Proteins are essential for the functioning of the body. We are used to thinking that foods of animal origin, such as meat, fish and dairy products, are the only protein source. Instead, we need to think again because even nuts, such as pistachios, cashews, almonds and peanuts, are a very precious source of high quality protein, as well as important health properties. This emerges from a recent review that appeared in the journal Nutrients thanks to a collaboration between British and American scientists (Derbyshire et al, Nutrients, 2023).
Proteins, what they are and what they are for
Proteins are molecules made up of amino acids and the precise sequence of amino acids determines the type of protein and its function. As mentioned in the introduction, proteins play an essential role in the body. In fact, proteins participate in the support and structure of the tissues, just think of the collagen of the connective tissue or the keratin of the nails and hair. Not only that, proteins are necessary for movement, allowing the muscles to contract and lengthen, for the body's defense against external threats, in fact antibodies are proteins, but they also guarantee the supply of oxygen, since hemoglobin, which carries oxygen to cells, is a protein, too. The amino acids that form proteins are 20, of these 20 amino acids 9 are essential, which means that they are not produced by the body but must be introduced with food. Until now it was believed that the only way to guarantee a complete supply of amino acids was to consume foods of animal origin, such as meat, dairy products and fish. But in reality, protein sources can also be of plant origin.
Proteins can also be vegetable
More and more scientific studies indicate that a healthy and balanced diet should include a limited intake of meat, especially red meat, but also poultry. Recently, scientific research has shown that those who regularly consume meat are more likely to develop different types of diseases, from pneumonia to diabetes and cellular degeneration (Papier et al, BMC Medicine, 2021). But how can you limit the consumption of meat without losing your protein intake? The report drawn up in 2019 by The Lancet was revolutionary, clearly indicating that for the health of humans and the planet it is necessary to arrive at a diet based on fruit, vegetables, whole grains, legumes, unsaturated vegetable oils and nuts. In particular, The Lancet report includes, together with legumes, nuts among the protein sources par excellence, to be taken in the amount of 25 grams per day.
In fact, nuts are too often underestimated but they are a true source of nutrients. The review deals with analyzing the properties of dried fruit, especially pistachios. As for the protein intake, pistachios provide all 9 essential amino acids, which are easy to digest. This means that the amino acids in pistachios are digested and assimilated by the body effectively. Indeed, there is a measure of the quality of the proteins contained in foods, based on their degree of digestibility. Casein, which is the milk protein, has a value of 1, which is the maximum, as well as soy and egg white proteins. Beef has an index of 0.92, lentils 0.6 and toasted pistachios 0.81, slightly less if not toasted. Cashew nuts have a protein digestibility index of 0.9, pine nuts 0.73, peanuts 0.7 and Brazil nuts 0.63. Almonds contain a wide range of amino acids but their proteins are slightly less digestible than the rest of dried fruit, with an index of 0.5.
Other valid reasons to consume nuts
In addition to proteins, nuts provide valuable nutrients, such as fibres, antioxidants and unsaturated fatty acids, which are important for heart health. Not only that, pistachios, almonds, walnuts and Brazil nuts bring mineral salts, such as potassium, phosphorus, selenium, magnesium, iron and zinc, but also vitamins such as E and K, in the latter case especially pistachios and cashew nuts. The consumption of nuts counteracts cellular degeneration, with a particular protective action on the pancreas and colon. Nuts, thanks to their antioxidant and anti-inflammatory action, help regulate blood sugar and do not cause an increase in body weight, contrary to what one might believe. Indeed, the high intake of nutrients helps reduce cravings for sweets and snacks and this has a positive impact on body weight. For example, it has been observed that the regular consumption of pistachios, reaching a maximum of 20% of the daily energy requirement, has even reduced the waist circumference in six months. Finally, nuts also improve mood and counteract anxiety, supporting the intestinal microbiota and increasing the levels of tryptophan, a precursor amino acid of serotonin, or good mood hormone.
Nuts, especially pistachios, cashews, walnuts, almonds, Brazil nuts but also peanuts and pine nuts, are to be considered an important food to include regularly in one's diet. In fact, nuts provide essential amino acids that are easily assimilated, thus supporting the muscles and other tissues of our body, stimulating the natural defenses and the oxygen supply of the blood. Not only that, nuts are a precious source of fibre, antioxidants and anti-inflammatory substances, they are good for the heart and the gut microbiota. In short, what are we waiting for to consume a bowl of mixed dried fruit, about 25-30 grams in all, perhaps accompanied by a cup of green tea?