Ready for the weekend? I can’t believe it is Friday already, the week has flown by so fast! I’ve got some excellent information for you on sports nutrition recommendations, as well as some newer research to keep an eye on that may be of particular interest to those who follow a vegan or vegetarian way of eating. Also, if you think heme iron for vegans is “impossible,” you may reconsider after reading this article!
In this issue:
- IAAF Consensus Statement on Nutrition for Athletes
- Is Combining Plant-based Proteins Optimal?
- Leghemoglobin and the Impossible Burger
IAAF Consensus Statement on Nutrition for Athletes
Topics specific to sports nutrition are not covered often on this website, but if you are looking for some more information on this topic, I’ve got what you need today! What follows are some key findings from the International Association of Athletics Federations (IAAF) Consensus Statement on Nutrition for Athletes. If you are looking for some bedtime reading, the complete articles can all be found here. The information in bold is directly quoted from their website (here) with additional comments added by me:
- The usefulness of high-fat, low-carbohydrate diets is limited to selected individuals, events or scenarios in distance events. As is often repeated in nutrition advice, there is no one-size-fits-all diet that is best for everyone, so don’t assume that you must hop on the low-carb, high-fat (LCHF) train.
- Low Energy Availability, which can result when athletes consume less fuel than they are using, is a primary cause of RED-S, formerly known as Female Athlete Triad syndrome, in which disordered eating, loss of menstruation and osteoporosis occur, but can also contribute to reduced testosterone levels and libido in men, poor bone health, increased risk of illness and injury, gastrointestinal disturbances, cardiovascular disease, impaired training capacity
andperformance. It is crucial to eat enough to meet your high energy needs as an athlete! Loss of periods in young women due to a diet change is not healthy and can even negatively impact athletic performance. Eating too few calories can hurt male athletes as well, even though they will not have a loss of periods as an indicator of malnutrition.
- Low Energy Availability is known to be a major risk factor in the development of bone stress fractures and should be corrected in both the prevention and treatment of such problems. Again, it is essential to ensure that you are eating enough. Fractures will keep you out of the game!
- A food first philosophy is promoted in relation to nutritional needs, and supplements should only be used under supervision to treat or prevent nutrient deficiencies. Only five supplements have an evidence base of contributing to performance: caffeine, creatine, nitrate/beetroot juice, beta-alanine
andbicarbonate. But there is a risk of ingesting banned substances in the use of any supplements. There is so much misinformation online regarding the use of performance-enhancing supplements in sports nutrition. Keep these five in mind when considering whether a website is providing credible information. Better yet, check in with a registered dietitian if you have questions about using supplements.
- Nutrition can help during the rehabilitation of muscular injuries. Goals should include adjustment to new energy requirements and distribution of protein intake to minimize the loss of lean mass and increase muscle repair.
- No direct benefits have been associated with the avoidance of gluten by clinically healthy athletes. There are some completely legit reasons to avoid wheat/gluten including celiac disease, non-celiac gluten sensitivity, and wheat allergy. All this is saying is gluten-free diets are not linked to improvements in training capacity or performance in healthy athletes. It is generally not too difficult to cover the micronutrients in foods that contain gluten with other foods if someone chooses to do so, particularly if they are eating meat and/or gluten-free grains.
- Vegetarian diets can theoretically support athletic demands, but special attention and good planning are required to ensure adequate intake of energy and specific nutrients that are less abundant or less well absorbed from plant sources (e.g., iron). Vegetarians and vegans have nearly twice the RDA for iron compared to omnivores. Beans and iron-fortified cereals are two great sources. Enjoy plant-based foods containing iron with sources of vitamin C.
- Evidence that carbohydrates (CHO) consumed during exercise can provide an additional benefit via the brain and nervous system. CHO can stimulate areas of the brain that control pacing and reward systems via communication with receptors in the mouth and gut. This “mouth sensing” of CHO provides another reason for
frequentintake of CHO during longer events,and shorter ones in which it may not be necessary to provide muscle fuel.
One final thing to mention is that the statement really focused on the importance of personalized nutrition, so don’t hesitate to use the information that is most helpful to you and discard what isn’t working.
Is Combining Plant-based Proteins Optimal?
Since we are on the topic of sports nutrition this week, vegan or vegetarian athletes might want to keep an eye on the results of a new study which is seeking to challenge the current paradigm that combining of plant proteins is not necessary for optimal muscle protein synthesis (MPS) in plant-based athletes. I first learned of the study in the Nutrition Diva podcast episode here and recently realized I had not seen the study results yet. With a little digging, I found out they will not come out until late in 2020. So, stay tuned!
Truth be told, I can’t think of a good reason not to enjoy legumes with grains; they pair perfectly. Cuisines worldwide have found delicious and unusual ways to serve them together. A favorite of mine is a soup recipe (
If you are completely unaware of what all of the fuss is about, unlike the protein in animal-based whole foods, most sources of plant-based proteins are lacking in one or more of the essential amino acids that humans cannot synthesize (and thus must get from the diet). The current position of the Academy of Nutrition and Dietetics is that it is not necessary to combine plant proteins within each meal to make them “complete,” rather, consuming a variety of plant-based protein sources daily should be sufficient to ensure that vegans (and plant-heavy vegetarians) get the essential amino acids that they need. If you are interested in learning which plant foods are lacking in which amino acids, Monica Reinagel, MS, LDN, CNS has a helpful chart (here) that I am including below:
For those trying to lose weight who are avoiding meat solely because of concerns about inflammation (NOT ethics) this recent study may be of interest to you (graphic by Layne Norton, PhD, via Twitter):
The participants were all older folks who had type 2 diabetes. Essentially what this study found is that losing weight leads to decreased chronic inflammation, whether the person is relying on animal protein or plant protein. So, the assumption that a diet rich in animal foods is automatically highly inflammatory may not be correct. (Want to read the entire study? Check out
Leghemoglobin and the Impossible Burger
Remember how I said above that vegetarians and vegans have nearly twice the RDA for iron compared to omnivores? That is because compared to the heme iron available in animal-based foods, the nonheme iron in plant foods is less bioavailable. Not only that, but the heme iron in meat is thought to help the body to increase absorption from nonheme iron sources. Vegetarians should be aware that milk is not a good source of iron and eggs contain a protein called phosvitin which binds to iron, leading to poor bioavailability of the mineral from this food source.
However, science appears to be changing things. You may have read about the Impossible Burger, a plant-based burger made with soy leghemoglobin, a food component that Impossible Foods Inc. states is “identical to the heme humans have been consuming for hundreds of thousands of years -- in meat from animals.” (But is it really? More on this below!) If this claim is true, this means that (at least in theory) soy leghemoglobin could be used as a highly bioavailable vegan heme iron supplement in the future. Interesting!
Though soy leghemoglobin was initially isolated from the roots of soy plants, this heme is currently being extracted from yeast that
Concerning safety, soy leghemoglobin did not go through human trials before being introduced to the public. Instead, a 28-day trial on rats was conducted, where the rats were given “over 100 times greater than the 90th percentile estimated daily intake” with “no observed adverse effect.” Based on this study, “as well as other information available to FDA,” the FDA concluded that they “have no questions at this time regarding Impossible Foods’ conclusion that soy leghemoglobin preparation is GRAS” (i.e., Generally Recognized As Safe) and a new type of burger was born.
Back to Impossible Foods’ statement that their soy heme is identical to animal heme. There was a study conducted back in 2006 (read it here) looking at the bioavailability of bovine heme versus soy leghemoglobin. Maize tortillas were fortified with different iron sources. They found the plant heme and animal heme to have similar bioavailability, while nonheme iron had lower bioavailability. Great right? Not so fast… they also found that soy heme did not help to enhance the absorption of nonheme iron. The authors suggested that “the positive effects of meat on nonheme iron absorption may be due to factors in meat other than the hemoglobin fraction. The enhancing effect of animal tissue on nonheme iron bioavailability was generally attributed to the “meat factors” rather than hemoglobin.” Can we rightfully call these heme types “identical” when they behave so differently depending on the food matrix that surrounds them?
One final thought…
Impossible burger ingredients: Water, Soy Protein Concentrate, Coconut Oil, Sunflower Oil, Natural Flavors, 2% or less of: Potato Protein, Methylcellulose, Yeast Extract, Cultured Dextrose, Food Starch Modified, Soy Leghemoglobin, Salt, Soy Protein Isolate, Mixed Tocopherols (Vitamin E), Zinc Gluconate, Thiamine Hydrochloride (Vitamin B1), Sodium Ascorbate (Vitamin C), Niacin, Pyridoxine Hydrochloride (Vitamin B6), Riboflavin (Vitamin B2), Vitamin B12.
Beef burger ingredients: Beef
Since I generally recommend a “foods first” philosophy to nutrition (i.e., get your nutrition from whole foods, not supplements or fortified highly refined foods), my preference is to stick with the beef patty because it contains nutrients within their natural food matrix, the form that humans have consumed for many thousands of years. That said, I’m highly interested in the use of soy heme as a highly bioavailable plant-based iron supplement to help those who choose to eschew meat but are struggling with iron deficiency.