Sports Nutrition – Page 5 – GUTSy Performance Nutrition

Iron + The Athlete: Considerations for Intake and Absorption

October 15, 2021by Rebecca1 Comment

I took my first formal nutrition class back in 2014. At the time, I already had a ton of nutrition knowledge, both from on-the-job training and from personal study, but I was beginning to realize I wanted to shift my career from public health into individual nutrition.

As a female and athlete (with digestive issues), I had always struggled with iron, despite eating a fairly high iron diet. At first, I also ate some red meat, and in my nutrition class, we had to complete a three-day food log and perform a nutritional analysis. I was easily meeting the recommended dietary allowance (RDA) for iron. When I asked my instructor about it, a locally practicing registered dietician, she told me, “If you’re consuming the RDA in iron, you should not have low iron status.”

That conversation turned out to be a good jumping off point for wanting to know a whole lot more about nutrition, and nutrient and lifestyle interactions.

If you’re an athlete (male or female), and you’ve ever wondered about what all the hype is on iron, or why you have low iron, or what exercise has to do with iron regulation and absorption, this article is for you.

The Role of Iron and How Iron Deficiency Impacts Athletic Performance

First let’s review what iron does in the body. When we speak about iron, we’re often speaking about it in the context of iron-deficiency anemia. There are many reasons for anemia, not just low iron stores, but iron-deficiency anemia is the most common. Anemia at its most literal means “without blood.” And that’s where we start to talk about iron (though again there are other nutrient depletions that can also cause anemia).

Iron is an essential part of oxygen transport and energy production at a cellular level, and is important for cognitive and immune function (1,2). Hence the reason you feel fatigued when your body is without iron. Note that low energy is also a feature of many nutrient deficiencies since many nutrients are involved in cellular energy production.

For endurance athletes, iron is dually important because it is used for multiple metabolic pathways, including 1) it is used for oxygen transport to the exercising muscle and 2) the production of ATP (energy) is highly reliant on iron.

Common symptoms of compromised iron status include fatigue, lethargy, negative mood, and poor performance during endurance exercise.

A Hormone Called Hepcidin and its Impact on Iron Absorption

Hepcidin is an inflammatory and iron-regulatory hormone that increases for 3 to 6 hours after exercise. This is likely a result of the exercise-induced inflammatory response, and associated increases in an inflammatory cytokine, interleukin-6 (IL-6). Increases in hepcidin result in a decrease in iron absorption as well as decreases in recycling iron from the gut.

So there’s likely a window of time following exercise where the body has altered iron metabolism.

Who is at risk for iron deficiency? The mechanisms that influence iron absorption in athletes

Traditionally, we think of compromised iron status as something that females suffer from. This is because women in their menstruating years generally lose iron through blood loss each month; whereas men should not be losing blood. However, active women are estimated to be twice as likely to present with Iron Deficiency Non-Anemia (stage 2 of iron deficiency) than sedentary, non-active women. Among athletes, we see much higher iron deficiency rates than in the general population with estimates of greater than 50% of female athletes and up to 30% of male athletes having compromised iron stores (1).

Both testosterone and estrogen can influence iron metabolism because they suppress hepcidin (more on this hormone above). When women are exercising at a high training load, this may result in an altered hormonal profile, with gonadotropin-releasing hormone (GnRH), which is a sex-hormone precursor, being suppressed. Consequently, luteinising hormone (LH), follicle stimulating hormone (FSH), and then estrogen will be suppressed. So lower estrogen leads to higher hepcidin (or at least less suppression of hepcidin), and thus more difficulty in absorbing iron.

Likewise, the same result can happen in males with a high training load, with gonadotropin-releasing hormone being suppressed, and consequently suppressed testosterone, and less suppression of hepcidin. In turn, chronically low testosterone in males may be linked to higher hepcidin levels, potentially impairing iron regulation.

Another variable is relative energy deficiency- what I call not eating enough for one’s activity level. Overall low energy availability (LEA) and energy intake may relate to either an overall deficit in dietary iron intake, and/or a dysfunction in iron absorption from the foods that are consumed.

Further, we’re also finding that the makeup of one’s microbiome also affects iron absorption, with iron-deficient individuals lacking lactobacilli species–a key species often cited with good health. Many other bacteria also require iron for growth (3).

Otherwise, vegetarian and vegan / plant-based diets can also impact iron absorption and stores since non-heme plant sources of iron are more difficult to absorb. A big one though, is the general state of your digestion. You have to have good digestive function to assimilate the nutrient.

Finally, some good news: the inflammatory response following exercise can be reduced after long exercise bouts of two hours or longer by consuming carbohydrates during exercise. Eating during exercise decreases the depletion of glycogen stores in the muscle (2), and ingesting carbohydrate during exercise has also been shown to improve the recovery response from long/high intensity efforts.

The Stages of Iron Deficiency:

Stage 1: Iron Deficiency: Iron stores in the bone marrow, liver, and spleen are depleted, indicated by ferritin values less than 35ug/L, Hemoglobin values > 115 g/L, (11.5) and transferrin saturation >16%

Stage 2: Iron-Deficient Non-Anemia: Red blood cell production decreases as the iron supply to the bone marrow is reduced, indicated by ferritin values less than 20ug/L, Hemoglobin >115 g/L (11.5), and transferrin saturation < 16%

Stage 3: Iron Deficiency Anemia: Hemoglobin production falls, resulting in anemia, indicated by ferritin values less than 12 ug/L, Hemoglobin <115 g/L, transferrin saturation less than 16%.

From current research, it appears that depleted iron stores (in stage 1) have minimal or no impact on physical performance, but this is likely particular to you as an individual–some athletes will notice the impact sooner.

What You Are Eating in Your Diet and Iron Status

The timing, amount and source of iron from your diet, in combination with the overall composition of the diet are all important factors to consider when looking at iron status. The most easily absorbed source of iron is heme iron (from meat).

The presence of Vitamin C can enhance non-heme iron absorption, but vitamin C is destroyed by heat (and light), so cooking a vitamin C-rich food into a dish will likely not help much. A couple squeezes of citrus juice at the end of cooking when the food is on your plate can be an effective method to get around this.

Otherwise, polyphenols, phytates, oxalates, calcium, zinc, copper, and vitamin E, which are all part of many nutritious, plant-rich diets and in particular are in whole grains, legumes, leafy greens, and tea and coffee, can decrease the amount of non-heme iron that is absorbed in a meal. Suddenly, your (or my) quinoa salad bowl with nuts, seeds, lentils, spinach and other dark leafy greens, and tahini or almond sauce is not a recipe for a hearty, iron-absorptive meal. Note, these are foods that are frequently on the high-in-iron list! And there are ways to prepare them to make their iron more absorbable, such as soaking, sprouting, fermenting, etc.

Want to Know More?

Within my nutrition practice, I specialize in endurance athletes and digestive imbalances. If you’ve struggled with chronically low iron, or recently have experienced it, I encourage you to reach out to me for more personalized support about how to boost iron around your exercise load.

References:

1). Sim, M., Garvican-Lewis, L.A., Cox, G.R., Govus, A., McKay, A.K.A.,…and Peeling, P. (2019). Iron considerations for the athlete: a narrative review. European Journal of Applied Physiology, 119: 1463-1478. https://doi.org/10.1007/s00421-019-04157-y.

2). McKay, A.K.A., Pyne, D.B., Burke, L.M. and Peeling, P. (2020). Iron Metabolism: Interactions with Energy and Carbohydrate Availability. Nutrients, 12: 3692. https://doi.org/10.3390/nu12123692.

3. Frame, L. (2021, October 7th). Mixed Diet and the Microbiome- Challenges with Complexity. Linus Pauling Institute Diet and Optimum Health Conference, Corvallis, OR, United States.

Nutrition + Health, Running

Barriers to Healing: Ownership or Attachment to our Struggles

September 28, 2021by RebeccaLeave a Comment

I’ve been reminded lately of barriers we put in place that prevent us from healing chronic health challenges, or negative habits.

That barrier is how we attach ourselves to and start to own our struggles.

Here are a few example statements that illustrate this:
– My typical GI struggles.
– I’ve always hated vegetables.
– I’ve always struggled with digestion. So have my parents.
– I’ve had that ever since I was kid. I’ve always had it.
– I never recover well during a (marathon) training cycle, and never get my nutrition and health to go right enough to be prepared for the race.
– My anemia pattern.

Another example is identifying with our diagnosis or diet pattern as if it were a job title. This is often easily visible on social media. You might witness or use something like IBS Warrior or Ulcerative Colitis Warrior, or Celiac next to a name in a bio, as an example.

I’ll use my past self as another example. For a long time, I felt like whatever medical mystery that presented as something autoimmune meant I’d be in daily chronic pain forever. This began at age 27. I was in constant fear and anxiety about the pain, and I felt like I couldn’t get outside that experience, even temporarily. Fast forward seven years and my body and mind feel remarkably different. The cloud of bleakness hanging over me, the fear of pain, the internal anguish that I couldn’t understand is no longer part of my everyday.

Yes, when it comes to healing something that has been chronic, finding the right nutrition plan and lifestyle practices are incredibly important. But healing is also energetic. You have to believe it’s possible. And you have to change your mindset and the energy you put around the process.

You have to believe your body is meant to heal.

And we start to believe what we say about ourselves. By saying we always struggle with something, that means deep down that we probably believe we will always struggle with it.

This simple, though definitely not easy, nugget of first changing what we say (out loud and internally) is what catalyzes healing. We start to believe lasting healing is possible. We seek out and then are put into connection with individuals who further light the healing pathway from whatever we’re currently experiencing – an autoimmune condition, IBS, chronic fatigue, a lifetime of emotional and disordered eating and body hate, weight woes, medical diagnoses that are largely written off, etc.

And sometimes our catalyst for healing is just an example from another person.

For instance, we all operate within a community, whether that’s in person in our daily lives, or people we follow online who influence us. Often, we identify with individuals who have journeyed through similar experiences and challenges as us.

What often distinguishes individuals who are incredibly good at healing themselves for the long term, and those that have chronic set-backs, lies in what the first group don’t spend their time doing.

These “experts at healing” don’t hang out in forums or self-help groups with individuals discussing the woes of their symptoms or how bad it is. They get out of their negative head space as soon as they notice they’ve fallen into it. They change their language in how they talk about their health. Instead of statements like “I always struggle with….” or “My faulty digestion….”, they view a health challenge as a temporary setback. My digestion is currently less than ideal — That’s a less permanent way to state that.

Or I haven’t yet arrived at the end of a training cycle feeling like I’ve nailed my nutrition and recovery strategies, but I believe it’s possible and I’m committed to exploring what has prevented me in the past.

Or My doctor believes I have lupus that I’ve put into semi-remission enough to be below the threshold for clinical diagnosis. I am not a victim. And I’m committed to my nutrition and lifestyle practices to continue my journey towards complete healing. This statement was my personal example.

In my case, I refused to mentally identify with or use the word lupus. For one, I didn’t have an actual diagnosis. But for me, that choice was energetic. This is similar to (before then) never using the words celiac, IBS, or dysbiosis about myself–though they were all either likely or true. These words we attach ourselves to are incredibly powerful. And here I am a handful of years later, and I haven’t thought about the words “autoimmune” or “lupus,” “IBS,” or “dysbiosis” as it relates to myself in quite a while.

Think about how you can shift the statements you make about your health. Catch yourself when you say what “you’ve always” said about your situation. Restate it in a less attached, or less in ownership, way.

Let the way you speak be a catalyst for how you think about your health.

*Note on the book pictured above: I don’t remember the plot. But I do remember it was part of my finding joy and rewiring how I thought about my health process.

Nutrition + Health, Running, Summertime

Training the Gut for and during Long Runs and Endurance Sports

June 29, 2021June 23, 2021by RebeccaLeave a Comment

Now that it’s full on summer, let’s check in about a topic that is pertinent for all the endurance athletes, and particularly runners, with wonky guts and/or rigid beliefs about fueling during longer efforts.

I’ve heard so many variations on the following over my years as a runner:
“I can’t eat anything before a run, ever.”
“I can’t eat anything during a run.”
“ I can’t drink anything more than a little water during a run.”
“I have no appetite for hours (or days) after a run and my GI is messed up for several days.”
“I’m not recovering from long runs or races as well as I used to.”

If you currently relate to any of those statements, I want you to know that the digestive system is highly adaptable. Gastric emptying as well as stomach comfort can be ‘trained’ during endurance activities.

Stored glycogen, or the amount of carbohydrates in our system already, are depleted after about 80 minutes at marathon pace, so for most athletes training for longer efforts, fueling with some sort of carbohydrate during exercise is essential. This training of the gut can improve the delivery of nutrients during exercise so during these long efforts, your system gets the fuel you need and are ingesting, and alleviates some (and perhaps all) of your negative GI symptoms.

How Can I Train my Gut?

What we currently know is that the stomach can adapt to ingesting large volumes of both solids, fluids, or combinations of the two.

Just think about those competitive eaters who can down dozens of hot dogs in a matter of minutes. Disgusting thought, I know, but they have to train their systems to do it! For endurance athletes needing fuel for the long run, we need to do our own version of gut training.

This happens both during and outside of exercise because eating a higher carbohydrate diet leads to our intestinal cells, called enterocytes, being able to absorb and utilize carbohydrates as fuel more efficiently.

To get sugar (carbohydrates) from our small intestine where absorption occurs into our blood, the sugar molecules mostly have to be transported across the membrane by glucose or fructose transporters. Think of a taxi transporting you from the airport to your destination. When we eat a diet high in carbohydrates, our body naturally increases the number of sugar taxis (glucose and fructose transporters).

You’ll notice some of these taxis are sodium-dependent, which is a super essential nutrient for endurance exercise, particularly in the summer, but a topic for another day.

We also know that increasing dietary intake of carbohydrates increases the rate of gastric emptying. This occurs rapidly with a change in diet, within just a few days. So what this means is that you can fuel with more carbohydrate before exercise, fuel with more carbohydrate during exercise, not feel like you’re running around with a giant, full, sloshy gut, and perform the training run or race better, because you were using the fuel you needed to perform adequately.

And, we also now have evidence that when you fuel with the appropriate amount of carbohydrates before, during and after an exercise bout, recovery from hard efforts is substantially improved.

When your body has all the sugar taxis it needs to get carbohydrates out of the digestive system and into the blood stream for circulation and use as fuel as quickly and efficiently as possible, and our body gets used to using carbohydrates added on the go as fuel, the chances of developing GI complaints during exercise are much smaller.

Win, win, and win, in my opinion.

How Much Carbohydrate Can and Should I Be able to Tolerate ?

How much carbohydrates you need or should consume during exercise depends on a few factors. One, how long you’re going to be out there. Two, the intensity of the effort. And three, your gender.

Exogenous carbohydrate oxidation, or the amount of carbohydrates we can use during exercise, peaks around 60 grams per hour when it comes from glucose only. When fructose is ingested in addition to glucose, carbohydrate oxidation rates are elevated above 60 grams per hour, to 90 to 120 grams per hour (when the gut has been trained). In women, however, we have evidence that carbohydrate oxidation rates appear to be maximized at about 60 grams of carbohydrates per hour (2). If you’re a female and looking to maximize your fueling and racing/recovering capacity, you can experiment with ingesting more than 60 grams per hour. This upper limit will likely be individual.

The current guidelines for fueling are to take in up to about 60 grams per hour of carbohydrates for exercise lasting up to two hours.

And when the effort lasts longer than 2 hours, men should experiment with increasing their intake to slightly greater amounts of carbohydrate (90g/hr), but women may feel best at sticking with 60 grams per hour. These carbohydrates should be a mix of glucose and fructose or maltodextrin and fructose. Virtually every sports nutrition product for use during exercise includes a mixture of carbohydrates these days so most people will not need to worry about getting the different sources. And most do-it-yourself whole food fuel sources will also include both fructose and glucose.

Note that sucrose, which is contained within many whole foods and is also what makes up simple table sugar, is a disaccharide, meaning it has two different sugar compounds, fructose and glucose.

Here’s another way to look at the timeline of fueling needs:

Exercise Duration	0-59 minutes	1 hour	2 hours	2.5 hours	3 hours
Grams of Carbohydrate Per Hour	none	30	30-60g : women Up to 70 g/hr: men (higher intensity = higher need)	30-60g : women Up to 70 g/hr: men	60 g: women (can experiment with more) Up to 90 g: men (can experiment with up to 120 g)

How Long Does Training the Gut Take?

If you’re training for a race and practicing fueling during long efforts, it doesn’t take more than a few days to a couple weeks to increase those sugar taxis in your gut. Based on animal data, an increase in dietary carbohydrate from 40 to 70% could result in a doubling of SGLT1 transporters over a period of two weeks (1).

But it’s important to practice your race nutritional strategy in training, get used to higher volumes of solid or liquid intakes, and higher carbohydrate intakes both during and outside of training.

As always with fueling for sports, it will take a little individual experimenting and tweaking to find what works for you so you’re less likely to end up looking like this during your next long run or race:

Will Training My Gut Fix all my Exercise-Related Digestive Woes?

Perhaps following the above recommendations will be a simple answer to fixing all your exercise-caused angry/sad midsection woes.

But many people with digestive systems that are more prone to upset also need to pay special attention to what you are and aren’t consuming, and how much you’re eating in all the hours outside of training. This can be very individual.

Want to Know More?

Within my nutrition practice, I specialize in digestive imbalances. Often when we’re experiencing chronic GI distress, fatigue, and/or malabsorption of foods and nutrients, there will be imbalances in several systems of the body simultaneously. I shared more about this topic in the nervous system’s role in part 1, the immune response and subsequent inflammation in part two, gut microbes and dysbiosis in part three and the importance of chewing our food in part four. Check those out or reach out to me for more personalized support for gut healing, or to go from not being able to tolerate fueling, to training your gut for the amount you need.

References:

1). Jeukendrup, A.E. (2017). Training the Gut for Athletes. Sports Medicine, 47(Suppl 1): S101-S110. https://doi.org/10.1007/s40279-017-0690-6
2). Wallis, G.A, et al. (2007). Dose-response effects of ingested carbohydrate on exercise metabolism in women. Medicine and Science in Sports and Exercise, 39(1): 131-8. https://doi.org/10.1249/01.mss.0000241645.28467.d3.