Week 8 (2) - vits, minerals and antioxidants Flashcards

Question

Electrolytes - Important MN’s:

Answer 1

* 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

Answer 2

* 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

Answer 3

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

Answer 4

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

Answer 5

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

Answer 6

- 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.

Answer 7

- 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