Nov 21, 2018Vegan diets can come with nutrient deficiencies
Vegan diets have become increasingly popular in recent years, including in the athletic community. As high school athletes see more and more of their favorite pro players trading in meats and dairy for plants and grains, they may be inspired to make the transition themselves. However, doing so safely requires education, planning, and often, the input of a sports dietitian.
A traditional vegan diet is plant-based and excludes all animal products, including meat, dairy, and eggs. Food items derived from animal sources are usually also removed, such as gelatin and honey. Most individuals adopt a vegan diet after they have lived as vegetarians for a length of time. In some cases, athletes consider themselves primarily vegan but occasionally eat select animal products, a diet many call “flexitarian.”
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When planned and implemented appropriately, a vegan meal plan can support the nutritional needs of most athletes. Overall, well-balanced vegan diets tend to be lower in saturated fat and cholesterol and higher in fiber, magnesium, potassium, vitamin C, vitamin E, folate, and a wide range of phytochemicals than diets that include animal products. However, vegans may have lower intakes of protein, vitamin B12, calcium, iron, vitamin D, and long-chain omega-3 fatty acids.
Here’s a closer look at some of these key nutrients that can be deficient in vegan athletes.
Needed for maintaining and building muscle and other tissues, protein is critical for athletes. Daily needs typically range from 0.5 to 0.8 grams per pound of body weight. But vegans should consume 10% more than the typical recommendations, because plant-based protein sources such as soy, legumes, nuts, seeds, grains, and vegetables, are more difficult to absorb than animal sources.
For example, a 140-pound runner requires 70 to 112 grams of protein per day. If the athlete is vegan, a more appropriate protein recommendation is 77 to 123 grams per day, or an extra 1 to 2 cups of soy milk daily. For a 220-pound football player, protein needs are 132 to 176 grams per day. If the player is vegan, the recommendation jumps to 145 to 193 grams of protein, or an additional 1/2 cup to 1 cup of peanuts daily.
Vegan diets are often low in B12, a critical vitamin naturally found in animal products. It is essential for the maintenance of optimal nerve function and healthy cells and prevention of megaloblastic anemia, which results in tired and weak bodies. Adding a B12 multivitamin or consuming ample vitamin B12-fortified foods such as soy milk, meat analogs, or sports bars, is essential to getting the recommended 2.4 mcg a day.
Adequate calcium intake is critical because it plays a key role in optimizing bone strength and is essential for muscle contraction. Some studies have also noted an increased risk of developing stress fractures in vegans due to the lack of this nutrient. Because plant-based diets typically don’t include dairy products, a main calcium source, vegans tend to fall below the daily recommendations of 1,000 to 1,300 mg.
Structured vegan diets should contain ample sources of highly bioavailable calcium from items such as broccoli, collards, fortified fruit juices, and calcium-set tofu to boost stores. Still, a calcium supplement is often recommended to meet needs.
An essential component of proteins and enzymes that maintain health, iron is also paramount in facilitating the delivery of oxygen to cells. When iron is low, fatigue, decreased performance, and lowered immunity can result. Because iron from plant-based foods is not absorbed as well as iron from animal sources, the recommended intake for vegans is 1.8 times greater. For example, an adult female vegan athlete should consume 32 mg of iron daily versus 18 mg for a non-vegetarian, and an adult male vegan athlete requires 14 mg per day rather than 8 mg.
Generally, a multivitamin containing iron is added to a vegan diet. Iron stores (specifically ferritin) should be monitored periodically in vegan athletes to ensure adequate levels for optimal training and performance. They can also add fermented food products–such as miso or tempeh — sprouted grains, and legumes to their diet, as the iron in these foods is absorbed more readily.
This micronutrient plays a key role in bone health and immune system function. Like iron, vitamin D levels are a common concern for athletes at many levels of competition, because low levels in the body may increase the risk of developing stress fractures and other bone-related problems. In addition, inadequate vitamin D consumption is associated with a weakened immune status, which could precipitate illness in athletes. Low vitamin D intakes, low serum vitamin D levels, and reduced bone mass have been reported in some vegan groups that were not using vitamin D supplementation. Therefore, vegan athletes should utilize a combination of periodic testing, supplementation, consuming vitamin D-fortified foods — such as fortified orange juice — and exposure to sunlight to meet their needs for this nutrient.
Omega-3 Fatty Acids
Vegan athletes may have a difficult time obtaining the recommended 1.1 to 1.6 grams per day of omega-3 fatty acids, which are found in fatty fish and fish oils. Omega-3s are critical for overall cardiovascular health, brain health, and disease prevention, and they have the potential to decrease inflammation in athletes. However, by combining nuts, seeds (especially flax), vegetable oils, algae, and some leafy greens with fortified foods such as soy milk, rice milk, and vegan bars, omega-3 fatty acid deficiency may become less of a concern. Supplements are also commonly utilized.