Consumers Association of Penang

Giving voice to the little people...since 1970

Antioxidants – Food’s amazing healing powers

broccoliThere's something magic in food that can save you from virtually every disease and it’s described in one word: antioxidants. Here’s what everyone should know about this miracle food substance.
 
 
Antioxidants are basically nature’s anti-ageing medicine. It protects against free radical damage in the body. Free radicals are unstable, high-energy, electrically charged molecules that can damage DNA and cell membranes. Cell damage of this sort could increase the risk of cancer and countless other illnesses.

Here’s how cell damage happens. Oxygen, the very stuff that gives life, can also take it away. Our cells are continually besieged by toxic forms of oxygen, causing bodily deterioration. Attacks by continual bursts of oxygen reactions, or destructive oxygen reactions in the body, clog arteries, turn cells cancerous, make joints give out and make the nervous system malfunction.

This process, called oxidation, is so gradual and internally painless, occurring over years in incessant microsecond bursts of destruction, that you don’t notice it until the cumulative damage gives rise to what we call symptoms of disease — inflammation, failing vision, chest pain, poor concentration and cancer.

Many destructive oxidants, which cause this process, come from the environment (eg: air pollutants, toxic industrial chemicals, pesticides, cigarette smoke and drugs).

The good news is that there is a way to slow down the destructive process — by feeding your cells antioxidant food compounds, mostly from plant food (fruits and vegetables) that strike down, intercept and extinguish rampaging oxygen molecules and even repair some of the damage.

Scientists have discovered an array of potent plant antioxidants with exotic names like quercetin, lycopene, lutein and glutathiones as well as the more familiar nutrients like Vitamins C and E, beta carotene and the trace mineral selenium that can save you from many health misfortunes.

These and many other substances in food may play a role in helping to prevent diseases such as cancer, cardiovascular disease, macular degeneration, and Alzheimer’s disease as they have the ability to neutralise free radicals, which are toxic by-products of natural cell metabolism.

The human body also produces antioxidants, but the process is not 100% effective and that effectiveness declines with age. Hence intake of antioxidants is highly advisable.

But studies show that you need to eat antioxidants as food, not swallow its extract in pill form. Research indicates there is little benefit from ingesting supplements. A better way, according to nutritionists at the Mayo Clinic, Rochester, Minnesota, US, is eating a diet rich in antioxidant-containing foods (USA Today, February 2008).

Food, rather than supplements, may boost antioxidant levels because they contain an unmatchable array of antioxidant substances. A supplement may contain a single type of antioxidant or even several. However, foods have thousands of different kinds, and it is not known which of these substances confer the benefits.

Take for example, carotenoids [responsible for the red, orange, and yellow hues of plant leaves, fruits, and flowers (as well as the colours of some birds, insects, fish, and crustaceans)], which are potent antioxidants. Some 600 different carotenoids are known to occur naturally, and new carotenoids continue to be identified.

Some examples of carotenoids include: Lycopene (that gives tomatoes their red colour), lutein and zeaxanthin (in corn and in leafy greens such as kale and spinach) and beta carotene (in carrots, spinach, peaches and sweet potatoes) alpha-carotene (found in carrots, pumpkin, and red and yellow peppers) and cryptoxanthin (from oranges, tangerines, peaches, nectarines, and papayas).

Similarly, about 600 variations of the antioxidant flavonoids, anthocyanins (colour pigments found in red/purplish fruits and vegetables, including purple cabbage, beets, blueberries, cherries, raspberries and purple grapes) exist naturally in nature.

Anthocyanins: Many Medicinal Values

Anthocyanins, an antioxidant that has received less attention than other flavonoids, has far-reaching effects. According to a report in Nutrition Science News (December 2001), many anthocyanins found in common foods, protect against a variety of oxidants through a number of mechanisms.

For example:
• Red cabbage anthocyanins protect animals against oxidative stress from the toxin paraquat.
• Cyanidins, found in most fruit sources of anthocyanins, have been found to “function as a potent antioxidant in vivo” in recent Japanese animal studies.
• In other animal studies, cyanidins protected cell membrane lipids from oxidation by a variety of harmful substances.
• Additional animal studies confirm that cyanidin is 4 times more powerful an antioxidant than Vitamin E.
• The anthocyanin pelargonidin protects the amino acid tyrosine from the highly reactive oxidant peroxynitrite.
• Eggplant contains a derivative of the anthocyanidin called nasunin, which interferes with the dangerous hydroxyl radical-generating system — a major source of oxidants in the body.

Studies show anthocyanins’ positive influences on a variety of health conditions. One reason is their anti-inflammatory properties, which affect collagen and the nervous system — as well as the heart.

In studies, protection from heart attacks through administration of grape juice or wine was strongly tied to the ability of the anthocyanin-rich products to reduce inflammation and enhance capillary strength and permeability, and to inhibit platelet formation and enhance release of nitric oxide (a chemical produced in the lining of the blood vessel, which is important for heart health).

Here’s how this antioxidant works for some health conditions.

Inflammation
In the course of inflammation, enzymes damage connective tissue in capillaries, causing blood to leak into surrounding tissues. Oxidants are released and further damage blood-vessel walls.

Anthocyanins protect in several ways. First, they neutralise enzymes that destroy connective tissue. Second, their antioxidant capacity prevents oxidants from damaging connective tissue. Finally, they repair damaged proteins in the blood-vessel walls.

Animal experiments have shown that anthocyanins effectively prevents inflammation and subsequent blood-vessel damage.

Allergies
Anthocyanins’ anti-inflammatory ability has been shown to help dampen allergic reactions. In one study, Bulgarian researchers gave animals histamine and serotonin, both of which cause allergic reactions and increase capillary permeability. The animals were supplemented with a variety of flavonoids. Anthocyanins were found to have the strongest anti-inflammatory effect of any flavonoid tested.

Brain and Neurodegenerative Diseases.
Anthocyanins’ effects on inflammation help explain many of their protective effects elsewhere in the body. The brain is particularly vulnerable to oxidative damage. Test-tube studies show that nasunin protects lipids in animal brain tissue from oxidation.

Cancer
Anthocyanins may have other potential benefits for humans. In the laboratory, they have been found to inhibit some human tumour cells. Cyanidin and delphinidin inhibit epidermal growth factor receptor in cancer cells, while malvidin is less effective.

Anthocyanins also have the ability to protect both large and small blood vessels from oxidative damage, including microvessel damage from high blood-sugar levels that cause complications in diabetics (In diabetic retinopathy, which damages eyesight, leaking, damaged capillaries is a chief cause).

It is a formidable antagonist to the following diseases:

Diabetes
One of the most serious diabetic complications is retinopathy, which can cause blindness. Retinopathy occurs when the body attempts to repair leaking, damaged capillaries, but does so by overproducing abnormal proteins.

Anthocyanins not only prevent capillaries from leaking in the first place, they also prevent abnormal protein proliferation. In one Italian study, 30 out of 40 people with retinopathy showed significant improvement after taking anthocyanin daily for several weeks. None of the control subjects improved.

Atherosclerosis
Because they protect large blood vessels, anthocyanins are excellent atherosclerosis (diseased and clogged arteries) fighters — in fact, it is the first line of defence against atherosclerosis. Anthocyanins prevent a key step in atherogenesis, oxidation of low-density lipoproteins (LDL — ie “bad” cholesterol, associated with arterial plaque formation). In test tube studies, bilberry* (a type of berry popular in the west) in even trace amounts effectively protects against LDL oxidation.

(*Researchers in a US Department of Agriculture-funded study concluded that bilberry is a “more potent” antioxidant than Vitamin C, or BHT (commonly used as a preservative).

Foetal retardation
In a human study conducted in Europe, researchers found that 55 women with intrauterine growth retardation (which manifests as a decreased rate of foetal growth), who took anthocyanins, experienced decreased oxidated LDL levels by almost 1½ times in 2 months. LDL levels rose in the control group.

Popular Folk Medicine
The use of anthocyanins for therapeutic purposes has long been supported by both epidemiological and anecdotal evidence.

The roles of anthocyanin pigments as medicinal agents have been well accepted in folk medicine throughout the world, and, in fact, these pigments are linked to an amazingly broad-based range of health benefits.

For example, anthocyanins from Hibiscus sp have historically been used in remedies for liver dysfunction and hypertension; and bilberry (Vaccinium) anthocyanins have an anecdotal history of use for vision disorders, microbial infections, diarrhoea, and diverse other health disorders. [Source: Journal of Biomedicine and Biotechnology, 2004; 1 December, 2004(5): 306-313]

Most Potent in Its Natural Form
"In terms of biological activity in the human body, an anthocyanin pigment is (almost) never acting independently. Typically, anthocyanins and other flavonoid components, or anthocyanins and other nonflavonoid phytochemicals, are interacting together in order to provide full potency … There are over 4,000flavonoids … with … large complex structures in the mixtures. Bioflavonoids like anthocyanins occur in mixtures within edible foods … Any plant containing anthocyanins includes a complex phytochemical cocktail.” says Mary Ann Lila from the Department of Natural Resources & Environmental Sciences, College of Agricultural Consumer and Environmental Sciences, University of Illinois, US.

For complete nutrition insurance, it is thus best to eat foods rather than supplements.

Antioxidant-rich foods also offer an array of health benefits, such as being high in fibre, protein, and other vitamins and minerals and low in saturated fat and cholesterol.

Though supplements containing antioxidants generally are considered safe, it’s best to avoid them as studies have now determined that they may not offer the same protection as food source antioxidants and may, in fact, be harmful, or toxic in higher doses (as is the case for Vitamin E).

Food: Best Antioxidant Insurance
Antioxidants are found in many foods. These include fruits and vegetables, nuts, grains, and some meats, poultry and fish. Some of the better food sources are:

  • Berries (blueberries, blackberries, raspberries, strawberries, and cranberries) (Note: Berries were a large part of early man’s diets. Our ancestors probably ate far more anthocyanins than we do. Some researchers feel that, by comparison, we are deficient in anthocyanins.)
  • Beans (small red beans and kidney, pinto, and black beans)
  • Fruits (many apple varieties with peels, avocados, cherries, green and red pears, fresh or dried plums, pineapple, oranges, and kiwi)
  • Vegetables (artichokes, spinach, red cabbage, red or white potatoes with peels, sweet potatoes, and broccoli)
  • Beverages (green tea, coffee, red wine, and many fruit juices)
  • Nuts (walnuts, pistachios, pecans, hazelnuts, and almonds)
  • Herbs (ground cloves, cinnamon or ginger, dried oregano leaf, and turmeric powder)
  • Grains (oat-based products)
  • Dessert (dark chocolate)

Cooking Methods and Antioxidant Levels
Some vegetable cooking methods may be better than others when it comes to maintaining beneficial antioxidant levels, according to a study in the Journal of Food Science. Results showed that, depending on the vegetable, cooking on a flat metal surface with no oil (griddling) maintained the highest antioxidant levels.

Researchers at the University of Murcia and the University of Complutense in Spain examined how various cooking methods affected antioxidant activity by analysing 6 cooking methods with 20 vegetables.

The 6 cooking methods were boiling, pressure-cooking, baking, microwaving, griddling and frying. Their findings showed the following:

  • The highest antioxidant loss was observed in cauliflower after boiling and microwaving, peas after boiling, and zucchini after boiling and frying
  • Green beans, beets and garlic were found to keep their antioxidant levels after most cooking treatments
  • The vegetables that increased their antioxidant levels after all cooking methods were green beans (except green beans after boiling), celery and carrots
  • Artichoke was the only vegetable that kept its high antioxidant level during all the cooking methods

Griddle-cooking helped maintain the highest levels of antioxidants, produced the lowest losses while “pressure-cooking and boiling [led] to the greatest losses, says lead researcher A. M. Jiménez-Monreal.

“In short, water is not the cook’s best friend when it comes to preparing vegetables.” (Source: Institute of Food Technologists)

 

For more information on Foods to Prevent Cancer, Foods to Prevent Heart Disease and Food Better Than Supplements, please see Utusan Konsumer May-June 2009.

Read about how protective foods like fruits and vegetables give us the antioxidants that we need in the CAP Guides, Fruits - A Nutrition Guide and Vegetables - A Nutrition Guide