Anti-nutritional substances, which include, among others Oxalates, phytates, thioglycosides, tannins or cyanogenic glycosides are provided to us, in addition to valuable nutrients, in food products. They make it difficult for the body to use valuable ingredients, and in higher doses are harmful to it. There is no need to completely give up eating products containing anti-nutrients, as you can reduce their negative impact by properly preparing meals.

Anti-nutrientsare compounds found in food that limit or prevent the use of nutrients (mainly minerals) by the body or have a detrimental effect on it. These may include:

  • substances that occur naturally in food of plant and animal origin;

  • compounds penetrating 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 shelf life.

A long-lasting and little-varied diet rich in anti-nutritional compounds may result in an increased demand of the body for selected nutrients.

Antinutrients: naturally occurring types of substances

  • Oxalates

Oxalates are present in food as soluble sodium and potassium s alts of oxalic acid and insoluble with calcium. Oxalic acid is readily absorbed from the gastrointestinal tract and calcium oxalate is absorbed after partial degradation in the stomach.

Oxalates in the human body come mainly from food, they are also a product of metabolism, among others Vitamin C. Their main dietary sources aresorrel ,spinach ,rhubarb , coffee and tea. In plants, the most oxalate is found in the petioles and lower leaves, and the least in the roots.

Occasional consumption of oxalate-rich foods does not adversely affect he alth, but frequent consumption of them with a simultaneous deficiency ofcalciumandvitamin Dw diet reduces absorption andthe use of these nutrients in the body, thereby reducing bone mineralization. The presence of oxalate also contributes to the malabsorption of magnesium, the 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.

  • Phytates

Phytic acidusually occurs in the form of phytates, i.e. the acid s alt with copper, zinc, magnesium, calcium, manganese, iron and cob alt. Its main food sources are grains and pulses. Phytates are found primarily in the seed coat of grain, hence whole grains and wholemeal products are much richer in them.

Phytic acid has strong chelating properties, which means that it binds minerals in the lumen of the gastrointestinal tract and limits their absorption. It is most effective in the case ofiron- it reduces its absorption by up to a half. Consuming up to 400 mg of phytic acid daily does not cause deficiency.

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  • Thioglycosides (glucosinolates)

Thioglycosides are goiter substances found in cruciferous plants such as cabbage, Brussels sprouts, cauliflower, broccoli. Thiocyanins, which bind iodine, are responsible for the anti-nutritional effect. They disrupt the absorption of iodine by the thyroid gland and limit the synthesis of thyroid gland hormones. Lowering the iodine concentration in the thyroid gland leads to an accumulation of mono- and diiodotyrosine, which results in a hypertrophy of the gland. The go-forming effect of glucosinolates is visible mainly in the case of insufficient iodine intake in the diet. Enzymatic degradation of thioglycosides occurs as a result of grinding vegetables, crushing tissues and chewing. Most of them are volatile, so you can greatly reduce their concentration by boiling in an open vessel.

  • Trypsin and chymotrypsin inhibitors

Trypsin and chymotrypsin inhibitors (protease inhibitors) are substances whose anti-nutritional effect is based on inhibiting the activity of enzymes that break down peptide bonds, making the protein from food less digestible and not fully utilized. They can also lead to inflammation of the pancreas. They are found mainly in the seeds of legumes: beans, soybeans, peas, broad beans, but also in wheat, potatoes and egg white. Under the influence of high temperature, e.g. during cooking, they are denatured and are no longer harmful. They can be found in soybean protein isolates.

  • Lectins

Lectins are glycoproteins that have the ability to bind to the intestinal epithelium, resulting in damage to the intestinal villi mucosa and cells. They can also lead to the clumping of red blood cells. In plants, they are found mainly in the seed germ, but also in leaves, roots, bark, fruits and vegetables. The main source of lectins in food are the seeds of legumes, especially beans. Lectins are poorly broken down by digestive enzymes, and some of them do not break down at high temperatures. They have the ability to pass unchanged through the gastrointestinal tract and disrupt metabolism in humans and animals.

  • Steroid glycoalkaloids

Steroid glycoalkaloids are a group of compounds found in nightshade plants, e.g. potatoes, tomatoes, peppers. They include, among others solanine, chalkonine and tomatin. In maturing plants, they play a protective role against pathogens and pests, demonstrating an activity similar to that of antibiotics. However, they can be toxic to humans and cause throat irritation, nausea, vomiting, diarrhea, headaches, circulatory and respiratory disorders. In ripe vegetables, the concentration of steroidal glycoalkaloids is negligible, but often their source in the diet is potatoes with a characteristic greenness, which has been stored at a temperature above 10 degrees Celsius or begins to germinate. Peeling vegetables significantly reduces the content of glycoalkaloids, as most of them are located just under the skin. Cooking does not reduce their concentration in the product, they are stable at temperatures up to 250 degrees Celsius.

  • Saponins

Saponins are found, among others in spinach, beetroot, asparagus and soybeans. They can cause damage and hemolysis of red blood cells, but are difficult to absorb from the gastrointestinal tract. Saponin poisoning causes gastrointestinal disturbances, and in extreme situations causes convulsions and paralysis of the nervous system.

  • Biogenic amines

Next on the list of anti-nutritional substances are biogenic amines. Most biologically active amines are compounds necessary for the functioning of the body. In the group of amines, however, there are those that are toxic to humans. The most common of all harmful compounds ishistamine , which can be found naturally in food, produced during the ripening process of cheese and as a result of inappropriate storage and deterioration of food.

Histamine occurs naturally in cheese, lactic acid fermented products such as sauerkraut and cucumbers, but most of all in fish and seafood. Its quantity is increasingwhen food is stored for too long. Consumption of large amounts of histamine leads to poisoning, heart and respiratory disorders, and allergic reactions such as itching and hives. In susceptible people, the symptoms are triggered by the consumption of 5-10 mg of histamine. The average toxic dose is considered to be a single consumption of 100 mg of amine.

  • Cyanogenic glycosides

Cyanogenic glycosides are compounds that release toxic hydrogen cyanide when broken down in the body. Prussian acid is quickly absorbed from the gastrointestinal tract, causing cellular hypoxia and symptoms of poisoning: headache, pressure drop, accelerated pps, vomiting, diarrhea, cramps, convulsions. In extreme cases, loss of consciousness, respiratory and heart problems may occur. However, it should be noted that the toxic dose is 1 mg / kg body weight, and it is difficult to deliver it to the body with food. The highest amounts of cyanogenic glycosides are found in cassava, beans, bamboo shoots and stone plant seeds (pears, apples, peaches, apricots, almonds). The most famous compound in this group isamigdalina .

  • Tannins

Although tannins belong to the group of antioxidant compounds, they are considered anti-nutritional substances because they inhibit the absorption of minerals from food andvitamins AandB12. The tannins are responsible for the tangy aftertaste of tea, coffee, cocoa, wine and unripe fruit. They are found in large amounts in dark berries, grapes, pomegranates, apples, nuts, and pulses.

  • Dietary fiber

The list of anti-nutritional ingredients also includesdietary fiber . Fiber hinders the absorption of minerals from food because it has a high ability to bind them. At the same time, it is of great importance for the functioning of the digestive tract and for overall he alth.

Worth knowing

How do I minimize the effects of anti-nutritional substances?

Anti-nutritional substances have a negative effect on the body, but are often also credited with having a beneficial effect on he alth. In order not to have to completely give up eating certain products, it is worth using techniques that reduce the concentration of anti-nutrients in food or eliminate their effects, e.g.

  • soaking pulses, almonds, nuts;

  • cooking foods 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;

  • avoiding eating unripe fruits and vegetables;

  • ensuring your iodine intake is adequate.

Anti-nutrients: importance in the prevention of civilization diseases

Fruits, flowers, leaves, seeds, roots and bark of plants are rich in polyphenolic compounds, which have already been classified by several thousand. In food, they are classified as non-nutritional or anti-nutritional ingredients, but they are antioxidant substances of great importance in protecting against cellular aging, cancer and civilization diseases, such asdiabetes type 2oratherosclerosis . The group of polyphenols includes, among others tannins, alkaloids, glucosinolates or glycosides, which are also considered anti-nutritional substances.

Examples of anti-nutritional substances of importance in the prevention and treatment of diseases are:

  • cruciferous glucosinolates- support the synthesis of detoxifying enzymes, accelerating the excretion of toxins and carcinogens from the body, inhibiting the development of cancer cells and metastasis;

  • legume saponins- form complexes with bile acids and cholesterol, accelerate the excretion of their excess from the body;

  • tannins- have antibacterial and strong antioxidant properties, protect against cancer formation, slow down the rate of cancer cell division;

  • 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 anti-cancer properties, reduces the risk of atherosclerosis and type II diabetes because it improves carbohydrate metabolism.

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