HPN 12: Fueling with Fructose Malabsorption, Loss of Appetite When Training, and Heavy Metals in Protein Powders — Poor Science or Cause for Concern?

December 13, 2019


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Welcome to episode 12 of Holistic Performance Nutrition (HPN) featuring Tawnee Gibson, MS, CSCS, CISSN, and Julie McCloskey, a certified holistic nutrition coach who you can find over at wildandwell.fit.

On this episode:

Intro banter

  • Tawnee shares about introducing new foods to Cora and how chicken liver & Vital Choice Salmon roe were a big hit.
  • Do babies eat intuitively (based on what they know they need) vs. preferentially (what they want)?
  • Tawnee’s Instagram stories has baby food recipes and tips.
  • How Julie gears up to run outdoors in winter conditions:

Hanna B. from Germany asks:

Fueling a MTB race with Fructose Malabsorption (and Hormone Tie In?)

So great to have Tawnee back on the show, I follow you on Instagram and love seeing all the chubby baby pictures, it makes my heart smile every time.

I have a question regarding fructose malabsorption in terms of fueling during a race.

After suffering from severe gastrointestinal issues for almost 8 months and having to bail on most of my cycling and running training, I was finally diagnosed with fructose malabsorption via a hydrogen breath test. It also explains why I would feel like taking gels (SiS isotonic gels) would almost make me feel slower and give me gut problems. It’s not just fructose from fruits I can’t have, but also onions, broccoli, certain beans, and a variety of other vegetables, as well as normal white/brown sugar as this is often up to 50% fructose. It seems I also only do well eating small portions. The upside is that now that I know what ails me, I can dial in my diet properly, and have started working out again despite losing a lot of fitness. Next year I’ll be racing an 84 km Mountain Bike Race with quite a bit of elevation, I will need a good 5 1/2 hours to complete that race, and I have no idea how to fuel it. The aid stations usually have isotonic drinks with sugar that I can’t have, nor can I have the watermelon or bananas or coke (ew) offered.

Since I am just re-starting my base training now and have a lot of time to test and get used to foods during a race, are there any practical tips you could give me?

I know that I will be using a lot of glycogen as it will be a hard race with a lot of climbing, so I would like to replenish that. I can have pure glucose, dextrose and maltodextrin. Does the body absorb these differently or is there any timing issue that I need to look out for?

I know you aren’t nutritionists per se, but since there are a few other fructose malabsorbant people in some of my Facebook groups, any answer from trainers would probably benefit them as well.

It was a fructose breath test, I’ll have to wait for a while to take a SIBO test. I’ve cut down on FODMAPs and it seems to help. However, even classifying FODMAPS isn’t easy as different websites list different things, and I’ll be fine with some foods listed as “bad”. Fiber is also still difficult, I’ve started adding psyllium husks to my morning smoothies to get my gut used to it. Water kefir seems to help, and my safe foods are white rice and boiled eggs. Ha. Maybe I can fuel a race with that.

I know this sounds insane but I have a feeling that my reproductive hormones play a part in this, as my periods have become very irregular when this started, although the GYN said everything is fine. He (my male GYN), says I don’t need a hormone test, so I’m looking for a new one to get tested.

As far as numbers, all I have are the lab results from the Fructose breath test.

I had 18 ppm as a baseline which was already high, then it went up to 55 after 15 minutes, 85 after 30 minutes and over 100 after 45 minutes. I had such pain that I had to go home and lie down.

It’s not easy and I’m thankful for any input.

What the Coaches say:

101 Definitions

  • Intolerance – dose dependent response. An individual will be able to tolerate some of that food, but if over consumed symptoms can start to occur. Can present as brain fog, skin issues, GI distress, headaches.
  • Malabsorption – contents or nutrients in the food aren’t digested properly because they are not successfully transported through the intestinal wall. Some contents will be absorbed, but some won’t.
  • Allergy – can’t tolerate any.

What is Fructose?

  • Monosaccharide – simple carbohydrate – stuck in small intestine and draws water to itself in the small intestine can cause painful diarrhea, etc.
  • Foods high in fructose: Apples, pears, mangos, melons, honey is 40% fructose, artichokes, cauliflower, onions, beets, sweet potatoes, high-fructose corn syrup soft drinks fruit juices, dried fruit.
  • There’s a limit to how much we can digest at once, a healthy amount of fructose in one sitting is 25-30mg or 2 apples.
    • If you have IBS or a level of leaky gut that will be WAY too much for you because you have less cells to digest it in your intestinal wall.
  • When you have too much at once, or have the malabsorption, they will sit in your SI and ferment, and can continue to travel down to the colon fermenting along the way causing more gas and bloating.
  • This undigested fructose is overfeeding your bacteria, so probiotic foods might not be a good call.

Fructose Malabsorption

  • Why is this happening?
    • Contrary to previous hypotheses, the study by Wilder-Smith et al. demonstrates that fructose intolerance with malabsorption may not be secondary to changes in the duodenal expression of the fructose transporters or their production. Despite GLUT5 and GLUT2 being established as the primary fructose transporters, the connection between a biological mechanism for fructose transport and malabsorption remains elusive.
    • Factors that may influence the degree of absorption include rapid small intestinal transit time, bacterial overgrowth, developmental patterns, and varying glucocorticoid and thyroid hormonal roles.”
  • Some level of intestinal permeability going on. From what? Celiac? Autoimmune? Inflammation? Stress? Pesticides? Antibiotics? Parasite?
  • You should be able to get to a point where you can handle at least some fructose again.

Healing Protocol

  • Start by focusing on healing the gut with the 5R Approach from the Institute of Functional Medicine:
    • Remove – allergens, parasites, yeasts, bacteria…some sort of elimination diet i.e. low fodmap
    • Replace – digestive secretions with HcL, digestive enzymes (Thorne Betaine HCL or Thorne BioGest)
    • Reinoculate – with pre and probiotics
    • Repair – antioxidants (zinc, ACES), glutamine (after inflammation has gone down), vitamin D
      • Glutamine may feed inflammation?
    • Rebalance – sleep, exercise, stress
  • Hormone tie-in?
    • Gut-brain axis – correlation between gut dysfunction and training/life stress.
    • Also, more comprehensive gut testing to see what else may be going on (GI MAP, etc.).
    • If you have gut issue, makes more difficult to heal irregular periods.
    • Stress affects gut and menstruation.
    • “HPA axis activation is also able to affect the composition of the gut microbiota and increase gastrointestinal permeability.”
    • Look into running a DUTCH test.
    • Take a step back and evaluate level of stress in life, get real with self. Will this require time off from training and racing? Or can you still achieve some level of training while healing? These are hard realities we have to get real with in our own unique journeys!
      • Defer MTB race to following year?
    • Low FODMAP can temporarily be very beneficial during a healing protocol, but not meant to be a long-term solution.
    • Don’t rely on psyllium husk (fiber supplement) alone. Do the work to fix your gut!
  • How to Support your Race?
    • Sports nutrition products are rampant in fructose so we have to be discerning to find a good alternative.
    • No fructose product like Vfuel (dextrose, maltodextrin, mct oil)
    • Make homemade white rice balls (a la Allen Lim), energy balls?
    • Create your own fuel using this resource (lists the amount of sugar and fructose in foods).
    • Able to have some fructose? Finding your sweet spot…we’ve gone overboard with the quantity of fruit we eat, could be what caused it.

Allison asks:

Loss of Appetite for Ironman Training

I am a 24 year old vegan triathlete training for my first Ironman in Florida on November 2nd. I am a former college soccer player and I did triathlons in the summer as a way to stay in shape, once I was done with soccer (around the end of 2017) I decided to get serious with training for triathlons. I have done several sprint and Olympic distance races, and 2 70.3s. I started training for my first full Ironman in May and have been steadily increasing my training load in preparation. My training schedule has been around 15-20 hours of training for several weeks now. In the past 2 weeks I have been struggling to eat on the days that I have long hours of training (usually on the weekends that I bike 4+ hours with a 3-4 mile run after and then a 14+ mile run the next day). Normally I want to eat every 2 hours because I’m so hungry but on these days I have to force myself to eat 1, maybe 2 meals if I can get the mental strength to do it. I’ve never had problems with eating enough food before and I don’t want to get to the point where lack of calories and nutrients causes an injury. I was wondering if you had any ideas as to why this is happening and if you had any advice on overcoming it.

What the Coaches say:

What’s going on?

  • Hormonal response:
    • Decrease in Ghrelin – stimulate hungers
    • Increase in Peptide YY – signal satiety
    • Endurance exercise can suppress ghrelin while increasing peptide YY, resulting in you not feeling hungry. This doesn’t mean you don’t need the calories though!
    • Stress shunts the blood away from digestive system.
  • No Effect of Exercise Intensity on Appetite in Highly-Trained Endurance Women
    • Similar to males, post-exercise appetite regulatory hormones were altered toward suppression in highly-trained women and independent of energy cost of exercise.

Listening to our body, doing good for our body

  • Good for you for being mindful of your health and caloric needs!
  • Intuitive eating is only good to a point. This is one case where we need to overrule that and instead do what we know is best for our body and health.
  • Julie shares personal experience of “not feeling hungry” and the detriments of following that.


  • Set up home environment for success to stimulate hunger post-workout.
  • Eat something quick and fast immediately and see if that then stimulates appetite for a full meal within another hour or two.
    • Things to try and eat when not hungry:
    • Aminos, collagen, easy to digest proteins and carbs.
    • Spoon & jar of nut butter, coconut butter.
    • Try pre-making a smoothie and sip on it right away, or spoonful of nut butter & banana, coconut butter, bone broth, and so on.
  • If you find yourself ravenous on your off days when you body is finally able to reset, that’s a sign to be more diligent with eating more during your training days.

Anonymous asks:

Are there heavy metals in protein supps?

Thanks as always for a great show. About protein supplements. Is it a good idea to limit protein supplements because heavy metals are found in many of them? https://www.consumerreports.org/dietary-supplements/heavy-metals-in-protein-supplements/ 

What about: 

  • Bone broth protein–is there an issue with Lead?
  • Vegan protein powders? They seem to be the worse on that article!

What the Coaches say:

Seeking out quality information

  • Being a skeptic and not believing everything we read or see. Identifying a true peer-reviewed study vs. mysterious reports.
  • The Clean Label Project, who’s making these claims, seems to have a lack of transparency and other problems with the scientific process.
  • “Detectable” Does Not Mean Unsafe
    • “Many plant-based products contain detectable or measurable levels of heavy metals like cadmium, lead, arsenic and mercury. These heavy metals and others are naturally occurring in the earth’s crust and its soil. As a result, heavy metals are detectable in many plant-based foods and plant-based supplement ingredients. Finding detectable levels of heavy metals in plant-based products is not a surprise and is not evidence of a health risk. It simply means the laboratory instrumentation is sophisticated enough to detect these elements.”
  • Heavy metals are almost impossible to avoid, but the dose makes the poison.

A need to worry about heavy metals?

  • Heavy metals are, unfortunately, all around us:
    • Exposure to this heavy metal is almost impossible to avoid. The most common environmental exposures are encountered through inhaling exhaust fumes, cigarette smoke, and industrial airborne pollutants. It can leach out of improperly fired ceramic pottery to contaminate food. Homes built prior to 1978 are likely to have been painted with lead paint. The most common environmental nonindustrial exposure to lead is from drinking water and in communities residing around incinerators, toxic dumps, and manufacturing industries utilizing and releasing lead into the env.
  • Heavy metals in other foods (namely fruits and veg) due to soil.
  • In the Clean Label Project report: the top 5 cleanest were whey protein, and worst 5 were plant-based:
    • “70% of protein powders tested detectable levels of lead”
    • “75% of plant-based powders tested positive lead”
  • Crisis with our soil quality, and it begs the question are other foods contaminated with heavy metals, not just protein powder?
  • We just can do our best – shop local, shop organic, and so on.
  • Whole foods first, use protein powders as a supplement not a food staple. Although, for athletes on a vegan plant-based diet this may be harder to achieve:
    • Chris Kresser – Why the Optimal Human Diet Includes Animal Protein – in this podcast, Kresser outlines how much protein supplementation is needed for those on vegan diets. Worth a listen if you eat plant-based to make sure you’re meeting your needs!
    • Does this higher need for supplements and powders veer us away from the original intention of eating a more whole-food plant-based diet?
  • Switch up foods, powders and supplements to maintain variety, different amino acids profiles and so on.

Nutrient Synergy

  • Eat as many whole foods as possible, limit your powders, and don’t worry about heavy metal toxicity unless your environment/career/water is loaded with it!
  • Mineral/Metal Competitors:
    • Selenium/Mercury
    • Calcium/Lead
    • Iron/Arsenic
    • Zinc/Cadmium
  • Calcium and lead are absorbed at the same site in the intestine, which prefers calcium over lead. If the diet contains adequate calcium, ingested lead passes through the GI tract and is excreted. Vit C with bioflavonoids helps neutralize the effects of lead in the system. Eating foods high in pectin such as apples helps reduce the amount of lead present in the digestive tract
  • Cadmium can be displaced using increased supplementation of calcium, zinc, magnesium and a trace mineral supplements such as alfalfa. Rutin, a common bioflavonoid included in many vitamin C supplements is also useful in displacing cadmium

Bone broth and bone broth proteins

  • The risk of lead contamination in bone broth diets.
  • “A small, blinded, controlled study of lead concentrations in three different types of organic chicken broth showed that such broths do indeed contain several times the lead concentration of the water with which the broth is made. In particular, broth made from skin and cartilage taken off the bone once the chicken had been cooked with the bones in situ, and chicken-bone broth, were both found to have markedly high lead concentrations, of 9.5 and 7.01 μg L(-1), respectively (compared with a control value for tap water treated in the same way of 0.89 μg L(-1)). In view of the dangers of lead consumption to the human body, we recommend that doctors and nutritionists take the risk of lead contamination into consideration when advising patients about bone broth diets.”
  • However, the EPA says the limit for what’s considered safe to consume is 15 ug/L.
  • Essential and toxic metals in animal bone broths
  • “The Ca and Mg levels in home-made or commercial broth/soup were found not to exceed low tenths of milligram per serving, or <5% of the daily recommended levels. The risks that are associated with the ingestion of heavy metals such as Pb and Cd in broth are minimal because the levels were in the ranges of a few μg per serving.”
  • Kara Fitzgerald’s in-house report testing bone broth:
    • “In short, we found very low-to-no lead in our three beef bone broth samples, whether organic or conventional, homemade or store-bought. Even better, most other toxic metals we tested in broth were undetected, or in amounts far below our concern threshold. The bovine collagen powder yielded  low-to undetectable levels of lead and other toxic metals.”
  • Perhaps be mindful of the source you use to make bone broth. Chickens can tolerate higher levels of lead. Seek out organic, pastured chicken and beef bones. Beef bones might be more pure. Also, how are you preparing your bone broth? What kind of metals may be leaching from the pots we use? Use high-quality pots and pans!
  • Bottom line: Don’t stress over heavy metals in bone broth.

Protein powder recommendations

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