Whole Grains vs. Refined Grains: Which is Healthier?

You may have heard that whole grains are a healthier choice than refined grains, but you may be wondering what exactly is the difference and how “bad” refined grains actually are. Here is a complete breakdown of whole grains vs. refined grains and a comparison of their health benefits.

What is the difference between whole grains and refined grains?

The difference between whole grains and refined grains is that whole grains contain the entire grain, which is made up of the bran, germ, and endosperm, while refined grains have been milled to remove the bran and germ.

When harvested all whole grains contain four primary parts (1):

• Hull: The inedible protective layer that is removed during processing.
• Bran: The multi-layered thin outer skin that contains antioxidants, B vitamins, and fiber.
• Germ: The embryo that sprouts when planted in soil that contains B vitamins, some protein, minerals, and healthy fats.
• Endosperm: The starchy middle layer and by far the largest portion of the grain that contains complex carbohydrates, proteins, and small amounts of vitamins and minerals.

A grain is considered a whole grain as long as all edible original parts; bran, germ, and endosperm, are still present in the same relative proportions as when the grain was growing in the fields. Refined grains are processed versions of whole grains as one or many of the grain’s original parts have been removed.

The Processing of Grains

While the exact process will vary from one grain to the next, all grains are processed from fields to whole grain foods and refined grain products via several critical steps. Here is an example of the processing of wheat from whole grain to flour (2, 3):

1. Harvesting: Wheat kernels are harvested from a field by a combine and transported to a processing plant. Upon arrival, wheat kernels are tested to determine how they will be treated, handled, and stored until the time of processing.
2. Cleaning: The wheat kernels are then cleaned to remove materials such as sticks, stones, and insects, and remove kernels that are not fit for milling due to it being broken, damaged, or small. The wheat is then processed in a machine to remove the outer husk from the kernels, resulting in whole-grain wheat.
3. Tempering: Cleaned wheat kernels are then conditioned to prepare them for the milling process. Water, steam, or heat is added to grains to toughen the bran and soften the endosperm, which allows them to separate more easily.
4. Grinding: The tempered wheat kernels are then fed through a milling machine where they pass through roller mills to separate the bran and germ from the endosperm. The resulting endosperm can then be ground on its own to make white flour, or the separated bran, germ, and endosperm can be ground together to make whole-wheat flour.
5. Sifting: The broken kernel particles are then sifted to separate larger particles from smaller particles. Larger particles are reground to ensure they are small enough to be finished flour.
6. Purification: Once sifted, the resulting flour is passed through the purification process, where gentle agitation and upward airflow separate the desired endosperm from bran particles and other impurities. This process is important for creating various grades of flour.

Flours may also undergo a bleaching process, where the finished flour flows through a device that releases a bleaching-maturing agent in measured amounts, or an enrichment process, where the flour passes through a device that measures out and releases specified quantities of vitamins and minerals.

Examples of Whole Grains vs. Refined Grains

It’s important to understand that all refined grains begin as whole grains and that whole grains can be found in unprocessed and processed food forms. All unprocessed whole grains can become processed whole grains or processed refined grains depending on what is done to them.

For instance, wheat kernels are the whole-grain version of wheat, and they can be consumed in their whole-grain version in the form of wheat berries or whole-wheat flour, or be milled to remove the bran and germ and turned into a refined grain and consumed in the form of white flour. Alternatively, rice can be consumed as a whole grain in the form of wild rice or brown rice, or be milled to remove the bran and germ and consumed as a refined grain in the form of white rice.

Examples of whole grains include amaranth, barley, brown rice, bulgur, corn, farro, kamut, millet, oats, quinoa, rye, spelt, and wheat berries, while refined grains include white rice, cornmeal, oat bran, and white flour.

Examples of Whole Grains:

• Wheat
• Corn
• Oats
• Brown Rice

Examples of Whole-Grain Foods:

• Wheat berries, cracked wheat, whole-wheat bread, whole-wheat pasta, whole-wheat flour
• Frozen corn, corn flour, cornmeal
• Steel-cut oats, rolled oats, quick-cooking oats, oat flour
• Brown rice cakes, brown rice noodles, brown rice flour

Examples of Refined Grains Products:

• White bread, white pasta, white flour
• Cornstarch
• Oat bran
• White rice, rice cakes, rice flour

What are enriched grains?

Enrichment is the process of adding nutrients back to grains that were lost during the milling process, due to the loss of the bran and germ (5). Enriched grains are refined grains that have thiamin, riboflavin, niacin, folic acid, and iron added after processing.

What are fortified grains?

Fortification is the process of adding nutrients into an ingredient or food that were not previously present, or at higher levels than were present originally (5). Fortified grains are refined grains that have certain vitamins and minerals added to increase their nutritional value.

Whole Grains vs. Refined Grains: Nutrition

Here is a nutritional comparison of whole grains and refined grains using wheat berries, all-purpose flour, corn, cornmeal, wild rice, white rice, steel-cut oats, and oat flour per 100-gram serving (7, 8, 9, 10, 11, 12, 13, 14).

Note: Unlike other grains, oats are rarely refined as all three parts of the oat kernel (bran, germ, and endosperm) remain intake regardless of processing and format. Therefore, except for oat bran, almost all oat products and oat flour qualify as 100% whole grain. 

Calories

Whole grains and refined grains contain a similar number of calories. Per 100-gram serving, wheat berries contain 354 calories and white flour contains 364 calories, corn contains 365 calories and cornmeal contains 364 calories; wild rice contains 357 calories and white rice contains 359 calories; and steel-cut oats contain 381 calories and oat flour contains 404 calories.

Protein

Whole grains contain more protein than refined grains because they contain the protein-rich bran, which is removed in the processing of refined grains. On average, whole grains contain 25% more protein their refined flour or refined grain products (15). For example, a 100-gram serving of wheat berries contains 18.8 grams of protein while a 100-gram serving of all-purpose white flour contains 10.3 grams of protein. Although whole grains are not considered complete protein sources, as they do not contain all essential amino acids, including high-protein whole grains in your diet is a good way to reach your daily protein intake.

Fat

Whole grains contain more fat than refined grains because they contain the germ. Although whole grains contain healthy fats, including omega-3 and omega-6 fatty acids, the germ is removed in the processing of grains as the fat content can limit the shelf life of whole grains and whole-grain products. For example, a 100-gram serving of corn contains 4.7 grams of fat while a 100-gram serving of cornmeal contains 1.7 grams of fat.

Carbohydrates

Refined grains contain slightly more carbohydrates than whole grains, however, the difference is negligible. Given the endosperm is the primary source of starch, both whole grains and refined grains are primarily sources of complex carbohydrates. For example, a 100-gram serving of wild rice contains 74.9 grams of carbohydrates while a 100-gram serving of white rice contains 80.3 grams of carbohydrates.

Fiber

Whole grains contain more dietary fiber than refined grains because they contain the fiber-rich bran, which is removed during the processing of refined grains. For example, a 100-gram serving of steel-cut oats contains 12 grams of fiber while a 100-gram serving of partially debranned oat flour contains 6.5 grams of fiber.

Sugar

Neither whole grains nor refined grains are substantial sources of sugar. The carbohydrate content of whole grains is primarily made of starch and fiber. On average, a 100-gram serving of whole grains and refined grains contains less than 1 gram of sugar, all of which is naturally occurring. However, the same cannot be said for refined grain products, which often contain large amounts of added sugar, which is why it is so important to read the ingredients and food labels on products you buy.

Other Factors to Consider

In addition to nutritional benefits, here are some other factors to consider in the discussion of whole grains vs. refined grains.

Micronutrients

Whole grains contain more micronutrients than refined grains since refined grains have been milled to remove the bran and germ, which are the vitamins and minerals. However, many refined grain flours and refined grain products are either enriched with the nutrients lost during the milling process or fortified with additional vitamins and minerals.

Glycemic Index

Whole grains tend to have lower glycemic index values than refined grains because they contain more fiber-rich bran, as well as more protein and fat. The additional fiber, protein, fat, and micronutrients in whole grains help to slow digestion and balance blood sugar. For example, steel-cut oats have a GI value of 52 while white bread has a GI value of 83 (16).

Preparation Method

Another important aspect in the discussion of whole grains and refined grains is the method in which they are prepared. All grains contain antinutrients, natural compounds that can impair digestion and nutrient absorption, however, the process by which grains are processed and prepared before consumption can mitigate or reduce their effects. Not only does removing the antinutrient-containing bran and germ during processing help, as is done with refined grains, but soaking, sprouting, boiling, and fermenting grains and grain products help to improve their health benefits (17).

Weight Loss

Whole grains are generally considered advantageous for weight loss since they are higher in fiber and protein, which makes them more filling foods than refined grains and refined grain products. Furthermore, refined grain products are typically more hyper-palatable and calorie-dense foods than whole grains, as they are often filled with added sugars and fats. However, it’s important to understand that both whole grains and refined grains can be consumed in a healthy diet and support a weight loss goal as long as you are in a calorie deficit.

Benefits of Whole Grains vs. Refined Grains

The benefits of whole grains include (18, 19, 20, 21, 22):

• Good source of dietary fiber,
• Support healthy digestion,
• Help control cholesterol levels, weight, and blood pressure,
• Lower risk of diabetes, heart disease, and other health conditions.

The benefits of refined grains include:

• Finer texture,
• Longer shelf life,
• Less expensive,
• More versatile cooking ingredients.

So, are whole grains healthier than refined grains?

Overall, whole grains are a more nutrient-dense choice than refined grains. Whole grains contain more fiber, protein, healthy fats, vitamins, and minerals than refined grains and have been linked to an array of health benefits. While whole grains do contain more antinutrients than refined grains, when properly prepared they are highly nutritious and an important part of a healthy and balanced diet.

However, not all refined grains are unhealthy, and refined grain products do not need to be completely avoided. There are many minimally processed forms of refined grains, such as cornmeal, white rice, and oat flour, which are good sources of complex carbohydrates, fiber, and micronutrients. Moreover, many forms of refined grain products, such as sourdough bread and white pasta, that are highly nutritious and can be included in a healthy diet.

Therefore, while whole grains are generally considered a healthier option than refined grains, the format in which grains are consumed and the balance of the overall diet they are consumed in, are important factors to consider.

It’s also important to note that some grain products are made with a mixture of whole grains and refined grains, therefore, only products made from 100% whole grains are considered whole grain foods.

The Bottom Line

Whole grains contain all parts of the grain, including the bran, germ, and endosperm, while the bran and germ have been removed from refined grains. While whole grains and refined grains contain a similar number of calories per serving, whole grains contain more protein, fats, dietary fiber, and micronutrients than refined grains. Overall, both whole and refined grains can be included in a balanced diet focused on whole foods with adequate protein and dietary fiber.