Free radicals, antioxidants and functional foods: Impact on human health
Free radicals are toxic byproducts of oxygen metabolism that can cause significant Anything that increases the production of or exposure to free radicals will. Production of free radicals in the human body .. It has been reported that there is an inverse relationship between the dietary intake of antioxidant-rich food and . Free radicals react (ROS) and reactive nitrogen species(RNS) are generated Formation of radicals in biological systems and consequences ofoxidation of biological damage pathways in relation to normal tissue injury.
According to the free radical theory of aging, first outlined infree radicals break cells down over time. As the body ages, it loses its ability to fight the effects of free radicals. The result is more free radicals, more oxidative stressand more damage to cells, which leads to degenerative processes, as well as "normal" aging.
Various studies and theories have connected oxidative stress central nervous system diseasessuch as Alzheimer's and other dementias cardiovascular disease due to clogged arteries autoimmune and inflammatory disorderssuch as rheumatoid arthritis and cancer cataracts and age-related vision decline age-related changes in appearance, such as loss of skin elasticity, wrinkles, graying hair, hair lossand changes in hair texture diabetes genetic degenerative diseases, such as Huntington's disease or Parkinson's The free radical theory of aging is relatively new, but numerous studies support it.
Studies on rats, for example, showed significant increases in free radicals as the rats aged. These changes matched up with age-related declines in health. Over time, researchers have tweaked the free radical theory of aging to focus on the mitochondria. Mitochondria are tiny organelles in cells that process nutrients to power the cell. Research on rats suggests that free radicals produced in the mitochondria damage the substances that the cell needs to work properly.
This damage causes mutations that produce more free radicals, thus accelerating the process of damage to the cell. This theory helps explain aging, since aging accelerates over time.
The gradual, but increasingly rapid buildup of free radicals offers one explanation for why even healthy bodies age and deteriorate over time. Causes Free radical theories of aging and disease may help explain why some people age more slowly than others.
Although free radicals are produced naturally in the body, lifestyle factors can accelerate their production. So, oxidative stress might be a reason why exposure to these substances causes disease. Antioxidants and free radicals Antioxidants can help to prevent the harmful effects of free radicals. Antioxidants can be found in berries, citrus fruits, soy products, and carrots. It is hard to watch television without seeing at least one commercial that promises to fight aging with antioxidants.
Antioxidants are molecules that prevent the oxidation of other molecules.
Free radicals: How do they affect the body?
Antioxidants are chemicals that lessen or prevent the effects of free radicals. They donate an electron to free radicals, thereby reducing their reactivity. The third line of defense is the repair and de novo antioxidants. The proteolytic enzymes, proteinases, proteases, and peptidases, present in the cytosol and in the mitochondria of mammalian cells, recognize, degrade, and remove oxidatively modified proteins and prevent the accumulation of oxidized proteins.
The DNA repair systems also play an important role in the total defense system against oxidative damage. Various kinds of enzymes such as glycosylases and nucleases, which repair the damaged DNA, are known. There is another important function called adaptation where the signal for the production and reactions of free radicals induces formation and transport of the appropriate antioxidant to the right site.
This detoxification pathway is the result of multiple enzymes, with superoxide dismutases catalyzing the first step and then catalases and various peroxidases removing hydrogen peroxide. Mn-SOD is present in mitochondria and peroxisomes. Fe-SOD has been found mainly in chloroplasts but has also been detected in peroxisomes, and CuZn-SOD has been localized in cytosol, chloroplasts, peroxisomes, and apoplast.
The first is a dimer consists of two unitswhile the others are tetramers four subunits. To this end, catalase is frequently used by cells to rapidly catalyze the decomposition of hydrogen peroxide into less reactive gaseous oxygen and water molecules.
This system is found in animals, plants, and microorganisms. There are at least four different glutathione peroxidase isozymes in animals. The glutathione S-transferases show high activity with lipid peroxides. These enzymes are at particularly high levels in the liver and also serve in detoxification metabolism. As it cannot be synthesized in humans and must be obtained from the diet, it is a vitamin. In cells, it is maintained in its reduced form by reaction with glutathione, which can be catalyzed by protein disulfide isomerase and glutaredoxins.
Glutathione has antioxidant properties since the thiol group in its cysteine moiety is a reducing agent and can be reversibly oxidized and reduced. In cells, glutathione is maintained in the reduced form by the enzyme glutathione reductase and in turn reduces other metabolites and enzyme systems as well as reacting directly with oxidants. Melatonin, once oxidized, cannot be reduced to its former state because it forms several stable end-products upon reacting with free radicals.
Therefore, it has been referred to as a terminal or suicidal antioxidant. In fact, uric acid may have substituted for ascorbate in human evolution. There are a number of synthetic phenolic antioxidants, butylated hydroxytoluene BHT and butylated hydroxyanisole BHA being prominent examples.
- Inflammation, Free Radical Damage, Oxidative Stress and Cancer
These compounds have been widely uses as antioxidants in food industry, cosmetics, and therapeutic industry. However, some physical properties of BHT and BHA such as their high volatility and instability at elevated temperature, strict legislation on the use of synthetic food additives, carcinogenic nature of some synthetic antioxidants, and consumer preferences have shifted the attention of manufacturers from synthetic to natural antioxidants.
It has been reported that there is an inverse relationship between the dietary intake of antioxidant-rich food and medicinal plants and incidence of human diseases. The use of natural antioxidants in food, cosmetic, and therapeutic industry would be promising alternative for synthetic antioxidants in respect of low cost, highly compatible with dietary intake and no harmful effects inside the human body. Many antioxidant compounds, naturally occurring in plant sources have been identified as free radical or active oxygen scavengers.
Research has demonstrated that nutrition plays a crucial role in the prevention of chronic diseases, as most of them can be related to diet. Functional food enters the concept of considering food not only necessary for living but also as a source of mental and physical well-being, contributing to the prevention and reduction of risk factors for several diseases or enhancing certain physiological functions.
Broccoli, carrots, and tomatoes are considered functional foods because of their high contents of physiologically active components sulforaphen, B-carotene, and lycopene, respectively. Green vegetables and spices like mustard and turmeric, used extensively in Indian cuisine, also can fall under this category. A nutraceutical is any nontoxic food extract supplement that has scientifically proven health benefits for both the treatment and prevention of disease.
The major active nutraceutical ingredients in plants are flavonoids. As is typical for phenolic compounds, they can act as potent antioxidants and metal chelators. They also have long been recognized to possess anti-inflammatory, antiallergic, hepatoprotective, antithrombotic, antiviral, and anticarcinogenic activities.
Many of these are present in medicinal plants. Indian systems of medicine believe that complex diseases can be treated with complex combination of botanicals unlike in west, with single drugs. Whole foods are hence used in India as functional foods rather than supplements. Some medicinal plants and dietary constituents having functional attributes are spices such as onion, garlic, mustard, red chilies, turmeric, clove, cinnamon, saffron, curry leaf, fenugreek, and ginger.
Some herbs as Bixa orellana and vegetables like amla, wheat grass, soyabean, and Gracinia cambogia have antitumor effects. Other medicinal plants with functional properties include A. Antioxidants prevent free radical induced tissue damage by preventing the formation of radicals, scavenging them, or by promoting their decomposition.
Synthetic antioxidants are recently reported to be dangerous to human health. Thus the search for effective, nontoxic natural compounds with antioxidative activity has been intensified in recent years. In addition to endogenous antioxidant defense systems, consumption of dietary and plant-derived antioxidants appears to be a suitable alternative.
Free radicals, antioxidants and functional foods: Impact on human health
Dietary and other components of plants form a major source of antioxidants. The traditional Indian diet, spices, and medicinal plants are rich sources of natural antioxidants; higher intake of foods with functional attributes including high level of antioxidants in antioxidants in functional foods is one strategy that is gaining importance.
Newer approaches utilizing collaborative research and modern technology in combination with established traditional health principles will yield dividends in near future in improving health, especially among people who do not have access to the use of costlier western systems of medicine. Footnotes Conflict of Interest: Methodological consideration for characterization for potential antioxidant actions of bioactive components in plants foods. Pathological roles of reactive oxygen species and their defence mechanism.
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