As we are becoming more informed and perhaps more wary about the connection between gluten consumption and illness, the conversation has recently extended to suggest that all grains should be avoided. This anti-grain consumption movement is predicated upon the diet of humans back in Paleolithic times, which consisted of wild game, fruits, vegetables and nuts.
So what’s the truth about whole grains? Are they a dietary angel or demon?
Let’s look to the research to see what science really tells us about these ancient staples of the human diet.
The Wide World of Grain
There is ample evidence that low-glycemic load whole grains (like oats, quinoa, teff, brown rice, and buckwheat) when eaten in moderation are not only a healthy part of the human diet, but reduce your risk of illness—particularly cardiovascular problems—and enhance gut microbiome health and diversity due to their prebiotic effects.1
A study2 recently published in JAMA Internal Medicine bears out the heart-protective effects of whole grains. In the study Dr. Hongyu Wu and his colleagues at the Harvard School of Public Health examined data on whole grain intake and mortality in 74,341 women in the Nurse’s Health Study3 and 43,744 men in the Health Professional’s Follow-up Study4—two of the largest cohort health studies ever published.
What they found was impressive. Each daily serving of whole grains correlated with a 5% reduction in mortality by all causes and a 9% reduction in cardiovascular mortality. The researchers also estimated that replacing a daily serving of refined grains with whole grains lead to a 4% and 8% reduction in all-cause mortality and death from cardiovascular disease respectively, and that replacing a serving of red meat with whole grains lead to a 10% reduction in total mortality and a 20% reduction in cardiovascular disease (CVD) mortality.
Amber Waves of Grain
We also know that whole grains provide an important source of food (olgiosaccharides) for the gut microbiome and thus have prebiotic effects. As we continue to learn more about the gut microbiome’s impact on our health, it’s becoming clear that the biodiversity of your inner ecology is an important factor in your overall health and has an impact on weight as well, as I spell out in my book The Gut Balance Revolution.
Indeed, some whole grains are veritable superfoods. Oats, for example, contain 4 grams of protein, 3.6 grams of satiating dietary fiber, and only 12 net grams of carbs per serving making them ideal for weight loss. The fiber in oats is digested slowly meaning in keeps blood glucose levels stable over time—a fact that has implications for those with blood sugar control issues and weight problems. And a recent study published by Dr. Joseph Keenan and his colleagues at the University of Minnesota showed that daily consumption of oats may reduce systolic blood pressure by as much as 7.5mm Hg and diastolic blood pressure by as much as 5.5mm Hg.5
Quinoa, another nutritional superstar is high in protein, contains a good dose of fiber (5 grams per serving), has a low glycemic load, and a study at the University of Milan showed that quinoa has a satiating effect—the highest among the gluten-free grains.6
While it is true that some whole grains do contain compounds that can be toxic, these are either easily removed (by washing) or only need to be avoided under special circumstances. For example, quinoa is coated with saponin, a potential toxic, bitter tasting chemical. All you have to do is wash it before you cook it, and you’re safe. It’s also high in oxalates, so if you have kidney stones you shouldn’t eat it. But for the rest of us this ancient whole grains is a superfood we can and should enjoy.
To my knowledge there is no research to suggest that whole grains are toxic or inflammatory to the human gut except is special circumstances—like gluten is in CD patients or perhaps in a subset of patients with autoimmunity, but that remains to be proven. And while it’s true that the caveman did not consume a lot of whole grains, the fact they have been with us for millennia and are considered an important part of some of the healthiest diets in the world (The Mediterranean and Baltic Sea Diets, for example) lends credence to the idea that they are not only harmless but essential for achieving optimal health.
Despite these facts, only about 5% of Americans get the recommended minimum amount of whole grains each day (five 28 gram servings or the equivalent of about a cup of oats).7 So it’s likely you aren’t getting enough and should consider adding more whole grains to your diet.
3 Tips for Eating Healthy Whole Grains
If you choose to integrate more whole grains in your diet (and I recommend you do with exceptions noted above), keep the following in mind.
Tip #1: Eat Moderately
While I’m all for whole grains, portion control is important when it comes to these foods. This is a case of the dose makes the poison or the remedy. Getting the daily recommended minimum of whole grains (or maybe a little more) correlates with many health benefits, but overdo it and your blood glucose levels may start swinging out of control. Stick with 1-2 cups of oats or other whole grains and you should be fine.
Tip #2: Broaden Your Repertoire
This is especially important for those of you who are gluten sensitive. The good news is that even if you are there are many non-glutinous whole grains available, and in my view they should represent the majority of the grains you consume.
Try certified gluten-free oats, quinoa, buckwheat, or teff. But keep the following in mind when you do.
If you choose teff, a stable grain at Ethiopian restaurants, be aware that teff breads are wheat-based so ask for pure teff.
Quinoa is high in protein but has potentially toxic saponins which require rinsing prior to consumption.
Corn is a common gluten-free grain substitute but it is highly allergenic, its oils are pro-inflammatory and much of today’s corn is derived from genetically modified organisms (GMOs).
A note of caution about oats: Some individuals who are gluten sensitive may have cross-reactivity to a gluten-like protein fraction of oats called avenins, so be mindful of this as you cross over to gluten-free grains.
Another word of caution: Many of the oats on the market have low-levels of gluten as many of the grains are processed in the same mills, so look for certified gluten-free oats that are processed separately from other grains.
Finally, there is a profound fear among individuals with celiac disease (CD) that the avenins in oats are toxic to their gut and provoke an autoimmune response. This is supported by some reports in the literature where celiac patients were fed oats and this caused their symptoms to flare up and lead to low-grade inflammation.8
Indeed, investigators from Australia, where oats are not permitted as part of a gluten-free diet, reported that only 8% of 73 celiac patients showed evidence of CD-like immune reactivity to oat avenins in their blood.9
However other studies fail to fully corroborate these findings. A subsequent study by a different group of researchers confirmed the avenin-induced immune reactivity in celiac disease patients following oat consumption, but concluded that the dose of this grain required to provoke a significantly meaningful response was substantial.10
The fact is, we just don’t know yet whether or not avenins in oats trigger symptoms in those with CD. It may be another case of the dose is the poison or the remedy. Or it could be that oats only affects some people. Keep your eyes peeled as the research in this area continues to grow.
Tip #3: Keep a Healthy Balance of Carbs
When making choices about your food keep in mind that diets which favor diversity—a rainbow of colors and fiber-rich carb sources have favorable health outcomes. The same applies for whole grains. There are many to choose from so do not stick with just one.
It’s also important to keep in mind that the amount of gluten (or anything really) you consume can make the difference between it being a health food or a health hazard. The dose makes the poison. Modern strands of wheat have been carefully selected to drive up their gluten content. If you enjoy and can tolerate whole wheat products, I suggest trying wheat berries or cracked wheat. Avoid refined, fiber-poor flours. Try adding small portions of fiber-rich grains that feed your inner garden of life to your meals instead.
1 Tuohy, Kieran M., Francesca Fava, and Roberto Viola. ‘The way to a man’s heart is through his gut microbiota’–dietary pro-and prebiotics for the management of cardiovascular risk. Proceedings of the Nutrition Society. 2014. 73(2): 172-185.
2 Wu H, Flint AJ, Qi Q, et al. Association between dietary whole-grain intake and risk of mortality two large prospective studies in US men and women. JAMA Intern Med. 2015: DOI:10.1001/jamainternmed.2014.6283.
5 Keenan, Joseph M., et al. Oat ingestion reduces systolic and diastolic blood pressure in patients with mild or borderline hypertension: a pilot trial. J Fam Pract. 51.4 (2002): 369.
6 Berti C, Riso P, Monti LD, Porrini M. In vitro starch digestibility and in vivo glucose response of gluten-free foods and their gluten counterparts. European journal of nutrition 2004;43:198-204.
7 US Department of Agriculture, US Department of Health and Human Services. Dietary Guidelines for Americans 2010, 7th ed. Washington, DC: US Government Printing Office, December 2010.
8 V. Sjoberg, et al. Noncontaminated dietary oats may hamper normalization of the intestinal immune status in childhood celiac disease. Clin Transl Gastroenterol. 5 (2014) e58 [published online first: 26.06.14].
9 Melinda Y. et al. Ingestion of oats and barley in patients with celiac disease mobilizes cross-reactive T cells activated by avenin peptides and immuno-dominant hordein peptides. Journal of Autoimmunity. 2014. DOI: 10.1016/j.jaut.2014.10.003
10 Hardy, Melinda Y., et al. Ingestion of oats and barley in patients with celiac disease mobilizes cross-reactive T cells activated by avenin peptides and immuno-dominant hordein peptides. Journal of autoimmunity. 2015, Jan. 56:56-65. doi: 10.1016/j.jaut.2014.10.003. Epub 2014 Nov 1.