In an interesting article, “Exercise-induced stress behavior, gut-microbiota-brain axis and diet: a systematic review for athletes“ was published in the Journal of the International Society of Sports Nutrition – Alison Clarke, talks about a suspected relationship that I have wondered for some time – and that is, endurance exercise impact on gut health and its systemic implications – notably mental health.
As we’ve published in other articles, it’s no surprise that the GI tract and gut takes quiet a hammering from endurance exercise. Think about it, endurance athletes subject themselves to exercise sessions lasting anywhere from two to eight hours or more. Here’s what’s happening in the gut,
- blood supply is shunted away from the gut, and redirected towards the working muscles, creating a relative hypoxic (low oxygenation) state, and commonly dehydrated state of the gastrointestinal cells,
- dramatic increase in inflammatory triggers (cytokines etc.) from the prolonged intense physical exercise,
- consumption of high simple-carb (gels, sugar bars/drinks) low fiber and little-no probiotic foods, resulting in imbalanced gut bacterial populations as well as mucous-membrane integrity breakdown.
In her study conclusions, the author highlights this exacerbated inflammation of the gut in athletes, resulting in altered ratios of gut bacterial (microbiome) populations – giving rise to alterations in hormones and inflammatory triggers – that are likely to be directly related to the athletes’ mental state (anxieties, depression) and as a result.
As endurance athletes, training for extended periods is the lifestyle we lead and cutting this out, isn’t really an option. But, taking a quick look at foods that could be worsening or improving gut health and mental state, is more than worthwhile, particularly in this year of social-change and societal isolation.
Ok, lets first put aside obvious foods that directly impact mental state – namely foods high in carbs (and caffeine), that spike our blood supply followed by a consequent insulin hit, and a subsequent crash in blood sugars making us feel dull and lacking energy.
I want to talk more about the foods that are consumed by endurance athletes that effect on the gut membrane integrity, the gut microbiome, and thereby possibly the mental state.
Carb Types – your Gut, your Mental State…
As highlighted above in point 3, its not just the fact that carbs are being used in high amounts by athletes – but it’s the type of carbohydrate and sweeteners being used. Training-racing drinks, bars and gels pervasively use fructose (note that ~50% of sugar, or sucrose, is fructose), and artificial sweeteners (sugar alcohols). In both animal and human studies, fructose and sugar-alcohols have shown there negative effect on gut microbiome populations, and increasing gut membrane permeability. Research has shown that increased gut membrane permeability from fructose consumption, resulted in LPS (Lipopolysaccharides, or gut endotoxins) being 2.6X higher in the circulation, than in cases where fructose was not added to the diet. In research on humans, endotoxin (LPS) levels were higher in obese, vs. non-obese cases, plus gut-membranes showed a lack of tight-junction proteins (gut membrane integrity marker) in obese cases, but not in non-obese. Aside from endotoxin exposure into the circulatory system, other systemic inflammatory triggers (i.e. TNF Tumor Necrosis Factor) are higher in fructose fed animals.
Multiple research efforts have been conducted, and papers published on the association of higher circulatory LPS and TNF levels, and depressive mood and neuro-inflammatory disease states.
Now again, sucrose/fructose intake is just one of three factors effecting the gut of the athlete, but we highlight it here – as its the one we can effect and improve.
What can we do: Healthy Gut, Upbeat Mood.
Firstly, lets compartmentalize exercise under the hour, vs. exercise over the hour. For sub-hour training sessions (or for that matter racing), no consumption of carbohydrate is needed, or warranted in light of the body holding ~2500 calories of glycogen in the muscles and liver – which should last 2hours or more. For endurance training lasting over the hour, and then beyond two hours – the athlete does need to consider fat and carbohydrate consumption, depending on the intensity – you can read more about that in this article.
Now for hydration-fueling during and after training/racing –
- Replace Fructose and sugar-alcohol based drinks, bars and Gels – and replace with SFuels TRAIN (MCT-collagen based calories, electrolytes and Glutamine). This formula avoids the use of fructose, and sugar alcohol based sweeteners, and uses Glutamine, as a proven amino-acid that re-establishes the gut membrane integrity, to stop the leaking of LPS out of the gut and into the circulation.
- Replace Fructose and sugar-alcohol based protein recovery shakes, shake-powders and bars with SFuels Revival Recovery shake (Whey Protein Isolate, high-dose Glutamine and BHB Ketone salts.) and SFuels LIFE Bars (Why protein Isolate, resistant Starch) to support recovery of muscle-connective tissue, gut membranes and intestinal microbiome populations.
What about every-day diet? Obviously, we want to cut bakc, if not avoid fructose consumption in our day to day diet. Here’s a list of foods you’re going to find higher in Fructose – and you will want to replace:
- sports/energy drinks – replace, with no fructose/sugar alcohol alternatives, like SFuels TRAIN, and SFuels Race+
- nutrition bars – replace with bars without added fructose, honey, sucrose, and dried fruits – like SFuels LIFE Bars,
- fruit juices – switch for your own home-made iced-tea, sweetening with monk fruit and a little lemon
- pop/soft drinks – just avoid these. Watch for sugar alcohols in ‘Zero’ calories sodas,
- dried/canned fruits – watch out for muesli and granola,
- fruits like apples, pears, mango, custard apples, dates – switch to fresh-natural whole fruit-foods like avocado, raspberries, peach, lemon-lime, apricots. Best to have with some fat-oil and fibre.
- sweetened yoghurts – avoid. Use a greek full-fat plain yoghurt, add some of the fresh fruits noted above, and mix in some SFuels LIFE – Strawberry Lemonade if you want some sweeter taste, and more fat.
- sauces (like ketchup, grill marinades etc.) – read the labels.
- salad dressings – read the labels
- and, obviously candies (check your granola bars) are full of it, specially high fructose corn syrup blends.
Here’s a guide on transforming every-day meals/recipes, high on sugar (commonly fructose and sucrose), to low-carb and low-no fructose.
From our companies philosophic point of view, Going Longer isn’t just about the one training session. Going Longer, is about being able to put in day after day, week after week, year after year of endurance training. Consistent training blocks, and the building of systemic health, longevity and a vibrant mental outlook. So when we designed our products we thought about your Endurance now, and the longevity of health and wellbeing into the future.
Well that’s our ‘Gut-Feel’ on it all, and keeping you upbeat. All the best in health, training and racing. Go Longer.