Week 8 (2) - vits, minerals and antioxidants Flashcards
Micronutrients (MNs):
- Micronutrients refers to the vitamins and minerals in foods and supplements
- They have several diverse functions in the body and aid in the absorption and metabolism of the macronutrients and support growth and development in various cells
- CHO and fat metabolism relies on b vitamins – have a supportive role
- They may also play a role in supporting athletic performance
Vitamins:
- We only synthesise a handful of vitamins in the body (Vit D, vit K)
- Generally, we have to get vitamins from the food that we eat
- There are 13 recognised vitamins
- Most were discovered from deficiencies, e.g., scurvy – vit C important in preventing this
Thiamin (B1)
- functions as part of a coenzyme to aid utilization of energy
- sources: whole grains, nuts, lean pork
-Adult RDA: 1.1-1.2mg
UL: ND
Riboflavin (B2)
- Involved in energy metabolism as part of a coenzyme
- Sources: Milk, yogurt, cheese
- Adults RDA: 1.1-1.3mg
- UL: ND
Niacin
- Facilitates energy production in cells
- Sources: Lean meat, fish, poultry, grains
Adult RDA: 14-16mg
UL: 35mg
Vit B6:
Absorbs and metabolises protein, aids in red blood cell formation
Sources: Lean meat, veg, whole grains
Adult RDA: 1.3mg
UL: 100mg
Pantothenic acid:
Aids in metabolism of carbohydrate, fat and protein
Sources: whole-grain cereals, bread, dark green veg
Adult RDA: 5mg
UL: ND
Folic acid:
Functions as coenzyme in the synthesis of nucleic acids and protein
Sources: green veg, beans, whole-wheat products
Adult RDA: 400ug
UL: 1,000ug
Vit B12
Involved in synthesis of nucleic acids, red blood cell formation
Only in animal foods (not plant)
Adult RDA: 2.4ug
UL: ND
Biotin
Functions as coenzyme in synthesis of fatty acids and glycogen
Sources: Egg yolk, dark green veg
Adult RDA: 30ug
UL: ND
Choline:
Important in cell membrane integrity and signalling, nerve transmission
Sources: Beef liver, chicken, codfish, wheat germ, cauliflower
Adults RDA: 425-550mg
UL: 2,000mg
Vit C:
Aids intracellular maintenance of bone, capillaries and teeth
Sources: citrus fruits, green peppers, tomatoes
Adult RDA: 75-90mg
UL: 2,000mg
Vit A (fat soluble):
Aids vision, formation and maintenance of skin and mucous membranes
Sources: Carrots, sweet potatoes, butter, liver
Adult RDA: 700-900ug
UL: 3,000ug
Vit D (fat soluble):
Aids growth and formation of bones and teeth, aids calcium absorption
sources: eggs, tuna, liver, fortified milk
Adults RDA: 15ug
UL: 100ug
Vit E (fat soluble):
Protects polyunsaturated fat, prevents damage to cell membrane
Sources: whole grain cereals and breads, green leafy veg
Adults RDA: 15mg
UL: 1000mg
Vit K (fat soluble):
Important in blood clotting
Sources: Green leafy veg, peas, potatoes
Adult RDA: 90-120ug
UL: ND
Minerals:
- Inorganic compounds essential in many reactions and processes in the body
- Can be divided into macro-minerals and micro-minerals also known as trace elements
- Trace elements are needed in smaller amounts than macro-minerals
- Minerals do NOT provide energy; but many assist in metabolism, growth and development – support the processes that generate energy
Difference between vits and minerals:
. Vitamins are organic and can be broken down by heat, air, or acid. Minerals are inorganic and hold on to their chemical structure. That means the minerals in soil and water easily find their way into your body through the plants, fish, animals, and fluids you consume. But it’s tougher to shuttle vitamins from food and other sources into your body because cooking, storage, and simple exposure to air can inactivate these more fragile compounds.
Micro minerals/ trace elements:
- Iodine: essential constituent of the thyroid hormones. Deficiency common
- Zinc: cofactor in over 100 proteins and enzymes
- Copper: component of several enzymes, cofactors and proteins
- Manganese: Catalytic cofactor
- Selenium: Antioxidant enzyme
- Molybdenum: Cofactor in iron and flavin-containing enzymes
- Fluoride: structure of bones and teeth
Importance of micronutrients in relation to athletic performance:
- Growth and building new tissues
- Antioxidants
- Oxygen transport
- Co-factors as enzymes * Immune function
Growth and building new tissues: Important Micronutrients
- Calcium – important for bone formation
- Phosphorus – important for bon formation and for support cell membranes
- Fluorine – important for teeth
- Vitamin D
- Vitamin C
- Calcium plays an important role in bone formation
- Deficiency can lead to osteoporosis (weak bones) and also stunted bone growth
- Phosphorus also important for cell membranes
- Fluorine important for protection against tooth decay; could be even more important for athletes who regularly consume sugary rich-foods
Oxygen transport - Important Micronutrients’:
- Iron - important component of haemoglobin and myoglobin
- Folic acid
- Phosphorus
- Oxygen carrying proteins, haemoglobin and myoglobin contain iron
- Iron deficiency can have important implications for those in endurance sports who rely heavily on muscle perfusion (blood flow and o2 transport is critical)
- Iron deficiency not uncommon – 15-25% in females
- Folic acid (vitamin B12) important for blood cell production
- Phosphorus helps support oxygen transport by encouraging o2 release into the local capillary networks
- Cytochromes produce energy via ETC – they are iron containing proteins
Co-factors in enzyme catalysed reactions - Important MN’s:
- B vitamins
- Zinc
- Magnesium
- Copper
- B vitamins important co-enzymes in RBC, carbohydrate, and fat oxidation
- Zinc is also important as a co-enzyme in energy metabolism
- Niacin and riboflavin particularly important for NAD and FAD production (these are important for energy production via the electron transport chain (ECT) as they are electron transporters), respectively
- Magnesium involved in ~300 chemical reactions; associated with exercise including energy production and muscle contraction.
- Magnesium also important for synthesis of enzymatic AOX
- Copper needed for proper iron function due to involvement in synthesising haemoglobin
Immune function - Important MN’s:
- Vitamin A
- Vitamin C
- Vitamin E
- Vitamin B6, B12 and folic acid
- Zinc, iron, selenium, magnesium, copper
- AOX effects of vitamin A, C and E helps support immune function by reducing free radical accumulation
- Folic acid and B12 important for production of immune cells and that fights off infections (innate immune cells: WBC)
- Zinc an important co-factor for the production of several immune cells and is an AOX
- Selenium helps synthesise co-factor for the production of AOX glutathione enzymes – has a role in antioxidation
- Copper affects immune cell and anti-body development
Electrolytes - Important MN’s:
- Sodium
- Potassium
- Chloride
- Sodium is important for maintaining water balance in cells and for nerve transmission and muscle contraction
- Potassium has similar functions as sodium; together they form the sodium-potassium pump – important for cell communication
Antioxidants – electron donors - Important MN’s:
- Vit C
- Vit E
- Vit A (beta-carotene)
- Copper
- Selenium
- Manganese
- Our bodies generate free radicals (oxidants) – when generated in excessive amounts they can damage cells and alter how cells function; they are linked to various diseases
- Molecules with antioxidant properties can stabilise free radicals – several 1000 work like this, key ones in the diet are vit C, E and beta-carotene
- Free radicals = unpaired electron – it wants to take an electron from a healthy atom to stabilise itself. When it takes this electron from a healthy atom it makes the healthy atom unstable.
- Molecules with antioxidants have spare electrons
- We produce free radicals during respiration – it is a stress response
Situations in which additional MN might be required:
1) - Hot, humid environments/ long duration exercise where sweat losses are high
- Magnesium, zinc, iron and sodium lost in greater quantities.
2) Weight making sports such as MMA, boxing which might require excessive weightless
- Most important two are calcium and iron (low iron causes fatigue)
3) Vegans at risk of vit B12 deficiency; cannot be obtained from non-meat sources
- Possibly also iron too; greatest source of heme iron, which is better absorbed, is meat
4) Vitamin D deficiency possible in climates where there is a lack of sunshine e.g., in the northern hemisphere
5) - Severe exercise induced muscle damage (e.g., strength recovery not evident > 7 days post) possible rationale for increased intake of antioxidant vitamins C & E
- Muscle gets damaged – inflammatory response = leads to increase in free radicals- this may cause further secondary damage, leading to less effective recovery
- Providing more antioxidants can dampen the increase in free radicals - This can be achieved more safely through eating foods that are rich in antioxidants e.g., vit C, E and polyphenols e.g., oranges and spinach
Redox balance
A balance between reduction and oxidation reactions
A balance of free radicals – free radicals on one side and antioxidants on the other
- Exercise generates more free radicals – e.g., via damage to muscle tissues and increased o2 – this is oxidative stress. Radicals now outweigh the endogenous antioxidants
- Consuming lots of vit C will lead to more antioxidants than free radicals
Effects of downhill running on free radical production
Recovery effects: muscles that are damaged also produce free radicals and therefore recovery could be delayed (muscle damage increases free radical production)
Down hill vs horizontal running – greater increase in free radicals after 3 days after downhill running.
- Causes = muscle are unaccustomed to downhill running, greater eccentric contractions when running downhill cause more muscle damage
Super foods:
- Several foods contain (poly)phenols (chemical compounds) that have antioxidant functions (amongst others) and are therefore tested for their ability to enhance performance and speed up recovery
- Polyphenols can dampen the free radical increase after exercise
- The results are mixed
- Polyphenols are often consumed in such small amounts that they are indirect antioxidants – they can indirectly upregulate other cells.
Research focus: to examine whether consuming large doses of vitamin C and E (as is common) can blunt muscle growth during resistance training (in untrained individuals)
- Findings: after 10 weeks of RT; those who consumed a Placebo had greater upper arm strength gains than those who consumed vit C and E
- Placebo group had greater % change in 1RM bicep curl
- *Several studies have not seen this effect
The effects of vit C and E on exercise-induced physiological adaptations: meta-analysis: - 8 studies – measured vo2 max
- Overall finding – there is no negative effect on vo2 max
- Large differences between studies
Data in animals – vit C and E are negative. Data in humans is less conclusive
General guidance = don’t consume high amounts of vit C and E as they can blunt training adaptations
