28 Feb. - 6 March 2002
Issue No.575
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Al-Ahram Weekly Online 28 Feb. - 6 March 2002 Issue No.575 |
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| Published in Cairo by AL-AHRAM established in 1875 | Current issue | Previous issue | Site map | ||
Strive for five
Can we eat our way out of the dire effects that pollution has on our health and bodies? Hala Sakr went grocery shopping
Fresh air to breathe, clean water to drink, a wealth of foods to eat; even the atmospheric umbrella that protects us against the harmful ultra violet rays emitted by the sun: nature's blessings are innumerable and all are provided in our environment.
Looking into food: what you eat can protect you from the daily onslaught of pollution
photo: Sherif Sonbol
Not only are we key players in protecting or harming our environment, but our actions also come back to benefit or haunt us. Just as modern technology has made our lives easier, it has also pumped new substances into the environment which may affect our health adversely.
Good health is definitely not a matter of luck. At least not any more. Although our health is influenced by the genes we inherit from our parents, it is also strongly affected by our lifestyles. Our choices do make a difference. Food and exercise, along with avoiding harmful substances such as tobacco, all work together to define our state of health. They cumulatively influence our bodies' ability to protect us from infectious agents, cancerous growths and the ever- increasing byproducts of 'modernisation' -- environmental pollutants, radiation, the potentially toxic substances we inhale such as car exhaust as well as pesticides and other chemicals that we ingest in our processed and cured food and drinks.
THE CULPRIT, FREE RADICALS: We all know how vital oxygen is to life. It is crucial for burning digested food to produce energy. However, the resulting exhaust of 'free radicals' can be detrimental. Free radicals are unstable, highly reactive molecular fragments that have a missing electron. To compensate, they steal an electron from any neighbouring molecule leaving it with an urge to find a new electron of its own. Hence, a potentially catastrophic cascade is unleashed. Such a process damages healthy cells and can even kill them. These effects are referred to as 'oxidative stress.' In addition to our metabolism, various environmental pollutants, including tobacco smoke, cause our bodies to generate free radicals. Stress and excessive (particularly sporadic) exercise can also produce them in excess.
A small amount of free radicals is needed to destroy invading viruses, bacteria and cancer cells. Any excess, however, damages vital proteins, lipids, carbohydrates, cellular DNA and other genetic matter.
Our bodies possess protective enzymes to repair most of the oxidative damage. Yet, over time, sustained 'oxidative stress' culminates in irreversible cellular changes and mutations. Our defensive mechanisms wane with age and the body becomes more vulnerable.
Consequences of this process range from harmful pigmented skin patches to more serious disorders such as cataracts, cancer and degenerative diseases -- including fatty plaques causing the clogging of arteries through oxidising low-density lipoproteins (LDL) -- what is known as 'bad' cholesterol.
Moreover, our antioxidant defences are not absolutely efficient. Their capacity can be exceeded by excessive free radical generation. Hence, we need external supplies of antioxidants to boost our internal means and ensure that our 'armour' is not pierced.
THE SOLUTION, ANTIOXIDANTS: Living in a highly polluted environment like ours, the elimination of many of the external assaults occurring in our daily lives is beyond our personal capabilities. Nevertheless, we do have the power to modify our own eating habits and change our lifestyle. "Science has proved that a plant diet rich in fruits, vegetables, whole grains and legumes and low in saturated fat, in addition to regular aerobic (in open air) exercise, comprise a regime that is recommended for our good health," says Mervat Ahmed Fouad, professor of medicinal plants at the National Institute of Nutrition. "Such a diet is apt to be rich in phytochemicals and antioxidants," she continues.
Antioxidants are substances that are simply 'anti- oxygen.' They scavenge free radicals and render them harmless. Working together in the body they maintain our health, boost the immune system and play a vital role in checking cancer cells. They are no magic concoctions but they do slow down aging and protect us against many diseases such as cancer, coronary heart disease and cataracts.
Antioxidants are also important to food manufacturers. The food industry relies on these chemicals to prolong the shelf life of foods. Free radicals have the same damaging effect on many of the components which make up the foods.
There are many kinds of antioxidants. Some are vitamins such as C and E. Vitamin C scavenges free radicals. It appears to cut risk of cancer, helps raise high-density lipoproteins (HDL) -- our 'good' cholesterol -- and may also help fight off infections.
Vitamin E works with vitamin C and carotenoids to fight free radicals. It also helps boost the immune system and works against heart disease by preventing the creation of fatty plaques (LDL).
Then there are carotenoids, like beta-carotene, which give fruits and vegetables their natural bright colours. Beta- carotene is the precursor of vitamin A and also works as an antioxidant by itself. There are other carotenoids as well.
New research shows it to be quite likely that many carotenoids work together to produce the antioxidant protection. Lutein, present in broccoli and spinach, protects against eye diseases. Lycopene is a powerful carotenoid antioxidant with the potential to protect against heart disorders and many other diseases, including cancer. Tomatoes are rich in lycopene. According to Gina Grant, a British nutritionist and personal trainer at GOLD'S GYM, one of the good things about Egyptian recipes is that tomatoes are used in abundance. They are highly nutritive, even when cooked, as more of their carotenes are set free but they still have to be eaten raw to make use of other nutrients they contain, such as vitamin C. The carotenoids of green leafy vegetables, meanwhile, are being studied for possible protective effects against eye disease.
Selenium is among the most important of antioxidant minerals. People living in areas where the soil is rich in selenium have a lower incidence of cancer. Although there is as yet no proof of the capabilities of selenium in that respect, this observation has triggered much research into the phenomenon. Selenium is found in grains but if the soil is poor, it may be absent.
Finally, there are phytochemicals -- compounds of vegetables and fruits which include many types of flavenoids. In addition to countering free radicals, they have been associated with protection against heart disease and cancer.
However, once all is said and done, researchers have yet to conclusively prove that antioxidants can actually cure us of the afore-mentioned diseases. Gehad Abul-Atta, professor of industrial medicine at Cairo University, told Al- Ahram Weekly that antioxidants 'mitigate' the adverse effects of pollution and oxidative damage. Although we still need to know more about issues such as what effectiveness, if any, individual antioxidant vitamins have in preventing certain conditions, their mechanisms of action, the optimum levels of intake and their long-term effects, one thing stands on its feet: the more vegetables and fruits we ingest, the better.
"I doubt that there can be any controversy over the positive effect of antioxidants. They are definitely useful in protecting us against metabolites and foreign materials that result from the polluted atmosphere," affirms Shafiqa Nasser, professor of public health at Cairo University and member of the health and environment committee of the National Women's Council.
A RAINBOW OF FOODS: Antioxidants are produced by the body but need to be constantly replenished through our diet. They occur naturally in many foods -- brightly coloured fresh fruits and vegetables, fish and grains. Eating a balanced diet rich in antioxidants could be the best way to improve our health. Grant stresses that "we need not be sick to eat healthy food. We are all at risk of ill-health, so increasing the antioxidants in our daily diet helps reduce this threat."
One should try to get different kinds of fruits and vegetables every day, because they each contain a different set of protective nutrients. The general agreement is that we should 'strive for five' servings of antioxidant-rich foods every day: three red, orange or yellow vegetables or fruits -- fresh or frozen -- and two dark leafy vegetables, fresh or frozen.
If one is at risk of cancer or heart disease, two more fruits or vegetables should be added. Six to eleven servings of whole-grain breads and cereals are also recommended.
This should be quite simple: orange juice for breakfast, a salad for lunch, two fruit snacks a day, and a salad or vegetable for dinner.
If we go by servings, things need to be more clearly defined. A serving should be 1/2 cup of cooked vegetables; or 1/2 cup chopped raw vegetables; six ounces of vegetable juice; or one cup of raw leafy greens. A serving of fruit should be one medium apple, banana, or orange; 1/2 cup fresh berries; about 15 grapes; 1/2 cup applesauce; 1/4 cup dried fruit; or 6 ounces fruit juice. One serving of breads or cereals would be: a slice of bread; one to one and a half ounces of dry cereal; 1/2 cup cooked cereal, rice, or pasta; 4 small crackers or 2 large crackers; 1/2 bagel, hamburger bun or English muffin.
According to the International Life Sciences Institute's (ILSI) concise monograph on antioxidants, diets typically consumed in many parts of the world -- including most of Western Europe and North America -- fall short of satisfying the optimum dietary daily needs of antioxidants.
"In Egypt, the problem is that our diet is not oriented towards healthy foods but, rather, towards foods with high starch and sugar content," Abul- Atta told the Weekly. "Our task is to get people to revert to the more healthy fruits and vegetables," he adds.
On the other hand, Grant notes that a major problem with the Egyptian diet is that everything is over-cooked so that all the goodness evaporates. "Foods need to be more crisp so that the nutrients are not cooked away," she continues. She wishes that Egyptians would consume more raw foods. "OK, a daily salad is great but still not enough. There is a lot of good stuff too -- raw carrots, raw onions, raw everything -- and you never see people having them," she says.
Raw foods always offer ample amounts of all essential nutrients. They should constitute at least 50 per cent of our daily diet. Juices contain a condensed level of antioxidants but they should be complemented by raw vegetables and fruits to get all the fibre that helps rid the body of toxins from the digestive tract.
One of the things Grant likes about Egypt is that vegetables and fruits are seasonal. "Most of the time, the tomato you are eating has only been picked last week. The taste is different, better," she comments. Back in Britain everything is available because they are brought from other places with all the prolonged freezing and on-shelf thawing and unfreezing involved. "Freezing in itself is not a problem, provided foods are used within a short time span. Extended periods of unfreezing, however, are deleterious to the nutritive value and even the taste," she explains.
NATURAL FOODS VS. SUPPLEMENTS: If little is good, then more must be better. With that belief in hand, many people often take large amounts of supplements without any professional consultation.
One wonders if natural foods can satisfy our needs for essential nutrients. Mervat Ahmed Fouad of the National Institute of Nutrition states that the isolation of active plant constituents and their provision as supplements has, in many cases, been found to reduce their efficiency compared to their being ingested as part of the whole plant. "The plant contains other compounds that enhance the effectiveness of the active part," she asserts.
The ILSI monograph on antioxidants shows that antioxidants not only interact synergistically but also exhibit 'sparing effects.' That means that one protects another against oxidative damage. Such interactions imply that combinations of antioxidants may be more effective than larger quantities of one single antioxidant.
Aida Muwafi, professor of food science at the National Institute of Nutrition, agrees: "Antioxidants from natural sources are more effective because phytochemicals and other antioxidants present are in a state of optimum balance".
Taking supplements has always caused a lot of debate within the scientific community. Doctors discourage taking high dose antioxidant supplements. Some normally antioxidant nutrients might give an opposite effect and increase oxidation if taken in large amounts. Vitamin C becomes a pro-oxidant if taken in high doses by a person with a large iron reserve. The benefits of high dose beta- carotene supplement are doubtful. Vitamin E in high doses can hinder blood clotting and increase the risk of bleeding.
According to an article by V. Herbert published in 1996 in the American Journal of Clinical Nutrition, pharmacological amounts of supplements -- i.e. above the recommended dietary allowance (RDA) -- should not be taken without the advice of a licensed health professional. The article stresses that moderation in all things is the essence of sound nutrition.
ULTIMATE PROTECTION: Experts argue that despite all the encouraging evidence, the importance of antioxidants cannot be overstated considering the present and forecast rates of pollution.
Salma Galal, professor of public health at Al-Azhar University, argues that one should not overlook the roots of the problem -- the horrifying state of our environment. "Pollution is everywhere around us, even in the food we eat. Should we stop eating, drinking, even breathing?" she wonders. "An overall vision to combat pollution is urgently needed taking into consideration all stressful social, psychological and cultural interactions," she continues.
Nasser confirms that if things do not change, neither antioxidants nor anything else can protect our health. "We need to reduce the load of toxic material and pollutants to which we are exposed. Fighting pollution is our ultimate protection" she concludes.
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