There is a lot of talk lately about the antinutrients in legumes and their benefits and here we tell you which are the myths and which are the truths.
Legumes, a food group that includes lentils, chickpeas, beans, peas, beans, beans, lima beans, soybeans, and even peanuts (which are legumes, not nuts as is often thought) have been surrounded by some myths against for many years. Many of these myths have been losing strength, in turn, with the promotion of vegetarian and vegan diets, which require a multitude of plant proteins as an alternative to animal proteins, and these proteins usually come precisely from legumes.
Among these myths is its high content of " antinutrients ", substances that prevent the proper absorption of other nutrients necessary for the body, especially minerals. Likewise, legumes have been shown to contain high amounts of substances derived from plants that, in excess, can be toxic to the human body (although, as we already know, all excesses are harmful). As the ancient physician Paracelsus said "Nothing is poison and everything is poison: the difference is in the dose”.
Today we will review some of these myths, and also the well-known benefits of legumes for general health, including their high protein content, although their biological value compared to animal proteins is lower because the latter do contain all the essential amino acids and the No vegetable proteins, although they can always be supplemented with the consumption of whole grains.
Legume antinutrients and toxicity: myths and misunderstandings
To begin with, we know that legumes contain a high number of lectins, a type of protein that depending on the dose can be toxic to the human body, and also phytates or phytic acid, which are known as "antinutrients" due to difficulty in absorbing other nutrients.
In fact, paleolithic diets tend to avoid legumes precisely in order to avoid these two components, based on studies such as the one published in the British Journal of Nutrition in 2000, where lectins were linked to inflammatory diseases, or another work published in the BMC Endocrine Disorders in 2005, where lectins were linked to resistance to leptin, one of the hormones related to appetite and whose malfunction increases the risk of obesity. However, these works suffered from a certain lack of data.
The truth is that we currently know little about lectins. We know that they are proteins that bind specifically to sugars and that they are found in high amounts in plants (and therefore also in legumes, seeds and nuts). What is known is that excess consumption is toxic to humans, something that also happens with other substances. What we also know is that, if food is cooked with lectins for 10 minutes at 100ºC, these proteins are denatured, that is, they lose their function and therefore their toxicity, as the study published in Methods in Molecular Medicine suggested in 1998. Therefore, fear of excess lectins makes no sense, because our diet today involves cooking legumes during this time and even longer.
On the other hand, we have phytic acid, the "antinutrient”, which is also found in legumes, nuts, seeds and plants in general. In fact, legumes would not be the foods with the highest amount of this substance, as nuts also contain it in high amounts.
In theory, phytates are capable of binding to minerals (calcium, iron, zinc, magnesium) and preventing their proper intestinal absorption during digestion, as well as hindering the activity of certain proteins at the body level. In their case, these compounds do not lose their function when subjected to high temperatures such as lectins, nor does it seem that the previous soaking of legumes affects them.
In the case of phytates, based on what we know so far, there is nothing to do. However, the current diet is able to compensate for this effect. In fact, studies carried out in this regard in individuals with a normal diet have not detected mineral deficiencies even though there were phytates in the diet, which would imply that large amounts of this antinutrient are necessary to have detrimental effects on health, as suggested by the published study in Molecular Nutrition and Food Research in 2009. The problem of phytates would become important in environments where malnutrition rages, and where mineral deficiencies are important: if there are already deficiencies of basic vitamins and minerals, phytates, still in small amounts, can aggravate the problem.
The known real benefits of legumes
Now that we have made it clear that the "damages" of legumes are not as they told us, let's see what real benefits these foods have, in addition to being a fairly inexpensive food today.
On the one hand, in addition to the well-known contribution of vegetable proteins (from 20% of its content in the case of chickpeas, up to 36% in the case of soybeans), legumes have been shown to possess a significant amount of nutrients, such as suggested a study published in the British Journal of Nutrition in 2012, focusing on chickpeas, which contain unsaturated fatty acids, calcium, magnesium, phosphorus and especially potassium, in addition to the aforementioned plant proteins.
On the other hand, the frequent consumption of legumes has also been shown to improve cardiovascular parameters, especially reducing total cholesterol and LDL cholesterol or "bad cholesterol" (although it is a misnomer), improving HDL cholesterol parameters or "Good cholesterol", and improving blood glucose control, as suggested by several studies, such as another work published in the British Journal of Nutrition also in 2012.
Likewise, a large amount of fiber has also been detected along with vegetable proteins in legumes, which enhances satiety and helps keep the risk of obesity at bay, again suggested by several studies published in 2012 in the British Journal of Nutrition.
In addition, some later systemic reviews have even linked the consumption of legumes with an improvement in blood pressure, such as the research published in the American Journal of Hypertension in 2013.
Finally, some authors have suggested some anticancer potential in these foods, but their conclusions are very preliminary and modest in this regard, so that benefit should not be taken into account at this time.