March 22, 2011 -- High intake of whole-grain cereal is linked to a lower risk of high blood pressure and hefty helpings of dietary fiber are linked to a lower risk of heart disease, especially for young and middle-aged adults, new studies show.
A study that looked at cereal consumption among 13,368 men who are participating in the Physician’s Health Study found that those who ate whole-grain cereals seven or more times a week had a 20% reduced chance of having high blood pressure compared to those who said they didn’t eat any cereal.
Even averaging a single bowl of cereal each week appeared to be protective, dropping the risk of high blood pressure by 11%.
Independent experts agree that cereal can be a top food choice. But they say it’s still important to read labels to make sure you’re not getting hidden surprises.
“Presumably, the ‘whole grain’ cereals that conferred the most benefit in this study provided more nutrient benefits in the form of vitamins and fiber than liability in the form of sodium and sugar. That’s not true of all cereals, however,” says David Katz, MD, MPH, director of the Yale University Prevention Research Center.
A second study, of more than 11,000 Americans who participated in the National Health and Nutrition Surveys (NHANES) between 2003 and 2008, found that young and middle-aged adults who reported the highest intakes of daily dietary fiber, averaging 22 to 23 grams a day, were significantly more likely to be at low risk for heart disease, compared to those who ate an average of 9 grams of dietary fiber daily. The same didn’t appear to hold true for adults over age 60, however.
Katz says there are several possible explanations as to why seniors who didn’t eat high amounts of fiber didn’t also have a drop in heart risk.
“The lack of benefit in older people may be of the ‘too little, too late’ variety,” Katz says. “Another possibility is that even if a high-fiber intake helps protect your blood vessels from premature atherosclerosis, the process may yet occur, just slower.”
Getting Enough Whole Grains and Fiber
Government guidelines recommend that Americans eat 25 to 38 grams of dietary fiber and 48 grams of whole grains daily.
But most people don’t even get close to those targets. It’s estimated the average American gets about 15 grams of fiber each day.
Similarly, studies show only 5% of Americans are reaching the 48-gram goal for whole grains.
That’s a significant deficit since studies have shown that whole grains have many important health benefits.
“Whole-grain consumption has been shown to decrease the harmful effect of the bad fat that you eat on the endothelium, the lining of blood vessels,” says study researcher Jinesh Kochar, MD, a gerontologist and a clinical fellow in medicine Beth Israel Deaconess Medical Center in Boston. “It’s also been shown to decrease the risk of diabetes -- about 40% decreased risk in those who get the recommended amounts of whole grains.”
“I think there’s strong biological data to support what we are seeing in this population-based study,” Kochar says.
Hongyan Ning, MD, a statistical analyst in the department of preventive medicine at Northwestern University’s Feinberg School of Medicine, says fiber has been shown to reduce heart risk in many different ways.
“Fiber has been shown to lower blood pressure, cholesterol levels, and lower BMI [body mass index],” Ning says. “Our study would seem to show the collected effect of all those benefits.”
Only 17% of the people in Ning’s study, however, got the recommended daily amount of fiber.
Cereals That Measure Up
Breakfast cereals can be an important way to get to the daily goal, as long as they’re high in fiber and low in sugar and sodium.
“We didn’t have any specific information on brands, but we did have categories of cereal -- whole grain vs. refined gain,” says study researcher Jinesh Kochar, MD, a gerontologist and a clinical fellow in medicine at Beth Israel Deaconess Medical Center.
Kochar’s study found those who reported eating cereals made with refined grains had a slightly lower risk of developing high blood pressure, but it wasn’t statistically significant after the researchers tried to rule out other factors known to influence hypertension risk, like regular exercise, fruit and vegetable consumption and smoking.
Kochar says he wasn’t able to tell how much sodium was in the breakfast cereals study participants were eating, and that might be important since cereal, like all processed foods, can be high in salt.
He also says notes that the study wasn’t designed to show cause and effect, so researchers can only report that they saw an association between cereal and high blood pressure.
“I think the take-home message with this is that whole-grain breakfast cereal consumption, along with certain lifestyle factors, moderation in salt and calories, and getting regular physical activity -- all of those things are likely to reduce your risk of hypertension,” Kochar says.