June 2014 Issue
Foods and Beverages for Heart Health — Managing Diabetes Isn’t Just About Blood Glucose Control
By Jill Weisenberger, MS, RDN, CDE
Vol. 16 No. 6 P. 12
Patients with diabetes often focus solely on blood glucose control to the exclusion of other health parameters. That’s no surprise since patients easily can measure their blood glucose, which can jump or plummet quickly and change the way they feel or put their health at risk.
Controlling blood glucose is critical to preventing long-term microvascular complications such as retinopathy and neuropathy. But equally important is the health of the heart and blood vessels because diabetes at least doubles the risk of heart disease.1 In fact, to prevent heart disease, controlling blood pressure and cholesterol are more important than blood glucose control.2 Unfortunately, less than 19% of Americans with diabetes have blood glucose, blood pressure, and cholesterol all at target levels.3
Healthful foods can help meet target levels, but many patients fear the foods that can protect their hearts because of their perceived effect on blood glucose. “It used to be that diabetes was synonymous with glucose control,” says Hope Warshaw, MMSc, RD, CDE, author of Diabetes Meal Planning Made Easy. “Now with data from numerous long-term research studies, both in type 1 and 2 diabetes, we know that control of glucose, lipids, and blood pressure are all key to getting and keeping people with diabetes healthy in the short and long term.”
Patients and nutrition professionals alike frequently have questions about the role of heart-healthy foods in the treatment and management of diabetes. Dietary patterns matter for overall health, explains David Katz, MD, director of the Yale-Griffin Prevention Research Center and author of Disease Proof. Yet, he says, “it’s still possible to make a meaningful contribution one food at a time, especially if the healthful food added replaces one that’s not healthful.”
The following is a discussion of foods and beverages diabetes patients should include in their diet and those they should limit.
Foods and Beverages to Include
• Fruit: “All that sugar!” is a common refrain dietitians hear from diabetes patients. Many are shocked that an RD would recommend they eat fruit or any carbohydrate-rich food.
New York-based dietitian Jennifer Hyman, MS, RD, CDE, CDN, reminds her patients of the nutrients, phytochemicals, and health benefits they fail to get when they omit an entire food group. “I try to encourage patients to look at the bigger picture in terms of total carbohydrates and to aim for a certain range of carbs at each meal. If they aim for a certain budget of carbs at meals, it gives the patient the flexibility to choose where those carbs come from,” she explains.
According to the 2010 Dietary Guidelines for Americans, consuming at least 2 1/2 cups of fruits and vegetables each day is associated with a lower risk of cardiovascular disease (CVD), including heart attack and stroke. In general, fruits are a rich source of potassium, a mineral important for healthy blood pressure because potassium blunts the harmful effects of sodium. Few Americans consume potassium in amounts equal to or greater than the Adequate Intake of 4,700 mg per day.4
For patients who shun carbohydrates in general or fruits in particular, RDs can explain calorie density. With food models, photos, or real food, dietitians can show patients the volume of fruit or other carbohydrate-rich foods they can eat that equals 200 kcal then compare that to 200 kcal of meats, oils, and solid fats. Patients should be impressed by the difference in the amount of food.
• Beans: Rich in dietary fiber, potassium, magnesium, folate, and a host of phytochemicals, beans are linked to lower blood pressure and a decreased risk of heart disease. Beans also have resistant starch, a type of fiber that, when degraded by the gut microbiota, cause the production of a short-chain fatty acid that appears to improve insulin action. If eaten in sufficient quantities, resistant starches can impact postprandial blood glucose due to both partial digestion and improved insulin sensitivity, Warshaw says. Eating at least four servings of beans per week is linked to a 22% lower risk of coronary heart disease compared with eating them less than once weekly.5
• Whole grains: The 2010 Dietary Guidelines state that whole grain intake may reduce the risk of CVD and is associated with a lower body weight. Whole grains are sources of magnesium, iron, selenium, B vitamins, and dietary fiber, with barley and oats being particularly noteworthy. The FDA allows a health claim on barley and oat products stating that 3 g of beta-glucan soluble fiber intake each day, as part of a diet low in saturated fat and cholesterol, may lower the risk of heart disease. Beta-glucan acts in the digestive tract to block cholesterol absorption and may improve insulin action.
• Nuts: The FDA allows a similar health claim on packages of nuts. In pooled data from several studies, researchers found that including nuts in the diet decreases both total and LDL cholesterol in a dose-related manner. On average, those who consumed nuts had a 5.1% reduction in total cholesterol and a 7.4% decrease in LDL cholesterol. Subjects with elevated triglycerides had a 10.2% decline in serum triglyceride levels. Diabetes patients can enjoy eating a mix of nuts because different types of nuts have health benefits.6
In other research, Katz and colleagues found that adding walnuts to the diets of patients with diabetes improved both glycemic control and endothelial function.7
• Cooking oils: Replacing saturated fats at approximately 5% to 7% of energy with unsaturated fats improves cardiovascular risk factors.8 Therefore, RDs can encourage patients to substitute butter, margarine, lard, and shortening with healthier cooking oils.
In one study, olive oil exhibited a unique benefit. When researchers gave about 2 T of olive oil daily to participants with endothelial dysfunction, the participants showed improved endothelial function compared with participants in a control group.9 Other appropriate oils include canola, peanut, soybean, and corn oils.
Because dietary fats don’t significantly affect blood glucose, many people with diabetes tend to consume excessive amounts. Hyman teaches patients that portion control is an important concept even when it comes to healthful foods.
• Tea: Studies suggest that drinking tea is associated with a reduced risk of heart attack and stroke and also may help lower blood pressure.10,11 “Flavonoids in tea, especially flavan-3-ols, theaflavins, and thearubigins, are strongly linked with lower CVD risk. The mechanisms seem to involve changes in cell signaling paths that lead to decreased inflammation, increased nitric oxide synthesis, decreased platelet aggregation, and potentially other functions, too,” says Karen Collins, MS, RDN, CDN, a speaker and consultant, and the author of the Smart Bytes blog.
Bottled tea, however, has few flavonoids. “One great option for warm weather is to teach people how simple it is to brew homemade iced tea,” Collins adds.
Caution Foods and Beverages
• Alcohol: Many consumers have heard that alcohol, particularly wine, protects the heart. Moderate alcohol intake also is associated with a reduced risk of type 2 diabetes, beginning with as little as one-half of a standard drink per day, or 7 g of alcohol.12 High intakes of alcohol, however, increase the risk of heart troubles and other chronic health problems, including accidents. Because of this, neither the American Heart Association nor the American Diabetes Association recommends that nondrinkers start drinking alcoholic beverages.
Since many diabetes patients will drink alcohol anyway, health professionals must caution those taking certain diabetes medications of the increased risk of hypoglycemia and the proper treatment for it. Dietitians should advise patients to consume alcohol only with carbohydrate-containing foods and to monitor blood glucose more often than usual, especially before driving and before bedtime. Some may need to monitor blood glucose during the night and into the following day because the development of hypoglycemia can be delayed.
The safe limit for alcohol consumption for diabetes patients depends on factors such as the medications they take and blood glucose control.
• Red meat: Many people with diabetes eat large amounts of protein-rich foods, including red meats, because they perceive these carbohydrate-free foods to be better for their diabetes. However, red meat, which includes beef, pork, and lamb, is associated with an increased risk of heart disease. Even lean red meats likely contribute to higher rates of cardiovascular problems. A study found that intestinal microbiota metabolizes carnitine in red meat to form trimethylamine, which can be metabolized to form trimethylamine-N-oxide, a compound associated with atherosclerosis.13
The American Diabetes Association recommends diabetes patients choose lean meats and follow the guidelines for the general population.
• Egg yolks: Eggs are the No. 1 source of cholesterol in the American diet.4 According to the USDA Nutrition Evidence Library, a review of epidemiologic studies showed that eating one egg per day isn’t harmful for healthy individuals but increases CVD risk in people with type 2 diabetes.14 “It makes sense to be prudent,” Katz says, “but eggs are more likely to be beneficial, especially if they displace less nutritious food.”
Eggs are satiating, contain an ideal protein, and have few saturated fats, Katz says, who has conducted soon-to-be published research in people with coronary heart disease in which subjects ate two eggs per day for six weeks. In his study, there were no adverse effects in lipids or blood vessel function. If patients are concerned, they can cook with more egg whites than egg yolks or use an egg substitute.
When counseling diabetes patients, it’s important for dietitians to tell them that managing their disease isn’t just about controlling blood glucose, and that there are many healthful foods and beverages they can enjoy that promote heart health. With empathy, RDs can teach the importance of controlling blood glucose, blood pressure, and cholesterol levels as well as the benefits of an overall healthful diet that includes a variety of heart-healthy, wholesome foods.
— Jill Weisenberger, MS, RDN, CDE, is a freelance writer and a nutrition and diabetes consultant to the food industry. She has a private practice in Newport News, Virginia, and is the author of Diabetes Weight Loss — Week by Week.
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