- Researchers have shown that people who eat more whole grains have a reduced risk of cardiovascular disease (CVD).
- However, there is less research looking at the effect of whole grain consumption on the early warning signs of CVD.
- The present study finds an association between people who eat more whole grains and improved measures of these early warning signs.
- Researchers also found an association between people who eat more refined grains and worsened measures of the early warning signs of CVD.
Researchers have demonstrated an association between consuming more whole grains and improved measures of risk factors for CVD.
In the research, which appears in the Journal of Nutrition, the researchers also found an association between eating more refined grains and worse measures of some of these risk factors.
The findings provide further evidence that increased consumption of whole grains has health benefits.
According to the World Health Organization (WHO), CVDs “are the leading cause of death globally.” In 2019, almost 18 million people died due to CVDs — the vast majority by either stroke or heart attack.
The Centers for Disease Control and Prevention (CDC) note that in the United States, a person dies from CVD every 36 seconds, accounting for 1 death in every 4.
To prevent CVD, the CDC advises that a person avoids smoking, avoids overweight and obesity, and stays physically active. The CDC also suggests a person should eat as healthy a diet as possible.
A 2015 review indicated that eating a healthier diet — including more fruit, vegetables, whole grains, legumes, fish, vegetable oil, and poultry — could reduce a person’s risk of CVD by a third.
More specifically, researchers have found significant evidence for the beneficial effects of eating more whole grains. This reduces the risk of CVD and death due to cancer, respiratory disease, infectious disease, and all-cause mortality.
However, there has been less research looking at the relationship between whole grain consumption and the early warning signs of CVD.
These early signs include a person’s waist circumference, blood pressure, levels of fasting plasma high-density lipoprotein (HDL), or “good” cholesterol, plasma triglyceride, and blood glucose.
The researchers conducted this study to explore the association between consuming whole grains and the early warning signs of CVD.
The researchers drew on data from the Framingham Heart Study, a long-term study conducted by the National Heart, Lung, and Blood Institute (NHLBI), which began in 1948. The researchers used data from the Offspring Cohort of the study, which started in 1971 and ended in 2104.
Around every 4 years, the participants in the Offspring Cohort gave their medical history to the researchers and underwent a standard physical exam. In the fifth examination cycle, beginning in 1991, the participants also provided information on their diet.
Researchers excluded participants who had diabetes at baseline and those who did not provide dietary information on two or more consecutive examinations. This left a sample size of 3,121 people.
The participants completed a food frequency questionnaire, allowing the researchers to determine the amount of whole grains they consumed.
The researchers found that participants who consumed the least amount of whole grains averaged a 1-inch (in) increase in their waist circumference between their 4-year examinations.
In contrast, participants who consumed the most whole grains only averaged a 0.5-in increase in their waist circumference.
The participants who consumed the least amount of whole grains had more significant increases in systolic blood pressure and blood sugar levels than the participants who consumed the greatest amount of whole grains, independently of waist circumference.
According to Dr. Nicola McKeown, senior and corresponding author of the study, and a scientist on the Nutritional Epidemiology Team at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, MA, “our findings suggest that eating whole grain foods as part of a healthy diet delivers health benefits beyond just helping us lose or maintain weight as we age.”
“In fact, these data suggest that people who eat more whole grains are better able to maintain their blood sugar and blood pressure over time. Managing these risk factors as we age may help to protect against heart disease.”
According to Dr. Caleigh Sawicki, who contributed to the study as part of her doctoral dissertation at Tufts, there are many reasons why whole grains may be beneficial to a person’s cardiovascular health.
“The presence of dietary fiber in whole grains can have a satiating effect, and the magnesium, potassium, and antioxidants may contribute to lowering blood pressure. Soluble fiber, in particular, may have a beneficial effect on post-meal blood sugar spikes,” said Dr. Sawicki.
Dr. Sawicki thinks that there needs to be more research to understand precisely why whole grains are beneficial — and how to get people to eat more of them.
“Our research is contributing to the vast amount of observational data to show that higher intake of whole grains is linked to improved health. But there is still a lot we don’t know about the mechanisms behind how whole grains may influence health,” said Dr. Sawicki.
“It might be the fiber in whole grain, or it might be one of many other nutrients or polyphenols — or all of them working together!”
“Another big challenge is, of course, actually getting people to switch from refined to whole grain foods. More research is needed to fully understand the barrier to consuming more whole grain foods.”
According to Dr. McKeown, increasing whole grains and reducing refined grains is particularly important for a U.S. demographic.
“The average American consumes about five servings of refined grains daily, much more than is recommended, so it is important to think about ways to replace refined grains with whole grains throughout your day.”
“For example, you might consider a bowl of whole grain cereal instead of a white flour bagel for breakfast and replacing refined grain snacks, entrées, and side dishes with whole grain options.”
“Small incremental changes in your diet to increase whole grain intake will make a difference over time,” said Dr. McKeown.
For Dr. McKeown, official health advice needs to continue to promote the benefits of consuming more whole grains in the diet.
“In the U.S., the current recommendation is to make half of your grain intake whole grain (so three or more servings per day), and in fact, since 2005, there has been a food-based recommendation for whole grains.”
“Perhaps, as dietary guidance is developed, a greater emphasis needs to be placed on the substitution of refined grains with whole grains, and greater communication on the unique nutritional properties of different types of whole grains,” Dr. McKeown told Medical News Today.
People also need educating about the variety of whole grains that are available, according to Dr. McKeown.
“If you ask a layperson to list all the types of fruits or vegetables available for them to eat, you’d get over a dozen listed, I’m sure — regardless of whether the person eats them or not!”
“But I am pretty sure it would be a challenge for people to identify whole grains foods beyond breads, pasta, and breakfast cereals. So there is still a good amount of consumer education that needs to happen for whole grains,” noted Dr. McKeown.