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NUTR 380 > Module 5: Vitamins and Mineral Recommendations for Athletes and Exercise > Flashcards

Module 5: Vitamins and Mineral Recommendations for Athletes and Exercise Flashcards

1
Q

What are vitamins and how are they obtained?

A
  • Organic compounds/catalysts involved in metabolic reactions
  • Must be obtained from the diet except:
    →Vitamin D: synthesized from sunlight
    → Vitamin K: synthesized by bacteria in the intestine
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2
Q

How long does it take for vitamin deficiency to develop?

A

3-4 weeks

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3
Q

What can happen with excess vitamins?

A

Excess can lead to toxicity (acute or chronic)

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4
Q

What form are vitamins in?

A

Several vitamins are in a precursor or provitamin form in foods and converted to the active form in the body. E.g. Beta carotene

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5
Q

What are the functions and requirements of vitamins for athletes?

A
  • Generally same amounts as general population
  • Athletes usually manage to have adequate levels because they eat a lot (except for calcium and iron)
  • If they do not have good energy availability then will have lower vitamin amounts
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6
Q

What are the macrominerals and the daily required intake?

A
  • Daily required intake >100mg or >0.01% body weight
  • Calcium, phosphorus, magnesium, sodium, sulfur
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7
Q

What are the microminerals/trace elements and how much is required daily?

A
  • Daily required intake <100mg or <0.01% body weight
  • Cobalt, chromium, manganese, molybdenum, arsenic, nickel, vanadium, iron, iodine, fluoride, zinc, selenium, copper
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8
Q

What two minerals are of greater concern in athletes?

A

Calcium and iron, thought that athletes have higher iron requirements

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9
Q

Are current recommendations for athletes enough?

A
  • The available evidence suggests that the current recommendations for micronutrient intakes for the general population are also adequate for athletes (with the exception of iron)
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10
Q

Are supplements necessary for athletes?

A
  • It is the joint position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine, that micronutrient supplements are unnecessary for athletes who consume a diet providing high energy availability (EA) from a variety of nutrient-dense foods
  • Micronutrient supplementation is only considered to be necessary for athletes who consume suboptimal amounts of micronutrients:
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11
Q

What can occur if an athlete has low energy availability?

A

Has been linked to micronutrient deficiencies
- if we ensure that an athlete has adequate EA, it is likely that they will also have adequate micronutrient status
- First target: make sure they are eating enough

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12
Q

What can lead to micronutrient deficiency?

A
  • Lack of nutritional knowledge leading to poor nutritional choices
  • Inadequate energy intake leading to low energy availability
  • Can all lead to compromised macronutrient density and quality thus leading to macronutrient deficiency
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13
Q

Can taking supplements improve performance?

A
  • Will not make you a better athlete to take vitamins if there is no evidence of deficiency
  • May have restored physiological performance/overall health if deficient
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14
Q

If an athlete is concerned about deficiencies what would you tell them?

A
  • Athletes who have adequate energy intake PLUS a diet that provides a variety of foods are unlikely to suffer from micronutrient deficiencies
  • Iron deficiency in female athletes is the exception to this generalized observation
  • Achieving adequate energy intake is critical for all athletes
  • For sport performance and general health and well-being
  • Athletes with LEA create a secondary risk for micronutrient deficiency because they are not consuming the amounts and diversity of foods needed to meet the otherwise manageable requirements for vitamins and minerals
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15
Q

Can exceedint the AI improve performance?

A

There is no evidence to show that exceeding the AI for any of the micronutrients results in performance gains unless the athlete is in a deficient state

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16
Q

What is the importance of blood in sport performance?

Function of RBC

A
  • Without oxygen, metabolic production of energy (ATP) is compromised
  • Red blood cells (RBC) or erythrocytes:
    → Deliver oxygen to working muscles
    → Carry CO2 back to the lungs
  • Oxygen carrying capacity of blood is proportional to [Hb] in RBC
    → Athletes need to have adequate numbers of RBC and adequate Hb within each RBC
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17
Q

What micronutrients are involved in Hb and RBC formation?

A
  • Micronutrients are co-factors for the enzymes responsible for Hb Synthesis or RBC formation:
  • Iron (most common)
  • Copper
  • Folate
  • Vitamin B12
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18
Q

What are the three pillars of nutrition:

A

Balance, variety, moderation

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19
Q

What is iron needed for?

A
  • Required for Hb and myoglobin production
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20
Q

What is heme?

A
  • Iron containing molecule at the centre of each Hb unit
  • Binds oxygen and CO2 reversibly
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21
Q

What is myoglobin?

A
  • An Fe and O2 binding protein found in the muscle tissue
  • Acts as a storage vessel for oxygen, as it holds oxygen inside cardiac and SM
  • Only found in the bloodstream when it is released following muscle injury (abnormal finding)
22
Q

What are the dietary forms of iron?

A
  1. Heme → better absorbed, found in meat, fish, and poultry
  2. Non-heme → less well absorbed, found in vegetables, fruits, eggs, milk, and grains
23
Q

What factors enhance or inhibit iron absorption?

A

Note: antacids often have a calcium base

24
Q

What are the RDAs for iron?

A
  • Adult men (all age groups): 8mg/day
  • Premenopausal women: 18mg/day
  • Postmenopausal women: 8mg/day
25
Q

What are the iron requirements for athletes and athlete sub groups?

A

Currently unknown. They are believed to be higher than in the general population

26
Q

If a person has iron deficiency, should they be taking the RDA amount?

A

They may require intakes far above RDA to replet their iron stores

27
Q

What is hepcidin?

A
  • A hormone that regulates iron metabolism in the gut and macrophages
  • Synthesized in the liver and acts as the major regulator of iron metabolsim in th body
  • Influences iron metabolism by degrading the iron transporter known as ferroportin (Fpn) located on the brush border membrane of duodenal enterocytes
  • A degradation of the fpn transporters can result in decreased dietary iron absorption from the small intestine
28
Q

Hepcidin is upregulated by __________

A

Intense physical activity (leading to more degradation of Fpn so less dietary iron is absorbed from the intestine)
- It is thought that this activity-driven upregulation of hepcidin decreases iron absorption, increases iron needs, and presents an additional risk for anemia

29
Q

Name the 5 key measures of iron status?

A
  1. Ferritin
  2. Transferrin Saturation
  3. Total iron binding capacity
  4. Hemoglobin
  5. Hematocrit
30
Q

What do ferritin levels reflect?

A
  • Serum ferritin levels reflect tissue iron stores
  • 1 ug ferritin/L = 8 mg stored iron
  • Decreases when iron status is low
31
Q

What does transferrin saturation reflect?

A
  • Transferrin is a protein that carries iron to cells
  • Transferrin saturation is a measure of how much iron is bound and being actively carried by transferrin
    → Normally 30% of transferrin is saturated with iron, with normal saturation ranges from 16-50%
  • Decreased when iron availability in blood is low and is a measure of iron status
32
Q

What does TIBC measure?

A
  • Measures the total capacity for transferrin to bind and carry iron
  • Increases if iron status is low
33
Q

What does low Hb indicate?

A

If low, iron shortages have been occurring for some time. Last one to go, one we measure the most

34
Q

What is hematocrit?

A
  • Measure of actual volume of RBC in whole bood to total blood volume
  • Low hematocrit = fewer RBC → Indicative of anemia (multiple causes)
35
Q

What is anemia? What are its causes?

A
  • Anemia is a generic term for any condition in which Hb levels are low
  • Anemia has multiple causes:
    → Some diet related
    → Others non-diet related
36
Q

What are the causes of iron deficiency anemia?

A
37
Q

What are the clinical symptoms of iron deficiency Anemia?

A
  • pallor
  • fatigue → loss of endurance capacity, reduction in strength
  • Lowering immunity
  • Itchiness
  • “Spoon” nails (koilonychia)
  • Decreased cognitive function
  • Inability to regulate temp
  • Pica (odd cravings - i.e. Clay)
  • Low Hb, hematocrit, and serum ferritin levels
38
Q

What are the 3 stages of iron deficiency?

A
  1. Iron deficiency (rarely detected unless happen to have blood work done)
  2. Iron deficiency erythropoeisis
  3. Iron deficiency anemia
39
Q

What is the prevalence of iron deficiency anemia in athletes?

A
  • Iron deficiency is a very common health concern for athletes
  • In the general population, the prevalence of iron-deficiency anemia among youth and adults is estimated at 2% to 5% in females and 1% to 2% in males
  • In athletes, iron deficiency affects:
    → Up to 52% of female adolescent athletes
    → 30-50% of athletes participating in endurance sports
    → Iron deficiency anemia is most common in female athletes (15-35%) but it is not an exclusively female athlete concern
    → 5-15% of the male athletes are also iron-deficient
40
Q

Why do athletes have enhanced iron requirements?

A
  • High physiological demands and requirements for iron associated physical activity
    → Hard training stimulates increased RBC and small blood vessels so need more iron (iron requirements highest for endurance athletes training at high intensity)
    → Growth increases iron requirements because of the corresponding increase in RBC and blood vessels
  • Inadequate consumption of dietary iron
    → Low intake of cereal grains, meats, or low energy intakes make iron consumption low
  • High iron loss, mostly from blood loss
    → injury, bloody nose, menstruation, digestive tract after extreme events, foot strike, heavy sweating
41
Q

What is foot strike?

A
  • Also called exercise-induced hemolysis
  • Damage to RBC in feet associated with running on hard surfaces with poor quality shoes leading to iron loss
  • RBC turnover higher in runners compaired to untrained controls
  • Suggested that mechanical damage to RBC occur as they pass through the capillaries of the foot during the footstrike phase
42
Q

What are the possible mechanisms for exercise-induced iron deficiency?

A
43
Q

What is the treatment for anemia?

A
  • The cause determines the treatment modality → determining the cause is critical
  • Need to know if bleeding, disease, or malnutrition is the primary cause
  • Iron supplementation is not a cure-all for every type of anemia
44
Q

What are the recommendations for iron supplementation when having iron deficiency?

A
  • 100-200mg elemental iron per day
  • Ferrous form of iron
  • Taken on an empty stomach with full glass of water or fruit juice
  • Taken in the morning or earlier in the day
  • Take with souce of Vit C
  • Should not be taken with calcium products (e.g. supplements, certain antacids, milk or milk products)
  • Avoid high-oxalate foods (e.g. coffee, tea, spinach, kale, broccoli)
  • If can’t take on an empty stomach bc of GI distress, take with a meal or throughout day
45
Q

During iron deficiency treatment how often should stores be checked and how long should therapy occur?

A
  • Check iron stores 2-4 weeks post therapy for repletion → if not replete, re-investigate cause
  • Check iron stores after 2-4 months to ensure ID doesn’t recur
    → If ID recures reinvestigate and/or refer for further assessment
  • Continue with iron therapy for additional 4-6 months if Hb normal
  • Maintenance with a low dose of iron therapy may be required for patients with ongoing needs, e.g menses, dietary, growth spurts
  • Iron diffusion at very low levels
46
Q

What is sports anemia?

A
  • Sports anemia is not a true form of anemia
  • Also called Dilutional pseudoanemia
  • No response to Fe-therapy
  • No markers of blood loss
  • Blood volume (amount of blood in total) expands in response to training → muscle mass expands, increased blood volume, cells and Hb lag behind
  • Hb production sometimes lags behing somewhat
47
Q

What is the treatment for sports anemia?

A
  • Treatment of true sports anemia is not necessary
  • Temporary and benign
  • Will resolve after with adeqaute rest from training, no treatment needed
  • No adverse effect on athletic performance and possible beneficial effects
  • Given time the situation will normalize provided dietary intake is adequate
  • Need to rule out dietary or medical causes of anemia
  • Sports anemia is a diagnosis of exclusion
48
Q

What happens to blood volume due to training?

A
  • Expansion of blood volume is an expected benefit of training
  • Blood volume expansion is a temporary effect of training
  • [Hb] may not be parallel to increase BV
  • Random blood draws, if taken at a time of BV expansion can mimic anemia BUT THIS IS NOT THE CASE
    → low Hb relative to blood volume
49
Q

What are the sport factors related to sport anemia?

A
  1. Type of sport → endurance sports change iron status assessment parameters more than other sports
  2. Intensity or duration of training → greater intensity or longer duration = greater chance for finding the sport anemia
  3. Adaptation to training → sport anemia is more likely to be found in early stages of new training regime rather than after a long period of adaptation
50
Q

What is hemochromatosis?

A
  • Most prevalent genetic disorder in North America
  • 1 in 300 canadians
  • Results in heightened iron absorption and excessive storage of iron in the skin, heart, liver, pancreas, pituitary gland and joints
  • Excess = bad
51
Q

Excess iron absorption and storage is related to what 2 things?

A
  • CHD
  • Cirrhosis of the liver and/or liver cancer
52
Q

An athlete came to you and said they started taken a supplement because they were worried about iron deficiency, what would you do?

A
  • All athletes should have their iron status checked before taking nutrient supplements that contain iron, including MVI
  • Would test their blood and get back to them, shouldn’t take their supplement until they are tested

NUTR 380 (12 decks)

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