Antioxidants: Defenders against damage from free radicals

Ordinarily speaking, body uses oxygen in most, but not all, bodily chemical reactions, particularly in the production of energy. It uses this energy to perform a variety of routine bodily functions that sustain life in the broadest terms such as defending itself against bugs (bacteria, fungi, viruses, you name it), and against other constant threats, so-called free radicals, being the inevitable byproducts of turning food into energy by the body itself, but also present in diet, in the air we breathe or the result of sunlight’s action on skin and eyes.

Free radicals come in many shapes, sizes, and configurations. All share a voracious appetite for electrons, stealing them from any neighbouring entity or substances that will yield them. According to the Harvard School of Public Health, such electron theft can radically alter the “loser’s” structure or function and inflict damage. For example, free radical damage can change the instructions coded in a strand of DNA. It can make a circulating low-density lipoprotein (LDL, sometimes called bad cholesterol) molecule more likely to get trapped in an artery wall, a process colloquially referred to as ‘furring up’. Or it can alter a cell’s membrane, changing patterns of entry into it and exit out of it of stuff.

The good news is that healthy bodies are not defenseless against free radical baddies. The body, long used to such relentless attack, makes scads of molecules that quench free radicals as surely as water douses fire. But we also extract free-radical fighters from our diet. These defenders are often lumped together as antioxidants and work by generously giving electrons to free radicals without turning into electron-scavenging substances themselves.

There are hundreds, probably thousands, of different substances that can act as antioxidants. The most familiar ones are vitamins A and other related carotenoids, vitamins C and E, beta-carotene, lycopene, minerals such as selenium and manganese, and superfoods rich in glutathione, coenzyme Q10, lipoic acid, flavonoids, phenols, polyphenols, phytoestrogens, and many more. We will take the top six or seven in this long list of free radical scavengers and supplements that contain them.

Vitamins A, C and E

These three are available separately or jointly in a variety of potencies and their recommended safe daily levels are well cited. Vitamin A is an important nutrient for the immune system, for sight and vision, and for bone health. It is a fat soluble vitamin capable of getting accumulated in the body, and is found in liver (‘fish liver oils’) and dairy products.

Vitamin C (or ascorbic acid) with its typical ‘tangy’ flavour should not be mistaken for citric acid, a culinary preservative. Vitamin C is water soluble and as such is best taken in lower potencies and higher daily frequencies. It supports the immune system, promotes absorption of iron by the body, and is essential for healthy skin and collagen production, and healthy gums and teeth.

Vitamin E actually refers to a group of eight fat soluble molecules, also rferred to as tocopherols. This vitamin is essential for healthy skin, red blood cells and nerves. Authoratitive studies have shown that this vitamin is best taken in low doses which is why in the UK, the Food Standards Agency recommends a daily intake of between 3-4mg or 4.5-6 IU. Sunflower seeds or oil, grape seed oil, nuts, broccoli, green vegetables and peppers are rich sources of vitamin E.

Beta-carotene

This is actually the precursor to vitamin A, discovered by a German scientist in 1831. Since then, about 50 carotenoids have been identified in the human diet of which alpha-carotene, beta-carotene, and beta-cryptoxanthin are considered “essential” because they serve as precursors of vitamin A (converted to vitamin A by the body). The celebrity of the carotenoids is of curse beta-carotene, an orange pigment found in most fruit and vegetables derived first from roots of carrots. Look for beta-carotene in carrots, red peppers, sweet potatoes, pumpkins and apricots.

Lycopene

This is a much researched antioxidant. Although it is strictly chemically a carotene related to vitamin A, it has no vitamin A activity. It is bright red and found in tomatoes, water melons, and papayas. As an antioxidant it is 100 times more potent as a free radical quencher than vitamin E and 125 times more potent than glutathione (another antioxidant). Although it is not considered crucial in the human diet, once ingested it is transported for storage into the liver, adrenal glands, the prostate gland and testes. These observations have been sufficient to persuade the US Food and Drug Administration (FDA) to allow broad claims be made about lycopene: “very limited and preliminary scientific research suggests that eating one-half to one cup of tomatoes and/or tomato sauce a week may reduce the risk of prostate cancer”!

Selenium and Manganese

These trace elements act as chemical catalysts in the proper functioning of enzymes; Selenium is essential for proper functioning of glucothioneperoxidase whose role is essentially to protect the body (but particularly lipids) against oxidative damage. Selenium is found in Brazil nuts, tuna, beef, poultry and grains. However experts believe their levels have diminished considerably in such foods over the years.

Manganese, found in tiny amounts in the body is a component of the antioxidant enzyme superoxide dismutase. It is found in small traces in bones, liver, kidneys and pancreas and plays a role in fat and carbohydrate metabolism, calcium assimilation into the body and blood sugar regulation. As a trace element it also plays a key role in healthy brain and nerve functioning. It is believed that some 37% of Americans do not get their recommended dietary intake of manganese through diet. Wheat germ, bulgur wheat and buck wheat all offer good sources of this trace element.

Coenzyme Q10 (Co-Q10) and alpha Lipoic acid

Coenzyme Q10 and alpha-lipoic acid are crucial components in the primary energy production cycle in the mitochondria – the cells’ energy production factory – and are powerful antioxidants. Research indicates that supplementation with CoQ10 may support normal heart function and maintain the health of gums. A study by a prominent epidemiologist in the mid 1990s suggests that the vast majority of patients taking statins in our combat against high cholesterol levels and the resulting cardiovascular and coronary heart disease are in fact also suffer from Coenzyme Q10 deficiency.

Pycnogenol

Pycnogenol, a water extract of the bark of the French maritime pine is grown in the coastal regions of south-west France. Its acive ingredients are believed to be proanthocyanidins. The unique source of Pycnogenol, the “pine bark” has a well-established monograph in which its therapeutic characteristics are summarised. There is such intense interest in pycnogenol that its has its own dedicated website. Please also view http://www.pycnogenol.com/ . As a free radical scanvenger, weight for weight it is believed to be at least ten times more potent than vitamin C.

Pycnogenol’s main health benefits are linked to its putative anti-aging effects; particularly in relatin to skin health (collagen and fibrin elasticity), and its diminutive effect on aging of the epithelia linning of arteries, which with the pssage of time lose elasticity and ultimately result in atherosclerosis. The recommended daily dose is 1mg per kilogram body weight taken with or after food to mask its natural acrid taste.

Turmeric

Referred to as the Indian mystic spice and derived from a rhizome, with its distinctive bright yellow colour and curious taste, turmeric is considered to be a central feature of any serious culinary joint used mainly in lamb dishes to neutralise meat odour and season it.

Medicinally, its active ingredients are a class of phytochemicals that include curcumin which has received the most attention. The phytochemicsls found in turmeric have been researched for potential benefits in cancer, Alzheimer’s disease, arthritis and diabetes. The United States National Institutes of Health (NIH) reports a significant increase in basic research into therapeutic benefits of turmeric with some seventy registered clinical trials currently ongoing. As an example of such basic research, turmeric has been reported to reduce severity of pancraetic-related lung injury in mice. Other research shows how compounds in turmeric (but not curcumin) have anti-fungal and anti-bacterial properties, and it is being investigated in how supplementation might alter response to chemotherapy.

Green Tea

Originated in China, it has an aromatic distinctive flavour different from black tea due to its flavonoids having undergone less oxidation during the preparation processing. Green tea has received much publicity with reports of evidence that regular green tea drinkers having a lower risk of heart diesease and ceratin cancers. Also green tea itself has not been shown to be thermogenic, a combination of green tea extract containing polyphenols and caffeine has been shown to induce thermogenesis, boost metabolic aret by up to 4% and stimulate fat oxidation.

Mangosteen

Actually purple mangosteen, is an exotic tropical native plant of south east Asia. Its packed with vitamins, xanthonoids such as mangostin and others having antoxidant properties that have been show to lower blod levels of C-reactive protein. Most but not all mangosteen juice products contain whole fruit puree and/or polyphenols, and are flavoured.

Quercetin

Quercetin is derived from Oak Forest, naturally occurring and widespread in nature. It has anti-histamine properties and as such is used in managing allergies in which histamine is either the allergic or inflammatory mediator. For example it has been shown to alleviate ocular and nasal symptoms of pollen allergy suggesting it has the ability to block release of histamine from immune cells and prostaglandins.

Variants of it have also been studied; for example in a 2007 study that assessed the anti-Hepatitis B effects of Hyperoside (published in the Acta Pharmacologica Sinica), it was shown that Hyperoside, the 3-O-galactoside of quercetin is a strong inhibitor of HBsAg and HBeAg secretion in 2.2.15 cells. In another study also published in 2007 in the Archives of Pharmacal Research it was shown that quercetin, quercitrin and myricetin 3-O-beta-D-galactopyranoside displayed inhibition against HIV-1 reverse transcriptase, all with IC50 values of 60 microM. The American Cancer Society claims that while quercetin has been promoted as being effective against a wide variety of diseases, including cancer, some early laboratory results appear promising. At supplementary concentrations quercetin is unlikely to cause any major problems or benefits. Yet from laboratory studies it is believed that quercetin may affect certain mechanisms of cancer; An 8-year follow up study has found the presence of kaempferol, quercetin, and myricetin in a normal diet was associated with a 23% reduction in risk of pancreatic cancer, a rare but frequently fatal disease, in tobacco smokers.

Quercetin may also have calcineurin properties similar to cyclosporin A and tacrolimus. The University of Maryland Medical Centre leads the research on therapeutic benefits of Quercetin.

An interesting molecule with much potential!