Questions and Answers About Sugars

Favorably Reviewed By: American Academy of Family Physicians Foundation

Think about foods you most enjoy eating. Chances are they contain some form of sugar. It could be the sugars in peaches fresh from the orchard, or the sugars contributing to the prized taste of your favorite ice cream.

Indeed, most people enjoy the sweet taste of sugars. But taste is only one of the important roles sugars play in food. For example, sugars help preserve jams, cereals, cakes, candies, cookies and drinks. Sugars also help produce the tender, moist texture of cakes and the golden-brown, crispy essence of many cookies.

As part of a balanced plan for healthy eating, you can enjoy sugars in moderation. This brochure answers questions you may have about sugars and their role in a healthful diet.

What are sugars?
Sugars are carbohydrates, which serve as the main energy source for the body. There are many types of sugars. They occur both naturally and as ingredients in many foods.

The most familiar sugar is sucrose. It is made of two simple sugars, fructose and glucose. Fruits and vegetables naturally contain fructose and glucose. Other sugars used in foods include invert sugar, corn syrup, high fructose corn syrup, honey, lactose (milk sugar) and other syrups. During digestion, all of these sugars except lactose break down into fructose and glucose. Lactose breaks down into glucose and galactose.

Why are sugars added to foods?
Sugars play important roles in foods. They add taste, texture and color to baked goods. They provide energy for yeast used in baking bread. They add body to yogurt. They help balance acidity in tomato sauces and salad dressings.

Certain sugars also play special roles in foods. Invert sugar helps keep sucrose from crystallizing in candies. Corn syrup is used in some foods because it is less sweet than sucrose.

Are sugars safe to eat?
Sugars are "Generally Recognized as Safe" by the Food and Drug Administration (FDA). In 1986 a review of research on sugars intake and safety concluded, "Other than the contribution to dental caries, there is no conclusive evidence on sugars that demonstrates a hazard to the general public when sugars are consumed at the levels that are now current and in the manner now practiced."

The Surgeon General's Report on Nutrition and Health, the National Academy of Sciences report Diet and Health, and Healthy People 2000: National Health Promotion and Disease Prevention Objectives by the U.S. Department of Health and Human Services support these conclusions.

How does the body use sugars?
Sugars are a source of energy for the body. During intense physical activity, they are the main energy source.

There are no nutritional differences among sugars. The body uses all types in the same way. During digestion, sugars such as sucrose and lactose and other carbohydrates such as starches break down into simple (or single) sugars. Simple sugars then travel through the blood stream to body cells. There they provide energy and help form proteins, or are stored for future use.

The brain and red blood cells can only use glucose for energy. During pregnancy, glucose also helps form cells and produce milk. The body can make its own glucose or get it from foods.

How do sugars fit into a healthful diet?
A healthful daily diet includes foods from five groups: Grains (includes breads, cereal, rice and pasta; Vegetables (includes 100% vegetable juices) ; Fruits (includes 100% fruit juices) ; Dairy from fat-free or low-fat milk, yogurt, cheese or calcium-fortified soy beverages; Protein Foods from meat, poultry, seafood, beans and peas, eggs, processed soy products, nuts, and seeds. Some foods in these groups naturally contain sugars, such as fruit or milk. Other foods in these groups may have added sugars, such as cakes, cookies or fruit canned in syrup. A healthful diet can include both types of food. When you cut calories, nutritionists advise foods lower in fat and sugars most of the time. This helps ensure an adequate intake of essential nutrients.

What is meant by the term "sugars" on a food label?
The nutrition panel on a food label lists the total amount of sugars in a serving of the food. This amount includes sugars found naturally in foods such as the sugars in raisins. It also includes added sugars. The ingredient list must name sugars from all ingredient sources in descending order by weight.

Unlike other nutrients, sugars do not have a recommended level of intake or percent Daily Value. The 2002 Institute of Medicine Dietary Reference Intakes (DRI) report concluded that while there is insufficient evidence to set an upper limit for total or added sugar intake, there is data to suggest consumption of key micronutrients (calcium, vitamin A, and zinc) is affected when added sugar intake exceeds 25% of calories.

What does "sugar-free" and "reduced sugar" mean on the labels of food packages?
The FDA closely controls the use of these terms on food labels. A "sugar-free" food must contain less than 0.5 grams of sugars per serving. A "reduced sugar" food must contain at least 25 percent less sugar per serving than the regular product.

Sugars may not be added to a food labeled "no added sugar," "without added sugar" or "no sugar added." Processing also must not increase the amount of sugars in the food.

Unless the food meets other requirements for low or reduced calorie products, "sugar-free," "no added sugar" or similarly labeled foods must feature another statement. The label must also state the product is not a reduced or low calorie food, or it is not for weight control.

Do sugars cause hyperactivity?
In the 1970s, anecdotal reports suggested sugars cause hyperactivity in children. Research, however, failed to confirm this theory. Hyperactivity was not seen in children after consistent high intakes or single large doses of sugars.

In a recent study, researchers examined the effect of eating sucrose (table sugar) on the behavior of children aged 6 to 10 years. The children were chosen for the study because their parents believed the children reacted negatively to sucrose. Preschool children were also studied. They are often considered sensitive to some foods. The researchers found no differences in the behavior of the children when they ate higher-than-normal amounts of sucrose compared to when they ate diets low in sucrose.

Actually, this and other research suggests sugars tend to calm both children and adults. This effect could go unnoticed due to other influences. For instance, the excitement of a birthday party or Halloween could override the calming effect of sugars.

Do sugars cause diabetes?
Researchers do not know why diabetes occurs, but they know sugars do not cause it. Diabetes is a disorder in the way the body handles sugars. People with diabetes either do not make enough insulin or they cannot use the insulin their bodies do make. Insulin is needed to use most sugars.

Diabetes treatment includes a balanced diet, regular exercise and medication when prescribed. According to The Academy of Nutrition and Dietetics, most people with diabetes can enjoy sugars in limited amounts.

Do sugars cause weight gain?
Sugars themselves do not cause weight gain. Excess body fat results when a person eats more calories than needed. Extra calories may come from any caloric nutrient (proteins, fats, alcohol and carbohydrates). Lack of physical activity also plays a significant role in obesity.

Do sugars cause hypoglycemia?
True hypoglycemia is very rare. It results from an underlying illness that affects the body's ability to maintain its blood sugar level. In hypoglycemia, blood sugar levels fall below normal. Symptoms such as shakiness and headaches may occur.

Sugars do not unusually affect blood sugar levels in healthy persons. Low blood sugar levels occur most often in people with diabetes who take too much insulin. The treatment in this case is to eat sugars such as those found in fruit juice, sugar cubes, hard candy or soft drinks.

Do sugars cause tooth decay?
Tooth decay is the result of many factors, including heredity and the make-up and flow of saliva. Sugars and other carbohydrates such as starchy foods also play a part. Bacteria on the teeth (dental plaque) feed on carbohydrates and make acids. The acids then break down the tooth to form a cavity.

Frequent snacks of foods that contain carbohydrates, especially those that stick to the teeth, may increase chances of decay.

The use of fluoride and better dental care has led to a decline of tooth decay in recent years. Experts also advise a balanced diet and brushing teeth after meals and snacks.

"Baby bottle mouth syndrome" is a significant cause of tooth decay in young children. Infants should not sleep with bottles filled with any carbohydrate-containing liquid. This includes milk, formula and fruit juice.

Sugars Used in Foods

  • Fructose—A monosaccharide or single sugar found in fruits, honey, and root vegetables. In nature, it combines with glucose to form sucrose and does not occur in isolation, it is always found with another sugar. About 1 1/2 times sweeter than sucrose. Glucose—A monosaccharide or single sugar found naturally in corn. In nature, it combines with fructose to form sucrose. It can also combine with glucose to form maltose, and with galactose to form lactose. Slightly less sweet than sucrose, glucose is the primary energy source for the body and the only source used by brain cells.
  • High fructose corn syrup (HFCS)—A liquid mixture of about equal parts of glucose and fructose from cornstarch. Same sweetness as sucrose.
  • Sucrose—A disaccharide or double sugar made of equal parts of glucose and fructose. Known as table or white sugar, sucrose is found naturally in fruits and vegetables. Appearing most abundantly in sugar cane and sugar beets, sucrose comes from these foods for commercial use.

Other sugars often used in foods include:

  • Corn Syrup
  • Lactose
  • Dextrose
  • Maltose
  • Invert Sugar