Beans have gotten a bad rap, especially for their more, ahem, audible qualities. But who gives a toot when they can contribute to lower blood pressure and a reduced risk for cardiovascular disease in people with Type 2 diabetes?
A study published in the Archives of Internal Medicine shows that individuals who consumed one cup of legumes each day were able to lower both blood sugar and blood pressure levels more effectively than those consuming a high-wheat fiber diet.
Legumes – a group of foods that include beans, lentils, chickpeas, peas, and soybeans – are known as low glycemic index (low GI) foods. The glycemic index is a measure of how high and how quickly food sugars raise blood glucose levels.
Legumes have been shown to improve blood sugar control in individuals with Type 2 diabetes, and they have the additional benefits of being generally low in fat, protein-rich, fiber-rich, high in folate, potassium, iron, and magnesium, and cholesterol-free. They are a good, healthy substitute for meat, which is often high in both fat and cholesterol.
For the study, researchers followed 121 men and women who were diagnosed as Type 2 diabetics. They were divided into two groups – one that was instructed to follow a healthy diet high in wheat fiber and another that was told to consume a healthy diet which included a cup of legumes (approximately two servings) daily.
At the conclusion of the three-month study, the bean diet group’s blood sugar levels over the previous two to three months, determined by a glycosylated hemoglobin (A1C) blood test, showed a drop of 0.5%, from 7.4% down to 6.9%. By contrast, the high-wheat fiber diet group saw a drop of 0.3 %, from 7.2% down to 6.9%. People with diabetes are advised to aim for levels below 7%, and reductions of 0.3% to 0.4% are considered meaningful by the FDA.
Both groups also saw a drop in blood pressure, which is considered normal at readings below 120/80. At the start of the study, average blood pressure for persons in the bean diet group was 122/72 mmHg; by the end, the average lowered to 118/69mmHg. Average blood pressure for high-wheat diet individuals began at 118/70 mmHg and remained steady throughout.
When predicting the participants’ risk of heart disease, the individuals on the bean diet saw a greater risk reduction than those on the high wheat fiber diet. The reduction was calculated using an equation that uses health measures including blood pressure, and it showed that the reduced heart disease risk was primarily the result of the bean diet’s effect on blood pressure.
There were no differences in gastrointestinal complaints amongst both groups, debunking the notion that legumes cause more gas and bloating than other sources of fiber.
But while the study results are good news, in an accompanying editorial, nutritionist Marion J. Franz notes that the bean diet group ate considerably more fiber – an average of 15.6g daily at the start of the study and 25.6g daily by the end of the study – than the high wheat fiber group who started at 16.6 grams per day and ended at 18.5g per day.
She stated, "Whether people with DM can eat the amount necessary to improve glycemic control is debatable, and, if legumes do improve glycemia, is it because of their low GI or high soluble fiber content?"
However, she does recommend that people with diabetes include 25-30g of fiber in their daily diet as it can help improve cholesterol and lower cardiovascular risk.
Lead study author Dr. David J.A. Jenkins, a professor of medicine and nutrition at the University of Toronto and St. Michael’s Hospital in Toronto, agrees, stating, "The public should be doing some preventive strategies using these foods. We are not introducing some novel ‘Frankenfood’ into the diet – this is really deep, traditional stuff."
The Bottom Line
With two-thirds of the population overweight or obese and an estimated 79 million Americans with elevated blood sugar levels (prediabetes), this is good news. This new study supports previous studies that have suggested a positive association between legumes and Type 2 diabetes.
Legumes are great for dieters, diabetics, and everyone in between because of their nutritional profile and low GI. Even the government is espousing the virtues of legumes. In the 2010 Dietary Guidelines, it is recommended that Americans:
“Replace protein foods (red meat, animal protein) that are higher in solid fats with choices that are lower in solid fats and calories (poultry, fish, beans, legumes, nuts).”
Many demographics that have higher rates of obesity and Type 2 diabetes (12.6% of non-Hispanic blacks, 11.8% of Hispanics, and 8.4% of Asian Americans per the American Diabetes Association) are familiar with the benefits of legumes, as they are included in many traditional dishes. Increasing intake may not be as difficult for these groups.
But for those who do not eat legumes often, the easiest way to incorporate them into your diet is by buying them in cans. Just be sure to choose brands with reduced sodium. S&W offers a line with 50% reduced sodium.
Some suggestions: Add garbanzo or white beans to salads; add beans and lentils to soups; make a three bean salad as a side dish; for dinner, pair chicken with black beans and whole grain rice instead of pasta or white rice.
Also, for those who are bean-averse, it seems what works on our kids works on us, too. Try this recipe for healthier brownies that include a hidden black bean surprise. The surprise is that even with the healthy addition, they are very delicious!