Lecture 6: Nutritional Supplements Flashcards
Functions of iron
1) Transport oxygen in blood via heme groups (e.g. hemoglobin + myoglobin)
2) Energy metabolism
3) Immune system
Iron requirements in males
- 14-18 years old: RDA = 11 mg/day
- Adult: RDA = 8 mg/day
Iron requirements in females
- 14-18 years old: RDA = 15 mg/day
- Adult: RDA = 18 mg/day
Why might females need more iron?
Menstrual loss
Best source of iron?
Organ meats + clams
Best source for iron bioavaliability?
Meats + fish (heme iron)
Why are non-heme forms of iron absorbed badly?
Plant-based products have other compounds that bind up iron
- Oxalates (fruits, veggies)
- Phytates (whole grains)
Enhance iron absorption
1) Eat with vit C
2) Eat with meat
3) Use iron cooking utensils
Reasons for iron deficiency (6)
1) Poor diet
2) Menstrual loss
3) Exercise induced hemolysis -> hematuria
4) Gastrointestinal losses
5) Inflammation
6) Small amounts in sweat
Types of iron deficiencies
1) Anemia
2) Iron deficiency w/o anemia
3) Sports anemia
__% of people on earth has anemia
25-30%
Anemia diagnosis: cut-off levels for hemoglobin
Men:
Difference between anemia & iron deficiency w/o anemia
Anemia = hemoglobin levels low
iron deficiency = serum ferritin levels low
Serum ferritin is an indicator of…
Fe storage in the body
Is iron deficiency w/o anemia detrimental to athletes? Which type?
Yes, endurance (high reliance on oxygen)
Define: sports anemia
Hemoglobin concentration is low because of high blood volume
Who should take Fe supplements?
Diagnosed anemic (blood work test)
Fe supplements come in the form of…
ferrous salts (gluconate, sulfate, fumarate)
Who is at risk for iron deficiency?
1) Female (athletes)
2) Vegetarians
3) History of anemia/iron deficiency
Hemochromatosis
Genetic condition; iron is accumulated in the liver instead of absorbed
AI for Ca intake
- 50 y.o. = 1200 mg/day
- At risk athletes = 1500 mg/day + 800 IU vit D
What affects Ca absorption?
- Vit D helps (milk)
- Oxalates hinder (vegetables)
- Caffeine, sodium, alcohol hinders
Ca supplementation may increase risk of…
heart attack
Why might Ca supplementation be risky?
Narrow range for optimal intake
- Adult = 1000 - 2500 mg/day
- > 50 y.o. = 1200 - 2000 mg/day
Benefits of milk (4)
1) Vit D
2) Calcium
3) Riboflavin (vit B)
4) 9 g best quality protein
How can vit D do so much?
modulate the expression of >1000 genes
Best effect of vit D + study finding
- Bone health
- High dose (>800 IU/day) prevents hip + non-vertebral fracture in people >65 y.o.
DRI for vit D
- 600 IU
- [Canadian osteoporosis] Low risk adults = 400-1000 IU
- [^] >50 y.o. or med risk = 800-1000 IU
Which organization will have the highest dietary vit D intake recommendation? Why?
Canadian Cancer Society
- vit D from diet > sun (skin cancer)
Ways to get vit D
- Fortified milk products
- Fatty fish
- Sunlight (way better source than any food)
Naked 10-20 min in summer sun = how much vit D produced?
As much as 10 000 IU
Sunlight is insufficient for vit D production where in the world?
Above or below 35 degrees latitude
biomarker for vit D
25-OH vit D
level for 25-OH vit D that indicates deficiency risk
RDI: <30 nmol/L
optimal level of 25-OH vit D
- RDI = 50 nmol/L
- Canadian Osteoporosis = 75 nmol/L
- GrassRoots Health = 100-150 nmol/L
What is the link between vit D and athletic performance?
Correlation, but vit D is about as good as general health.
Define: free radical
Capable of existence w/ unpaired electron
1993 study found that vit C supplementation…
reduced incidence of post-race symptoms of URI infection in ultramarathon runners
URI =
upper respiratory infection
1996 study found that vit E supplementation…
reduced risk of cardiovascular death + non-fatal heart attack
Vit C supplementation might be bad because (study findings)…
- Study found no change in damage/immune function with supplementation
- Decrease muscle mitochondria biogenesis
- Decrease endurance capacity (prevent cellular adaptation to exercise)
Vit E supplementation might be bad because (study findings)…
- No improvement in performance
- Increased lipid peroxidation + inflammation during exercise
Why might anti-oxidants be harmful?
Megadose of antioxidants => antioxidants become pro-oxidants
What is lipid peroxidation
Free radical reaction involving lipids. Electrons stolen from lipids in cell membrane -> harmful
When might antioxidant supplementation be ergogenic?
When you are deficient (e.g. vit C deficiency is scurvy)
