Reductive Stress: An Argument Against Anti-Oxidants for Athletes & Everyone Else? Plus: AGE-Reduced Diets for Health & Weight Loss & Iron For Women in the Military

It's sort of funny that the mental fatigue is reduced, but the physical performance stagnates w/ iron supplementation.

You will probably already have seen the results of the latest study from the Norwegian School of Sport Sciences which provides additional evidence that "vitamin C and E supplementation interfere[s] with exercise-induced signalling in muscle cells after a session of strength training, by reducing the phosphorylation of p70S6K and mitogen activated protein kinases (MAPKs: p38 and ERK1/2)", two proteins with significant effect on the exercise induced increase in protein synthesis and corresponding increases in the overall adaptation to exercise, and "have the potential to adversely affect cellular adaptations to exercise in healthy individuals." (Paulsen. 2014).

To put this results into perspective I will briefly recap the main message of a corresponding review of the "sense and non-sense" of antioxidant supplementation in athletes from the University of Florida  to kick off today's installment of the Short News that will then turn towards the beneficial health and anti-obesity effects of AGE-reduced diets and the need for iron supplementation in physically active women.

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• Antioxidant supplementation in athletes, sense or non-sense? The bottom-line of the latest review of the literature appears to be clear: Non-sense! Why? Well, according to Powers & Sollanek (2014)...
• Regular bouts of endurance exercise will increase the endogenous antioxidant enzymes in the trained skeletal muscles. In view of the fact that this translates to an improved ability to protect against exercise-induced oxidative stress in skeletal muscles, supplements appear to be less useful for athletes than they are for sedentary individuals, anyways. 

• 

  Figure 1: . Illustration of the relationship between radicals (i.e., oxidants) and antioxidants in the determination of redox balance (i.e., balance between oxidants and antioxidants). Note that an increase in radicals or antioxidants results in a disturbance in redox balance. Figure from Powers & Sollanek (2014), redrawn from Powers et al. (2004)

  While there is consistent evidence of the beneficial health effects of an increased fruits and vegetables consumption, foods have two major advantages over vitamin supplements: (1) they contain a plethory of compounds with antioxidant activity, which differ in their cellular locations and radical scavenging capacity and will thus act synergistically; and (2) the amount of antioxidants is small enough to assume that ther is a limited risk of an antioxidant "overdose" and consequent i.e. "reductive stress" (see Figure 1) by consuming a diet rich in both fruits and vegetables.
• In contrast to fruits and vegetables, the ingestion of megadoses of antioxidant via dietary supplements (e.g., vitamin E) can increase the risk of toxicity and the associated possibility of negative health consequences.
Accordingly, the authors of the review conclude that "consuming megadoses of antioxidants via supplements is not recommended" (Powers. 2014).


• An AGE restricted diet reduces serum AGE and indices of body fat, study shows. In a 12 week randomized, controlled study scientists from the Universidad Guanajuato observed that the consumption of an AGE-reduced diet alone and in conjunction with exercise lead to a decrease in serum advanced glycation end product (AGE) levels and body fat - the addition of exercise provided additional benefits and lead to significant reductions in blood lipid levels.
  

  

  Figure 2: Changes in weight, waist, fasting blood glucose and blood lipids after 12 weeks on AGE reduced diet, exercise and exercise + AGE reduced diet (Macías-Cervantes. 2014)

  What is difficult to tell, though, is whether the reduction in body fat is a result of reduced AGE-levels in the diet and corresponding reductions in the blood of the participants or simply a consequence of eating a healthier diet - I mean, food products that are high in AGE are characteristic of the modern Western junk-food diet. It is thus also not surprising that the low AGE diet was both ~50% lower in AGEs and 26% lower in energy.
   
• Iron supplementation improves indicators of iron status and emotional fatigue in female offiers-in-training, study shows. Researchers who are working for the US military have recently been able to show that the exercise-induced decrease in iron-status in female officers during military training can be ameliorated by supplements with 18mg of iron that were consumed on a daily basis over the course of the 13-week study (Boot. 2014).
  

  

  Figure 3: Changes in selected markers of fatigue in iron vs. placebo supplemented women (Booth. 2014)

  As you can see in Figure 3 the provision of extra iron did not just blunt the decrease in serum ferritin in the ADFA students who participated in around 20 hours of classes (mainly lectures) and 2–7 hours of organized physical training (PT) per week, it did also have a significant effect on the emotional fatigue (-4.2 to -0.6 95% CI, P = 0.04).
  
  What is somewhat surprising, though, is that the effects on physical fatigue parameters were neither significant, nor positive.

Bottom line: There are new studies on the effects of food and supplements on our health on a daily basis. Things that we believe to be true today may be falsified tomorrow and agents that may be good for some people (like iron for athletes) and potentially bad for others are rather the rule than the exception.

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Accordingly, it's important to look beyond the ostensibly obvious results like "low AGE diets promote fat and weight loss". While this may be true, even the cursory analysis of the study results in today's SuppVersity short news indicates that the obvious conclusion that reducing AGEs would mechanistically reduce body fat is probably flawed. Rather than that people who avoid high AGE foods will necessary avoid foods with high energy density, consume less energy and lose weight in response to a reduction in energy intake - not in response to the reduced intake of AGEs. Problems like these are why it is important to look beyond the conclusions in the abstracts and / or come back to the SuppVersity regularly for short and in-depth analyses of the latest studies | Comment on Facebook.

References:

• Booth, Christine K., Julia E. Carins, and Iain K. Robertson. "Randomised double-blind, placebo-controlled trial of iron supplementation attenuates fatigue and declining iron stores for female officers-in-training." RegisteR Now! 22.3 (2014).
• Paulsen, G., et al. "Vitamin C and E supplementation alters protein signalling after a strength training session, but not muscle growth during 10 weeks of training." The Journal of Physiology (2014). 
• Powers, Scott K., et al. "Dietary antioxidants and exercise." Journal of sports sciences 22.1 (2004): 81-94.
• Powers & Sollanek. "Endurance Exercise And Antioxidant Supplementation: Sense Or Nonsense?-Part 1." Sports Science Exchange 27.137 (2014): 1-4.