the discovery of insulin, the only course of treatment involved dietary measures. Because people with diabetes were extremely limited in the amount of carbohydrate they could eat, the prescribed diets were usually high in protein and/or fat and often involved eating very strange foods, such as suet, blood, and even 10–40 egg yolks every day! Bread, pasta, and even fruit were off limits.
In the early 1900s, Dr. Elliot Joslin recommend limiting protein intake to 1 gram per kilogram of body weight because too much protein in the diet was found to increase both nitrogen and glucose in the urine, further aggravating diabetes. Have you ever been told that approximately 50–60% of the protein that you eat gets converted into blood sugar? This information came about in the 1930s using eggs, casein, and meat as the basis for studies of how protein affects metabolism in people with diabetes. Some health care professionals still use this information today, although more recent studies have challenged whether this “fact” is indeed true.
Much has changed over the years regarding the best diet for someone with diabetes. Because there are only three main nutrients to work with, diets have ranged from high fat to high protein to high carbohydrate. Even today, with some of the most advanced treatments for diabetes ever, leading health and diabetes authorities still can’t agree upon the best diet for people with diabetes. Some believe a higher-protein diet is best, whereas others argue that a high-carbohydrate diet is the way to go, because a higher-protein diet could lead to some possible health problems down the road. Who is right? Although we may not have a definitive answer right now, read on to learn more about this controversial nutrient.
WHAT IS PROTEIN?
The word “protein” comes from the Greek word proteios, which means “of the first rank.” No wonder we give it such importance in our diets! A protein is an organic substance made up of carbon, hydrogen, and oxygen (just like carbohydrate), but unlike carbohydrate, protein also contains nitrogen. These atoms are arranged into amino acids, which are linked into chains to form protein molecules. Amino acids are the building blocks of proteins, and there are 22 amino acids that are linked together in various combinations to form different types of protein molecules. Nine of these amino acids are called “essential” because our bodies cannot make them; they must be obtained from foods that we eat. It is important that we eat foods that contain essential amino acids because our cells need all 22 amino acids to make body proteins.
WHY DO WE NEED PROTEIN?
Protein has many important functions in the body. These include:
• creating new cells when old ones die
• forming antibodies (which fight viruses and bacteria)
• creating visual pigment to help us see
• forming enzymes (for example, digestive enzymes)
• forming certain hormones (such as insulin)
All of the cells in our bodies contain protein. In fact, approximately 50% of the body’s weight comes from protein. Our hair, nails, muscle, cartilage, bone, and body fluids contain many different kinds of protein.
When we eat foods that contain protein, the protein is broken down into its building blocks, the amino acids. Our bodies then decide how those amino acids will be used and arrange the amino acids in a specific order, based on what types of proteins are needed. For example, the protein needed to help blood to clot (called thrombin) will have a different sequence of amino acids than the kind of protein needed to make insulin. Whatever amino acids are left over from protein synthesis will be stored as…you guessed right, fat.
Most people in the U.S. grow up believing that a meal isn’t a meal unless it contains a source of protein, usually in the form of a piece of steak, a hamburger, or a chicken breast. After all, who could stay healthy just by eating a plate of spaghetti? Surprisingly, although we do need to eat protein every day, we need much less than you may think. On average, people in the U.S. get approximately 15% of their calories from protein, which translates into 1.5 grams of protein per kilogram body weight. This is twice what is needed to meet our daily requirements, whether we have diabetes or not. Only about three percent of Americans have a protein intake that is below the recommended amount.
The recommended dietary allowance (RDA) for protein is 0.8 grams per kilogram body weight for adults. (We actually need only 0.6 grams of protein per kilogram body weight to stay healthy, but a margin of safety is built into the RDA). To give you an example, a man who weighs 170 pounds (77 kg) needs 62 grams of protein in his diet every day. A woman who weighs 130 pounds (59 kg) only needs 47 grams per day. Infants, children, and adolescents require more protein for growth and development; therefore the RDAs are higher (0.9–2.2 grams per kilogram of body weight per day). Protein needs are increased during pregnancy and lactation as well.
Diabetes and Protein Requirements
You’ve learned that there is no longer a set diabetic diet for people with diabetes. The best “diet” is one that will help you best control your diabetes and stay healthy. Also, recommendations for various nutrients can vary, depending on the type of diabetes you have and how well you are able to manage your diabetes. The American Diabetes Association states that there’s no good evidence that aiming for a protein intake between 15 and 20% of calories should be modified.
More recently, however, some studies are showing that people with type 2 diabetes may actually benefit from a slightly higher protein intake. The theory that approximately 50–60% of protein in the diet gets converted to blood glucose (dating back to the early part of this century) has been challenged. A few studies have shown that blood glucose levels do not rise in people with type 2 diabetes who eat a diet containing a moderate amount of protein. Perhaps not as much protein is metabolized into glucose as we once thought. A similar effect has been seen in people with type 1 diabetes, although large amounts of protein do require more insulin to prevent high blood glucose levels (insulin is needed to help the body use protein, fat, and carbohydrate). Other studies have shown that a slightly higher intake of protein may lead to more weight loss compared with a more traditional, lower-fat eating plan and can even lower your risk for heart disease. Furthermore, eating a little more protein can help curb your appetite while preserving lean body mass if you’re trying to lose weight. For these very reasons, the Joslin Diabetes Center nutrition guideline for people with type 2 diabetes recommends that between 20 and 30% of calories come from protein.
Does this mean that if you have type 2 diabetes you can eat more protein in your diet without it affecting your diabetes control? The answer varies from person to person. The best way for you to determine how protein affects your blood glucose control, whether for a meal or a snack, is to be diligent about checking your blood glucose levels after eating. It’s also important not to eat too much protein because extra protein means extra calories. There is also the risk of too much protein worsening diabetic kidney disease and leading to other health problems, such as osteoporosis, kidney stones, and possibly certain types of cancer. It’s important to talk with your dietitian about how much protein you need to stay healthy.
WHERE IS PROTEIN FOUND?
Once you know how much protein you need every day, you then need to learn what foods contain protein. However, you most likely know this already! Chances are, you are picturing steak, pork chops, turkey, and fish. Animal sources of protein include:
• red meats (beef, pork lamb, veal
• poultry (chicken, turkey, duck, goose)
• seafood (fish, shellfish)
• dairy foods (milk, yogurt, cheese, eggs)
These animal protein foods contain all of the essential
