Whole grains have been consumed for tens of thousands of years (1).
But many modern diets, such as the paleo diet, claim that eating grains is bad for your health.
While refined grains are definitely linked to health problems like obesity and inflammation, whole grains are another story.
There are legitimate health benefits to eating whole grains, including a lower risk of diabetes, heart disease and high blood pressure.
This article lists the top nine health benefits of whole grains, as well as who might want to avoid them.
What are whole grains?
Grains are the seeds of grass-like plants called cereals. Some of the most common varieties are corn, rice and wheat.
Some seeds of non-grass plants, or pseudocereals, are also considered whole grains. These include buckwheat, quinoa and amaranth (2).
Whole grain kernels have three parts (3):
- Bran: This is the hard, outer shell. It contains fiber, minerals and antioxidants.
- Endosperm: The middle layer of the grain is mostly made up of carbs.
- Germ: This inner layer has vitamins, minerals, protein and plant compounds.
Grains can be rolled, crushed or cracked, but as long as these three parts are still present in their original proportion, they’re considered whole grains.
Refined grains have had the germ and bran removed, leaving only the endosperm.
Although enriched refined grains have had some vitamins and minerals added back, they’re still not as healthy or nutritious as the whole versions.
There are many kinds of whole grains, including:
- Brown rice
- Whole rye
- Wild rice
- Wheat berry
Products made from these foods are also considered whole grain foods. These include bread, pasta and some breakfast cereals.
When you’re purchasing processed whole grain products, make sure you read the ingredients list to make sure they’re made entirely from whole grains, not a mixture of whole and refined grains.
Also keep an eye on the sugar content, especially in the case of breakfast cereals, which often contain large amounts of added sugar. Seeing “whole grain” on the packaging does not automatically mean that the product is healthy.
Bottom Line: Whole grains contain all three parts of the grain. There are many different kinds, including whole wheat and whole corn, oats, brown rice and quinoa.
1. They’re high in nutrients and fiber
Whole grains deliver many important nutrients. Here are some of the key nutrients found in whole grains:
- Fiber: The bran provides most of the fiber in whole grains.
- Vitamins: Whole grains are particularly high in B vitamins, including niacin, thiamin and folate (4, 5).
- Minerals: They also contain a good amount of minerals, such as zinc, iron, magnesium and manganese.
- Protein: Whole grains provide several grams of protein per serving.
- Antioxidants: Several compounds in whole grains act as antioxidants. These include phytic acid, lignin and sulfur compounds (6).
- Plant compounds: Whole grains deliver many types of plant compounds that play a role in preventing disease. These include lignans, stanols and sterols (7).
The exact amounts of these nutrients differ depending on the type of grain.
Nevertheless, to give you a sense of their nutritional profile, here are the key nutrients in one ounce (28 grams) of dry oats (5):
- Fiber: 3 grams
- Manganese: 69% of the RDI
- Phosphorous: 15% of the RDI
- Thiamin: 14% of the RDI
- Magnesium: 12% of the RDI
- Copper: 9% of the RDI
- Zinc and iron: 7% of the RDI
Bottom Line: Whole grains deliver a variety of important nutrients, including vitamins, minerals, protein, fiber and other healthy plant compounds.
2. They lower your risk of heart disease
One of the biggest health benefits of whole grains is that they lower your risk of heart disease, which is the leading cause of death worldwide (8).
A 2016 review analyzed the results of 10 studies and found that three one-ounce servings of whole grains daily may lower the risk of heart disease by 22% (9).
In fact, eating up to seven ounces of whole grains per day was linked to a lower risk of heart disease.
Another recent Spanish study looked at the types and amounts of grains and other carbs eaten by 17,424 adults and followed them for over 10 years (10).
Those who ate the highest proportion of whole grains in relation to their total carb intake had a 47% lower risk of heart disease.
The researchers concluded that heart-healthy diets should include more whole grains and fewer refined grains.
While most studies lump together all types of whole grains and make it hard to tease apart the benefits of individual foods, whole grain breads and cereals, as well as added bran, have been specifically linked to a lower risk of heart disease (9).
Bottom Line: Eating whole grains may lower your risk of heart disease, especially when they replace refined grains.
3. They lower your risk of stroke
Whole grains may also help lower your risk of stroke (11).
In an analysis of six studies including nearly 250,000 people, those eating the most whole grains had a 14% lower risk of stroke than those eating the fewest (11).
Furthermore, three compounds in whole grains — fiber, vitamin K and antioxidants — can reduce the risk of stroke.
Whole grains are also recommended in the DASH diet and Mediterranean diet, both of which may help lower the risk of stroke (12).
Bottom Line: As part of a heart-healthy diet, whole grains may help lower your risk of stroke.
4. They reduce your risk of obesity
Eating fiber-rich foods can help fill you up and prevent overeating. This is one reason high-fiber diets are recommended for weight loss (6).
Whole grains and products made from them are more filling than refined grains, and a lot of research suggests that they may lower your risk of obesity.
In fact, eating three servings of whole grains daily was linked to lower BMIs and less belly fat in a review of 15 studies including almost 120,000 people (14).
Another study that reviewed research from 1965 to 2010 found that whole grain cereal and cereal with added bran were linked to a modestly lower risk of obesity (15).
Bottom Line: A lot of research from the past 45 years has suggested that whole grains are linked to a lower risk of obesity.
5. They lower your risk of type 2 diabetes
Eating whole grains in place of refined grains may lower your risk of type 2 diabetes (16).
A review of 16 studies concluded that replacing refined grains with whole grains and eating at least two servings of whole grains daily could lower the risk of diabetes (17).
In part, this is because fiber-rich whole grains can also help with weight control and prevent obesity, a risk factor for diabetes (18).
Moreover, studies have also linked whole grain intake to lower fasting blood sugar levels and improved insulin sensitivity (19).
This could be due to magnesium, a mineral found in whole grains that helps the body metabolize carbs and is also tied to insulin sensitivity (18).
Keep in mind that this refers to prevention only. If you already have type 2 diabetes, then you may need to limit high-carb foods like grains (including whole grains), because they can raise your blood sugar levels.
Bottom Line: Fiber and magnesium are two nutrients in whole grains that help lower your risk of type two diabetes.
6. They support healthy digestion
The fiber in whole grains can support healthy digestion in a couple of ways.
First, fiber helps give bulk to stools and prevents constipation.
Second, some types of fiber in grains act as prebiotics. This means they help feed the healthy, good bacteria in the gut, which are important for digestive health (6, 20).
Bottom Line: Due to their fiber content, whole grains help support healthy digestion.
7. They reduce chronic inflammation
Inflammation is at the root of many chronic diseases.
Fortunately, some evidence suggests whole grains can help tame inflammation (21).
In one study, women who ate the most whole grains were least likely to die from inflammation-related chronic diseases (22).
Also, in a recent study, people with unhealthy diets replaced refined wheat products with whole wheat products and saw a reduction in inflammatory markers (23).
The results of these and other studies support public health recommendations to replace most refined grains with whole grains (24).
Bottom Line: Eating whole grains regularly could help lower inflammation, a key factor in many chronic diseases.
8. They can reduce the risk of cancer
Research on whole grains and cancer risk have provided mixed results, although they do show promise.
A 2016 review of 20 studies on the topic reported that six of the studies showed a reduced risk of cancer, while 14 studies showed no link (25).
Current research suggests that whole grains’ strongest anti-cancer benefits are against colorectal cancer, one of the most common types of cancer in men and women (26, 27).
Additionally, some health benefits linked to fiber may help lower the risk of cancer. These include its role as an antioxidant and a prebiotic (26, 28, 29).
Lastly, other components of whole grains, including phytic acid, phenolic acids and saponins, may also slow the development of cancer (26).
Bottom Line: Whole grains may help prevent colorectal cancer, one of the most common types of cancer.
9. They’re linked to a reduced risk of premature death
When you lower your risk of chronic disease, you often lower your risk of dying prematurely.
In fact, a 2015 study suggested that whole grain intake specifically lowered the risk of dying from heart disease, as well as any other cause (30).
That study used data from two large cohort studies — the Nurses’ Health Study and the Health Professionals Follow-Up Study. The researchers adjusted for other factors likely to influence death rates, such as smoking, body weight and overall eating patterns.
The result was compelling: every one-ounce serving of whole grains was linked to a 5% lower risk of death (30).
Bottom Line: Whole grains are linked to a lower risk of dying prematurely from any cause.
Whole grains are not for everyone
While whole grains are healthy for most people, they might not be appropriate for all people at all times.
• Celiac disease and gluten sensitivity
Some grains contain gluten, a type of protein that some people are allergic or sensitive to.
Having a gluten allergy, celiac disease or gluten sensitivity can cause a range of symptoms, including fatigue, indigestion and joint pain.
Gluten-free whole grains, including buckwheat, rice, oats and amaranth, are fine for most people with these conditions.
However, some people have difficulty tolerating any type of grain and experience digestive distress and other symptoms.
• Irritable bowel syndrome
Some grains, such as wheat, are high in short-chain carbohydrates called FODMAPs. These can cause symptoms in people with irritable bowel syndrome (IBS), which is very common.
There are other medical conditions that require people to avoid fiber.
Diverticulitis, an inflammation of little pouches in the intestine, needs to be treated with a very low-fiber diet.
Ironically, eating fiber can help prevent this disease from developing in the first place.
Bottom Line: Some people have difficulty tolerating grains. The most well-known issue is with grains that contain gluten.
How to incorporate whole grains into your diet
There are many ways to incorporate whole grains into your diet.
Perhaps the simplest thing to do is find whole grain alternatives for the refined grains in your diet.
For instance, if white pasta is a staple in your pantry, find a 100% whole wheat (or other whole grain) pasta to replace it with. Do the same for breads and cereals.
Be sure to read the ingredients list to see if a product is made from whole grains.
Look for the word “whole” in front of types of grains. For instance, you’ll want “whole corn,” not “corn.” Remember, if it simply says “wheat” (not “whole wheat”) it’s not whole.
You can also experiment with new whole grains that you may not have tried before, such as quinoa.
Here are some different ideas for adding a variety of whole grains to your diet:
- Make a cooked porridge out of oatmeal or other grains.
- Sprinkle toasted buckwheat groats on cereal or yogurt.
- Snack on popcorn.
- Make polenta out of whole grain cornmeal.
- Swap out white rice for brown rice, or for a different whole grain, like quinoa or farro.
- Add barley to vegetable soups.
- If you bake, try using whole grain flours, such as whole-wheat pastry flour.
- Use stone-ground corn tortillas, rather than white tortillas, in tacos.
Bottom Line: There are many ways to work whole grains into your diet. Replacing refined grains with whole grains is a good place to start.