Food of plant origin is the source of many biologically active substances. Among them one of the most important groups are compounds with antioxidant. In a large simplification can say that antioxidants inhibit the reactions that occur with oxygen or ozone. They may also act indirectly by binding some of the prooxidants.
In food, free radicals are formed for example. as a result, frying, smoking, as well as storage in abnormal conditions. Sometimes arise in the human body – m.in. under the influence of UV radiation, stress, nutritional or chemical toxins.
The human body has ways of combating free radicals. Such action is characterized by enzymes: dysmutazę ponadtlenkową, crystallizing and peroxidase-glutationową. Effective protection are also antioxidants contained in foods. These include: fruits, vegetables, legumes, cereal grains, oil seeds, tea and herbs and spices. The problem appears when is created more free radicals than the body can neutralize. Functions of the body’s defenses are heavily impaired, which leads to oxidative stress. This, in turn, can trigger the formation of changes in the structure of nucleic acids, proteins, lipids and carbohydrates.
Antioxidants in food
Epidemiological studies indicate a clear relationship between morbidity on ischemic heart disease and consumption of foods rich in flavonoids. Therefore, it is recommended that you consume a day 5 servings of fruits and vegetables which are polyphenols.
Also keep in mind that the biological activity of antioxidants depends on their digestibility. Unfortunately, how many antioxidants learn our body depends on how much of the input substances is digestion, absorption, and turned to the metabolic processes. Proof that some polyphenols from foods is absorbed Entero, is m.in. increase in antioxidant capacity of blood plasma after consumption of a product containing polyphenols (such as red wine or tea).
Vegetables as a source of antioxidants
Vegetables are usually less antioxidant capacity than fruit. Largest peroxyl radicals binding capacity: garlic, kale, spinach, cabbage, Brussels sprouts, broccoli and beetroot; radicals hydroxide best binds kale and Brussels sprouts. In the table below summarizes the selected vegetables and their ORAC value, providing a binding capacity of free radicals. The higher the ORAC value, the greater is the ability to absorb free radicals oxygen.
High content of antioxidants also has tomatoes and preparations thereof obtained. They contain significant amounts of lycopene. Lycopene prevents oxidation of LDL, which inhibits the growth of atherosclerotic process and, consequently, reduces the incidence of heart disease.
Tomatoes contain about 30 mg/kg wet weight of lycopene. It is worth noting that the processing processes tomatoes and cook them in the form of ketchup, tomato sauce or concentrate this content increases. To the diet, which is rich in tomatoes and tomato products, Mediterranean diet. Denmark on the basis of these ingredients are eaten with olive oil, which further increases the bioavailability of lycopene.
Do not forget also about garlic. Strong antioxidant properties of vegetables derive from organic content of sulphur compounds (sulphide and diallilu disulphide and allicin). Bulbous vegetables noteworthy red onion and shallots, containing significant amounts of quercetin.
The bottom line: the antioxidants contained in vegetables have the ability to scavenge free radicals oxygen. The accumulation of free radicals of oxygen in the body contributes to the formation of oxidative stress, which is at the root of many diseases. Eat approximately 500 g of fruit and vegetables a day, to reduce the risk of heart disease and cancer. It is believed that the increase this effect promotes the variety of fruit and vegetable intake.