Whole Grains 101

whole grains 101

Health Studies on Whole Grains

Whole grain bread is healthy.

Every day, more and more studies show the benefits of whole grains. We regularly post new studies here, where you can browse through them at random. Or, you can use our filters to hone in on a specific question, such as "Does barley reduce the risk of diabetes?" or "What's the research about whole grains and hypertension?"

Filter the studies below by selecting a grain and/or a disease/condition, then click apply.


Whole Wheat Can Improve Inflammation and Influence Gut Bacteria

Researchers are increasingly turning to gut bacteria to learn more about complex conditions such as inflammation. To study this relationship, scientists randomized 63 overweight and obese adults to a diet containing either whole grains (in the form of shredded wheat) or refined grains (in the form of white bread and crackers) for 4-8 weeks. In addition to decreased inflammation in the whole grain group (a good thing!), the scientists found that one of the most abundant beneficial plant compounds (ferulic acid) from whole wheat is released and absorbed in the gut, where it is likely metabolized. In line with other studies on how whole grains improve gut health and diversity, the researchers also found that whole-wheat consumption positively influenced bacterial communities in the study participants.
American Journal of Clinical Nutrition. 2015 Feb;101(2):251-61. (Vitaglione P et al.)

Healthy Diet with Whole Grains Protects Against COPD

Chronic obstructive pulmonary disease (COPD), a type of lung disease, is commonly associated with smoking, even though up to one third of COPD patients have never smoked. In order to determine how other lifestyle factors may influence the risk of COPD, researchers analyzed over a decade of eating habits and new COPD cases from over 73,000 adult nurses in the US. The scientists concluded that diets high in whole grains, nuts, heart-healthy fats (polyunsaturated and omega-3), and low in red meat and sugar-sweetened drinks were associated with a significantly lower risk of COPD. This study adds to the growing body of evidence that whole grains are a vital component of an overall healthy diet.
British Medical Journal. 2015 Feb 3;350:h286. (Varraso R et al.)

Whole Grain Intake Can Lower Death Risk

Eating more whole grains may help you live longer! Researchers from the Harvard School of Public Health analyzed data from over 110,000 adults. The scientists found that every one-ounce serving of whole grains was associated with a 5% lower total risk of death, or a 9% lower risk of death from heart disease. Whole grain intake was not significantly associated with cancer mortality. The researchers of this study conclude “these results are in line with recommendations that promote increased whole grain consumption to facilitate disease prevention.”
JAMA Internal Medicine. 2015 Jan 5.  [Epub ahead of print] (Wu H, et al.)

Whole Grain Oats Can Improve Insulin Sensitivity and Cholesterol

The benefits of oats on blood sugar and cholesterol are well known, but new research suggests that the gut might also be involved. In a small study in Utah, 24 mice were fed a diet of either whole grain oat flour or refined (low bran) oat flour for eight weeks. The whole grain group had vastly different gut microbiota (the friendly bacteria in the gut) than the refined oat group, including twice as many beneficial Lactobacillacea. Those fed the whole grain oats also had significantly improved insulin sensitivity (a measure of how well a body is able to regulate its own blood sugar), 9.9% lower total cholesterol and 11% lower non-HDL (a combination of LDL and VLDL or “bad cholesterol”). The researchers speculate that the changes in gut microbiota could be a mechanism for improved insulin sensitivity and cholesterol, and conclude that these findings “further confirm the beneficial effect of whole grain oats.”
Journal of Nutrition. 2014 Dec 10. (Zhou A et al.)

Healthy Whole Grain Diets Filled with Friendly Bacteria

We know that healthy microbes are present in yogurt and other fermented foods, but research is showing that these friendly bacteria are actually present all throughout healthy diets. Researchers at the University of California, Davis measured the microbes in meals from three common diets: the standard American diet (consisting of fast food and convenience foods, and no whole grains), a vegan diet (which included oatmeal and peanut butter, a vegetable and tofu soup with soba noodles, and a Portobello burger on a whole wheat bun), and a healthy diet based on the USDA dietary guidelines (which included whole grain cereal with fruit and yogurt, a turkey sandwich on whole wheat bread, and a quinoa, chicken, and vegetable dinner). Researchers found that the microbe level in both whole grain diets outnumbered that of the standard American diet lacking in whole grains. The USDA diet had 1.3 billion microbes per day, the vegan diet had 6 million microbes per day, and the standard American diet had only 1.4 million microbes per day. While it's unclear whether the benefit can be traced directly to whole grains or to a combination of interacting factors, this study points to the overall benefits of a healthy diet including whole grains.
PeerJ. 2014 Dec 9. (Lang J M et al.)

Popped Amaranth Can Improve Blood Vessels and Cholesterol

Amaranth is a tiny grain that is often eaten popped, like popcorn, and is thought to have cholesterol lowering properties. To study this cholesterol lowering process, researchers in New Zealand fed 27 rabbits a high cholesterol diet or standard diet, and then gave some of the rabbits in the high cholesterol group popped amaranth. The scientists found that eating amaranth restored endothelial function (blood vessel health) to “nearly normal” during the 21-day recovery, and also substantially lowered total cholesterol and LDL (“bad”) cholesterol.  
Food & Function. 2014 Nov 19;5(12):3281-6. (Caselato-Sousa V M et al.).

Whole Grains Associated with Improved Bone Mineral Density

Low bone mineral density causes bones to become weaker, increasing the chance of fractures and osteoporosis. To determine the relationship between diet and bone health, researchers analyzed the food intakes and bone mineral density of over 1800 Korean adults. Four different dietary patterns emerged from this data (rice and kimchi; eggs, meat, and flour; fruit, milk, and whole grains; and fast food and soda). The ‘fruit, milk and whole grains’ pattern was associated with higher bone mineral density at multiple sites for both men and women, while ‘rice and kimchi’ pattern was only associated with higher bone mineral density in the arms. The other food patterns were not linked with bone health.
European Journal of Clinical Nutrition. 2014 Nov 5. [Epub ahead of print] (Shin S et al.)

Whole Grain Rye May Improve Cholesterol

Rye, the principal grain consumed in traditional Scandinavian diets, is a fiber-rich food associated with satiety, weight management, and blood sugar control. In a European study, 158 people were assigned to either a standard Nordic diet (with lots of refined grains) or a healthy Nordic diet (rich in whole grains, fruits, vegetables, and low fat dairy) consuming their usual calorie level. Whole grain wheat and rye intake was verified using blood biomarkers. Researchers found that a high intake of whole grain rye (as measured using a plasma biomarker) was associated with decreased LDL (“bad” cholesterol), and an improved LDL to HDL ratio, while the biomarker for whole wheat consumption was not associated with any change in cholesterol.
PLoS One. 2014 Oct 23;9(10):e110827. (Magnusdottir OK et al.)

Antioxidants in Whole Wheat Unaffected During Baking

Whole grains are starting to gain recognition as being rich sources of antioxidants, but many wonder if these antioxidants are affected during processing, such as bread baking. To test this theory, scientists at the University of Maryland measured phenolic acid (antioxidant) content in flour, dough, and bread fractions from three whole and refined wheat varieties. As expected, “all phenolic acids measured were more abundant in whole wheat than refined samples.” The researchers also found no significant change in antioxidant levels after the breads were baked. “Thus, the potential phytochemical health benefits of total phenolic acids appear to be preserved during bread baking.”
Journal of Agricultural and Food Chemistry. 2014 Oct 20 [Epub ahead of print] (Lu Y et al.)

Whole Grains Promote Healthy Gut Microbes

Low diversity of gut microbes is associated with obesity and disease, so it’s important for any healthy diet to increase the variety of these friendly bacteria. In a study in Europe, 20 healthy adults were placed on a 3-week diet rich in whole grains (about 40g fiber, mostly from bread and muesli, and less than 2oz red meat) and a 3-week diet rich in red meat (at least 7oz red meat, and minimal fiber), with a 3-week washout in between. After the red meat diet, diversity of gut microbes remained stable, but after the whole grain diet, the diversity significantly increased. Additionally, although the diets were designed to be isocaloric (meaning that both diets had the same amount of calories), the whole grain intervention produced statistically significant decreases in BMI, weight, and body fat mass, leading researchers to hypothesize that “WG products influence energy utilization.”
PLoS One. 2014 Oct 9;9(10):e109606. (Foerster J et al.)

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