Antinutrient

Antinutrients are natural or synthetic compounds that interfere with the absorption of nutrients. Nutrition studies focus on antinutrients commonly found in food sources and beverages. Antinutrients may take the form of drugs, chemicals that naturally occur in food sources, proteins, or overconsumption of nutrients themselves. Antinutrients may act by binding to vitamins and minerals, preventing their uptake, or inhibiting enzymes.

Throughout history, humans have bred crops to reduce antinutrients, and cooking processes have developed to remove them from raw food materials and increase nutrient bioavailability, notably in staple foods such as cassava.

Antinutrients can be therapeutic, such as anti-diabetic drug Acarbose, anti-obesity drug Orlistat which all reduce effective caloric intake.

Phytic acid has a strong binding affinity to minerals such as calcium, magnesium, iron, copper, and zinc. This results in precipitation, making the minerals unavailable for absorption in the intestines. Phytic acids are common in the hulls of nuts, seeds, and grains and of great importance in agriculture, animal nutrition, and in eutrophication, due to the mineral chelation and bound phosphates released into the environment. Without the need to use milling to reduce phytate (including nutrient), the amount of phytic acid is commonly reduced in animal feeds by adding histidine acid phosphate type of phytases to them.

Oxalic acid and oxalates are present in many plants and in significant amounts particularly in rhubarb, tea, spinach, parsley, and purslane. Oxalates bind to calcium, magnesium and iron, preventing their absorption in the human body.

Glucosinolates prevent the uptake of iodine, affecting the function of the thyroid and thus are considered goitrogens. They are found in plants such as broccoli, Brussels sprouts, cabbage, mustard greens, radishes, and cauliflower.

Protease inhibitors are substances that inhibit the actions of trypsin, pepsin, and other proteases in the gut, preventing the digestion and subsequent absorption of protein. For example, Bowman–Birk trypsin inhibitor is found in soybeans. Some trypsin inhibitors and lectins are found in legumes and interfere with digestion.

Lipase inhibitors interfere with enzymes, such as human pancreatic lipase, that catalyze the hydrolysis of some lipids, including fats. For example, the anti-obesity drug orlistat causes a percentage of fat to pass through the digestive tract undigested.