During cooking lipids in red meat can undergo chemical changes that result in the formation of malondialdehyde. Malondialdehyde forms by oxidation of arachidonic acid which is found in high amounts in the fats associated with red meats. Malondialdehyde is of interest to nutritional scientists because evidence implicates this chemical in the development of cancer and cardiovascular disease. Malondialdehyde is carcinogenic because it is able to react with deoxyadenosine and deoxyguanosine in DNA and form DNA adjuncts that can cause mutations. Malondialdehyde is implicated in the development of cardiovascular disease because it is thought to cause Schiff base formation when it reacts with lysine residues of apolipoprotein B in low density lipoproteins. These altered lipoproteins may then bind to macrophage receptors in endothelial cells which causes the formation of foam cells which lead to atherosclerotic lesions.
It is possible to inhibit the formation of at least some of the malondialdehyde with the use of antioxidants during cooking. Spices are good sources of antioxidants and some evidence suggests that the use of spices decrease the formation of malondialdehyde. For example, research published in the American Journal of Clinical Nutrition in 20101 used the herb oregano to inhibit the formation of malondialdehyde in the cooking of hamburgers. Addition of 19 mg of rosmarinic acid from oregano reduced the formation of malondialdehyde during cooking by 71 % compared with control burgers. Eating the control burgers caused an increase in the plasma malondialdehyde levels of subjects, but not in subjects consuming the treatment burgers. The researchers also recorded a 49 % reduction of malondialdehyde in the urine of subjects who consumed the treated burgers compared with controls.
Antioxidants are known to decrease the oxidative stress within those who regularly consume them in foods and supplements. Oxidative stress caused by free radicals is implicated in a number of diseases including cancer and heart disease. Many studies are now showing that herbs and spices are an excellent way to increase the antioxidant content of the diet because they are such rich sources of a number of unique antioxidants not present in other foods. In fact, Studies show that weight for weight, herbs and spices have the best antioxidant capacity of any foods (here). Incorporating herbs and spices into cooking is recommended because it is not only a good way to increase plasma levels of antioxidant compounds but also because it can prevent the formation of lipid peroxides in the food itself during cooking.