What is the Importance of Grains and Beans in the Diet?

By Alyssa Fernandes, BS, Dietetic Intern and Master’s Student

Do you ever wonder what happens to food after you eat it? Why that gurgling sound is coming from your stomach? What is the meaning of the french sounding “legume” word you keep hearing? Or if there is really that much difference between white bread and wheat?

Let’s start to answer these questions and more by taking a tour of your insides!

Digestion

Digestion is “the process in the alimentary canal by which food is broken up”.[1] Digestion happens physically by chewing, and chemically by the action of “enzymes”.1 Enzymes are proteins that your body makes to support the many chemical reactions that happen in your body. The enzymes that we make for digestion are called “digestive enzymes” (go figure). They break up the food we eat into little baby pieces so that we can absorb them.

The Digestive System

The organs that form our digestive system are the mouth, esophagus, stomach, small intestine, large intestine (aka colon), rectum, and anus.[2] This is the route our food takes every time we eat – no matter what. The food we eat comes in direct contact with each of these organs, however, digestive enzymes are only present in the mouth, stomach, and small intestine.2

All foods are made up of macromolecules. The three macromolecules are carbohydrates, fat, and protein. These 3 macromolecules are digested differently, by different enzymes, in different parts of the digestive tract. See chart below.

OrganMacromolecules Digested
Mouthcarbohydrates, fat
Stomachprotein, fat
Small Intestinecarbohydrates, protein, fat

Absorption

Absorption is the other function of the digestive tract. Absorption is the uptake of the digested pieces of food (nutrients) you ate into your body’s circulation.[3] Most of the nutrient absorption occurs in the small intestine.3 The large intestine is responsible for absorbing the remaining water, sodium, and potassium that the small intestine missed.3

Grains and Beans

At this point you should be feeling pretty proud of yourself because you have been a master of digesting and absorbing food your entire life. Congratulations!

Let’s re-center our focus on grains and beans, the digestion and absorption of grains and beans, and how these foods affect your digestive system.

Beans

Most of us have heard of beans. Some of us have heard of legumes. Some of us still don’t understand what a legume is.

Legumes include all forms of beans and peas from the Fabaceae family.[4] There are thousands of different species of legumes. This family includes “pulses” which are the dried seeds of legumes. Well known legumes are chickpeas, beans (navy, cannellini, kidney, black-eyed peas), peas lentils, lupins. Legumes can be consumed in many forms such as split, ground (flours), dried, canned, cooked, or frozen.

So yes, beans are legumes.

Pinto beans

Legumes provide fiber, protein, carbohydrates, B vitamins, iron, copper, magnesium, manganese, zinc, and phosphorus.[5] They are naturally low in fat and free of cholesterol.5 They also have a low glycemic index, which means they have a relatively low impact on blood glucose levels when we eat them.5 Evidence shows that legumes can play an important role in the prevention and management of health conditions such as type 2 diabetes, hypertension, hyperlipidemia, and obesity.5

Despite all of these amazing properties, only ~8% of U.S. adults report eating legumes on any given day.

Grains

Grains are the edible seeds of specific grasses belonging to the “Poaceae” family.[6] Examples of grains are wheat, oats, rice, barley, rye, corn, triticale, millet, sorghum, spelt, freekeh, farro, kamut, and eikorn.6 I challenge you to reread that sentence out loud. Preferably in public.

The grains listed above are all “true” grains because they are true members of the Poaceae family.6 Quinoa, amaranth, and buckwheat are “pseudo-grains” because they are not true members of the Poaceae family. However, the nutrient content of pseudo-grains is similar to true grains and they are prepared similarly, so we let them join the club.6

These days, grains are divided into two subgroups: whole grains and refined grains. Whole grains contain the entire grain kernel, which includes the bran, germ, and endosperm. Refined grains were once whole grains before they were milled. Milling is a process that removes the bran and germ from the whole grain. While milling grains gives them a finer texture and improves their shelf-life, it reduces their nutrient content significantly. Milling reduces the dietary fiber, iron, and B vitamins naturally found in whole grains.

Most refined grains are “enriched”. This means that B vitamins and iron are added back to the refined grains after the milling process. Fiber, however, is not added back to enriched grains.

If you remember nothing at all, just remember this image:


Make it GRAIN more BEANS!

Join Elevated Nutrition and Wellness at The Plantology Cafe for an information filled evening

Thursday, October 25th, 2018 from 6:30 pm – 8:00 pm

Registered Dietitian Nutritionist, Eleanor Baker is going to squish myths about grains, discuss the way your body digests beans, and how to properly incorporate these things into your everyday life by maximizing essential nutrients and vitamins.

Of course there will be food too.  Plantology will have a build your own grain and bean bar, along with a cooking demo on a fast, simple, but delicious bean dip you can take to all your holiday parties!  This won’t be your everyday workshop, but rather a fun experience of introducing you to new foods and ways to improve digestibility and all around gut health.


  1. Digestion. Dictionary.com website. https://www.dictionary.com/browse/digestion. Accessed October 2018.
  2. Macronutrient Digestion. University of Florida Distance Learning. https://files.distance.ufl.edu/FoHN/documents/textbook/week5_annotated_reading.pdf. Accessed October 2018.
  3. Dimer J. In What Digestive Organ Are Nutrients Absorbed. Livestrong website. https://www.livestrong.com/article/436603-in-which-digestive-organ-are-nutrients-absorbed/. Published August 2017. Accessed October 2018.
  4. Types of Legumes. Grains & Legumes Nutrition Council website. https://www.glnc.org.au/legumes/types-of-legumes. Published 2018. Accessed October 2018.
  5. Polak R, Philips EM, Campbell A. Legumes: Health Benefits and Culinary Approaches to Increase Intake. Clin Diabetes. 2015 Oct; 33(4): 198-205.
  6. Types of Grains. Grains and Legumes Nutrition Council. https://www.glnc.org.au/grains-2/types-of-grains/. Accessed October 2018.

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