While the main focus of this unit will be nutrition, students will also be incorporating information they have learned previously in a unit about plants. This information will help them to not only plant their gardens, but also connect to an underlying theme of
. Students will recall what they have learned about how plants use energy (from the sun) to make food and grow. This knowledge will then be tied into the idea that food is a necessary item that provides us with energy, vitamins, and nutrients needed for healthy growth in our own bodies as well. Unlike plants, humans cannot make their own food. Therefore, we rely on the energy that is stored in plants and transferred to us when we eat them.
I think this will be something easy for my students to connect to. For example, many of my students love to play sports or outside games. They can relate to feeling energized and ready to play for hours, as opposed to feeling tired and run down. The same is true for plants: they need certain things to help them make food, grow and thrive, just as we do. That energy in plants (along with specific vitamins and minerals) can be transferred to us by simply eating those plants. Energy is actually being transferred for growth all the time - from sun to plants, from plants to people and animals, and back into to soil when things die.
Students will need a basic understanding of how plants develop from seeds, as well as how they grow and make food and what is needed for proper plant care. Because this unit will focus mainly on nutrition, it is important that students have a general understanding of the following concepts beforehand:
1 Plants begin life as seeds and need specific elements to begin growth (namely water and soil)
2 Soil provides nutrients for the developing seed, and water softens the seed coat, allowing for germination to begin.
3 Once the seed sprouts (that is, grows above the soil), the plant will need sunlight in order to begin making food.
4 Plants make their own food (sugar) through a process called photosynthesis.
5 During photosynthesis, a plant uses sunlight, carbon dioxide, and chlorophyll (found in the plant) to make food. This food gives the plant energy to grow.
6 Plants also produce oxygen during photosynthesis, which is released into the air.
7 Energy is transferred from plants to humans when we consume the plants. The nutrients in the plants give us energy and help us to remain healthy and grow as well.
As students internalize this idea of necessary energy, we can then take an in depth look at exactly where they are getting their energy. This will really begin our study of nutrition. My experience teaching a short nutrition unit this year quickly taught me that my students really have no understanding of which foods are healthy for them and which ones are not. Thus, a good place to start is with the book
Good Enough to Eat
by Lizzy Rockwell. What I like about this book is that it gives students an easy to understand guide to how different foods can do different things for our bodies. It describes the various nutrients that everyone needs, such as carbohydrates, fats, protein and various vitamins, as well as what they do. For example, Rockwell describes how we need energy for many daily activities, and carbohydrates can provide this for our bodies, keeping them going for a long period of time (1). She also mentions how protein gives us energy but is also used for building and repairing muscles and bones (1). Fat is also an energy source, but needs to be eaten in moderation (1). Students will also begin to understand that sugary foods give us energy as well, but the quality of that energy is very different from that which we get from healthy foods because it is used so quickly (1).
Students will use their science notebooks throughout this unit to record their newfound information. For example, after reading this book, students can record the following vocabulary words and write a definition so they can refer back to it at any time:
carbohydrates, protein, fats, sugar, and energy
The next step will be to help students understand just which foods are those that will provide them with the energy they need and make them feel better. The book
Eat Healthy, Feel Great
by William and Martha Sears and Christie Watts Kelly, will help to do just that. The authors classify foods into three different categories. The first group, called green-light foods, contains those foods that give you plenty of energy to play and also help you grow and be strong. The green color is indicative of "go" so children know these foods are good to eat and they can eat how ever much they want of them (2). The second group is called yellow-light foods. It contains foods that are ok to eat some of the time and will give you some energy, although not as much as green-light foods. Students can link the yellow light to "slowing down" and thinking about only eating these foods once in while (2). The last group, the red-light foods, contains those foods that really do nothing for the body nutritionally or energy wise. Students should be encouraged to "stop" and stay away from these foods if they can, as they can make you feel tired and overly full (2).
The three light system will be really easy for my students to understand, and will also provide them with a quick way to know which foods are better for them. To give them practice with this, I intend to give them pictures of a variety of types of foods. They will then work in small groups to classify the foods into the three groups. Although I don't expect them to classify them all correctly the first time, the activity will lend itself to a discussion about their selections as well as why certain foods are indeed "green-light," "yellow-light," or "red-light." Because the focus of this unit is on healthy foods that grow, I will also let students know that items that come from nature, (and minimally processed) are nearly always "green-light" foods and thus very healthy. They can then make three lists in their notebooks, one for green light foods, one for yellow light foods, and one for red light foods. This will serve as a quick reference for my students when they are at home and not sure which foods are the best to eat.
The next thing I want students to do is to take their new knowledge and examine their own diets for a period of time. They will do this through a food diary, which they will keep for several days in their journals and record everything they eat or drink. When food diaries are complete, students will analyze their own diets in terms of the three light system. Foods will be color coded so students can tell at a glance if they are eating too many yellow and red light foods, and not enough green light foods.
As students begin to understand which foods are healthy for them, I will have them dig deeper and research what it is that makes these foods so healthy. More specifically, students will work in groups and be given several pictures of fruits and vegetables of various colors. They will then use the internet and/or library books to search for these fruits and vegetables and discover what vitamins and/or minerals they contain, as well as how they help our bodies. Students will complete a research worksheet and report their finding back to the class. We will then compile our data into a class chart, sorting items by color and looking for similarities in nutrition among color groups. This chart will then make a quick reference for students for other activities in this unit.
This is where the title "Eating the Rainbow" will come into play. The specific nutritional value of fruits and vegetables can be determined simply by looking at their color. According to David Heber, in his book
What Color is Your Diet
, "each colored fruit or vegetable provides a unique benefit to the diet, so you don't want to eat only fruits and vegetables of a single color, [but rather, many different colors]" (3). Students will learn the basics of this by finding out what vitamins are present in specific color fruits and vegetables
Specifically, students will research the following fruits and vegetables, focusing on the effects of these vitamins on the body. Students will not be expected to find all nutrition information on these foods, but some of the major vitamins and minerals and benefits, such as those listed below. I have grouped the foods according to their color and have added information after the groupings about the overall health benefits of eating foods from each specific color group. This information will be for teacher reference and used to give students additional information as the class chart is made. Students will also be expected to complete color group charts in their science notebooks and thus always have this information available to them for quick reference.
The Red Group
- contain vitamin C, which may aid in helping the body recover from illnesses and boost the immune system (4).
- contain vitamin C (see above), help to fight cancer (4)
- contain vitamin C (see above) and lycopene, which may reduce risk of cancer (4).
- a great source of vitamin C (see above) and vitamin A (beta-carotene), which may help in the health of eyes (4).
Just looking at the list of fruits and vegetables above, one will almost immediately notice some things they have in common. First of all, all of these fruits and vegetables contain high amounts of vitamin C. Vitamin C is necessary for a healthy immune system and may help you recover more quickly from colds and viruses. It also aids in the repair of broken bones (5).
These foods are also very high in antioxidants. Antioxidants in plants help protect them from the damaging effects of the sun, and also serve to help protect our bodies from damage and disease as well (4). In humans, antioxidants help to fight heart disease and cancer. According to James A. Joseph et al, "as our bodies utilize oxygen, they also turn some of it into free radicals - oxygen molecules that are unstable because they have an unbalanced number of electrons" (4). These are damaging to our bodies because free radicals try to stable themselves by attacking stable molecules. Antioxidants can help by attacking free radicals before damage is done. However, they are only effective if there are enough antioxidants present to outnumber the free radicals (4). Thus, it is important to include antioxidant rich foods in one's diet in order to help ward off diseases (such as cancer) that may attack the body.
Although third graders will not need such an in-depth explanation of these antioxidants, what they can take away is that fruits and vegetables in the red group are disease fighters and can help you to stay healthy.
The Orange Group
- contain vitamin A (beta carotene) which is crucial for eyesight (4)
- contain vitamin A (see above) and vitamin E (4).
contains vitamin A (beta carotene) (4).
contains vitamin A (beat carotene) and fiber (4).
Winter squash -
contains vitamin A (beta carotene) (4).
The orange group is most obviously a great source of vitamin A. The vitamin A in these fruits and vegetables come from the orange pigment, beta carotene. Vitamin A has some amazing health benefits. First and foremost, this vitamin is responsible for keeping the eyes healthy. "It also plays a critical role in maintaining the immune system, the skin, and the so-called epithelial cells that line every organ. . .[where] 85% of cancers start" (4).
Some new studies are also suggesting that vitamin A may play a role in memory and learning. Researchers believe that if you are deficient in this vitamin, you may have more difficulty learning and remembering things, and boosting your intake may help to improve this (4). Beta carotene can also repair DNA and "aid in a type of cellular communication that can help stifle malignancies" (4) better than any other carotenoids, which are a type of plant pigment (4).
It would be important for students to understand that foods in the orange group can certainly help to improve eyesight and even improve your ability to learn and remember.
The Green Group
- contains the phytochemical lutein (for eye health) and folate, as well as many other vitamins (4).
- also contains lutein and folate, as well as a variety of other vitamins (4).
- contains lutein and folate, as well as vitamins A, C, K, and E (4).
- again, contains lutein and folate, as well as vitamins A, C, B6, and potassium (4).
As emphasized by James Joseph in The Color Code, "green is the color of life" (4). All of this life, however, has chlorophyll to thank for it. Chlorophyll allows plants to use energy from the sun to make food. Although we don't eat green plants for their chlorophyll, these fruits and vegetables do contain large amounts of phytochemicals, which really promote healthy life. One of these phytochemicals, lutein, also plays a major role in eye health, and can help prevent diseases like macular degeneration, cataracts, and retinal diseases (4).
Folate, which is present in all of the above listed green plants, has already gained recognition as being critical for the healthy development of fetuses in pregnant women. However, folate is also now recognized as helping to prevent heart disease "because it helps your body dispose of a troublesome amino acid called homocysteine, which seems to make blood vessels susceptible to damage" (4).
Overall, it would be beneficial for students to understand that green plants can help to improve eyesight and also keep your heart healthy. They should also recognize that the darker shade of green a plant is, the more vitamins and nutrients it contains, and thus, the better for you it is.
The Blue-Purple Group
- contains powerful antioxidants (called anthocyanin pigments) which contribute to protection of the brain as one ages, as well as some protection from Alzheimer's Disease, and also protect the body from the stress of free radicals (4).
- also contain high levels of antioxidants (anthocyanin pigments) (4).
- again, contain those wonderful antioxidants (see above) (4).
- also contains anthocyanin pigments (4).
The most marvelous quality of the plants in the blue-purple group has to be the presence of powerful antioxidants called anthocyanin pigments, which give many of these plants their vibrant color. These antioxidants have been noted to produce amazing anti-aging effects on the brain when laboratory studies were conducted. These antioxidants actually protect the brain from deterioration by free radicals. This may in fact help the elderly stay active longer and keep memory and functioning in tact as we age (4).
The antioxidants have also been studied for their effect on Alzheimer's disease. Recent evidence suggests that they may indeed be helpful in slowing down this disease. The antioxidants in grapes and eggplant may also aid in lowering bad cholesterol and keeping arteries more elastic. Eggplant may even help to prevent wrinkles as we age (4).
Overall, students should be taught that plants in the blue-purple group have amazing antioxidants that help keep us young. Students should think of these plants as helping to keep the brain healthy and aiding in our thinking and memory. These plants can also help to keep our bodies young, and overall improve our health and the way we feel.