Nutrition and Immune Function

Question 1

How can athletes increase their susceptibility to URI symptoms

Answer 1

Symptoms of upper respiratory infections are why immunity is
Important in sport
- Prolonged exercise can increase chances of developing these symptoms
- Environment(pollution, cold air) affecting immune system

Question 2

What is the window of infection for athletes?

Answer 2

• 2hrs after exercise
  Data shows that: there is a window of infection after exercise, due to less immune cells to fight off pathogens

Question 3

What athletes is restricting energy intake most likely to effect?

What impact does this have on their immune system?

Answer 3

• boxers, cyclists, F1 drivers could to make weight, restricting food intake so not gaining all important nutrients needed for optimal immunity
• Illness in athletes is very important as it can cause them to miss training sessions, therefore missing adaptations

Question 4

Describe:
innate immunity
adaptive immunity

Answer 4

• innate immune system - already present, that people have from birth
• Adaptive immunity - more specific to pathogen, use of memory of previous exposure to eliminate pathogens

Question 5

What impact can low CHO diets have on stress hormones?

will this impact immunity?

what are the limitations to this research?

Answer 5

Stress hormone, cortisol, sig increase on low CHO diet 2 h post-exercise
- Cortisol decreases the activation of immune cells needed to fight off pathogens

- While CHO might reduce immune disturbances, there is little evidence that this translates to reduce incidence of illness. CHO might only confer an immune-related benefit when the exercise is prolonged in nature, not necessarily exhausting, and/or intermittent or of short duration.

Question 6

Can dehydration impact immune function?

Answer 6

• We want increased neutrophil degranulation, this is done through increased CHO
• Dehydration can also lower degranulation - impacting immune function

Question 7

Why is glutamine important for immunity of athletes?

Answer 7

Glutamine is an important energy source for both the innate & adaptive immune system (especially leukocytes)

Levels seem to rise during short duration HI exercise but fall during prolonged LI exercise

Question 8

What is the role of glutamine in relation to immunity?

does its supplementation help?

Answer 8

Glutamine lower in those reporting an infection & acute fatigue (B) and chronic fatigue (C) (or overtraining syndrome)
- People without an infection had higher glutamine

despite studies showing increase glutamine concentrations, there are several studies that have found no benefit on glutamine supplementation on either immune parameters or illness incidence (Gleeson, 2008).
* Limitation of mainly survey data
Those reporting no infection after prolonged exercise:
* Glutamine <80%
* Placebo >48%

Question 9

Why might increasing protein intake be beneficial to immune function?

Answer 9

• Increasing protein during intense training, gives your immune cells more chance to fight off pathogens
  
  • Problem: 3g/kg BM/day is a lot of protein intake, not feasible

Question 10

Name some vitamins important for immune function:

Answer 10

Water soluble Vitamins:
- Vitamin C
- Vitamins B6, folic acid, B12
Fat soluble vitamins:
- Vitamin A
- Vitamin D
- Vitamin E

Question 11

Does vitamin D impact the presence of URTI symptoms?

Answer 11

• Vitamin D has several roles in the immune system, and is important for upregulating various cells that fight off infection (Gleeson, 2016).
  
  • A few recent studies have suggested that supplementing with vitamin D could reduce URTI symptoms in the general population – likely that these effects would translate to athletes (many of who are vitamin D deficient).
  • Concluded that when Vit D supplements are consumed, it is beneficial for immune function, most beneficial in the winter months

Question 12

What is the benefit to immunity of probiotics?

Answer 12

• Caution; limited studies available and optimal dose/type of probiotic required for best results unknown
  
  • May help the gut microbiota, very important to have a healthy gut
  • Past 10yrs there have been 6 studies on probiotic effects, 0.63 is a moderate effect size for probiotics aiding immune function
  • Not transferrable as there are different strains of probiotics