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.


Regular Whole Grain Consumption May Reduce Breast Cancer Risk

Eating whole grains daily may help keep breast cancer at bay. Approximately 1 in 8 women are diagnosed with breast cancer, and lifestyle factors are thought to play an important role in prevention. To determine the relationship between eating patterns and breast cancer, researchers analyzed the diets of 250 newly diagnosed female breast cancer patients, and 250 age-matched controls (without cancer). The scientists found that eating whole grains at least 7 times per week was associated with a decreased risk of breast cancer.
Journal of the American College of Nutrition. 2015 Apr 27:1-7 [Epub ahead of print] (Mourouti N et al.)

Whole Grains and Cereal Fiber Linked with Longevity

A growing body of research suggests that whole grains may help you live longer. Boston scientists analyzed data from over 367,000 adults, and found that those with the highest intake of whole grains had a 17% lower risk of death from all causes compared to those who ate the least whole grains. Additionally, those eating the most whole grains had a lower risk of several disease-specific deaths, ranging from 11% for respiratory disease, up to 48% for diabetes. Similarly, a high intake of cereal fiber (the fiber from grain foods) was associated with a 19% lower risk of death from all causes, and a 25-34% lower risk of disease specific deaths. Whole grains offer a healthy diversity of protective nutrients, and this research suggests that cereal fiber is certainly among them.
BMC Medicine
. 2015 Mar 4;13:59 (Huang T et al.)

Whole Grain Intake May Decrease Heart Disease Risk

Heart disease is the leading cause of death in the US and other industrialized countries, so lifestyle changes, including diet, are important. To analyze the link between whole grain intake and coronary heart disease, Chinese researchers combined the results of eighteen different studies following over 400,000 people. The pooled results of their analysis suggest that a higher intake of whole grains is associated with a reduced risk for coronary heart disease. These results were significant in the fifteen cohort studies included (which followed subjects over a period of time to track how diet influenced their health), but not in the three case-control studies (which started with coronary heart disease cases and matched controls, then attempted to trace back the lifestyle differences between these groups). This study adds to the growing body of evidence that whole grains are a heart-healthy choice.
American Journal of Cardiology. 2015 Mar 1;115(5):625-629. (Tang G et al.) 

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.)

Habitual Refined Grain Consumers Shift Preferences to Whole Grains

In a small European study, researchers supplied 33 adults who rarely eat whole grains (less than one ounce per day) with diet advice and a variety of whole grain foods. The participants increased their whole grain intake by 500% for six weeks (averaging six ounces per day) so that the scientists could assess diet’s relationship with gut bacteria, body fat and blood chemistry (like blood pressure and cholesterol). While the scientists found no significant health changes during this short-term experiment, what was remarkable is how the participants’ attitudes towards whole grains changed throughout the study. According to the researchers, nearly two thirds (65%) of the participants who provided post study data said they now prefer whole grains, “citing benefits such as improved bowel movements and appetite suppression, as well as taste.” Additionally, “the majority of subjects reported that it was not difficult to achieve the required level,” and a whopping 76% of subjects intend to continue eating and purchasing whole grains.
The Journal of Nutrition. 2015 Feb;145(2):215-21 (Ampatzoglou A et al.)

Diet with Whole Grains May Reduce Alzheimer’s Risk

It appears that a ‘grain brain’ may be protective against Alzheimer’s. Researchers studied the relationship between eating patterns and Alzheimer’s in 923 retired adults in Chicago over an average of 4.5 years.  The scientists rated participants’ diets based on how closely they adhered to the Mediterranean diet, the DASH diet (a healthy diet used to treat hypertension that emphasizes fruits, vegetables, whole grains, low fat dairy, and limited sweets and salt) and the MIND diet. The MIND diet is a hybrid Mediterranean-DASH diet that emphasizes foods associated with brain health, including 3 servings per day of whole grains (more than any other food group), along with green leafy vegetables, berries, nuts, olive oil, and fish. The groups most closely following either the MIND diet or the Mediterranean diet cut their risk of Alzheimer’s dementia by more than half (53% for MIND and 54% for Mediterranean), while those closely following the DASH diet were 39% less likely to develop Alzheimer’s. Even those moderately following the MIND diet were at a 35% lower risk.
Alzheimer’s and Dementia. 2015 Feb 11. pii: S1552-5260(15)00017-5. [Epub ahead of print] (Morris MC 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.)

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