mexico  People in Southern U.S. synthesis vitamin D all year round  Up to 97% of Canadians have inadequate blood vitamin D levels during winter and early spring  If sun exposure is inadequate, RDA for 19-50 year old adults is 15μg/d (600 IU)  If you live far from the equator, and particularily in winter months, you likely have inadequate sun exposure  Few foods naturally contain vitamin D (oily fish, cod liver oil)  Thats why we fortify foods such as milk (~10μg/d vitamin D per liter) 1 table spoon of Cod Liver Oil = 1360 IU of vitamin D Wild salmon has almost 25 μg (1000 IU) in a 3 oz serving People who synthesize litter or no vitamin D, and must obtain it from diet  Canadians in winter months  People who cover all their skin  People who stay indoors between 10AM-3PM  Elderly (older skin has fewer vitamin D making compounds)  People who wear sunscreen Sunscreen and Vitamin D  Best times of day for Vit D synthesis are when exposure to UV rays are discouraged to prevent skin cancer  BUT, SPF of 8 decreases vitamin D production in skin by 95%; SPF of 15 by 98%  What to do? o Continue to practice “safe sun” o Expose hands, arms and face to sunlight between 10AM and 3PM for ~5-10 minutes, 2-3 times per week Tanning Beds  UV-B rays between 290-310 nanometers are ideal for vit D synthesis  Some tanning bets use only UV-A rays  Those that use UV-B rays can increase blood vit D by >100% o Not surprisingly, tanners have greater bone density than non tanners What happens if we consume too much vitamin D?  UL is 100μg (4000 IU)/day  Not possible through sun exposure o Our skin limits vitamin D production  Next to impossible through dietary intake  However, excess supplementation is possible o May cause Hypercalcemia (high blood calcium levels) o Calcium deposits in organs What happens if we consume too little vitamin D?  Bone problems o Ca absorption decreases o Triggers the overproduction of a hormone which activated osteoclast; results in bone loss o Fewer minerals deposited on collagen matrix  Results in rickets in children; and osteomalacia (soft bones), osteopenia and osteoporosis in adults Vitamin D roles in health  Decrease risk of cardiovascular disease  Increase cancer cell death  Improve insulin sensitivity  Improve neuromuscular function  Prevent autoimmune diseases (e.g., Type 1 diabetes, multiple sclerosis) MS – Background  Disease of central nervous system  Attacks myelin (protective sheath surrounding nerve fibers) o Loss of balance & coordination, muscle spasm, weakness, fatigue, double vision, speech & swallowing difficulties o Partial or complete paralysis  Good new: normal to near-normal lifespan  Cause? o Autoimmune disorder (immune system “turns” on the body) o Inheriting MS susceptibility not enough (70% of identical twins are discordant for MS)  Prevalence shows striking geographic distribution o Canadians amongst highest prevalence worldwide (111 per 100,000)  US = 92 per 100,000  Spain = 77 per 100,000  Argentina = 14 per 100, 000 Vit D and MS: What’s the link?  T cells: white blood cells which can “turn: on the body o Leading to autoimmune disorders including MS  VDR found in cells of immune system, including T cells o Regulation of T cells influenced by vit D status  Genetic evidence that MS is associated w/a variant od VDR gene o This means that VDR cannot bind to vit D o Vit D cannot fulfill its functions  MS is virtually unknown at the equator o Prevalence of MS in Brazil is 4 per 100,000  People w/ MS tend to have low vit D levels o Majority have low bone mass, more fractures  Taking a daily multivitamin with 10 μg (400 IU) vitamin D decreases risk of developing MS by 40% Week 10: Blood Health What is blood?  Plasma (Fluid: water and electrolytes) makes 55% of blood volume  Red blood cells (45% of blood volume)  White blood cells (part of the immune system) and platelets (for blood clotting makes less than 1% of blood volume What does blood do?  Transports oxygen and nutrients  Removes waste products  Helps with the healing process (blood carries platelets for clotting)  Support the immune system (blood carries white blood cell
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