Are whole grains unhealthy? There’s countless people out there making this claim but there’s also plenty of people who promote consuming grains as part of a balanced diet.
This article reviews the science behind the most common reasons why people consider whole grains to be unhealthy.
For more information about lectins and carbohydrates as well as phytic acid, FODMAPs and saponins, check out my article reviewing claims that legumes are unhealthy. Some of the research on these topics overlap!
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Is Gluten Bad for You?
Questioning whether gluten is bad for you is certainly a hot topic but it isn’t always being discussed from an evidence-based viewpoint.
As a Registered Dietitian, this is one of the most common questions I’m asked, especially in the context of a vegan diet (my nutrition specialization).
Rather than listening to your neighbour or some online troll, let’s see what science has to say about whether gluten is bad for you. Remember, nutrition is a science, not an opinion.
What is Gluten?
Gluten is the major protein found in wheat grains (wheat and its derivatives, barley and rye). I’ve always found it interesting that gluten is often demonized whereas protein is held up on a pedestal – gluten IS protein.
More specifically, gluten is a mixture of different protein molecules. From a culinary perspective, gluten provides structure to baked goods or other recipes.
Medical Conditions Related to Gluten
Most people can tolerate gluten without any concerns. However, there is a very small subset of the population who have Celiac disease, wheat allergy, or non-Celiac gluten sensitivity.
Celiac disease is an autoimmune response to the gluten protein. Celiac disease affects about 1% of the population and is diagnosed with medical test (blood test + small intestine biopsy).
The only treatment for Celiac disease is a 100% gluten-free diet.
If you have Celiac disease, working with a Registered Dietitian can be a great way to navigate this dietary restriction and ensure you meet your nutrient needs and health goals!
It’s important to note that Celiac disease is NOT an allergy to gluten.
Wheat allergies are one of the more common food allergies. Wheat allergy is not the same as Celiac disease.
Someone with an allergy to wheat will experience some type of allergic reaction to the consumption of wheat.
Wheat allergy can be diagnosed at a medical allergy clinic and sometimes elimination/ reintroduction diets are trialed, under the supervision of a healthcare professional.
As with Celiac disease, the treatment for wheat allergy is avoidance of foods that contain wheat. Barley and rye, which contain gluten, are not the same as wheat and may be tolerated by someone with wheat allergy.
Unlike Celiac disease, a wheat allergy may be outgrown, whereas Celiac disease is life-long.
If you have any dietary allergies, working with a Registered Dietitian can be a great way to navigate a balanced diet.
Non-Celiac Gluten Sensitivity aka Gluten Intolerance
Non-celiac gluten sensitivity is a controversial topic. Non-Celiac gluten sensitivity is generally diagnosed when someone is having a reaction to wheat or gluten without the medical diagnosis of Celiac disease or wheat allergy.
A more common term for non-Celiac gluten sensitivity is gluten intolerance.
There is debate as to the legitimacy of non-Celiac gluten sensitivity as a diagnosis. There are variable presentations and symptoms associated with this disorder, and it is frequently self-diagnosed, especially with the popularity of gluten-free diets.
The main reasons for the debate over non-Celiac gluten sensitivity as a diagnosis is whether gluten is the problem, or if the symptoms people experience are related to some other component of the grain.
FODMAPs (poorly digested carbohydrates) are often referenced as another possible, and likely, cause of the symptoms people with non-Celiac gluten sensitivity experience.
One study found no effect of gluten consumption in patients with self-reported non-Celiac gluten sensitivity 1. This study pointed to FODMAPs as a possible cause of patient’s symptoms 1.
A Registered Dietitian’s Thoughts on Non-Celiac Gluten Sensitivity
My thoughts about non-Celiac gluten sensitivity are that if you feel better without gluten in your diet, then that’s great! Please make sure to speak with a nutrition professional (aka a dietitian) to make sure you are still getting adequate nutrition.
If you remove gluten from your diet and don’t feel better, or only slightly better, there may be another issue going on. Please consult a healthcare provider to help you navigate through finding a diet that works best for you.
Sometimes, when someone goes gluten-free, they also make many other changes to their diet. These other changes may also be responsible for the improvement in health. If possible, make dietary changes one at a time, so you can truly figure out what is working for you. A dietitian can help you through this process.
Is a Gluten-free Diet Healthy or Harmful?
If you have any of the above conditions (diagnosed by a doctor or licensed healthcare provider who can make such a diagnosis), then there is a need to remove gluten (in the case of Celiac disease), wheat (in the case of wheat allergy), or a trial of FODMAP elimination (possibly in the case of non-Celiac gluten sensitivity).
If you do not have any of the above conditions, evidence shows that eliminating gluten from your diet may actually be harmful.
Gluten-free foods tend to be lower in important nutrients including fibre, iron, and B-vitamins.
The companies that make gluten-free products need to replace the gluten with something else and the alternatives aren’t always equal in nutritional value.
One study found people consuming larger amounts of gluten had lower risk of heart disease 2. Gluten-containing whole-grains showed a positive effect in reducing risk of heart disease 2. The authors of this study concluded that a gluten-free diet may eliminate heart healthy whole grains, and lead to an increased risk of heart disease 2.
Summary: Is Gluten Healthy or Harmful?
It seems that unless there is a medical reason for avoiding gluten, consumption of gluten, specifically from whole-grains, is healthy. Consumption of gluten-containing whole grains, as with whole grains in general, has a positive impact on reducing heart disease risk 2.
Gluten-free products may be nutrient-poor compared to their gluten counterparts. Despite this, a gluten-free label has a bit of a health halo. Just because something is gluten-free, does not mean that it is the healthier choice. Just the opposite may be true.
Gluten is not bad. It can be a great source of protein, especially for those on a plant-based or vegan diet.
Vital wheat gluten (aka gluten flour) is a pure gluten extract that is used to make seitan, or plant-based meat alternatives. It creates meat alternatives that have a chewy and “meat-like” texture, which can be great for vegans who don’t want to give up the taste and texture of meat. Vital wheat gluten is a great low-carb source of vegan protein.
Lectins and Health: Are Lectins Bad for You?
Lectins have become another hot topic in the nutrition world. Some people have even stated lectins are the new gluten: in other words, lectins are the new compound in food that is receiving a round of fear mongering.
Proponents of lectin-free diets state that lectins are toxic and responsible for poor health. They typically mention that lectins cause leaky gut syndrome, systemic inflammation, skin irritation, prevent nutrient absorption, and interrupt signaling between cells in our body.
What are Lectins?
Lectins are proteins that are widely found in nature and bind to carbohydrates 3.
Lectins have “hemagglutinating” ability, meaning when lectins are added directly to blood cells in a petri dish, the red blood cells clump together 3.
How something reacts in a petri dish is not the same as how something reacts when eaten. There isn’t good evidence that a high-lectin diet has a negative impact on health although some lectin-containing foods must be cooked properly.
What Foods are High in Lectins?
Food that are high in lectins include:
- Beans (kidney, black, navy, white etc.)
- Whole grains
Nightshade vegetables including:
- Bell peppers
Do you Need to Avoid Foods High in Lectins?
Food high in lectins have been shown to have positive health benefits including lower risk of heart disease, lower risk of type 2 diabetes, decreased cancer risk, improved weight management, decreased risk of mortality and lower systemic inflammation 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16.
There are many notable health benefits to consuming legumes and whole grains. Vegetables are also consistently linked to positive health outcomes 17, 18, 19.
Raw, or undercooked legumes (excluding peanuts) contain lectins and can cause adverse reactions in humans (nausea, vomiting, bloating, diarrhea) 3. However, numerous studies show that when legumes are cooked properly (soaked then boiled or canned), lectins are completely destroyed 4.
There is no evidence I could find that the type of lectins found in vegetables are harmful (raw or cooked).
There are of course people who have difficulty digesting the foods listed above. Whether this is related to the lectin content of this food or something else (ex. FODMAPs) isn’t something there’s adequate research on.
If you are having digestive concerns or other issues, working with a doctor and Registered Dietitian can help get to the root cause of the problem and allow you to find an eating pattern that meets your individual nutrition needs.
Carbohydrate Content of Grains: Are the Carbs in Grains Bad?
Low carb eating is very “in” right now. Carbs seem to get the blame for everything from diabetes to cancer to weight gain to mood swings and the list goes on. But nutrition is not black and white and anyone claiming it is might be misleading you (at best) or just lying (at worst).
Carbs are the preferred energy source for the body and in particular, the brain. Repeat after me: carbs are energy for me and my body; they fuel my brain and allow me to live my life and enjoy my food.
Carbs aren’t “good” or “bad”. They are just a component of food that allows the body to function. If you’ve ever been on a low carb diet and felt sluggish or had difficulty concentrating, there’s a good chance the carb restriction was playing a role in how you felt.
Complex Carbs vs Simple Carbs
Complex carbohydrates are typically those that also contain fibre, vitamins, minerals and antioxidants. Sources of complex carbohydrates include:
- Whole grains
All of these sources of complex carbohydrates have been linked with positive health benefits 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19.
Simple carbohydrates are typically found in products that are refined in some way. Examples of simple carbohydrates are:
- White flour/ refined grains
- Fruit juices and sugar-sweetened beverages
- Pastries, cookies and other desserts
- Chips, French fries
These foods typically have had the fiber removed, and may have also lost some of their other nutritional content (vitamins, minerals, antioxidants).
Both of these options provide the body with energy. Yes, even refined foods provide nutrition, just not as much as a more whole-food option.
Both can be part of an overall balanced diet however, the health benefits referenced below are typically referring to more complex sources of carbohydrates.
Conclusion: Are Grains Bad for You?
Gluten, lectins and carbohydrates are not harmful for human health (unless you have Celiac disease, a wheat allergy, diagnosed gluten sensitivity, or eat certain raw legumes). So no, grains aren’t “bad for you”.
Whole grains in particular are associated with many positive health outcomes. Refined grains can also be a part of a balanced (and enjoyable) lifestyle.
Always speak with a doctor before changing your diet or taking new supplements. Please read our full website disclaimer.
- No effects of gluten in patients with self-reported non-celiac gluten sensitivity after dietary reduction of fermentable, poorly absorbed, short-chain carbohydrates
- Long term gluten consumption in adults without celiac disease and risk of coronary heart disease: prospective cohort study
- Phaseolus vulgaris lectins: A systematic review of characteristics and health implications
- Toxicity Assessment of Common Beans (Phaseolus vulgaris L.) Widely Consumed by Tunisian Population
- Association of whole grain intake with all-cause, cardiovascular, and cancer mortality: a systematic review and dose-response meta-analysis from prospective cohort studies
- Non-soy legume consumption lowers cholesterol levels: a meta-analysis of randomized controlled trials.
- Food groups and risk of type 2 diabetes mellitus: a systematic review and meta-analysis of prospective studies
- Effect of non-oil-seed pulses on glycaemic control: a systematic review and meta-analysis of randomised controlled experimental trials in people with and without diabetes.
- Diabetes Canada clinical practice guidelines, 2018: Chapter 11 – Nutrition Therapy
- Whole grain-rich diet reduces body weight and systemic low-grade inflammation without inducing major changes of the gut microbiome: a randomised cross-over trial
- Role of dietary soy protein in obesity.
- Effects of dietary pulse consumption on body weight: a systematic review and meta-analysis of randomized controlled trials.
- Association between dietary whole grain intake and risk of mortality: two large prospective studies in US men and women
- Association between whole grain intake and all-cause mortality: a meta-analysis of cohort studies
- Whole grain-rich diet reduces body weight and systemic low-grade inflammation
- Whole-grain consumption is associated with a reduced risk of noncardiovascular, noncancer death attributed to inflammatory diseases in the Iowa Women's Health Study
- Consumption of fruit and vegetable and risk of coronary heart disease: a meta-analysis of prospective cohort studies.
- Fruit and vegetable consumption and breast cancer incidence: Repeated measures over 30 years of follow-up.
- Fruit and vegetable consumption and risk of type 2 diabetes mellitus: a dose-response meta-analysis of prospective cohort studies.
This reference list is not intended to be comprehensive.
About Nicole Stevens
Nicole is a vegan Registered Dietitian (RD) and founder of Lettuce Veg Out.
She helps people thrive on a vegan diet with balanced recipes and easy-to-understand nutrition science.
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