In the 1990s, the prevalence of diabetes took a sharp and unexpected upward turn, according to annual surveys of more than 100,000 participants conducted by scientists at the U.S. Centers for Disease Control and Prevention in Atlanta. Their study, "Diabetes Trends in the U.S.: 1990-1998," appeared in the September 2000 issue of Diabetes Care .
Diabetes is a potentially devastating disease that tends to be taken less seriously than it should because its beginning symptoms may not be alarming. However, its slow progression can lead to recurrent infections and ulcerations, nerve damage, gangrene (which often results in amputations), blindness, kidney failure, heart disease and stroke. Individuals with diabetes have a reduced life expectancy.
About 16 million Americans have diabetes, according to the National Institute of Diabetes and Digestive and Kidney Diseases' latest estimates. As a result of the new research, that figure could increase by several million.
he study found that in eight years, the prevalence of diabetes among adults in the United States rose by 33 percent, from 4.9 percent in 1990 to 6.5 percent in 1998.
Among Hispanics, it increased by 38 percent, going from 5.6 percent to 7.7 percent. Among African-Americans, it increased by 26 percent, going from 7.0 percent to 8.9 percent.
These numbers are cause for concern. But by far the most worrying are those in the 30 to 39 age group. There, the prevalence increased by 70 percent, from 2.1 percent in 1990 to 3.7 percent in 1998.
The youngest age group that the study considered, those 18 to 29, showed only a 9 percent increase. The increase among older age groups ranged from 40 percent among those 40 to 49 down to 10 percent for those over 70.
Jan Norman is a registered dietitian and Certified Diabetes Educator who is a past President of the American Association of Diabetes Educators and manages the diabetes control program at the Washington state Department of Health. She is concerned about the reported increase in diabetes among those in their 30s.
The onset of complications takes a long time, but complications become practically inevitable given enough time, she said. In earlier times, when people were typically diagnosed in their 50s, you could almost expect that they would die of something else before serious diabetes complications set in. But people diagnosed at 30 have to expect to live many years with complications, unless they carefully control the disease.
Who is at risk?
About 90 to 95 percent of people with diabetes have Type 2, formerly called adult-onset diabetes. The risk factors for developing Type 2 diabetes are well known.
- People who have close relatives with Type 2 diabetes are much more likely to get it themselves.
- During same time period as the diabetes explosion, Centers for Disease Control scientists have documented an increasing prevalence of obesity. That study, "The Spread of the Obesity Epidemic in the United States, 1991-1998," appeared last October in the Journal of the American Medical Association.
Indeed, 75 to 80 percent of people with Type 2 diabetes are obese. Although experts agree that obesity has not been shown to cause diabetes, obesity is listed as a risk factor for diabetes because the two occur together at a very high rate. It appears that the same factors that contribute to obesity also may contribute to diabetes and that losing excess weight does reduce diabetes risk.
- People over 40 and particularly those older than 60 are much more at risk.
- High blood pressure and high cholesterol are additional risk factors.
- Dietary intake of high-glycemic carbohydrates appears to be a risk factor, based on two large studies:
The Journal of the American Medical Association reported the findings of the Nurses' Health Study of 65,173 U.S. female registered nurses. The study concluded that a diet high in carbohydrates that have a high glycemic index appeared to be a risk factor for Type 2 diabetes in women.
A study of 42,759 male health professionals reported in Diabetes Care likewise showed that a diet high in high-glycemic carbohydrates increased the risk for men to get Type 2 diabetes.
- People who are of Hispanic, African-American or Native American descent are all at greater risk of developing diabetes. The rates of Type 2 diabetes among Mexican-Americans and Puerto Ricans are 110 to 120 percent higher than among non-Hispanics. Diabetes among African-Americans is 60 percent higher. Native Americans have the highest rates of diabetes of any group in the world. Half of the Pima Indians living in the United States have diabetes—but not those living in Mexico, because they have a different diet.
- Individuals who do not exercise are at higher risk for virtually all health problems, including diabetes.
Why is there an epidemic now?
Although many authorities feel that we don't yet have enough information to identify causes, some experts believe the reasons for the parallel epidemics of diabetes and obesity are clear.
Too many carbs?
The idea that carbohydrates are the most important dietary factor in the diabetes explosion has come into much greater prominence in recent years. The theory is that overconsumption of carbohydrates stresses the body to produce too much insulin, which may lead to insulin resistance and eventually diabetes in susceptible individuals.
One expert who has helped to popularize this view is Richard K. Bernstein, an endocrinologist who has Type 1 diabetes himself. He has reversed most of his own complications of diabetes with a very low-carbohydrate diet and recommends to all his patients who are on insulin no more than 6 grams of carbohydrate at breakfast and 12 grams each at lunch and dinner.
His most recent book is Dr. Bernstein's Diabetes Solution: A Complete Guide to Achieving Normal Blood Sugars (Little Brown, 1997). His Web site is www.diabetes-normalsugars.com .
Diabetes is a disturbance of carbohydrate metabolism in which blood sugars rise above normal, Bernstein said. "That is due to a number of different causes."
Is it carbohydrates that are causing the diabetes epidemic? "Absolutely," he said. "If you put most patients on a low-carbo diet, the craving will go away."
It happens that both carbohydrates and protein will raise blood sugar in a diabetic and insulin levels in a nondiabetic. Fat will have no effect on either. Fat is a freebie.
Dr. Richard K. Bernstein
Bernstein's diet is not calorie-restricted in the usual sense. "We don't count or limit calories, because it is not calories that make you fat," he said. "It happens that both carbohydrates and protein will raise blood sugar in a diabetic and insulin levels in a nondiabetic. Fat will have no effect on either. Fat is a freebie."
The incidence of diabetes is increasing exponentially, and it is preventable, Bernstein said. "Things can be the way they were. You just have to eat the way you used to eat 30 or 50 years ago."
Too many calories, not enough exercise
Marion Franz is a registered dietitian and certified diabetes educator. She chairs the American Diabetes Association task force that currently is revising its nutrition recommendations and principles for people with diabetes. Franz maintains that the total calorie intake is more important than whether the calories are from carbohydrates or fat. The reason Bernstein's diet works is that it is low-calorie, whether it is limited or not, she said.
Eating less food, eating smaller portions and eating fewer calories should lead to weight loss, Franz said. "Eating less is more important than the composition of the diet."
But the best way to prevent diabetes isn't any particular diet—it is staying active, she said.
It has been demonstrated in a number of studies that people who stay physically active regardless of their weight decrease their risk of all chronic diseases, including diabetes.
"It has been demonstrated in a number of studies that people who stay physically active regardless of their weight decrease their risk of all chronic diseases, including diabetes," she said.
Peter Beyer, associate professor of dietetics and nutrition at the University of Kansas Medical Center in Kansas City, agrees with Franz.
"The NHANES (National Health and Nutrition Examination Surveys) data and other surveys show that we are eating more calories," he said. "We are eating a lower percentage of fat, but the actual amount of fat is not reduced. We are getting fatter because of the increase in caloric intake as well as a decrease in activity. Part of it is an increase in the portion size of what we think is a normal meal."
An analysis of trends in food intake by Lisa J. Harnack and colleagues at the University of Minnesota supports Beyer's observations. According to their report in the June 2000 issue of the American Journal of Clinical Nutrition , Americans had 15.2 percent more food energy (calories) available to them in 1994 than they did in 1970. "Data regarding trends in food purchasing and preparation suggest that Americans are eating more meals outside the home, relying more heavily on convenience foods and consuming larger food portions."
What can you do?
Anyone can benefit from good nutrition and exercise, but those factors are especially important if you are among those at risk for developing diabetes.
Although there is still intense controversy and debate about which dietary approach is best (see the related article, "Do 'heart healthy' diets cause diabetes?"), there are several points on which most experts agree.
- Favor nutrient-dense, whole foods. That means reduce your intake of sugar and other "empty calorie" refined carbohydrates (white flour, white rice, etc.) in favor of complex carbs (whole fruits, whole grains, whole starchy vegetables, etc.). Avoid fried foods and other foods high in saturated or hydrogenated fat.
- Avoid or reduce non-foods and "anti-nutrients" (foods that can create extra nutritional demands by forcing your body to work harder). That means reduce your intake of alcohol, caffeine, soft drinks and foods that are high in artificial ingredients or have little nutritional value of their own.
- Although there are some who disagree, an increasing number of nutritional experts are recommending that you pay attention to the glycemic effect of foods and gravitate toward foods or combinations of foods that don't raise blood sugar too quickly. The glycemic effect is more of a factor for some people than others, but it is a recurrent theme among many nutritional experts. (For more about the glycemic index, see the related story, " The glycemic index of foods .")
- The recently revised USDA dietary guidelines now include exercise. The USDA Dietary Guidelines for Americans, 2000 recommends at least 30 minutes of moderate exercise daily for adults (preferably more) and at least 60 minutes for children. Regular physical activity:
- Increases physical fitness.
- Helps build and maintain healthy bones, muscles and joints.
- Builds endurance and muscular strength.
- Helps manage weight.
- Lowers risk factors for cardiovascular disease, colon cancer and Type 2 diabetes.
- Helps control blood pressure.
- Promotes psychological well-being and self-esteem.
- Reduces feelings of depression and anxiety.
Most adults do not need to see their health care provider before starting to become more physically active. However, consult your health care provider if you are planning a vigorous activity plan and have one or more of the following conditions:
- Chronic health problems such as heart disease, hypertension, diabetes, osteoporosis or obesity.
- High risk for heart disease.
- Over age 40 for men or 50 for women.
This article originally appeared on NutriNews.com on November 10, 2000.
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