A poor quality diet could predispose vegan athletes to macronutrient and micronutrient deficiencies, compromised immunity, reduced strength and limit training adaptions. This post provides nutrition advice for vegan athletes to ensure optimal balance, health and performance gains can be achieved.
Why is a balanced diet important for vegan athletes?
Vegetarian and vegan diets tend to be lower in protein, fat vitamin B12, riboflavin, vitamin D, calcium, iron and zinc compared to diets including animal products.
An athlete with a poor quality vegan diet is potentially more likely to have deficiencies in certain macronutrients (protein, omega 3) and micronutrients (B12, vitamin D, iron, zinc, calcium and iodine), limiting their ability to train, recover and perform optimally.
Macronutrients for vegan athletes
If insufficient energy is consumed on a vegan diet, this can compromise an athletes’ immune function leading to undesired illness and time off training or competition.
Inadequate protein or carbohydrate intake may lead to weight loss in vegan athletes which could translate into lost muscle mass, reduced strength, a lower work capacity and lack of training adaptations.
It is essential for vegan athletes to optimise their protein intake. This requires paying attention to both the quantity and quality of protein being eaten.
Plant based protein sources are incomplete, missing essential amino acids and containing less BCAA than animal based protein sources.
It is no longer necessary to combine protein sources each meal to achieve a complete amino acid profile – providing there is enough variation in protein sources eaten each day.
Supplemental protein in the form of protein powders can be very useful for vegan athletes, especially if eating adequate protein through whole foods is difficult/inconvenient.
There is emerging evidence that plant based protein powders can improve recovery after training and support muscle hypertrophy.
Plant-based protein is less digestible meaning vegan athletes might need to consume more protein than meat eaters to compensate for poor digestibility
Vegan athletes should aim for protein intakes of:
- 1.4-2.0g/kg/day during weight maintenance or weight gain periods
- 1.8-2.7g/kg/day for weight loss periods to account for reduced digestibility and low biological value of plant-based sources.
Vegan diets are typically rich in carbohydrate foods rich in fibre and resistant starch, such as grains, legumes, fruit and vege. However, a high fibre diet can promote gastric distress and bloating, particularly if the increase in fibre is done rapidly.
Vegan diets may be lower in omega-3 fatty acids which may have health and performance implications as omega-3 fats increase nitric oxide production and heart-rate variability
Consuming a microalgae oil rich in DHA and EPA may be useful for vegan and vegetarian athletes as this has been shown to raise both blood EPA and DHA levels. To achieve DHA levels of 500-1000 mg, 1-2g microalgae or 2-4 capsules would be necessary. Flaxseed, walnuts and chia seeds are other valuable food sources.
Micronutrients for vegan athletes
Vegan athletes should prioritise food sources containing vitamin B12, iron, zinc, calcium, iodine and vitamin D.
Long term B12 deficiency results in irreversible neurological damage, with 50% of vegans B12 deficient and an additional 21% showing very low levels of B12 in their blood. Most vitamin B12 supplementation practices are inadequate to achieve B12 sufficiency.
Bioavailable plant based B12 is unusual unless the plant has been contaminated by manure of from animal waste. This is because the plant-based forms are inactive. Suitable food sources include B12 fortified breakfast cereal, nutritional yeast and supplements. Spirulina supplements often claim to be a source of vitamin B12, but this is an inactive form. Read more about spirulina.
There is a limited capacity to absorb oral vitamin B12 supplements. Of a 500ug supplement, only 10ug might be absorbed. Vegans are advised to take up to 6ug per day of supplemental B12. Where this can’t be achieved by food and supplements alone, subcutaneous or intramuscular injections are critical. Vegan athletes should be very conscious of monitoring their B12 levels for their longterm health.
Nutrition surveys suggest that vegans eat similar amounts of iron to omnivores. Despite a lower bioavailability of plant-based iron, low iron intakes and low iron levels in the blood results in intestinal adaptations to increase absorption.
Dietary inhibitors such as polyphenols, tannin (coffee, tea, cocoa) and phytates (wholegrains legumes) reduce absorption. To optimise bioavailability, vegan athletes should choose wholefood iron sources, reduce consumption of inhibitors (tea coffee cocoa), consume vitamin c rich foods to enhance absorption and soaked, sprouted and fermented foods in the diet
Current recommendations suggest that vegetarians and vegans increase their iron intakes by 80% to – 14mg/day for men and 33mg women.
Zinc is required for cell growth repair and protein metabolism, with higher requirements in men than women. Vegans may need 50% more zinc than omnivores due to poor bioavailability and phytate reducing absorption.
Plant based zinc rich foods include pumpkin seeds, hemp, grains, nuts and beans. Soaking, fermenting and sprouting nuts and grains can help reduce phytate levels and increase nutrient bioavailability.
Vegans should consume 16.5mg zinc (male) 12mg/day (women).
Studies suggest that vegans have a higher risk of fracture and habitually consume less calcium. Calcium plays an important role in blood clotting, nerve transmission, muscle stimulation, vitamin D metabolism and bone structure.
A calcium intake of 1000mg/d considered sufficient for most athletic populations
Plant based sources of calcium include beans, pulses and green veg, particularly broccoli, bok choy and kale. Spinach and rocket/arugula contain oxalates that limit calcium absorption. Read a previous post about plant-based sources of calcium.
Iodine is a trace element necessary for physical and mental growth and development, thyroid function and metabolism. Vegans can have both excessively high and low intakes depending on their diet.
Certain vegetables including cabbage and cauliflower decrease iodine utilisation if consumed in large amounts. However, cooking destroys many of these compounds making the goiterous effect likely unless consuming large quantities of these vegetables raw.
Seaweed and sea vegetables are concentrated vegan friendly sources of iodine.
Vitamin D is essential for calcium absorption and bone health. The best source of vitamin D is spending small amounts of time with the skin exposed to the sun. Vegan friendly versions of cholecalciferol (D3) are derived from lichen – 200-1000IU per serving. Wild mushrooms are a natural source of vitamin D and you can bump up the vitamin D content of mushrooms by sticking them upside down in the sun before eating them. Read more about why you should put your mushrooms in the sun.
Creatine supplementation can improve short-term high-intensity exercise performance, muscle hypertrophy and maximal strength, with the greatest benefit shown in athletes with low muscle creatine stores. Those following vegetarian and vegan diets have reduced muscle creatine stores. Vegetarians who supplemented with creatine increased fat-free mass, maximal strength and type II muscle fibres. Vegan friendly creatine powders are available (capsuled creatine supplements not suitable).
To achieve muscle creatine saturation, creatine dosing of 20g/day for 3-7 days followed by a daily maintenance dose of 3-5g should be followed. Taking 3-5g/day for 4 weeks has a similar effect. Taking creatine together with protein and carbohydrate may increase retention by insulin mediated storage.
Vegetarians may have lower muscle carnosine, with beta-alanine supplementation shown to improve high intensity exercise by buffering excess protons, scavenging free radicals and reducing fatigue.
Optimal beta-alanine dosing of 4-6g/day for 2-3 weeks is recommended.
Reference: Rogerson, D. (2017). “Vegan diets: practical advice for athletes and exercisers.” Journal of the International Society of Sports Nutrition 14(1): 36.