In the first part of this article I’ve talked about energy, carbohydrates, proteins and supplements in the context of vegan diets and sport. Today I will focus on mironutrients that are often deficient in vegan diets and therefore can indirectly compromize sport prestations.
Current evidence suggests that a vegan diet is not superior to an omnivorous diet in terms of enhancing performance or recovery in athletes. In other words, vegan or not, the diet has to be balanced and deliver all macro- and micronutrients to support optimal physical performance.
In general, people who follow a strict vegan diet intuitively often have a suboptimal intake of protein, iron, calcium, vitamin B12 and vitamin D. Deficiency of one or several of this nutrients can compromize health and physical performance. Therefore, optimal vegan sports nutrition requires (more) careful consideration, planning and evaluation.
Iron
The absorption of iron by the body depends directly on the source of dietary iron: it can be heme and non-heme. Heme iron is found exclusively in animal products and is better absorbed by the body. Non-heme iron is found in both animal and plant foods and is absorbed worse. However, it has been observed that the body of vegetarians adapts and absorbs non-heme iron much better than the body of carnivores.
The following plant foods are a good source of iron: tofu, soybeans, parsley, lentils, all kinds of beans, tomato juice, cocoa powder, dark chocolate, wheat products (bread, couscous, bulgur, pasta).
Concomitant use of iron with vitamin C improves the body’s absorption of iron. Therefore, it is good to add fruits and vegetables (which are a good source of vitamin C) to all meals if possible.
Calcium
Calcium is a mineral most often associated with healthy bones. But it also plays an important role in blood clotting, muscle contraction, and regulating normal heart rhythm. Therefore, it is an important mineral for athletes.
The recommended dietary allowance of calcium (RDA) for adults is between 950 and 1200 milligrams per day.
Please refer to this article for the best vega(n) calcium sources.
Vitamin D
Vitamin D (cholecalciferol) is needed for the optimal absorption of dietary calcium. In addition, vitamin D plays a role in the proper functioning of the muscles and the immune system.
Sunlight is the main source of vitamin D. The human body can produce vitamin D by itself under the influence of sunlight in the skin. In the spring, summer and autumn, the advice regarding vitamin D is to spend at least 15 to 30 minutes between 11 a.m. and 3 p.m. with your head and hands uncovered in the sun every day. When a larger part of the body is exposed, a shorter time is sufficient. Your body then produces vitamin D and stores it. In the winter months, the sun is too low (in the Netherlands) to produce vitamin D. You then use the stock you have built up.
In theory vegans are more at risk because they don’t get any vitamin D from food at all (unless they eat a lot of fortified foods). In the winter months, almost all of us produce too little vitamin D (once again, I am talking about my country of residence, the Netherlands).
In the Netherlands, a recommended daily allowance (RDA) of 10 micrograms of vitamin D applies to everyone but persons over the age of 70. For them, the RDA is set to 20 micrograms per day.
Vitamin B12
Vitamin B12 (cobalamin) is found almost exclusively in animal products: meat, fish, dairy products, eggs. Algae, mushrooms, and fermented soy products contain some B12, but not in active form. It is believed that B12 from plant sources is not absorbed. Strict vegetarians who do not consume such products should not forget to periodically take this vitamin in the form of supplements or fortified foods.
The recommended daily allowance of vitamin B12 for women and men aged 19 and above is only 2.8 micrograms.
Please read this article if you want to learn more about vitamin B12.