Legumes are the edible seeds of plants (herbs, shrubs, trees) belonging to the Fabaceae family, or legumes, characterized by the presence of a pod (in which the seeds are contained) that opens when it reaches maturity.
The most common are: beans, lentils, chickpeas, broad beans, soybeans, peanuts, peas and grass peas.
Green beans and broad beans are also legumes, but due to their low protein content and high water content, they are considered vegetables. Peanuts, on the other hand, due to their particularly high fatty acid content, are more similar to oily nuts, such as walnuts, almonds, hazelnuts, etc.
First of all, it would be more correct to ask whether they are a source of protein or carbohydrates. In other words, are they more similar to meat or cereals? Legumes are foods of plant origin that are considered a source of vegetable protein. However, compared to animal proteins, those in legumes are not complete proteins, as they lack certain essential amino acids. In particular, they are low in the amino acid methionine, which is present in cereals. Legumes must therefore be consumed together with cereals to complete their amino acid profile (we talk about protein complementarity).
Legumes mainly contain carbohydrates and proteins, in different proportions depending on whether the legume is dry or fresh: on average, 40-65% of 100 g of dry legumes consists of carbohydrates and 21-36% of proteins; while for fresh legumes, the values correspond to half or a third of the percentages of dry legumes.
But how much protein do they contain compared to meat?
Apparently a lot, but in reality very little! 100 g of chicken breast contains 31 g of protein, while 100 g of dried beans contains 24 g, which is a good amount, but I am talking about dried legumes. In reality, 100 g of cooked beans contain only 7.4 g. So, to get the same amount of protein as 100 g of chicken, we would have to eat about 300 g, which is equivalent, to give you an idea, to more than 2 cans of canned legumes.
This is a considerable portion, but not impossible to eat. However, there is another problem. Beans also provide carbohydrates, so in 300 g of boiled beans, we would find about 50 g of carbohydrates, which is a lot if we consider that we would also have to add a cereal to complete their amino acid profile.
Soybeans contain 37 g of protein per 100 g of dry product and are the legume with the highest protein content, together with lupins, which come in second place with 36.2 g of protein per 100 g of dry product. These values differ significantly from other dried legumes, whose protein values range between 20 and 26 g of protein, including peanuts (29 g protein/100 g product).
Which legumes should you use? And how should you combine them?
Fresh pulses: among fresh pulses, we distinguish the most common beans, peas, green beans, broad beans and lupins, but also chickpeas, soya beans, carob, tamarind and the almost forgotten roveja.
The absolute star of recent years is soya, which has taken on greater importance due to the benefits associated with the phytoestrogens and isoflavones it contains. This increased consumption can also be attributed to their nutritional values, including their higher protein content and better digestibility compared to other legumes, or to the countless variations, such as soya sprouts or soya milk, which is often used as a substitute for cow's milk.
Tinned legumes: tinned legumes are available on the market in both dried and cooked forms, ready to eat.
Canned legumes are preserved in cooking water or brine, which should be drained off to minimise residues of phytic acid, an anti-nutritional element capable of chemically binding to various minerals.
The presence of salt in the preserving liquid also means that the nutritional values are not as high as those of dried legumes. Very often, tinned soya beans contain a kind of jelly, which is the end result of the gelatinisation process caused by the release of amylose from the beans following their hydration during cooking.
Peeled legumes: in order to limit the unpleasant effects (especially for those suffering from irritable bowel syndrome) following the digestion of legumes, peeled legumes are often used, mechanically with a vegetable mill or already peeled.
A sensible practice would be to accustom the intestinal bacterial flora (microbiota) to receiving increasing doses of legumes, with increasing frequency, taking into account the soaking and cooking instructions analysed above.
The average portion of boiled legumes is approximately 120-150 g, providing approximately 10 g of protein and a sufficient amount of carbohydrates to allow us to combine them with a cereal to complete their amino acid profile. A meal consisting of legumes, cereals and vegetables is therefore a complete meal which, if well balanced, provides the right amount of carbohydrates and a good protein intake.
But should they also be combined with proteins?
Not necessarily, but if for particular reasons we want to increase our protein intake, then yes, we can also add other protein sources, even those of a different nature than legumes.
Are they vegetables? NO, one thing is certain... legumes are not a side dish!
(Article by biologist and nutritionist Giusto Cristina)
