Department of Food Science and Human Nutrition
Extension
Colorado State University
Fort Collins, CO 80523-1571
Healthy Heart Beats
July-September 2008
Vol 30, Issue 3
Nutrition and Research Updates
- Low Fat Dairy Foods Linked to Decreased Risk for Heart Disease
- Drinking Coffee May Reduce Heart Disease
- U.S. Obesity Trends
- Are Ketogenic Diets Effective?
Low Fat Dairy Foods Linked to Decreased Risk for Heart Disease
Researchers in the United States and Norway measured the kidney function of more than 5,000 adults who were participants in the Multi-Ethnic Study of Atherosclerosis and ranged in age from 45 to 84 years. Participants did not have clinical cardiovascular disease. Dietary patterns including both plant and animal foods were observed. The albumin-to-creatine ratio (ACR) was used to measure kidney function which has been linked to risk for cardiovascular disease.
Daily low fat dairy food consumption and a dietary pattern rich in whole grains and fruits were inversely associated with ACR or healthier kidney function. Low fat milk and milk products was the only food group which showed that it alone was significantly linked to a reduced risk for kidney dysfunction. By contrast, a dietary pattern characterized with high consumption of beans, tomatoes, refined grains, high-fat dairy foods, and meat food groups and nondairy animal food consumption were each positively associated with ACR.
The study's authors cited other research suggesting milk protein, vitamin D, magnesium and calcium may additionally contribute to milk's possible heart health benefits, potentially improving kidney function. Additional studies are needed, but a DASH-like dietary pattern excluding meat likely could be successful.
Source: American Journal of Clinical Nutrition, 2008, 87(6): 1825-1836. (June).
Drinking Coffee May Reduce Heart Disease
Drinking up to six cups of coffee a day may lower the overall odds of dying prematurely, mainly because it cuts the risk of dying from heart disease. "Our results suggest that long-term, regular coffee consumption has several beneficial health effects," says Esther Lopez-Garcia, lead author of the Harvard School of Public Health report. The study examined the relationship between coffee and mortality of 41,736 men and 86,216 women with no history of cardiovascular disease (CVD) or cancer. The men were followed for 18 years, the women for 24 years.
The results showed that as coffee consumption increases, the overall risk of death decreases. The association is explained mostly by a decrease in CVD deaths, Lopez-Garcia says. The inverse association between coffee consumption and mortality was stronger in women. Women who drank two to three cups of coffee a day, for instance, had a 25% lower risk of dying from heart disease than non-drinkers. "Coffee has some beneficial effects on inflammation and endothelial function, which are the first stages of CVD development," Lopez-Garcia says.
Researchers warn that the study does not prove that coffee is linked to longevity because other factors may be protective, Lopez-Garcia says. A measurement error also could be possible, because consumption levels were self-reported. "More research is necessary to be able to recommend consuming coffee on a health basis," she says. "Our study is not enough to make such a statement." The findings suggest that a component other than caffeine explains the relationship between coffee and a lower risk of death, Lopez-Garcia says. Participants who drank both decaf and caffeinated coffee had lower death rates than non-drinkers.
Since the study was conducted among health care professionals, extrapolation of results to the general population should be made with caution. The conclusions also do not negate the potentially detrimental short-term health effects of drinking coffee with caffeine, such as anxiety and sleep problems.
Source: Annals of Internal Medicine, 2008, 148(12): 904-914. (June).
U.S. Obesity Trends
More than a quarter of all adult Americans over age 18 are now obese, the latest U.S. government figures show. The percentage of U.S. adults who reported being obese grew by nearly 2 percent between 2005 and 2007, from nearly 24 percent to 25.6 percent according to the Centers for Disease Control and Prevention. CDC researchers used data from the Behavioral Risk Factor Surveillance System, an annual telephone survey of more than 350,000 adults.
Alabama, Mississippi, and Tennessee had the worst rates, with 30 percent of adults reporting weights that made them medically obese. Colorado had the slimmest population, with 18.7 percent of people reporting weights that put them in the obese category-still higher than the Healthy People 2010 goal to reduce obesity to 15 percent or less.
Obesity is defined as having a body mass index (BMI) of 30 or above. BMI is calculated using height and weight. BMI takes into account variations in build for all but the most heavily muscled athletes. People are considered overweight when they have a BMI of 25, and the health effects of obesity and overweight, such as diabetes, heart disease and cancer, increase steadily as weight goes up.
"The epidemic of adult obesity continues to rise in the United States indicating that we need to step up our efforts at the national, state and local levels," said Dr. William Dietz, director of the CDC's Division of Nutrition, Physical Activity, and Obesity. "We need to encourage people to eat more fruits and vegetables, engage in more physical activity, and reduce the consumption of high calorie foods and sugar sweetened beverages in order to maintain a healthy weight," Dietz said.
By region, people who live in the South are the heaviest with 27 percent reporting obese. Just over 25 percent of adults in the Midwest, 23 percent in the Northeast, and 22 percent in the West were obese. The CDC recently reported that the childhood obesity epidemic has leveled off after surging for about 20 years, with 16 percent of young people obese.
A government BMI table is available at http://www.nhlbi.nih.gov/guidelines/obesity/bmi_tbl.htm. For more information on obesity trends, including maps, go to http://www.cdc.gov/nccdphp/dnpa/obesity/trend/maps/.
Source: http://www.cdc.gov/media/pressrel/2008/r080717.htm (July 17, 2008).
Are Ketogenic Diets Effective?
A two-year study comparing the effectiveness and safety of one of three diets: low-fat, restricted-calorie; Mediterranean, restricted-calorie; or low-carbohydrate, non-restricted-calorie (Atkins-like) was conducted using 322 obese individuals, most of whom were men. The rate of adherence at two years was nearly 85%. Both the length of time and the rate of adherence were longer than observed in previous studies. The participants ate their main meal together in a controlled cafeteria environment. The dieters were counseled on an eating plan for breakfast and dinner.
The low fat diet restricted cholesterol and calories from fat; low fat grains, vegetables and fruits were emphasized. The Mediterranean diet followed a similar regimen and included poultry, fish, olive oil and nuts. The low carbohydrate diet only set limits for carbohydrates, but not for calories or fat and dieters were urged to choose vegetarian sources of fat and protein.
Participants in the low carbohydrate group averaged a weight loss of 10.3 pounds. The Mediterranean diet group lost 10 pounds followed by 6.5 pounds in the low fat group. When the cholesterol levels were compared among the three groups, the Atkins-style dieters showed the greatest improvement in the ratio of cholesterol to HDL, a marker for heart disease. This group's ratio was 4 to1. The American Heart Association recommends an optimum ratio of 3.5 to 1.
The researchers concluded that Mediterranean and low-carbohydrate diets may be more effective alternatives to low-fat diets than the traditional low-fat diet. Cholesterol levels improved more with the low-carbohydrate diet though all participants lost weight and improved cholesterol. "I think these data suggest that men may be more responsive to a diet in which there are clear limits on what foods can be consumed, such as an Atkins-like diet," said Dr. William Dietz, of the Centers for Disease Control and Prevention. "It suggests that because women have had more experience dieting or losing weight, they're more capable of implementing a more complicated diet."
Source: New England Journal of Medicine, 2008, 359(3): 229-241. (July).
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