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A new study found that eating refined grains is associated with a greater risk for coronary artery disease while eating whole grains was linked with a lower risk. Javier Díez/Stocksy
  • A new study has found that eating refined grains was linked with a greater risk for coronary artery disease.
  • It also found that eating more whole grains seemed to have the opposite effect.
  • Refined grains have a great deal of their nutritional content removed during the refining process.
  • Nutritionists say that the nutrients removed — especially fiber — help protect the heart.
  • They recommend starting slowly and making healthy swaps as you increase your intake of whole grains.

A new study that is being presented this week at the American College of Cardiology Middle East 2022 Together With the 13th Emirates Cardiac Society Congress, reports that eating more refined grains was linked with a greater risk for premature coronary artery disease (PCAD).

Additionally, consuming whole grains was associated with reduced risk.

Coronary artery disease (CAD) is characterized by reduced blood flow to the heart muscle due to a buildup of atherosclerotic plaques in the heart’s arteries. It is considered to be premature when it develops at an earlier age than generally expected. For this study, those ages were defined as 55 for women and 65 for men.

PCAD can lead to chest pain or heart attack as the coronary artery narrows or plaques rupture and block blood flow. Smoking, high cholesterol, high blood pressure, and diabetes put people at greater risk for developing this condition.

This study is significant because it is one of the first to look at how the type of grain eaten is related to heart disease in a Middle Eastern population. The study participants were all citizens of Iran.

The team of researchers, led by Mohammad Amin Khajavi Gaskarei, MD, of the Isfahan Cardiovascular Research Center and Cardiovascular Research Institute at Isfahan University of Medical Sciences in Isfahan, Iran, recruited 2,099 people with PCAD from various Iranian hospitals who had undergone coronary angiography (X-ray imaging of the heart’s blood vessels).

Altogether, 1,168 people with healthy coronary arteries were recruited, while there were 1,369 who had CAD with blockages equal to or above 75% in at least one coronary artery or equal to or above 50% in the left main coronary artery.

Their diet was assessed using a food frequency questionnaire to see how much whole or refined grains they were taking in before being diagnosed with heart disease.

Upon analysis of the data, it was found that higher intakes of refined grains were associated with increased PCAD risk. Higher intakes of whole grains, on the other hand, were linked to reduced risk.

The conference is being held October 7-9, 2022 in Dubai, United Arab Emirates.

According to Samantha Snashall, a registered dietitian at The Ohio State University Wexner Medical Center, who was not a part of the study, there is a big physical difference between whole and refined grains.

“Physically, whole grains contain all parts of a wheat kernel (the bran, endosperm, and germ),” said Snashall.

The process of milling grains into white flour removes both the germ and bran from the endosperm.

Snashall said the main reason that these parts of the grain are removed is to improve shelf life, texture, and chewability. The fats within the germ can make grains spoil more quickly. Also, the fiber found in the bran can make grain products more chewy and dense, which many people do not enjoy.

However, this also makes refined grains nutritionally very different from whole grains. “Each part of the kernel has different benefits to it,” she noted.

“The bran, which is the outer layer, contains a large source of fiber, B vitamins, minerals, antioxidants, and phytochemicals,” said Snashall. “The most inner layer is the germ. This is where more nutrients such as B vitamins, Vitamin E, healthy fats, and more antioxidants will be found.”

Without the bran and germ, only the inner portion of the grain, the endosperm remains. The endosperm is mostly carbohydrates, along with some protein and very few B vitamins, she noted.

Snashall said whole grains are overall better for your health because they contain more nutrients, which include:

  • fiber
  • healthy fats
  • vitamins
  • minerals
  • antioxidants
  • phytochemicals

Refined grains, on the other hand, are mainly just starchy carbohydrates.

She also noted that fortification doesn’t really make refined grains equivalent to whole grains.

“[T]hey won’t have as much as the whole grain counterpart,” noted Snashall. “Nor will they have the antioxidants and phytochemicals that whole grains have.”

When it comes to heart health specifically, she said fiber is an important component of whole grains.

“Fiber helps lower our cholesterol levels, specifically our LDL cholesterol (“bad cholesterol”) which can be impacted by other foods we consume (trans fats and some saturated fats).”

Additionally, refined grains are more likely to be used in foods that contain added sugars, like cookies or pastries, according to Snashall. Sugar is linked to an increased risk of heart problems.

She does note, however, that just because something is labeled “whole grain,” this does not automatically make it healthier.

“Whole grain cookies, pastries, and specialty breads like cinnamon raisin can still have plenty of added sugars,” she said.

Samantha Coogan, Program Director of the Didactic Program in Nutrition and Dietetics at the University of Nevada, Las Vegas, suggests that you start slowly and make sure you are taking enough fluid when you first begin eating more whole grains.

The reason? They’re higher in fiber, especially soluble fiber.

Fiber helps with intestinal motility, Coogan explained, but introducing it too quickly can lead to constipation, bloating, gas, and discomfort.

US Dietary Guidelines recommend eating 25 to 34 grams of fiber per day from whole foods. Women should shoot for the lower end of the range at about 25 grams per day, while men should aim for the higher end of the range at 34 grams per day.

“Start with a lower amount at first,” Coogan advised. “If you don’t regularly consume fiber, start with 10 to 15 grams per day, then increase by about five grams every three to four days until you reach your goal, depending on your individual symptoms/comfort.”

Coogan said it’s natural to see a bit of bloating at first or even constipation. However, this will pass as your body adjusts.

If you’re stuck for ideas on foods to eat, Coogan noted that one way to get more whole grains is to simply swap out white bread for whole grain or eat brown rice instead of white.

She also suggests adding corn to salads and salsas and recommends eating popcorn. In addition to being a popular snack food, it’s also a whole grain.

According to the Whole Grains Council, one way to ensure that you are getting adequate whole grains is to look for their stamp. Three foods with the 100% Stamp or six foods with any Whole Grain Stamp are equal to three servings.