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Grains like millet, brown rice and oats can help lower cholesterol levels. eleonora galli/Getty Images
  • A new review has found that ancient grains like oats and brown rice can improve type 2 diabetes.
  • More research is needed to better understand the association between these grains and diabetes.
  • Aside from incorporating more ancient grains in your diet, experts recommend portion control and eating more heart-healthy fats and lean protein.

A new meta-analysis found that ancient grains (oats, brown rice, and millet) can improve health outcomes in people with type 2 diabetes.

The findings were published in the journal Nutrition, Metabolism and Cardiovascular Diseases this week.

The review included 29 randomized controlled trials and 13 were meta-analyzed.

Results showed for those with type 2 diabetes, oat consumption could improve cholesterol levels. However, further research is needed to learn more about the relationship between ancient grains and diabetes.

How ancient grains can improve heart health

Oats, brown rice, millet, and all other “ancient grains” are considered whole grains. Whole grains include not only starch, but also fiber, vitamins, minerals, and healthy fats.

“When we consume starch, it’s quickly digested into sugars and then absorbed into our bloodstream,” said Dr. Nate Wood, physician at the Yale School of Medicine and culinary school graduate. “This can cause a blood sugar spike. Over time, we know that these blood sugar spikes can lower our body’s sensitivity to insulin, which is the problem in type 2 diabetes.”

However the healthy fats and especially the fiber contained in whole grains like oats, brown rice, and millet work to slow the speed with which the sugar from the grain is absorbed into our bloodstream, reducing glucose spikes.

Reducing the number of glucose spikes in the blood can help preserve our body’s insulin sensitivity, which helps reduce the risk of developing diabetes. This is one big reason that eating whole grains is linked to lower rates of type 2 diabetes, Wood explained.

How fiber helps your heart

Oats, brown rice and millet are also good dietary sources of soluble fiber.

“Soluble fiber has been found in studies to have a positive impact on T2D [type 2 diabetes] and blood lipids [cholesterol and triglycerides,]” said Nancy M. Ryan, MS, RD, inpatient diabetes coordinator at Greenwich Hospital. “Soluble fiber absorbs water in the intestinal tract and the gel that forms can slow gastric emptying. This may decrease the after-meal rise in blood glucose in T2D.”

Soluble fiber also binds with bile salts in the intestinal tract, reducing absorption of these salts back into the body and reducing the amount of bile salts available to the liver to manufacture cholesterol, Ryan explained.

Additionally, soluble fiber also supports a healthy microbiome, the beneficial bacteria in the intestinal tract.

“These bacteria have a positive impact on the immune system and anti-inflammatory effects,” Ryan stated.

Dr. Marie-Pierre St-Onge, associate professor of nutritional medicine at Columbia University Vagelos College of Physicians and Surgeons explained, “These grains are typically whole grains, which means that they have not been stripped of their bran and therefore provide more fiber than refined counterparts. Higher fiber intakes produce more stable blood glucose patterns with less pronounced spikes upon consumption.”

More study needed

While the research found positive benefits of the grains for overall health, the different studies examined different types of grains and over a variety of time periods. As a result, experts said more studies will be needed to verify the findings.

The authors note that most of the studies indicated a positive impact on measures of blood sugar management and lipid profiles.

However, the small number of studies for each of the grains limited the ability to come to a definitive conclusion that ancient grains improve blood sugar management and blood lipid control in individuals with type 2 diabetes.

Reducing type 2 diabetes symptoms with dietary and lifestyle changes

Experts say to help manage type 2 diabetes staying on track with diet is key, especially by monitoring the intake of simple carbohydrates. These carbohydrates can break down quickly leading to blood sugar spikes.

“Reducing overall sugar intakes not only from refined grain products (bakery products, sweets, desserts) but also from beverages, is a longstanding recommendation to reduce blood sugar swings in patients with [diabetes,]” St-Onge stated.

“But, aside from diet, patients should also consider other lifestyle behaviors that are important for health, including obtaining sufficient sleep and exercise.”

In managing type 2 diabetes, Ryan explained it is important to consider three treatment goals to monitor: blood sugar, blood lipids, and blood pressure. Dietary modifications should take these three goals into account.

The American Diabetes Association does not promote one specific diet or way of eating.

“The emphasis is on supporting an eating pattern and food choices that support these three goals, including a variety of nutrient-rich foods, incorporating preferred foods and foods with cultural meaning/value,” said Ryan.

There are many strategies to achieve these goals.

“The first step is knowing which foods contain carbohydrates as that is the nutrient that will raise blood glucose the most after eating. With that knowledge, portion management can be very helpful,” Ryan stated.

Additionally, including heart-healthy fat (such as nuts, nut butters, avocado, olive oil) and/or lean protein (such as chicken, turkey, fish, lower fat cheese) at meals and snacks blunts the after-meal rise in blood glucose, Ryan explained. Slowing down our eating pace also reduces the after-meal rise in blood glucose.

Also, the order in which we eat the foods on our plate can make a difference.

“If we eat vegetables (cooked vegetables and/or salad) first, then our protein (chicken, turkey, fish, lean meat) and finally our starch (potato, rice, pasta), slows down the rise in blood glucose after eating,” said Ryan.

If the person with diabetes is not meeting their personal management goals, meeting with a registered dietitian/nutritionist can be very helpful. Collaboratively, a plan can be developed to support diabetes goal attainment. The contact information for a registered dietitian/nutritionist near you can be found on the website for the Academy of Nutrition and Dietetics.


A new review showed ancient grains can improve cholesterol levels in people with type 2 diabetes.

Aside from incorporating more ancient grains in your diet, experts recommend portion control, and eating more heart-healthy fats and lean protein.