Vitamins Flashcards
Vitamins are important for RBC formation, nucleotides for DNA, neurotransmitters, strong bones.. What vitamins do we need for these processes?
RBC formation: we need B-vitamins (B6, 12, folate): to make nucleotides for DNA
Neurotransmitters: we need B12
Strong bones: B,C (collagen), ETC.
What is an important cycle for B-vitamins?
methionine cycle
The methionine cycle is metabolically connected with the A. Vit B is needed for the conversion of B into C. Otherwise, problems with the D arise. Then you cannot make enough E, then RBC are not able to F
A folate metabolism
B Homocysteine
C methionine
D CNS
E DNA
F Divide (anaemia)
What is the best B6 status assessment?
- Whole blood/red blood cell B6: best mid-term indicator, not sensitive for inflammatory status (~50-180 nmol/L)
- Plasma/serum values significantly lower than whole blood levels!
Why do some tests for B6 status not indicate an intoxication, when in fact there is an intoxication?
Because there are 6 vitamin B6 vitamers:
- PLP is biologically active B6 vitamer!
- Most tests measure only PLP (routine labs), full B6 profile not common (research labs only)
- Might be intoxicated with the other monomers, but not PLP, which is the only one to show up on the test
How can folate be assessed?
- Plasma/serum folate: most widely used marker, ‘short term’
- Whole blood/red blood cell folate: best mid-term indicator, but laborious and prone to error (depends on Ht measurement), red blood cell = can be 100 days old (look back in time)
- ‘Total folate’ test most common in routine labs
- ‘gold standard’ microbial assay, but sensitive to e.g. antibiotic treatment
And more
How can B12 be assessed and what is an issue?
Direct plasma/serum B12 analysis (~ 200/300–600 pmol/L)
● Functional markers (holo-TC or methylmalonic acid) better than B12?
● Lack of standardisation between different B12 tests! Different results from different labs
What are deficiency signs of B6?
neurological dysfunction
What are deficiency signs of folate?
anemia, fatigue
What are deficiency signs of B12?
anaemia, fatigue, cognitive impairment
What are deficiency signs of vit D?
weak bones/fractures
- Deficiency increases risk of autoimmune diseases and can have profound effect on human immunity, inflammation, muscle function
Which is likely to be a public health concern?
B6, Folate, B12, D
Folate, vit D
Why does exercise not increase your vitamin requirements?
Vitamins are often co-factors and not usually lost during exercise.
What is a common statement about vit B which is not true?
‘All B-vitamins are excreted by the urine anyways’ they are water-soluble but this is not true: still toxic.
Are there vit B recommendations for the athletes? What are risk groups?
- With a balanced diet, no immediate concern for B-vitamin deficiencies
- Risk groups for deficiency: dietary restrictions, vegans (B12), use of certain medication (e.g. proton pump inhibitors, metformin)
Vit D: - Deficiency increases risk of autoimmune diseases and can have profound effect on human immunity, inflammation, muscle function. What is the accepted status marker for vit D?
25(OH)D = accepted status marker (25-hydroxy vitaminD3) in blood
It is estimated that X% = insufficient/deficient 25 (OH)D level at baseline (end of winter season). Fluctuation during seasons. Outdoor exercise elevates vitamin D levels
70%
What are some genomic and non-genomic functions of Vit D + muscle?
Genomic events
● Nuclear receptor
● Gene transcription and protein synthesis
● Muscle cell proliferation and calcium uptake
Non genomic events
● Calcium uptake sarcolemma
● MAPK signalling pathways
At what concentrations can you get hypercalcaemia?
(> 100 μg/day for extended
periods), but this intoxication from excess supplementation is very rare
Recommendations vit D?
- Stimulate outdoor exercise! (but consider skin cancer risk!)
- Screen athletes
● At least biannualy: late summer, winter
● history bone injury, frequent illness, restrained eating and indoors; strict vegetarians - Correct deficiencies (< 75 nmol/L)
- D3 slightly more effective than D2
- Dose
● Sun exposure
● 100 IU increases serum 25(OH)D ~2.5 nmol/L
● > 10.000 IU/day toxicity
ROS: the good and bad part?
Good: oxidative stress is a key ‘signal’ to promote adaptation & training (as well as to activate DNA repair mechanisms etc
Bad:
* Leads to cellular damage: DNA, proteins, lipids, Etc
Immune cells can also make ROS. Its function is..
against microbes
Recall three antioxidant vitamins
A,E,C (amongst others?)
Recall three endogenous zntioxidant systems with examples
Nonenzymatic systems
● Glutathione, bilirubine, coenzyme Q10
Enzymatic systems → detoxification
● Superoxide dismutase (SOD), glutathione peroxidase, catalase, etc.
Dietary factors! → scavenging
● Vitamin C, vitamin E, carotenoids, polyphenols
Why is it good to be careful with reducing oxidative stress?
- Some studies say that it hampers cellular adaptation to endurance training
Connect the right nutrient to the right words
- CH
- HFLC
- Protein
- Fluid
- Micronutrients
- Ergogenic aids
A winning edge
B stay hydrated
C prevent deficiencies
D training adaptation -> reduce CH reliance
E skeletal muscle reconditioning
F fueling HI exercise
1 F
2. D
3. E
4. B
5. C
6. A
