Athletes have special needs when it comes
to fuelling for optimized performance.
Nutrition requirements are continuously shifting depending on the
desired activity as well personal goals such as weight loss or improvements to
lean muscle mass. There are a growing number of vegetarian athletes at the
amateur and professional levels which raises discussions on whether or not an
athlete is put at a disadvantage when choosing to eliminate some or a majority
of animal derived foods. While there are
several types of different vegetarian diets, including but not limited to lacto-,
ovo- and macro-, we are going to discuss the general trends that are seen
within vegetarian diets and their impact, or lack thereof on sport performance.
The major areas that vegetarians are
perceived to be at a disadvantage are with regards to protein quality, creatine
stores and iron bioavailability. As long as vegetarian athletes understand
these potential blind spots, strategies can be put in place to ensure what is
not consumed in diet is added to their targeted supplement regimen. This might
also require some changes to nutrient timing to ensure that nutrients, such as
iron, are given the best chance to be absorbed and utilized.
Protein intake is critical to the exercise recovery
process. The amino acids from protein are important building blocks that make
sure muscle repair and adaptation are maintained. Protein is also important for
promoting healthy aging and improving appetite regulation (Phillips, Chevalier, & Leidy, 2016). How much protein do we need? Protein needs can
increase when moving from endurance to strength based exercises, the research
indicates that athletes should look to maintain intake of at least 1.2 g/kg
bodyweight per day for endurance specific sports with some studies examining
strength and power sports showing benefit at 1.6-2.4g/kg bodyweight per day (Jager, et al., 2017).
protein source matter?
Vegetarian specific proteins have less
diversity when it comes to amino acid content compared to animal sources so
this means sometimes you have to consume more to guarantee you reach the right
amount and diversity of amino acids for success. To support a balanced protein intake,
vegetarians are encouraged to consume many different types of proteins (i.e.,
soy, rice, hemp, pea, pumpkin etc.) to have a well-rounded consumption of
essential amino acids (Joy, et al., 2013). One amino acid in particular, leucine,
is most important for stimulating muscle protein synthesis (Katsanos, et al. 2006). Leucine is not as
concentrated in vegetarian protein sources and as such, vegetarian athletes
need to make sure their intake equals 2-3 grams of leucine per protein serving,
to maximize muscle repair. This is as
easy as consuming 2-2.5 cups of lentils. One interesting study also looked at whey vs
soy proteins to answer the question of whether or not levels of testosterone
and estrogen changed and its effect on resistance training (Kalman, et al. 2007). It was found that 25 g of
soy protein taken within one hour after training had no significant changes to
testosterone or estrogen levels compared to a blend of whey concentrate and
isolate. This challenges the notion that soy isoflavones might alter exercise
adaptation via sex hormone modulation in resistance trained athletes. It would
be interesting to see this study followed up with longer duration, additional subjects,
and more stringent dietary controls.
home message: protein source does not matter as
long as you are getting the right amount, quality and diversity of protein.
Leucine is critical and if you are not able to reach the necessary amount of
leucine per serving of protein than vegetarian athletes are encouraged to add a
branch chain amino acid or leucine supplement for adequate maintenance of
skeletal muscle mass.
Well-designed vegetarian diets are diverse
in fibre, healthy fats, macro and micro nutrient intake but there are some nutrients
that are difficult to maintain. Iron and vitamin B12 in particular can be hard
to source for many vegetarians (Barr & Rideout, 2004). Both iron and vitamin B12 are important to
maintaining the body’s iron stores to prevent anaemia. In sport, especially
endurance athletes, anemia results in reduced muscle enzyme activity as well as
lowered oxygen and carbon dioxide transportation. As a result, athletes will
have reduced performance or early plateau with increased fatigue, weakness, and
potentially dizziness during activity (Chartard,
et al. 1999). Iron and vitamin B12 are difficult to absorb from vegetarian
sources. Non-animal sources of iron such as leafy greens, cereals, breads etc.
typically have marked reduction in intake due to the presence of calcium, phytate,
and bran. Vitamin B12, is a critical
part to iron metabolism , along with copper, so vegetarians must make sure they
have consistent intake. As athletes can lose iron from training, sweating,
bleeding, and menstruation this is an area vegetarian athletes are advised to
seek out lab testing to make sure their
needs are being met.
Omega 3 fatty
acids are important for cardiovascular health, management of the inflammatory
response and are also thought to improve heart-rate variability (Rogerson,
Omega 3s from vegetarian sources are
typically limited to algea or must be manufactured by the body through the
conversion of alpha-linolenic acid to EPA and DHA. Unfortunately not eveyrone
is efficient at this conversion raising the need for additional
supplementation. Still, there is
rational for improving the amount of flax, hemp, chia, and walnuts to optimize
intake of alpha-linolenic acid on top of a vegetarian sourced omega 3 fatty
Vegetarian diets are naturally low in
creatine, one of the most important ergogenic aids to performance. Sourced from
meat, fish and poultry, creatine improves short-term high intensity exercise,
strength and muscle growth. Supplementation of 3-5 g per day for four weeks of
creatine monohydrate in vegetarian athletes show improvements to fat free mass
and functional muscle changes compared to omnivores (Rogerson, 2017). There are a lot of myths regarding the
safety of creatine but it is still considered to be generally safe, well
tolerated by most, and available in synthetic non-animal sourced forms.
Vegetarian athletes are as capable of
succeeding as any other athlete provided their diet and supplement regimen is
finely tuned. Poorly constructed
vegetarian diets will leave athletes at a disadvantage so it is important that
these athletes ensure their protein intake is optimal along with attention to
their individual needs for nutrients such as iron, vitamin B12, and omega 3
fatty acids as well as ergogenic aids such as creatine.
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Lowery, R. P., Wilson, J. M., Purpura, M., De Souza, E. O., Wilson, S. M., et
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supplementation on body composition and exercise performance. Nutrition
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