Anti-nutrients in food where they occur, how to reduce their effect?
Anti-nutritive substances, which include, among others, oxalates, phytates, thioglycosides, tannins or cyanogenic glycosides, are provided to us, in addition to valuable nutrients, in food products that hinder the body’s use of valuable ingredients, and in higher doses are harmful to it. You do not have to completely give up eating products containing anti-nutrients, because you can reduce their negative impact by preparing meals accordingly. ”
Anti-nutritive substances are compounds found in foods that limit or prevent the use of nutrients (mainly minerals) by the body or have a detrimental effect on them, including
substances occurring naturally in food of plant and animal origin
compounds permeating food from a polluted environment, such as residues of plant protection products, fertilizers, substances used in the technological process
compounds intentionally added to food to improve its properties and durability.
Anti-nutritive substances types of substances occurring naturally
Oxalates are found in food as soluble salts of oxalic acid with sodium and potassium and insoluble with calcium. Oxalic acid is easily absorbed from the gastrointestinal tract, and calcium oxalate is absorbed after a partial decomposition in the stomach.The oxalates in the human body come mainly from food, there are also the product of metabolism, including vitamin C. Their main sources in the diet are sorrel, spinach, rhubarb, coffee and tea.In plants, most oxalates are found in petioles and lower leaves, and least in roots. Occasional consumption of products rich in oxalates does not translate negatively affect your health, but frequent eating with calcium and vitamin D deficiency in the diet reduces absorption and use of these ingredients in the body, thereby reducing bone mineralization. The presence of oxalates also contributes to impaired absorption of magnesium, formation of kidney stones, arthritis and heart problems To reduce the negative effects of the substance, it is recommended to consume less than 40-50 mg of oxalate per day.
Phytic acid is usually found in the form of phytates, i.e. the acid salt with copper, zinc, magnesium, calcium, manganese, iron and cobalt.The main sources in the diet are cereal grains and legume seeds.Fitates are found primarily in the seed coat of seed, hence The phytic acid has a strong chelating ability, which means that in the light of the digestive tract binds minerals and limits their absorption.It works most strongly in the case of iron – it reduces its bioavailability even by half. up to 400 mg of phytic acid per day does not cause deficient states.
Thioglycosides are free-growing substances that are found in cruciferous plants, eg cabbage, brussels sprouts, cauliflower, broccoli. Thiocyanides that bind iodine are responsible for the anti-nutritional effect. They disrupt iodine absorption by the thyroid gland and limit the synthesis of thyroid hormones. in the thyroid leads to the accumulation of mono- and diiodidotyrosine, resulting in hypertrophy of the gland The glucogenic activity of glucosinolates is mainly visible in the case of insufficient iodine intake with diet The enzymatic distribution of thioglycosides occurs as a result of grinding vegetables, crushing of tissues and chewing. so you can greatly reduce their concentration by cooking in an open dish.
Trypsin and chymotrypsin inhibitors
Trypsin and chymotrypsin inhibitors (protease inhibitors) are substances whose anti-nutritional action consists in inhibiting the activity of enzymes that break down peptide bonds, which makes the food protein become less digestible and is not completely used. They can also lead to inflammation of the pancreas. all in the seeds of bean legumes, soy beans, peas, broad beans, but also in wheat, potatoes and egg white, etc. Under the influence of high temperature, for example during cooking, they peg denaturation and cease to be harmful.They can be found in soy protein isolates.
Lectins are glycoproteins that have the ability to bind to the intestinal epithelium, which results in damage to the mucosa and intestinal villi cells, can also lead to the clumping of red blood cells, in plants mainly in seed embryos, but also in leaves, roots, bark, fruits and The main sources of lectins in food are legume seeds, especially beans, Lectin is poorly broken down by digestive enzymes, some of them do not also break down at high temperatures, they have the ability to pass unchanged through the digestive tract and disturb metabolism in humans and animals.
Steroidal glycoalkaloids are a group of compounds found in solanaceous plants, e.g. potatoes, tomatoes, and paprika, including, among others, solanine, chalclinin and tomatinina.In ripening plants they have a protective function against pathogens and pests, showing activity similar to antibiotics. However, they can be toxic to humans and cause irritation of the throat, nausea, vomiting, diarrhea, headaches, circulatory disorders and breathlessness. In mature vegetables the concentration of steroid glycoalkaloids is negligible, but often their source in the diet are potatoes with characteristic greening, which were stored in temperature above 10 degrees Celsius or begin to germinate.The peeling of vegetables significantly reduces the content of glycoalkaloids, because most of them are just below the skin.The cooking does not reduce their concentration in the product, they are stable at temperatures up to 250 degrees Celsius.
Saponins are found, among others, in spinach, beetroots, asparagus and soy.They can cause damage and haemolysis of red blood cells, however, they are difficult to absorb from the gastrointestinal tract.Therapy with saponins causes gastrointestinal disturbances, and in extreme situations causes convulsions and paralysis of the nervous system .
Further on the list of anti-nutritive substances are biogenic amines.Most of biologically active amines are compounds that are essential for the functioning of the organism.The most common among harmful compounds is histamine, which can be found in food naturally, The hystamine occurs naturally in cheeses, lactic fermented products like sauerkraut and pickled cucumbers, but above all in fish and seafood, which increases when food is stored for too long. large amounts of histamine leads to poisoning, heart and respiratory disorders and allergic reactions, like pruritus and urticaria. In susceptible individuals, the symptoms are caused by intake of 5-10 mg of histamine. The average dose is considered to be 100 mg of amine.
Cyanogenic glycosides are compounds that release toxic hydrogen cyanide during the breakdown in the body. Prussin is rapidly absorbed from the gastrointestinal tract, causing cell hypoxia and symptoms of headache, pressure drop, accelerated pps, vomiting, diarrhea, cramps, convulsions. it may be that the toxic dose is 1 mg / kg body weight and it is difficult to deliver it to the body with food. In the largest amounts, cyanogenic glycosides are found in the cassava, beans, bamboo shoots and seeds of stone plants (pears, apples, peaches, apricots, almonds). The most well-known compound in this group is amygdalin.
Although tannins belong to the group of antioxidant compounds, they are considered anti-nutritive substances because they inhibit the absorption of minerals from foods and vitamins A and B12. Tannins are responsible for the tart of tea, coffee, cocoa, wine and immature fruits. large quantities of dark berries, grapes, pomegranates, apples, nuts and pulses of legumes.
On the list of anti-nutritive ingredients you also need to mention dietary fiber.” Fiber hinders the absorption of minerals from food because it has a high capacity to bind them, at the same time is of great importance for the functioning of the digestive tract and for overall health.
How to minimize the effect of anti-nutritive substances?
Anti-nutritive substances have a negative effect on the body, but often also have a beneficial effect on health.In order not to completely give up the consumption of certain products, it is worth using techniques that lower the concentration of anti-nutritive substances in food or reduce their effect, e.g.
soaking seeds of legumes, almonds and nuts
cooking of products rich in thioglycosides and protease inhibitors
combining products rich in oxalic and phytic acid with calcium sources, e.g. dairy, egg
peeling vegetables and fruits from the skin
avoiding eating unripe fruits and vegetables
ensuring proper consumption of iodine.
Anti-nutritive substances of importance in the prevention of civilization diseases
Fruits, flowers, leaves, seeds, roots and bark of plants are rich in polyphenolic compounds, of which several thousand have been classified. In food they are included in non-nutritive or anti-nutritious ingredients, however, these are antioxidant substances of great importance in protection against cellular aging, cancer and civilization diseases, such as type 2 diabetes or atherosclerosis. Among the polyphenols are tannins, alkaloids, glucosinolates and glycosides, which are also considered as anti-nutritional substances.
Examples of anti-nutritive substances of importance in the prevention and treatment of diseases are
cruciferous glucosinolates – support the synthesis of detoxifying enzymes, accelerate the excretion of toxins and carcinogens from the body, inhibit the growth of cancer cells and metastasis
saponins of legumes – they form complexes with bile acids and cholesterol, they accelerate the excretion of their excess from the body
tannins – have antibacterial and strong antioxidant properties, protect against the formation of tumors, slow down the rate of division of cancer cells
dietary fiber – regulates the rhythm of bowel movements, binds excess cholesterol and accelerates its excretion from the body, inhibits the absorption of heavy metals and toxins, is a very important factor in the prevention of colorectal cancer
phytic acid – has anticancer activity, reduces the risk of atherosclerosis and type II diabetes, because it improves carbohydrate metabolism.Posted on: November 12, 2018