Content Objectives
While researching information concerning chemicals my students were consuming either through their snacks or at mealtime, what I thought I knew about those topics was not going to be anywhere near the information I needed to prepare and effectively teach my unit titled “Chemical Footprints”. For one thing I discovered most of the information I had available to access on the pesticide segment was at least from eight years ago or even older. I also found when I wanted to research the effects that hormone diffusors / synthetic estrogens were introducing into genes and their structures, there were few articles I felt I could understand enough to write comfortably about mutations and how they can affect future generations. I went through an intense phase deciding what information to include and / or omit in my unit. I finally decided to base my curricular unit on teaching my students about chemicals that will influence the direction of their health.
A short background addressing genetics and DNA (deoxyribonucleic acid) will start to establish pertinent information influencing benefits and controversies of manipulating biology yields.
Heredity and DNA
The year was 1851 when Gregor Mendel started to notice pea plants could have the characteristics of their parents however some of the plants were yellow and some were green. His curiosity and years of study and hard work led him to generate the foundation to the science of genetics and heredity. The timeline from 1869-1952 demonstrates specific important scientific discoveries preceding 1953. The following website www.genomes.gov /pages:/geneticstimeline20 supplied the following segments: 1869 Frederick Miescher isolates DNA from cells and calls it “nuclein”. In 1909 Wilhelm Johannsen creates the word “gene” to name Mendel’s unit of heredity. He also designated terms genotype and phenotype to differentiate between the genetic traits of individuals and their outward appearance. Going forward to 1911 Thomas Hunt Morgan’s experiments with Drosophila (fruit flies) increased scientific understanding of gene coding and genetic linkage. Other major milestone from 1952 – 1953 include Alfred Hershey & Martha Chase showing that only the DNA (and not protein) of a virus needs to enter a bacterium to infect it, providing strong support for the idea that genes are made of DNA.
Surfacing a year later was the detection of structural DNA (the genetic material that transports information across generations, passed from parent to offspring.). Rosalind Franklin, Francis Crick, and James Watson introduced the structure of DNA to the scientific community, and relayed vital information on how DNA replicates itself during cell division.
Environmental Toxins
Bisphenol A (BPA) is a chemical found in hard plastic bottles and in the linings of food and beverage cans. It has been associated with development of brain, breast and prostate cancer in laboratory studies. Phthalates, such as DEHP, are chemicals used to make plastic soft, including plastic food wrap. DEHP has been shown to affect male reproductive development, sperm quality, and male hormone levels in laboratory and human studies.21
BPA and phthalates can leach into food and drink from the linings of cans and plastic packaging. It’s not practical to evade packaging materials altogether; however, a good choice would be to choose fresh or frozen foods as much as possible. Studies have shown that people who go out to dinner a lot have higher levels of BPA in their systems.22 To reduce the BPA levels in your body consider eating more meals at home that contain fresh ingredients. When you do eat out, choose “sustainable” restaurants to dine out. They will guarantee fresh and healthy food choices.
Food and drinks that are stored in plastic can potentially amass chemicals leaked from those containers, especially if the foods are acidic. Storing your leftovers in glass will be a much better option. The rate of chemicals leaching into food is also dependent on temperatures. The warmer it gets the more likely leaching will occur.23 A recommended alternative is to use heat-resistant glass containers when you microwave. Another way to protect yourself from exposures is to heat your food on top of the stove. When you see a label saying a container is safe for microwaving food in, or to be loaded in the dishwasher the label is designating the container as safe not you. Also when considering safe appliances (non BTA) coffee makers should be looked at with a critical eye. BPA and phthalates may be found in their plastic containers and/ or in the tubing dispensing the water.
Evidence has not been easily attainable. More focus had been given to water and air pollution. Chemical companies have an advantage to using their chemicals to manufacture plastic water bottles, hand sanitizer, food storage containers etc. Anything to make life easier! If only that were true!
Food additives
HFCS –
One hears about high fructose corn syrup and how it has recently been excluded from food sources. What is it, and why is it so serious? Before 1966, high-fructose corn syrup (HFCS) was not considered to be the sweetener of choice in American households. One would find sucrose or table sugar sitting on the tables / counter tops to be used as the prime sugar source.
Mass-produced from cornstarch through a complex manner, HFCS emerged as a formidable alternative to sugar. It was cheaper to manufacture, significantly sweeter than sugar, easily transported, and simple to pour (especially in beverages).24 In fact, between 1970 and 1990, Americans' intake of HFCS increased more than 10,000 percent -which is far greater than changes in intake for any other food, according to an article in the American Journal of Clinical Nutrition.25
HFCS is different than regular corn syrup. It is half glucose, and half fructose. Glucose sets off reactions throughout the body that translates to an energy source. It is an integral component aiding in the production of leptin, (appetite controller). Leptin is increased, and ghrelin, a stomach hormone, is reduced, which erases the hunger feeling.26 When fructose is present it performs differently than glucose. It does not increase leptin levels, nor does it decrease ghrelin levels. It is not an insulin secretor, and is thought to aid in fat storage.
Aspartame
Aspartame aka Equal or Nutra-sweet is another sweetener that is much sweeter than sugar. It is made from two proteins - aspartic acid and phenylalanine mixed with methanol. Methanol is found naturally in fruit juices, and many other foods.27 When ingested as a sugar supplement, aspartame functions and is digested just as the aspartame that is found in milk, meat, vegetables, and fruits. Health studies have shown that aspartame always appears to be safe for consumption.28 As time progresses more adverse information is becoming available though. With the help of social media, and technology, adverse health effects are surfacing. Phenylketonuria is a rare genetic disease. People that have PKU must control their intake of phenylalanine. The list of foods with designated amounts of servings people deemed safe can be found on the International Food Informational Council website. Aspartame is considered a safe sugar substitute for people living with diabetes. Aspartame has been given a clean bill by the Epilepsy Institute and no evidence of promoting seizures has been documented. Not everyone is convinced it is safe, however. There are people and organizations that still believe Aspartame is a threat to health and wellbeing of many Americans. Those individuals have stated that articles concerning the safety of aspartame are biased and the manufacturers only support articles that judge the sweetener safe. Controversial matters have arisen because aspartame should be classified as a drug instead of an additive.29 A campaign is underway to enlist corporations that produce aspartame to collect data that supports the supposition that serious medical issues are induced by eating the supplement. When the companies are ready and the data is procured, they will petition the FDA to take another look at Aspartame.
MSG –
One of the most contentious food additives in the world today is monosodium glutamate. (MSG). It is the most common form of glutamic acid, a building block of proteins.30 Glutamic acid in its’ natural environment is not detrimental to humans nor does it set out to improve flavor in foods. MSG becomes a problem when processing plants hydrolyze MSG to generate “free glutamates”. 31 At this point, MSG becomes a flavor enhancer, and can be found in a plethora of foods – Chinese, prepared foods, snacks, salad dressings, canned meats etc. One of the hallmark actions that MSG creates is fooling your brain receptors into thinking that the taste of the food is heartier than it really is.32 MSG is an appetite suppressor that causes you to feel hungry after eating large amounts of food. Eating Chinese food is a great example of being hungry an hour after you eat it.
MSG can be placed on cheaper cuts of meat, older vegetables, and food that has not spoiled yet to improve the quality of it. It is found worldwide because of its nature to enhance food flavor and potentially increase the supply of foodstuff available to people in developing countries. The savory flavor associated with foods that have MSG in it is called "umami” which has now been widely accepted as the “fifth” taste.33 Monosodium glutamate continues to inspire controversy among those who link the additive to serious neurological side effects and other undesirable health effects. MSG also has been traced to the increase in brain lesions in animals.34 Scientists are now developing solid information concerning the adverse reactions people have been experiencing with MSG. The information has been compiled and is available for people to access by going to www.truth in labeling.org.
Pesticides
An esteemed pioneer ecologist in the early 1960’s was Rachel Carson. Her groundbreaking book Silent Spring was instrumental in getting the pesticide DDT banned from commercial usage. She protested the environmental contamination caused by toxic chemicals that accumulate in the tissues of plants, animals and humans. It was not until six years after her death that Congress passed the National Environmental Policy Act establishing the Environmental Protection Agency. The EPA banned the domestic production of DDT.35 As the unit progresses I plan on having students research Rachel Carson, and her activism towards ecology.
It started out as a fable brilliantly describing an idyllic environment where nature and humans coexisted symbiotically. As the story progressed over a relatively short period of time, the tides started to turn. Carson alluded to the environmental change as, “One Spring an evil blight crept over the entire area and everything began to change”.36 The story continues to illustrate chickens, cows, sheep and pigs contracting strange disorders and eventually dying from those exposures. The once vibrant habitat bore the brunt of the aforementioned blight. The idyllic setting was reduced to a wasteland. Dirty rivers, trash-laden paths, and filthy air now replaced the vivacious region. The setting Carson wrote about was fictional, however communities across America’s farm belt have confirmed they experienced similar circumstances, and happenings.
“It is only within the moment of time represented by the twentieth century that one species-man-has acquired significant power to alter the nature of his world, and it is only within the past twenty-five years that this power has achieved such magnitude that it endangers the whole earth and its life.37 The villains turned out to be DDT and other organophosphates. Who knew that her book Silent Spring would become the best seller and initiate a movement for the eradication of DDT (and other pesticides) at a time when women had little credibility with male dominated companies? The book led to the formation of the EPA and helped launch the Environmental Movement.
Pesticides are known to be one of the extremely useful and beneficial agents for
preventive loss of crops as well as diseases in humans.38 A benefit would be for crops to grow successfully in developing countries and lessen the starvation and hunger rates there.
An essential threat to our existence is our contamination of Earth’s environments with materials possessing incredibly harmful substances that accumulate in the tissues of plants and animals, penetrating germ cells, to ultimately splinter genetic materials.39
Hormones
Consumer advocates are concerned about growth and sex hormones in the food supply, but it's unclear whether these hormones truly are bad for our health. According to the FDA there has been little research conducted about the health problems of hormones contributing to cancer, early puberty in girls, and to cancer and health problems in humans. For years, consumer advocates and the public have felt that manipulating growth hormones in cows may increase another hormone, insulin-like growth factor, (IGF) which mimics the effects of human growth hormone in harmful ways. In fact, research has found that milk from recombinant bovine growth hormone (rBGH)- treated cows contains up to 10 times more IGF than other milk.40 The more this information goes public it will challenge the research based articles that state in order for there to be a problem with either IGF, or rBGH one has to drink an inordinate amount of milk to be worried about adverse health effects states the FDA.
Antibiotics
Antibiotics as with hormones will cause animals to grow faster, gain weight and their meat will be leaner. Antibiotics are routinely given to farm animals to compensate for unsanitary conditions in their pens.41 A major route antibiotics enter the environment is through their waste. Antibiotics are not fully digested and will come in contact with the ground. At that point they will leach and enter ground or well water supplies posing a major health issue for humans.42 Health care costs has steadily increased yearly, and at the highest count the cost exceeded 4 billion dollars.43
The subject of giving antibiotics to farm animals has led people to economically look at ending the practice. Supporters of ending the practice feel it can be profitable for both the farmers and the public. The use of administering antibiotics to animals would be prohibited if the meat is stated and certified organic. Implementing and following the labeling policy would save vast amounts of money. It could also decrease the expense to everyone by reducing drug resistant bacteria.44
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