Several famous athletes have revealed recently that they follow a vegan diet, such as runner Scott Jurek and basketball player John Salley.
Many of these athletes even go so far as to credit their eating habits with their excellent athletic performance. Although these athletes may have had success following this type of eating style, does it work for all athletes?
Vegan diets have become increasingly popular as a way to manage and possibly prevent chronic disease. Plant-based diets are associated with several health benefits including a lower risk of heart disease, diabetes, obesity, and cancer.
Eating a well-planned plant-based diet can be nutritionally adequate for the average person. But, vegan diets take plant-based eating to the most restrictive level. When adopting a restrictive eating patter, athletes do need to consider their special nutrient needs to help support their physical performance.
The main difference between vegan and vegetarian is the quantity of animal products that are eliminated from the diet. Vegetarians do eat mostly plants, but may allow some dairy, eggs, or even fish in their diets. Vegans, on the other hand, eliminate all animal products from the diet. They may avoid supplements from animal sources or even clothing made from leather or animal products.
The primary motivation for many people in adopting these types of eating habits may be health, but ethics and religion can also be a motivating factor.
Athletes do have special nutrition needs in order to support a high level of performance. Intense athletic activity can lead to mildly suppressed immune function, by increasing natural killer cells and neutrophil function. This change in the immune system is believed to increase susceptibility to bacterial infections, compromising training. Obviously, athletes want to avoid illness and it has been demonstrated, that those who adopt a vegan diet high in plant foods do tend to get sick less often, likely due to the immune-boosting properties of these foods.
In addition, a high level of physical performance puts athletes at risk for increased oxidative stress, leading to the formation of free radicals which can cause long-term damage to the body increasing risk of disease. High-antioxidant foods help neutralize free radical formation and reduce oxidative stress. Most fruits and vegetables contain a high amount of antioxidants, therefore eating a diet high in plants will help attenuate some of the damage caused by intense physical exercise.
There is the potential for a well-planned vegan diet to be highly beneficial to help with faster recovery for athletes from the antioxidants in plant-based foods. But, as previously mentioned there are several specific considerations that must be made to maintain nutritional adequacy and meet the naturally high nutrient needs of high-performance athletes.
There is limited research on vegan diets and athletic performance, but based on available studies there does not seem to be a decrease in performance for those who follow well-planned vegan diets.
Yet, some concerns remain about nutrient adequacy. You need to pay more attention to your diet than the average person.
There are seven primary nutrients of concern for athletes that may be lacking in vegan diets: omega-3s, iron, zinc, iodine, calcium, vitamin D, and vitamin B12.
Omega-3 fatty acids are essential to human health, meaning they must be consumed in the diet. They are also highly anti-inflammatory, which may be beneficial for athletes as exercise increases inflammation levels.
Although plants do contain one type of omega-3, called ALA, there is no source of the other two omega-3 fats EPA or DHA in a vegan diet.
The problem is that ALA is the non-active form of omega-3s and must be converted to active EPA or DHA before being used by the body. This is an extremely ineffective conversion, with only 1% of ALA becoming activated on average. Vegan athletes may want to consider supplementing with EPA or DHA, due to the known health benefits of these healthy fats.
Adequate iron intake is of critical important for athletes, as iron is used to transport oxygen to muscles. Without iron, the muscles would not be able to perform any type of athletic activity. There are two types of iron in food: heme and non-heme. Heme iron comes from animal foods and is three times better absorbed than non-heme iron.
Regardless of the type of iron, bioavailability is notoriously poor, even with a mixed diet of plant and animal foods. Iron absorption drops even lower to only about 5% for vegetarian or vegan diets.
That being said, athletes who follow a vegan diet need to be sure to eat high iron foods regularly such as beans, fortified cereals, or green leafy vegetables.
Vitamin C helps absorb iron, therefore high iron foods should be paired with high vitamin C foods. For vegan female athletes, iron needs are particularly high, therefore they should be monitored regularly for iron deficiency and may need iron supplementation.
Zinc helps support immune function and gene expression. But, similar to iron, it is not well absorbed from plant foods due to the phytate content of these foods. Phytate binds to zinc in the digestive tract, lowering absorption significantly. Zinc is also better absorbed when consumed with protein, making a mixed diet higher in absorbed zinc overall.
A 2009 study found that vegetarians have a higher prevalence of zinc deficiency when compared to non-vegetarians. Athletes should therefore consider supplementation in order to provide adequate zinc in the diet or consider increasing their intake of high-zinc plant foods such as hemp or pumpkin seeds.
Most plant foods are low in iodine due to soil depletion of this mineral, which is necessary for thyroid function. Iodized salt is the highest contributor of iodine intake in the Western diet, but it is hard to account for in the diet.
A 2003 study found that 80% of vegans were deficient in iodine. For vegan athletes concerned with iodine intake, adding seaweed to the diet may be a good option or a multivitamin supplement that includes iodine can help meet needs.
Calcium is necessary for bone health and muscle function. There are many plant foods that contain calcium, such as green leafy vegetables, nuts, and seeds.
Bioavailability of calcium in these foods is a significant concern. Certain components in plant foods, such as oxalic or phytic acids, can reduce the ability of the body to absorb calcium from plant foods. For example, soy beans which are considered high in calcium, have been shown to have a bioavailability of only 30-40%.
In planning a nutritionally adequate diet for a vegan athlete, the low bioavailability of calcium in plant foods should be a consideration.
Many people are deficient in vitamin D these days, it is believed to affect up to 50% of the population, as food is generally a poor source of this vitamin. The best food sources of vitamin D are fish and fortified milk, although mushrooms do have a small amount. Most of our vitamin D needs can be met from sun exposure, but many of us spend a significant amount of time inside, leading to deficiency.
Vitamin D is necessary for bone health, calcium absorption, and muscle function.
Athletes who follow a vegan diet may want to consider being tested for vitamin D deficiency and may require a high dose supplement to improve levels.
Vitamin B12 is of particular concern for vegans as it is exclusively found in animal foods. It is necessary for DNA synthesis and nervous system function. Deficiency can result in irreversible neurological damage and an increased risk for heart disease.
Most vegans supplement with vitamin B12, since there is no other source of this critical vitamin available in a plant-only diet.
The biggest concern in terms of nutrition for vegan athletes may getting enough protein. Protein is needed for muscle synthesis and proper recovery after exercise. Exercise causes muscle breakdown, therefore some replenishment of protein is necessary after physical activity to rebuild muscles.
Athletes have a greater protein needs than non-athletes with levels set at a minimum of 1.4 grams per kilogram per day for muscle maintenance, double of what sedentary people need. Protein needs may be even higher depending on the type of physical activity performed. Check out our indepth article titled "How Much Protein Do You Need a Day to Build Muscle".
Even with the higher protein needs of athletes, a 2009 study found that by simply increasing calories to meet requirements for athletes, protein needs were met in 97% of cases.
Researchers concluded that vegan or vegetarian athletes should focus on consuming adequate calories to support physical activity, which in turn will help meet protein needs for most.
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There are several benefits of following a vegan diet, in terms of antioxidant content, faster recovery after exercise, and the potential for a reduced risk of chronic disease. But, there are some special considerations that must be made for athletes because of the potential for vitamin and mineral deficiencies. Therefore, if you are an athlete considering a vegan diet, be sure to give special care to hit all the important vitamins and minerals. It's definitely doable! Good luck!
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