Carbohydrates, Fats and Micronutrients in a Plant-Based Diet

During the previous two posts we have talked about whether a Plant-Based Diet (PBD) is possible for athletes and about proteins. But what about carbohydrates and fats? And micronutrient deficiencies?

Regarding the amount of carbohydrates, since they are very well represented in PBDs, it will make it easier to meet the intake recommendations for them, thus ensuring optimal glycogen concentrations and therefore avoiding the onset of early fatigue during exercise. Some studies have observed that the intake of legume-based sports bars, with a low glycemic index, before a simulated soccer match improved performance, and even in other studies, they showed better preservation of muscle glycogen during the simulated match compared to a meal based on potatoes and eggs. Although not all results have been similar, so we will have to wait to see more results.

As I was saying, fiber is very interesting for health, but in the context of sports performance, a high intake before a competition can cause gastrointestinal problems. In addition, the greater satiety can lead us to not consume an adequate amount of energy, which could lead to health and performance problems. It is important to keep this in mind.

Fats are a fundamental element of our diet. The star fats today are those known as polyunsaturated omega-3 fatty acids. We need to consume this type of fat since we are not able to synthesize sufficient amounts. As we have already seen, among the essential fatty acids, we have the derivatives of alpha-linolenic acid (ALA) and the derivatives of linoleic acid. Our cells, from ALA, produce the two main omega-3 fatty acids, EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). You can find ALA in different types of seeds, nuts, vegetable oils, and EPA and DHA mainly in fish and seafood. The problem is that in PUFA, especially in vegans and vegetarians, the content of EPA and DHA is low. In addition, the conversion of ALA to these fatty acids is quite inefficient and variable, depending on sex, health status, diet composition, etc.; its synthesis can even be affected if linoleic consumption is very high. However, there does not seem to be a risk of deficiency in adults, which could be due to the higher average intake of ALA. There is no recommended daily intake of EPA or DHA, so it seems prudent at least, given their beneficial effects, to consume enough ALA.

Moving to the micro territory, all micronutrients, with the exception of vitamin B12, can be found in adequate amounts in a PBD. However, and as I already mentioned to you, attention should be paid to iron, zinc, and calcium.

The cobalamin or vitamin B12 It is an essential nutrient, and as we have seen several times, this implies that we must take it through the diet. Since it is only found in foods of animal origin (meat, eggs, dairy), if you are vegan, you must incorporate it through a supplement. It is true that very small amounts exist in nutritional yeasts or it is present in some algae such as nori, and you can also take it through fortified foods (soy drink, almond…) but the amount or its variability makes supplementation necessary most of the time. I repeat, you must supplement with cyanocobalamin if your diet is vegan. Its deficiency is very dangerous, leading to alterations of the central nervous system, alterations in the formation of red blood cells (megaloblastic anemia), deficiencies in the production of methionine (involved, for example, in the synthesis of creatine), which can limit your health and also your performance.

The iron, as we have already seen, it is a fundamental micronutrient for health and performance. Neither excess nor deficiency is good. Plant-based foods contain non-heme iron. As you will remember, this is less bioavailable, to which must be added the interference that phytates or other substances present in a plant-based diet can produce in its absorption. However, the consumption of iron in a plant-based diet can be adequate and high; what we must control is its bioavailability. For this, it is advisable to increase the iron content of the diet (32 mg per day for women and 14 mg/day for men who follow a plant-based diet). The use of substances that enhance iron absorption is interesting. Just as with iron, plant sources of zinc They are less bioavailable due to the presence of anti-nutrients, which can make the requirements higher if you do a PBD (approximately 50% more zinc). Different cooking techniques improve the bioavailability of this mineral, such as soaking, sprouting, fermentation, or the use of organic acids like citric acid. For both iron and zinc, fortified foods are also a good choice.

A mineral that, due to its functions, receives a lot of attention is calcium. It seems as if drinking cow's milk were the only way to get calcium through the diet. However, it is also found in plant-based foods, although it is less bioavailable. Again, phytates and fiber, and especially oxalates, interfere with its absorption in BPDs. Some vegetables, such as cabbage, broccoli, or cauliflower, do not contain oxalates and are a good source of calcium.

The vitamin D, I would be just as concerned in a person who follows a plant-based diet as in an omnivore. As we have already seen, the deficiency is common and the main factor is not what you eat, but sun exposure.

Another vitamin that emerges in importance is K. Of the two active ones, K1 (Phylloquinone) is found in green vegetables and oils, and K2 (Menaquinone) is mostly of bacterial origin, although a small part (Menaquinone-4 or MK-4) can be formed from vitamin K1. Therefore, it seems that a single PBD would be enough to supply the needs of MK-4.

Therefore, as a summary, we can say that carbohydrates should not represent a problem in a WFPD, although you should take into account the fiber intake that is implicitly involved in this type of diet. It is important to know that the intake of some micronutrients that are essential, such as iron, zinc, calcium, vitamin D, and iodine, may be compromised. However, if your diet is well-designed, the main focus of attention and mandatory supplementation requirement would be vitamin B12.

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AUTHOR Fernando Mata (Col. AND-01053) MSc Physiology; MSc. Biomedicine; MSc. Nutrition; PhD. Student General Director of the Center for Advanced Studies in Nutrition