What are the roles of antioxidants in human body?

Antioxidants are natural compounds found in foods that help protect the body from armful free radicals.

The researches show that human diseases are mediated by oxidative stress and imbalance between pro-oxidant and antioxidant factors. The human body has several mechanisms to counteract oxidative stress produced in situ, or be externally supplied by food and/or supplements.

The majority of the available research on the role of antioxidant has focus on vitamin E. Vitamin E is the major antioxidant in the lipid environment of cellular and subcellular membranes, and also in plasma lipoproteins, protecting the vital phospholipids from peroxidation.

The vitamin, chiefly α-tocopherol, is specifically and actively incorporated within biological membranes where it stabilizes the lipoprotein structure.
What are the roles of antioxidants in human body

Nutritional quality of sunflower oil

Sunflower is relatively low in the saturated fatty acids, palmitic and stearic but it is rich in the unsaturated fatty acids, oleic and linoleic. With its high amount of polyunsaturated fat, sunflower oil may be good choice to help lower high cholesterol levels.

Its polyunsaturated fatty acid composition is superior to all oils except safflower oil; hence, it offers a popular approach to the prevention and/or cure of cardiovascular diseases.

It is an excellent source of vitamin E, which may enhance the body’s immune response to certain disease.

Like other oils, it has no cholesterol and no sodium. Sunflower oil is used as cooking and salad oil and in the manufacture of margarine sometimes as a pure sunflower products, but more often it belongs with other vegetable oils.
Nutritional quality of sunflower oil

What is tocotrienols?

Tocopherols and tocotrienols which are collectively known as tocochromanols, belongs to the group of vitamin E compounds.

Tocotrienols occupy a special place due to their unique chemical structure and properties. They are generally located in seeds and fruits; however, there is a high variation in the relative abundance for each tocotrienols homologue.

Tocotrienols are a group of four amphipathic molecules (alpha, beta, gamma, delta) that differ in the number and position of the methyl groups in the polar head.

Delta-tocotrienols tends to be the predominant form found in seeds, followed by alpha and gamma forms, whereas gamma-tocotrienols is the predominant form in fruits.

The gamma-tocotrienols is the most prevalent form in nature and it also appears to be the form with strongest potential for dietary health benefits.

Most tocotrienols from market are derived form rice bran oil and palm oil. Presently marketed forms of tocotrienols contain mixed tocotrienols in their unesterified forms.

The major sources of tocotrienols are plant, oils, and the richest sources are palm oil, rice bran oil, palm kernel oil and coconut oil.

Tocotrienols are not found in the green parts of plants but, rather in the bran and germ fraction of certain seeds and cereals. All of the natural tocotrienols are fat-soluble, water insoluble oils.
What is tocotrienols?

Human Deficiency of Vitamin E

Vitamin E was discovered in 1922, but not until 1983 that vitamin E was demonstrated to be dietary essential for human beings.

Vitamin E deficiency was first describe in children with fat malabsorption syndromes, principally abetalipoproteinemia, cystic fibrosis, and cholestatic liver disease.

They have been reports of vitamin E deficiency symptoms in person with protein calories malnutrition.

The frequency of human vitamin E deficiency is very rare, deficiency is usually associated with disease of fat malababsorption such as cystic fibrosis.

In individual at risk, it is clear that vitamin E supplements should be recommended to prevent deficiency symptoms.

Without vitamin E, the red blood cells break open and spill their contents, probably due to oxidation of the polyunsaturated fatty acids in their membranes.

The classic sign of vitamins E deficiency, known as erythrocyte hemolysis, is seen in premature infants, born before the transfer of vitamin E from the mother to the infant that takes place in the last week of pregnancy.

The primary human vitamin E deficiency symptoms is a peripheral neuropathy characterized by the degeneration of the large caliber axons in the sensory neurons.

Other vitamin E deficiency symptoms observed in humans include spinocerebellar ataxia, skeletal myopathy, and pigmented retinopathy.

Prolonged vitamin E deficiency also can causes neuromuscular dysfunction involving the spinal cord and retina of the eye.
Human Deficiency of Vitamin E

Vitamin E Sources and Functions

It was discovered in 1922 in vegetable oil given the name ‘tocopherol’. Vitamin E, of which there are four different forms, is fat soluble.

The four have the same name except with the prefixes alpha-, beta-, gamma-, and delta-, (the first four letters of the Greek alphabet).

Only alpha-tocopherol contributes toward meeting the human vitamin E requirement and it is the most common form of vitamin E in food.

It is our body’s major fat soluble antioxidant. It protects vulnerable polyunsaturated lipids in cell membranes, in blood and elsewhere throughout the body.

The richest dietary sources of vitamin E are the vegetable oils. Safflower and olive oil contain the highest proportion of alpha-tocopherol, followed by soybean oil.

Curiously enough, these oils are also the richest sources of polyunsaturated fatty acids, which vitamin E protects from oxidation.

Nuts and seeds such as sunflower seeds, are among the best food sources.

In western diet, vitamins E intake derives mainly from fats and oils contained in margarine, mayonnaise, salad dressing and desserts, and increasingly also from fortified food (e.g., breakfast cereals, milk, fruit juices).

Vitamin E helps reduce oxidation of lipid membranes and the unsaturated fatty acids and prevents the breakdown of other nutrients by oxygen.

Some scientists compare the function of vitamin E on the cell membrane to a lightening and nullifying the damage that occurs of lightening strikes. This function of vitamin E is also performed and enhanced by other antioxidants, such as vitamin C, beta-carotene, glutathione (L-cysteine), coenzyme Q and the mineral selenium.

In fact, there is a direct recycling process for vitamin E that requires the immediate presence of beta-carotene, vitamin C, flavonoids, and coenzyme Q to work.

Observational studies have suggested that high intake of antioxidant including vitamins E, may lower the risk of some chronic disease, especially heart disease.

Different forms of vitamin E, other than alpha-tocopherol, have immuno-regulatory functions,

Alpha-tocopherol is the most common form of vitamin E in plasma and tissues and the most extensively studied for its beneficial effect on immune function, probably because it is the exclusively component in most vitamin E supplements.
Vitamin E Sources and Functions

Source of of vitamin E

Vitamin E is present in human tissues and it is necessary for normal metabolism. It is found to be widely distributed in foods.

Much of the vitamin E in the diet comes from vegetable oils and products made from them, such as margarine and salad dressings.

Among vegetable oils, the content of vitamin E isomers differs vastly. Some vegetable oils such as olive, safflower and sunflower are rich in alpha-tocopherol, while other oils such as sesame seed, soybean, maize and rapeseed oil are rich in gamma-tocopherol.

Wheat germ oil is especially rich in vitamin E. While major sources of vitamin E in Japan are fish and shellfish.

Vitamin E also can be found in sweet corn, cashews, almonds and peanuts. Avocadoes are another good sources of vitamin E.
Source of of vitamin E

Vitamin E as antioxidant

Vitamin E is a fat-soluble vitamin that exists in eight different forms. Each form has its own biological activity, the measure of potency or functional use in the body.

It is actually two sets of four compounds each, the tocopherols (alpha, beta, gamma and delta) and the chemically related tocotrienols (alpha, beta, gamma and delta).

Alpha-tocopherol is the most active form of vitamin E in humans, and is a powerful biological antioxidant. It is the major lipid soluble found in cells.

The alpha-tocopherol form is the one found in the largest quantities in human blood and tissue. Small amounts of the gamma from are also found.

Antioxidants such as vitamin E act to protect body cells against the effects of free radicals, which are potentially damaging by-products of the body's metabolism. Vitamin E serves as one of the body’s chief defenses against damage by free radicals.

Most notably, vitamin E prevents the oxidation of the polyunsaturated fatty acids, but is protects other lipids and related components (e.g. vitamin A) as well.

Research and the clinical experiences of physician show beyond a doubt that vitamin E is good for the heart. The role of vitamin E as a heart protector has been building for decades.

However, of low vitamin E intake may enhance the effect of selenium deficiency, which is associated with increased risk of fatal cancer.
Vitamin E as antioxidant