The effects of ingesting pesticides in the very small amounts present in vegetation are unknown. Bruce Ames, Ph.D., director of the National Institute of Environmental Health Sciences Center at the University of California at Berkeley, who has devoted his career to examining this question, believes these minute amounts pose no risk at all.
He and other scientists support this view because humans and other animals are exposed to, small amounts of naturally occurring toxins with every mouthful of organically grown, natural food. The body normally breaks down self-produced metabolic wastes and naturally occurring carcinogens in foods, as well as pesticides, and excretes these harmful substances every minute. Since 99.99 percent of the potential carcinogenic chemicals consumed are naturally present in all food, reducing our exposure to the 0.01 percent that are synthetic will not reduce cancer rates.
These scientists argue that humans ingest thousands of natural chemicals that typically have a greater toxicity and are present at higher doses than the very minute amount of pesticide-residues that remain on food. Furthermore, animal studies on the carcinogenic potential of synthetic chemicals are done at doses a thousand fold higher than what is ingested in food. Ames argues that a high percentage of all chemicals, natural or not, are potentially toxic in high doses - "the dose makes the poison” - and that there is no evidence of possible cancer hazards from the tiny chemical residue remaining on produce.
Others believe a slight risk may be present, though that risk may be difficult to prove. There certainly is a justifiable concern that some chemicals have increased toxicity and are potentially harmful at lower doses than are used in rodent experiments. No scientist believes that this means we should reduce our consumption of vegetation, but many (including me) believe it prudent to reduce our exposure to the multiple toxic residues present in our food supply. I certainly advocate avoiding the skins of foods that are reported to have the most pesticide residues. And, of course, all fruits and vegetables should be washed before eating.
If you are concerned about pesticides and chemicals, keep in mind that animal products, such as dairy and beef, contain the most toxic pesticide residues. Because cows and steers eat large amounts of tainted feed, certain pesticides and dangerous chemicals are found in higher concentrations in animal foods. For example, dioxin, which is predominantly found in fatty meats and dairy products, is one of the most potent toxins linked to several cancers in humans, including lymphomas. By basing your diet on unrefined plant foods, you automatically reduce your exposure to the most dangerous chemicals.
According to the Environmental Working Group," these are the "Dirty Dozen" consistently most contaminated fruits and vegetables, ranked from highest to lowest:
7. bell peppers
12. imported grapes
It would make sense to purchase organically grown versions of these foods.
Onions, sweet corn, asparagus, sweet peas, cabbage, eggplant, broccoli, tomatoes, and sweet potatoes are the vegetables least likely to have pesticides on them. Avocados, pineapples, mangoes, kiwifruit, papayas, watermelon, and grapefruit are the fruits least likely to have pesticide residues on them.
It makes good sense to peel fruits if possible, and not to eat potato skins unless you are able to purchase pesticide-free potatoes. Remove and discard the outermost leaves of lettuce and cabbage if not organically grown; other surfaces that cannot be peeled can be washed with soap and water or a commercial vegetable wash. Washing with plain water removes 25 to 50 percent of the pesticide residue.
Every study done to date on the consumption of food and its relation to cancer has shown that the more fruits and vegetables people eat, the less cancer and heart disease they have. All these studies were done on people eating conventionally grown, not organic, produce. Clearly, the benefit of conventional produce outweighs any hypothetical risk.
(Dr. Joel Fuhrman, M.D., ‘Eat to Live)