Game Changers, a recent Netflix special on the impact of a vegan diet, caused quite the buzz in the sports science world. While many in the science community are debunking and clarifying the research and evidence behind the film’s claims, I’m more concerned about supporting the vegan athlete with the knowledge needed to perform at the highest level. The vegan diet requires more diligent planning and attention to specific nutrient intakes than does the omnivore diet, and the demands of training and recovery have their own particular needs.

At Thorne, we believe in the one-size-fits-one approach to health and performance, which definitely applies to fueling plans for athletes. With any meal plan that restricts specific food sources, we must consider what nutrients could be lacking and address these deficiencies long-term.

A well-known study by Barr et al. examined the impact of vegetarian and non-vegetarian diets and concluded: “Short-term interventional studies in which subjects consumed vegetarian or non-vegetarian diets for test periods also detected no difference in performance parameters based on the presence or absence of foods derived from animal tissues. In line with these findings, previous reviews of the scientific literature have concluded that a well-planned and varied vegetarian diet can meet the needs of athletes.” 1

The focus should be on one crucial phrase in Barr’s summary – “well-planned and varied.” Studies on the impact of vegetarian and vegan diets now allow us to focus on several key areas to ensure we meet the “well-planned and varied” aspects of Barr’s recommendations:

  • Adequate total calories to fuel energy needs for the body, as well as training and recovery
  • Adequate omega-3 fatty acids, protein, and amino acids to support recovery, as well as muscle growth and repair
  • Adequate sources of the vitamins B12 and D, and the minerals iron, zinc, calcium, and iodine
  • Adequate creatine and beta-alanine intakes to support training and performance 

Macronutrient Considerations

We recently discussed the importance of adequate energy availability in athletes, and the impact that the continued failure to meet total calorie intake can have on health and performance issues. When compared to their counterparts, vegans have the lowest total calorie intake and the lowest protein and omega-3 fat intakes, two nutritional factors closely tied to long-term athletic performance. Vegans report average protein intakes of 83 grams per day, while omnivores report average intakes of 113 grams per day.2

A good general recommendation is 1.0-1.5 g protein per kg of weight daily for optimal health during moderate training; while more extreme training can require 1.5-2.2 g protein per kg of weight daily.*3  

Proteins, however, are not created equal when it comes to muscle growth and repair; plant-based proteins are often lower in essential amino acids than their animal-based counterparts. Essential amino acids are those parts of the protein we can’t make ourselves, so they must be obtained through the diet.

And plant-based proteins are significantly lower in three key essential amino acids: lysine, methionine, and leucine. Fortunately for the vegan athlete, lysine and methionine are found in legumes, grains, seeds, and nuts; so pairing these foods with plant-based protein powders can provide a complete amino acid profile. Thus, leucine is the biggest concern for vegan athletes. 

Leucine plays a vital role in stopping muscle breakdown after training and conditioning and initiating the recovery process,* and 2-3 grams of leucine are needed to start the recovery process.

Further complicating the protein picture, plant-based proteins are 10-40 percent less bioavailable – meaning your body has a harder time using the protein – than animal-based options. Therefore, vegan athletes are encouraged to aim for the upper range of athletic protein recommendations.

Omega-3 fatty acids represent a group of other essential nutrienst for athletes because they promote cardiovascular health, joint health, mental focus, immune function, and the body’s normal response to inflammation from exercise.*

In general, vegans consume lower amounts of omega-3 fatty acids than non-vegans,4 while athletes also tend to consume less than the recommended amount of omega-3s. A recent study of NCAA Division I football players found that 34 percent had significantly low omega-3 blood levels, while the remaining 66 percent had moderately low levels. None of the athletes surveyed had adequate omega-3 levels!5

Although vegans can obtain omega-3s from nuts and seeds, the plant version comes in the form known as alpha-linolenic acid (ALA), which the body must then convert to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Unfortunately, the conversion of ALA is inefficient, with only about eight percent converting to EPA and 0.5 percent converting to DHA. A good supplementation recommendation is 1-2 grams of combined DHA and EPA, with a higher concentration of DHA for all athletes, including vegans.

Micronutrient Considerations

The vegan diet, with its higher-than-average intake of fruits and vegetable, provides ample vitamins, minerals, and antioxidants, with a few exceptions.

Vitamin B12 is found only in animal products, so vegans are not able to obtain it in sufficient amounts in their diets. As such, an estimated  50 percent of vegans are deficient in vitamin B12and supplementation is recommended for vegan athletes.

Iron carries oxygen throughout the body; so low iron can manifest as weakness, fatigue, shortness of breath on exertion, dizziness, drowsiness, and irritability.* Athletes need approximately 1.5 times as much iron as non-athletes.

And vegans probably need almost twice as much iron from their diet as non-vegans because plant-based sources of iron are absorbed more poorly than animal-based iron. Blood loss from injury and muscle damage, as well as GI bleeding associated with extreme endurance activities, further decreases the body's iron stores. But always check iron levels before assuming extra iron supplementation is needed.

Zinc is an essential mineral that must be obtained in the diet or via supplementation. Zinc is vital for growth, immune function, testosterone metabolism, and numerous other functions inthe body.*

The majority of zinc in most diets comes from animal products, and although whole grains contain zinc, large intakes of whole grains are associated with a decrease in the amount of zinc absorbed because of zinc’s propensity to bind to compounds found in whole grains.

Calcium, essential for optimal bone and muscle health,* is another mineral often lacking in vegan athletes because it is found primarily in dairy products, and although there are plant-based sources of calcium, compounds in these plants can inhibit calcium absorption. Vegans consume 40-percent less calcium than non-vegans, resulting in a higher risk of bone fractures. Vegan athletes are encouraged to look for fortified milk alternatives and juices, or calcium supplements, to obtain the recommended 1,300 mg of calcium daily.

Vitamin D protects a number of important functions in the body.* In addition to supporting healthy bones and muscles, it supports cardiovascular health and immune function.* Vitamin D is synthesized from exposure to sunlight and is lacking in most foods, vegan or otherwise. Because the importance of vitamin D in athletes is well established, supplementation should be considered. 

Performance Supplement Considerations

Creatine is an amino acid  that supports increased work capacity and the power output of muscle, while also promoting physical endurance, gain of lean body mass, and cognitive function.* For athletes, creatine helps the body more efficiently create the energy needed to engage in exercise.*

It plays an essential role in the body's production of cellular energy because it helps make ATP, the form of energy used by all cells.* Strenuous regular exercise and muscle damage both increase the physiological need for creatine. Daily supplementation of 3-5 grams of creatine is recommended for all athletes, and there is some concern that vegan athletes start with lower creatine stores than their omnivore peers.

Beta-Alanine supports muscle capacity and resists muscle fatigue to benefit athletic performance.* Beta-alanine, an amino acid that promotes and maintains muscle endurance and output, has been shown to benefit athletic performance by supporting the production of carnosine in muscles.* Similar to creatine, vegan athletes often have lower levels of carnosine than meat-consuming athletes. The recommendation is that athletes consume 3-6 grams of beta-alanine daily when training.

As with any individual fueling plan, with adequate knowledge and planning, the vegan diet can support athletic performance and training at the highest level. Given the intricacies of understanding optimal vegan nutrition, as well as optimal athlete nutrition, vegan athletes should seek guidance from a sports dietitian or sports medicine team member to ensure both their human needs and their performance needs are being supported.


References

  1. Barr S, Rideout C. Nutritional considerations for vegetarian athletes. Nutrition 2004;20(7-8):696-703.
  2.  Clarys P, Deliens T, Huybrechts I, et al. Comparison of nutritional quality of the vegan, vegetarian, semi-vegetarian, pesco-vegetarian, and omnivorous diet. Nutrients 2014;6(3):1318-1332.
  3. Thomas D, Erdman K, Burke L. Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and athletic performance. J Acad Nutr Diet 2016;116(3):501-528. 
  4. Rogerson D. Vegan diets: practical advice for athletes and exercisers. J Int Soc Sports Nutr 2017;14:36. 
  5. Anzalone A, Carbuhn A, Jones L, et al. The omega-3 index in National Collegiate Athletic Association Division I collegiate football athletes. J Athl Train 2019;54(1):7-11.
  6. Gilsing A, Crowe F, Lloyd-Wright Z, et al. Serum concentrations of vitamin B12 and folate in British male omnivores, vegetarians, and vegans: results from a cross-sectional analysis of the EPIC-Oxford cohort study. Eur J Clin Nutr 2010;64(9):933-939.