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dcyphr | Vegan diets: practical advice for athletes and exercisers
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Contributors
Daniel Amuedo

I am a premedical student at Missouri St...

Janet Hsu

Hi! I am a Molecular, Cellular, and Deve...

Abstract 

    Social media has rapidly grown as a medium to disperse information. The popularity of social media has led certain movements such as veganism to become more visible to the average person. This exposure helps veganism to become more accepted by the mainstream. Despite this there is a lack of research on how to properly manage a vegan diet for athletic causes. The researchers of this study reviewed applicable research papers regarding vegan diets. There is little data regarding sports nutrition specifically. Veganism can create nutritional challenges that need to be accounted for. The reviewed articles mention Sufficiency of energy, protein, vitamin B12, iron, zinc, calcium, iodine and vitamin D, and the lack of long chain fatty acids. However, these can all be managed with strategic food management and proper supplementation. The purpose of this paper is to show that an inclusive and healthy vegan diet can be created for athletes. Beta-alanine and creatine were suggested as supplements that could be of great use to vegans. However, empirical research is needed to observe the effects of these diets in athletes.


Background 

    Veganism is a form of vegetarianism that prohibits the consumption of any animal or animal product. The increased visibility of celebrities that abide by veganism suggests veganism could be more wide-spread accepted. However, poorly planned vegan diets can produce deficiencies in certain macronutrients (protein, n-3) and micronutrients( Vitamin B12 and D; iron, zinc, calcium, iodine). Vegan diets are even purported to have potential performance benefits due to the antioxidant(polyphenols), extra micro nutrients( vitamin C, E) and carbohydrate rich foods that aid in recovery. However, there are no studies that provide data on this subject.

     In order for a balanced diet basic dietary requirements must be met. In order for this to be applicable to athletes it must also be sufficient for their energy requirements. This is the aim of this research paper. The researchers wanted to provide practical recommendations for dieticians, coaches, or trainers who work with vegan athletes. Special attention will be given towards achieving proper macro/micro nutrients requirements for athletes. 


Main Text 

Information in this review has been gathered from a broad range of academic disciplines. In some instances, recommendations in this article have yet to be proved via empirical investigation. 


Energy 

Omnivorous diets provide sufficient energy to most athletes. Very large athletes may have a harder time acquiring the proper caloric intake. On the other end is athletes with very low body weight who are at risk for developing low density bones as a result of their training and eating habits. Additionally high intensity training can reduce appetite along with various other factors such as hectic travel schedules. 

 The consequence of not acquiring enough energy is far reaching. Potential loss of immune function, weight loss, and reduced muscle power and tone. Managing a proper diet can be difficult for those not a vegan diet. The harmful effects of an improper diet can be inflated by a diet that promotes early satiety. The vegan diet is rich in fibre and emphasizes raw foods. These all lead someone to early satiety when eating a meal, and can cause less calories to be ingested. This can lead to restricted macronutrient (protein) absorption. Having early satiety in meals is good for weight loss regiments, but can cause issues in athletes who require high calorie meals. However, increasing eating frequency and intake of energy dense foods such as seeds, oils, and nuts can be helpful to meet the caloric needs of the athlete. Careful monitoring of unwanted body mass fluctuations would help the athlete to better tailor their diet to their caloric needs. 


Macronutrients 

(1)  Protein 

     The general consensus is that athletes require more protein than non-athletes. Strength training athletes are recommended 1.6-1.7grams per kg of body mass per day, whereas endurance is recommended 1.2-1.4grams per kg of body mass per day. This is significantly more than the 0.8grams per kg of body mass per day recommended for non athletes. The role of protein in the human body is not obvious. The balance between Muscle Protein Breakdown (MPB) and Muscle Protein Synthesis (MPS) is known as Net Protein Balance (NPB). In order to build muscle an athlete must achieve elevated levels of MPS. This will promote recovery, adaption, and muscle building. However, in conditions where the athlete consumes less overall calories than normal they might still require elevated protein intake to preserve muscle mass. 

     Vegan athletes however consume less protein than their omnivorous and vegetarian equivalents. Plant-based protein is often incomplete. It is missing essential amino acids, and contains significantly less Branched Chain Amino Acids (BCAA) than their animal protein counterparts. The amino acid Leucine appears to be a trigger of recovery and (MPS). Evidence suggests that milk-based proteins might be superior to other protein sources at promoting MPS. This is thought to be due to the higher concentration of (BCAA). Similarly, it has been found that regular consumption of milk protein gives better muscle growth than the Soy-protein equivalent. The amino acids commonly missing from plant protein are lysine, methionine, isoleucine, threonine and tryptophan. Lysine is commonly absent from grain. However foods such as beans and legumes are rich in Lysine. Lysine can also be obtained from soy beans and lentils. BCAAs can be found in seeds, tree nuts, and chickpeas. The Academy of Nutrition and Dietetics (AND) recommend vegans/ vegetarians consume a variety of foods to meet their protein requirements. High protein foods are uncooked Pumpkin seeds, uncooked Lentils, uncooked black beans, raw almonds, tofu, oats, and Quinoa. At this time plant based protein supplements are less researched. Further research is required to understand the effects of animal protein supplementation in a vegan diet if protein acquisitions from wholefoods proves implausible. 


Protein Digestibility 

Systems created to quantify a protein's digestibility both show that animal-derived protein scores higher than plant-based protein. Important plant-based protein sources such as rice, peas, and hemp score significantly lower than animal-derived. To compensate for the lower digestibility of plant-based protein it is advised that vegans consume a higher than recommended dose of protein. This would account for the decreased digestibility of the plant-based protein. 


(2) Carbohydrate

Vegan diets tend to be high in carbohydrates. It has been suggested that endurance athletes adopt vegan diets in order to meet their carbohydrate needs or to assist in weight management. In order to achieve more than required protein consumption it is recommended that vegans consume lentils, grains, pulses, and beans daily. The issue with this is that those foods are high in fiber and thus contribute significant bulk and increase the satiety signal. This leads to decreased intake and prolonged satiety feelings.  For athletes with higher caloric needs this may prove to be ineffective. High fiber diets can also cause Gastrointestinal issues for some individuals. Therefore to meet this caloric intake it is recommended that vegan athletes consume foods such as rice, pasta, noodles, and buckwheat to meet their caloric intake. 


Carbohydrate Timing and Supplementation 

Carbohydrate doses can be scaled with respect to the intensity and duration of the athletic event. Generally, carbohydrates are vegan-friendly and their consumption is reasonable for vegan athletes. Alternatively, calcium fortified fruit juice as a liquid carbohydrate might serve two purposes. It can provide adequate carbohydrate requirements while meeting the calcium requirements simultaneously. 



(3) Fat

Vegan diets are typically lower in saturated fats than omnivores. This is associated with less cardiovascular issues such as heart disease, hypertension, type II diabetes, excess cholesterol, or cancer. However, the harmful effects of fat consumption are not universally agreed upon. Lower fat consumption can have negative effects on testosterone production in males. Which might be of importance to athletes trying to maximize muscle growth. However, evidence has shown that vegan males do not have statistically significant lower levels of testosterone than omnivores. The relationship between athletic performance, hormones, and fats requires additional research. Attention should be paid to quantity and quality of consumed fats. Adequate consumption 0.5-1.5grams per kg of body mass per day is easily achievable for vegans by consumptions of oils, avacadods, nuts, and seeds. 


(4) ALA, EPA and DHA 

Vegans do not eat marine life, thus they appear to consume less n-3 fatty acids. Vegans have overall lower levels of n-3 Fatty acids inside their blood. n-3 fatty acids are important for normal growth and development, cardiovascular health, immunity, and in chronic disease. n-3 fatty acids also increase nitric oxide production and improve heart function. n-3 fatty acids also contain anti-inflammatory properties, antithrombotic, antiarrhythmic, vasodilatory, antiproliferative properties. Both n-6 and n-3 fatty acids are essential and the n-3 (EPA) and n-6 (DHA) are under consumed by vegans. Thus vegans are encouraged to combine food sources of ALA with supplemental DHA from microalgae oil to optimize a vegan’s n-3 intake. Optimization of the vegan diet for n-3 intake is currently lacking at the time of this article's writing. However, recommendations of 1-2 grams per day of EPA and DHA in a 2:1 ratio have been suggested for athletes elsewhere. 



Micronutrients 

    Proper micronutrient intake is crucial to all athletes. It has been recommended that special attention be given to Vitamin B12, iron, zin, calcium, iodine, and Vitamin D intakes.    


(1) Vitamin B12

    Animal and Dairy products contain large amounts of vitamin B12 (cobalamin). Therefore vegans are at increased risk of developing B12 deficiencies. There are no plant based sources of cobalamin. The only time cobalamin would be in a plant is if it was contaminated with manure from animal waste. Cobalamin is vital to nervous system function, metabolism, homeostasis, and DNA synthesis. Short term B12 deficiencies led to changes in blood cells and neurological issues. Long term B12 deficiencies can lead to irreversible neurological damage. 

    Roughly 50% of vegans tested are low for B12 and 21% are considered very low. Surprisingly vegans who took B12 supplements did not have blood levels statistically different than vegans who didn’t take B12 supplements. Which indicates that supplements are not enough to achieve sufficient vitamin B12 levels. Sources suitable for vegans are breakfast cereals enriched with vitamin B12 and nutritional yeast. It is estimated that only 2% of Vitamin B12 supplements will be absorbed into the body. Vegans are advised to consume up to 6 ug per day of vitamin B12. 


(2) Iron

Vegans and Vegetarians consume similar levels of iron as omnivores. Most likely due to consumption of whole-grains and legumes. However, the iron found in plant matter is in the non-haem form that is less useful to the body than the haem form that is found in animal matter. Vegan diets also commonly contain dietary inhibitors such as polyphenols tannin (found in coffee, tea, and coca) and phytates (found in whole grain and legumes). These inhibitors reduce the amount of iron absorbed from the diet into the body. Research has shown that male vegans tend to have sufficient iron stores, but female vegans do not. This can lead to anemia. Due to the iron type, and the presence of polyphenol inhibitors it is advised that vegans consume up to 1.8 times the normal recommended amount for omnivores. It has been suggested that high iron intakes cause other mineral interactions and cardiovascular issues. Vegan athletes should eat wholefood iron sources, reduce consumption of inhibitors, contain foods, and incorporate soaked, sprouted and/or fermented foods to their diets. Females with large menstrual loss may consider taking additional iron supplements 


(3) Zinc 

Zinc is vital for various enzymatic processes involving DNA. Zinc has similar absorption issues to iron. Some studies say that vegans do not need to pay special attention to increased consumption as the body adjusts to decreased zinc intake. While others suggest consuming 50%% more zinc than recommended. Common sources of zinc are beans, whole grains, nuts, and seeds. Zinc should not be consumed at the same time as other supplemental forms of folic acid, iron, calcium, copper, or magnesium. Doing so will decrease the absorption of zinc. Multivitamins might not be enough to ensure the proper amounts of nutrients are absorbed. It is recommended that vegans consume zinc rich foods such as hemp, pumpkin seeds, and other grains, nuts and beans. 


(4) Calcium 

    Large amounts of Calcium are found in dairy products. Vegans have been shown to be at a higher risk of bone fracture due to decreased calcium intake. This can be especially problematic for growing children or teens. As with most nutrients the body can change the amount absorbed from a diet to better meet the body's needs. It is reported that protein rich diets do not promote calcium excretion. They actually work to increase calcium retention and bone metabolism. Calcium is necessary for blood clotting, nerve transmission, muscle stimulation, vitamin D metabolism, and maintaining bone structure. Vegan athletes should consume plant-based sources of calcium such as beans, pulses, and green vegetables to achieve 1000 mg per day. Broccoli, bok choy and kale are particularly high in calcium. Green vegetables such as spinach and arugula contain a compound that inhibits calcium absorption. Vegans athletes are also advised to eat calcium fortified foods if whole-foods are not plausible for their lifestyle. 


(5) Iodine 

    Iodine is an essential element needed for physical and mental growth + development. It also plays a pivotal role in metabolism. Vegans eat either excessively large or small amounts of iodine depending on their diet choices. A study found that 80%% of Slovakian vegans were iodine deficient. However, another study found that vegans consumed too much iodine from seaweed.  Excessively high or low levels of iodine consumption can lead to thyroid dysfunction. Goitrogens, found in cabbage, cauliflower, and rutabaga decrease iodine utilization. Large amounts of these vegetables can cause thyroid dysfunction. However, cooking such foods tends to destroy most of the Goitrogens making this effect not likely. Iodine in seaweed has shown to be unreliable, which is why it is suggested that iodized table salt is a good solution for vegans. It can also be found in potatoes and cranberries. 


(6) Vitamin D

    Vitamin D is a fat soluble vitamin produced in the skin by contact with UV radiation. It is important for calcium absorption, bone health, and many physiological processes. It can be found in animal products and fortified foods but is mostly acquired from exposure to the sun. Dietary intake is required when sun exposure is not enough. There exist varying supplements with different degrees of absorption into the body. The optimal level of Vitamin D for athletes has yet to be researched properly. 


Supplements and Ergogenic Aids 

(1) Creatine 

    Research shows that vegan/vegetarian diets reduce the creatine stored in muscles. Creatine is an organic acid synthesized in the body from an amino acid (arginine, glycine, and methionine). Meat, fish, and poultry all contain Creatine. Its performance enhancing effects are well studied. It increases short-term high-intensity exercise performance, muscle building, and maximum strength. Vegan athletes should consider creatine supplements to compensate for the reduced creatinine levels from their diet. Dosing creatine requires muscle saturation. Regimens for 20 grams per day for a week followed by 3-5 grams per day as maintenance. Athletes could also chose to take 3-5 grams per day for 4 weeks to achieve the same amount of muscle saturation 


(2) Beta Alanine  

    Meat and poultry are the main sources for beta-alanine in the diet. Supplementation has shown to increase muscle carnosine concentrations. Carnosine is protein found in skeletal muscle and the central nervous system. It is shown to lead to improvements in high-intensity exercise performance by getting rid of free radicals. The effectiveness of Beta-alanine supplementation has been confirmed in exercises that are longer than one minute. The effects below one minute remain unclear. Further research is needed to verify and explore its application. 


Conclusions 

In general vegan diets tend to be lower in calories, protein, fat, vitamin B12, n-3 fats, calcium, and iodine than omnivorous diets. However, vegan diets are higher in carbohydrates, fiber, micronutrients, phytochemicals, and antioxidants. With proper selection and attention to macro/micro nutrients a vegan diet can attain a good balance. Supplementation with creatine and Beta-alanine might offer performance benefits to vegans who already have lower levels. Further research must be done to understand the performance enhancing effects of Beta-alanine and creatine. However issues with digestibility must be addressed. Increasing the amount of macro/micronutrients might be a way to combat the issues with digestibility and absorption. The shortcomings of this study is that there is no direct research of veganism in sports. To circumvent this tissue information was gathered from varied sources and compiled. Inferences were made based upon available data. Therefore, many of the recommendations in this article require authentication. The researchers want this article to act as guidance and a catalyst for future research into this topic. The main strength of this review is its complete analysis of the variables.