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Nutrition 101
Why is Nutrition Important
“You are what you eat.” We have heard this saying many times. It isn’t exactly true, but what you eat does have a major effect on how much you weigh, your health, and the likelihood of developing a chronic disease. The foods you decide to eat determine the nutrients your body gets.
The nutrients in our diet give us energy and are necessary for our growth and function. Every nutrient does one or more function, but we need all nutrients together for our bodies to work properly.
I’m sure you hear the word calorie all the time. We don’t actually eat calories, but we eat food that provides energy measured in calories. Food and the energy it provides are necessary for life. There are six classes of nutrients that we need to stay alive and well. These nutrients are carbohydrates, lipids, proteins, water, vitamins, and minerals. A healthy diet gives us the right amount of calories for a healthy weight, a balance of carbohydrates, proteins, and fats, plenty of water, and adequate amounts of vitamins and minerals.
Guidelines for a Healthy Diet
Today there are many different guidelines for a healthy diet. Some tell us the amount of individual nutrients we need and others describe whole diet lifestyles that encourage health and prevent disease.
Dietary Reference Intakes
The current standard for nutrient intake in the United States is the Dietary Reference Intakes (DRIs). The DRIs give recommendations for energy, vitamins, minerals, protein and amino acids, carbohydrates, fats, water, and electrolytes. Values have been determined for each gender and different stages of life. The DRIs can be helpful in keeping your diet healthy.
Food Guide Pyramid
The Food Guide Pyramid is a tool for planning diets that meet nutrition recommendations. MyPyramid includes five food groups: Grains, Vegetables, Fruit, Milk, and Meat & Beans. The different size color stripes indicate the amount of foods from that group you should be consuming. Therefore, the wider the stripe the more foods you need to eat from that group. MyPyramid recommends a range of servings for each food group and the serving sizes for each group are standardized. MyPyramid is flexible enough to meet the needs of almost everyone.
| Record and analyze your diet using the Menu Planner on www.mypyramid.gov |
Food Labels
How do you know if a food you eat is a good source of calcium or how much protein it has? You can find this information and much more on the food label. Food labels give you information about the nutrients that are in food and how it fits into the diet. They can help you choose foods wisely and can have an effect on the nutritional quality of your diet.
- The Nutrition Facts list the amounts of calories and nutrients per serving
- It is important to look at the serving size and then how many servings there are in the entire container
- The % Daily Value is the percentage of the nutrient in the food for a 2000 Calorie diet
- The ingredient list tells you what is actually in your food
- The ingredients are listed in order from greatest to least by weight
What are Nutrients?
Carbohydrates – What are they? Carbohydrates, or carbs as we usually call them, are made up of carbon, hydrogen, and oxygen. They include sugars, starches, and fiber.
What do they do in the body? The main job of carbs in our bodies is to provide energy. The main source of this energy is glucose.
What foods are they found in? Carbs are found in grains (breads, cereal, pasta, etc.), fruits, starchy vegetables (corn, peas, potatoes) and milk products. They can also be found in sweets. It is better to get our carbs from grains, fruits, vegetables, and milk because they contain vitamins and minerals with their calories.
Fats – What are they? What we usually think of as fat is a type of lipid called a triglyceride. Each triglyceride has three fatty acids attached to glycerol. Phospholipids and sterols are two other types of fat.
What do they do in the body? Fat gives us energy and helps our bodies perform necessary physiologic functions. Fat is a major source of energy because each gram of fat is 9 Calories, while carbs and protein have only 4 Calories per gram.
What foods are they found in? Healthier fats can be found in some fish, like salmon & swordfish, nuts, avocados, vegetable oils, & olives. Unhealthy fats are found in fatty meats, butter, cream, bakery goods (doughnuts, pastries), fried foods, and full fat dairy (whole milk, ice cream). Choose more fish and plant sources of fat and limit foods high in animal fats.
Proteins – What are they? Protein is made up of amino acids. There are about 20 amino acids found in protein. Each different protein has a different number, combination, and order of these amino acids. Amino acids are a carbon atom attached to a hydrogen atom, an amino group, an acid group, and a side chain. The nitrogen in amino acids makes it different from fats and carbs.
What do they do in the body? Protein does many things in the body. It gives structure to our bodies, speeds up metabolic reactions, moves molecules, protects us from injury and infection, helps us move, and regulates fluid balance and acidity.
What foods are they found in? Nine of the amino acids we need must be eaten in the diet because we cannot make them. Meat, fish, beans, nuts, seeds, milk, yogurt, cheese, and eggs are good sources of protein. It is important to eat lean cuts of meat, take off the skin from poultry, and eat fat-free or low-fat dairy products.
| Are you a vegetarian or vegan? Well-planned vegetarian diets are healthy. You don’t need to eat animal foods to stay healthy. Other sources of protein for vegetarians and vegans include soy-based products, beans, seeds, nuts, grains, and vegetables. |
Vitamins
Vitamins are organic compounds that help us regulate our bodies’ processes. Vitamins are critical in building and maintaining healthy bone and muscle tissue, supporting our immune system so we can fight off illness and infection, and ensure healthy vision. Vitamins do not contain energy (calories); however, vitamins do play a major role in the use of energy from fats, carbohydrates, and protein.
There are two types of vitamins: fat-soluble and water soluble. Our bodies do not make vitamins and therefore we must consume them through our diet. Both types of vitamins are important to our health and can be obtained through a variety of foods.
Fat-Soluble Vitamins
| Vitamin | Functions | Food Sources |
| Vitamin A | Antioxidant | Eggs |
| Eye sight | Dairy products | |
| Bone growth | Fortified cereals | |
| Skin | Carrots | |
| Cantaloupe | ||
| Spinach | ||
| Mango | ||
| Tomato juice | ||
| Vitamin D | Bone Health | Milk |
| Salmon | ||
| Fortified cereals | ||
| Vitamin E | Antioxidant | Vegetable oils |
| Immune function | Nuts | |
| Nerve function | Seeds | |
| Soybeans | ||
| Fruits/vegetables | ||
| Fortified cereals | ||
| Vitamin K | Blood clotting | Spinach |
| Collard greens | ||
| Turnip greens | ||
| Lettuce | ||
| Broccoli | ||
| Brussels sprouts | ||
| Cabbage | ||
| Canola oil |
Water-Soluble Vitamins
| Vitamin | Functions | Food Sources |
| Vitamin C | Antioxidant | Citrus fruits |
| Skin | Potatoes | |
| Iron absorption | Strawberries | |
| Immune function | Tomatoes | |
| Cauliflower | ||
| Kiwi | ||
| Broccoli | ||
| Leafy green vegetables | ||
| Cabbage | ||
| Bell peppers | ||
| B Vitamins | Energy metabolism | Whole grains |
| Growth and development | Fortified breads | |
| (Thiamin, Riboflavin, Pyridoxine, Folate, Cobalamin) | Blood cell formation | Fortified cereals |
| Dairy foods | ||
| Meats | ||
| Tomatoes | ||
| Potatoes | ||
| Mushrooms | ||
| Sunflower seeds |
Minerals
Minerals are inorganic substances, meaning they do not contain carbon. Minerals have many important jobs within our bodies including: fluid balance, energy production, and bone and blood health. Minerals are classified according to how much we need in out diet and how much of the mineral is found in our bodies. The two classifications include: major minerals and trace minerals.
| Mineral | Functions | Food Sources |
| Calcium | Bone and teeth structure | Skim milk |
| Maintains nerve function | Low-fat cheese | |
| Supports muscle function | Low-fat yogurt | |
| Regulates blood pressure | Kale | |
| Turnip greens | ||
| Broccoli | ||
| Brussels sprouts | ||
| Cabbage | ||
| Phosphorus | Bone and teeth structure | Milk |
| Assists with fluid balance | Meats | |
| Energy metabolism | Eggs | |
| Sodium | Maintains pH balance | Sodium is found in abundance in our diets through processed and packaged foods and therefore it is easy to consume excess amounts. Look for low-sodium alternatives. |
| Regulate muscle function | ||
| Assists nerve function | ||
| Aids in absorption | ||
| Potassium | Regulate muscle function | Whole grains |
| Regulates nerve function | Potatoes | |
| Maintains healthy blood pressure levels | Bananas | |
| Tomatoes | ||
| Orange juice | ||
| Milk | ||
| Spinach | ||
| Cantaloupe |
* Other major minerals include chloride, magnesium, and sulfur.
Trace Minerals
| Mineral | Functions | Food Sources |
| Iron | Assists transportation of oxygen in our bodies | Meat |
| Energy metabolism | Poultry | |
| Antioxidant functions | Fish | |
| Zinc | Antioxidant function | Meat |
| Energy metabolism | Poultry | |
| Assists immune function | Whole grains | |
| Fortified breads | ||
| Fortified cereals |
Water
Water is an inorganic nutrient that is vital to our survival. Drinking enough water balances fluid inside and outside of our cells, regulates nerve and muscle function, transportation of nutrients, and excretion of wastes. Our bodies do not have the ability to store enough water so we must replace the water we lose every day.
Water needs vary greatly among individuals and is affected by age, body size and composition, health status, physical activity level, and environmental conditions. Use the following link to access the Hydration Calculator to determine your individual needs.
www.beverageinstitute.com/hydration
Managing Your Weight
What is a Healthful Body Weight?
- A weight that is appropriate for your age and height
- A weight that you can achieve and sustain without constantly dieting
- A weight that is acceptable to you
- A weight that is based on your family history of body shape and weight
- A weight that promotes good eating behaviors and allows you to participate in regular physical activity
How Can You Evaluate Your Weight?
Determine Your Body Mass Index
Body mass index (BMI) is a commonly used guide to assess the ratio of a person’s body weight to his or her height. You can calculate your BMI by using the following equation or by using the BMI calculator.
|
BMI = weight (lb) x 703 Height (in)2 |
BMI is a useful indicator of your overall health. Research has shown that the risk for developing type 2 diabetes, high blood pressure, heart disease and other chronic illnesses increases greatly when BMI is greater than 30.
Assess your Fat Distribution
Where your fat is located is also an important part of your health. This is because fat distribution, or body shape, is known to affect your risk for certain diseases.
An apple shape is known to increase your risk for many diseases. It is thought that the fat location associated with the apple shape causes problems with the metabolism of fat leading to unhealthy changes in cholesterol, blood sugar and blood pressure.
A pear shape does not seem to have the same negative effects on your health. Women tend to store fat in their lower body and thus are more likely to be pear shaped than men. A research study including more than 10,000 people found that 64% of women are pear shaped and 38% of men are apple shaped.
How Can You Achieve and Maintain a Healthy Weight?
Balance What You Eat with What You Do
Weight gain or weight loss is the result of changes in our food intake and physical activity. The relationship between what we eat (ENERGY IN) and what we do (ENERGY OUT) is called energy balance. The following diagram shows how changes on either side of the equation can affect your weight.
More IN than OUT over time = weight gain
Same IN and OUT over time = weight maintenance
More OUT than IN over time = weight loss
It is important to know that your ENERGY IN and ENERGY OUT don’t have to balance every day. It’s having a balance over time that will help you stay at a healthy weight for the long term.
How Am I Supposed to Meet My Nutrition Needs?
You Can Get It All from Food
Most people can get all of the nutrients they need from food without having to take supplements, but this requires that you eat wisely and choose less processed foods and more fruits and vegetables. A healthy diet provides all the right amounts of energy, carbs, fat, protein, vitamins and minerals. Eating healthy means that you eat a variety of foods from all the food groups. Another important part of a healthy diet is how nutrient-dense your food choices are. When we say nutrient density we mean the amount of nutrients in the food per calorie. By choosing nutrient dense foods you can achieve your nutrient needs without overloading on calories. For example, a baked potato has more nutrients per calorie that potato chips and therefore would be a more nutrient dense food choice.
Fortified Foods Can Help
Fortified foods are not hard to find; in fact, it might be harder to find foods that are not fortified with extra vitamins and minerals. A fortified food has additional nutrients that were added during processing that may or may not have been in the original food.
The most common fortified foods include bread and cereal because they are so common in our everyday diet. Commonly added nutrients include niacin, iron, thiamine, riboflavin and folic acid (or folate).
Is a Supplement Necessary?
More than half of adults in the United States take some of dietary supplements. Supplements are available everywhere in health food stores, grocery stores, drug stores, etc. People choose to take supplements for a variety of reasons including energy boost, cure sicknesses, and weight loss. Supplements may be beneficial or even necessary in some cases but they also have to potential to cause harm.
Do not assume that the government has checked out the safety of a supplement. The FDA can take a product off the shelf it is shows to cause harm but it is the responsibility of the company to test the supplement for safety before it is sold. Supplements do not need FDA approval to be sold to consumers.
Developed by:
Chelsea Crabtree and Brianna Laderbush
Dietetic Interns, 2009-2010
The Dietetic Internship Program at Vanderbilt
Sources:
Grosvenor MB, Smolin LA. Nutrition: Everyday Choices. Hoboken, NJ: John Wiley & Sons Inc. 2006.
Thompson J, Manore M. Nutrition: An Applied Approach. Glenview, IL: Pearson. 2005.