Walnuts: Naturally Nutritious

Grade Level

6 - 8

Purpose

Students will interpret and compare nutrition labels to make healthy food choices and learn about the nutritional value of walnuts. Students will also have a walnut taste test and use walnuts in a recipe. Grades 6-8

Estimated Time

Two or Three, 50-minute sessions

Materials Needed

Internet access
Various food nutrition labels
Naturally Nutritious student handout & answer sheet
Raw, unshelled walnuts
Nutcrackers
Walnut Taste Testing sheet
Cooking with Walnuts recipe sheets
Raw walnut piece
Toasted walnut piece
Unshelled walnut
Paper napkin or towel
Pencil
Taste Test Parent Permission Form

Vocabulary

orchard: a place where fruit or tree nuts are grown

walnut: the large wrinkled edible seed of a deciduous tree, consisting of two halves contained within a hard shell that is enclosed in a green fruit

Did You Know?

99% of the US walnut production takes place in California due to it's ideal climate for growing walnuts.¹
The Greeks called walnuts karyon, which means "head" because they thought the shell resembled a human head and the walnut kernel looked like a brain.²
The most common culinary use for walnuts is in salads.²
A healthy walnut tree can produce crops for approximately 100 years.

Background Agricultural Connections

Walnuts grow on trees and are typically harvested using mechanical shakers that shake the nut to the ground during harvest time in September through November. There are many walnut orchards in California due to its ideal climate for growing walnuts. Walnuts are harvested by machines which sweep the fallen walnuts into rows, and then the nuts are collected and taken to a processing plant where they are dried, sorted, and cleaned. Walnuts may be sold with their shells intact (“inshell”) or removed (“shelled”). Shelled walnuts are sold whole, in halves, or in pieces of various sizes.

Like a finely tuned engine, our bodies function best when we take good care of them. Choosing nutritious foods for our meals can help prevent certain diseases and obesity. A balanced diet should include protein, fat, carbohydrates, vitamins, minerals, and water.

Sources of protein include: fish, meat, poultry, dairy, eggs, nuts, and beans. Sources of carbohydrates include: fruits, vegetables, whole grains, and beans. Vitamins and minerals are found in most of these foods. For example, oranges are a good source of vitamin C, bananas are a good source of potassium, beef is a good source of iron, and milk is a good source of calcium.

A certain amount of fat is also an essential component of a healthy diet. Fat is the main energy storage molecule in the body. Our bodies require a certain amount of fat for cell growth, insulation from cold, energy production, and helps our body absorb vitamins A, D, E, and K until our body is ready to use them. Fat forms a protective layer around our internal organs and helps keep our skin and hair healthy.

Fat supplies calories and essential fatty acids to our diet. Sources of dietary fat are animal and dairy products, nuts, and oils. The Dietary Guidelines for Americans 2010 recommends that teenagers limit total fat intake to no more than 25 – 35% percent of total daily calories. For example, if a person eats 2,000 calories per day and 500 of those calories are from fat, this would fall in the 25 percent range. Fat has nine calories per gram. To find out how many grams of fat in 500 calories, divide 500 by nine to get 56 grams of fat.

There are different types of fat in food. Unsaturated (mono and poly unsaturated) fats are usually liquid at room temperature and are often referred to as oils. The Dietary Guidelines for Americans 2010 recommend getting the majority of necessary fat calories from unsaturated fat. Studies show that unsaturated fatty acid, when consumed in appropriate quantities, is associated with low blood cholesterol levels. This in turn leads to a lower risk of cardiovascular disease.

Saturated fat should be consumed in limited quantities but there is no dietary requirement for this kind of fat. Scientific research indicates there is evidence that the higher intake of most saturated fatty acids is associated with higher levels of blood total cholesterol and low density lipoprotein (LDL) cholesterol. This may be a risk factor for cardiovascular disease.

What Makes Walnuts Nutritionally Noteworthy?

Walnuts are an excellent source of one type of unsaturated fat (polyunsaturated fat) Alpha-linolenic acid, an omega-3 fatty acid (2.5 grams/ounce). Research has shown that omega-3 fatty acids may help prevent coronary heart disease (CHD).
One ounce of walnuts provides four grams of protein and two grams of fiber. Walnuts are also a good source of magnesium (10% DV) and phosphorus (10% DV) which are both important minerals involved in the body’s processes.

Nutrient dense walnuts are part of a healthy diet. They have a high level of essential Omega-3 fatty acids (2.5 grams/oz.). Omega-3 fatty acids have been shown to reduce the risk of coronary heart disease.

Walnuts make an easy snack because they can be eaten with no preparation at all. Many people enjoy eating walnuts raw and toasted. The shell of the walnut helps to keep the kernels fresh before eating. Walnuts add flavor and crunch to salads, main dishes, breakfast dishes, and even desserts.

When buying walnuts, it is important to properly store them if you are not going to eat them right away. Store walnuts in airtight containers in the refrigerator or freezer to maintain freshness. If stored in a warm place, the oil in walnuts can chemically change, causing them to spoil over time.

Engage

As a class, discuss the students’ ideas about what types of foods should be included in a healthy diet. Make a list on the board of healthy foods.
Reinforce that nutritious meals can help prevent certain diseases and obesity. A balanced diet should include protein, fat, carbohydrates, vitamins, minerals, and water.

Explore and Explain

Distribute one copy of the Naturally Nutritious student handout to each student.
Review the first page with the students and allow them to complete the worksheet.
Explain that the class will be conducting a taste test with walnuts which provide many nutritional benefits. Prior to the taste test, ask about any food allergies and send home the parent consent form for parents to approve.
Distribute the walnut tasting sheet and napkin. Instruct students to use their pencil to divide their napkin into three sections. Label the sections, raw, toasted, and in-shell.
Provide each student with a piece of toasted walnut, raw walnut, and a freshly shelled walnut.
Instruct students to taste each walnut and fill out the walnut tasting sheet.
Allow students to share their thoughts and opinions in a class discussion.

Elaborate

Watch the America's Heartland video clip, Walnuts: Harvesting Good Health. This video clip shows walnut harvesting and processing in a California orchard.

Evaluate

After conducting these activities, review and summarize the following key concepts:

Food labels provide information to evaluate the nutritional content of foods.
Walnuts provide valuable nutrients to our diet including protein and unsaturated fats.
California produces more walnuts than any other state in the nation. This is due to ideal climate and growing conditions.

Sources

Acknowledgements

A partnership project of California Walnut Board and California Foundation for Agriculture in the Classroom. Image submitted by California Foundation for Agriculture in the Classroom. Nutrition information gathered from www.walnuts.org, www.nlm.nih.gov, and www.mayoclinic.org.