Refined grains

The link between whole grains and colorectal cancer prevention is well established, but researchers wonder how this relationship plays out in patients who have already been diagnosed with colon cancer. In this study, researchers analyzed the eating habits and health status of 1,024 patients with stage III colon cancer. After 7 years, patients eating 3 or more servings of refined grains per day had a significantly higher risk of cancer reoccurrence or death from any cause. Replacing 1 serving of refined grains with 1 serving of whole grains daily was linked with a 23% lower risk of cancer reoccurrence or death from any cause. Eating 3 or more servings of whole grains daily trended towards lower risk as well, but the relationship was not statistically significant.
JNCI Cancer Spectrum. 2018 Feb;2(2):pky017. (Brown JC et al.)

Carbohydrates are the building blocks of a balanced diet, but not all carbs are created equal. To see how diet might relate to bladder cancer risk, researchers analyzed the diets of 578 adults with bladder cancer and 608 controls without bladder cancer. Those regularly eating high glycemic index and glycemic load foods (foods that are more rapidly absorbed into the bloodstream, thus spiking your blood sugar) were more likely to have bladder cancer, as were those who regularly ate refined grains like bread and pasta. However, these results were not as strong in people who regularly eat vegetables. People who regularly eat whole grains and/or legumes tended to be less likely to have bladder cancer, but the results were not statistically significant.
British Journal of Nutrition. 2017 Nov;118(9):722-729. (Augustin LSA et al.)

Why worry about calorie counting when whole grains can keep you satiated and help you lose weight? Researchers randomly assigned 50 Danish adults to a whole grain or refined grain diet for 8 weeks each, with a 6-week washout period in between. All of the participants were overweight, obese or had large waist sizes, and also had slightly high levels of blood sugar, cholesterol, or blood pressure before the study. The participants lost significantly more weight on the whole grain diet (- 0.4 pounds) compared to the refined grain diet (+ 2 pounds). This is likely because people naturally ate fewer calories on the whole grain diet, as whole grains are more satiating. Additionally, the whole grain diet (especially rye foods) significantly lowered inflammation (measured by IL-6 and CRP). However, the researchers noted no significant changes in insulin sensitivity (an indicator of how well your body is able to manage blood sugar), or the gut microbiome over the 8-week study.
Gut. 2017 Nov 1. pii: gutjnl-2017-314786. [Epub ahead of print.] (Roager HM et al.)  

Wholesome plant foods are the foundation of a healthy diet, but not all “vegetarian” foods are equally nutritious. To see how different variations of plant-based diets relate to the risk of developing coronary heart disease (when plaque builds and hardens in the heart’s major blood vessels and decreases blood flow), researchers analyzed data detailing what more than 200,000 people ate over 20 years and separated people into three versions of plant based diets: overall plant-based diet (includes all plant foods and some animal foods), healthful plant-based diet (includes healthy plant foods like whole grains, fruits, and vegetables), and unhealthful plant-based diet (includes sugar-sweetened drinks and refined grains). Not surprisingly, they found that the second choice – eating fewer animal foods and more healthy plant foods – was linked with a lower risk of developing coronary heart disease, while eating more animal foods and more unhealthy plant foods was linked with an increased chance of developing coronary heart disease.
Journal of the American College of Cardiology. 2017 July; 70(4):411-422. (Satija et al.)

Whole grains are thought to help prevent type 2 diabetes, but researchers want to learn more about this protective effect. In a review of 14 randomized controlled studies, scientists found that whole grain foods led to better post-meal blood sugar management than refined grain foods. However, the medium- and long-term effects (6 weeks or more) on fasting blood sugar were not significantly different between whole grain and refined grain meals. 
Nutrients. 2017 Jul 19;9(7). pii: E769. (Marventano S et al.)

Foods that moms choose during pregnancy may have an impact on their children’s health down the line. In a study of more than 500 mother-child pairs in Denmark, in which all of the moms were diagnosed with gestational diabetes (diabetes during pregnancy), Harvard researchers found that substituting 1 serving of refined grains per day with whole grains in the mom’s diet during pregnancy was associated with a 10% lower risk of the child being overweight or obese at age 7. They also found that eating more than 4.3 servings of refined grains per day during pregnancy was linked with nearly double the risk of children becoming overweight or obese at age 7 compared to those who ate fewer than 1.8 servings of refined grains per day. These results were especially strong in kids who were breastfed for less than 6 months.
American Journal of Clinical Nutrition. 2017 June 7. [Epub ahead of print.] (Zhu Y et al.)

Healthy diets nourish both people and the planet, and the savings can be quite impressive. Scientists in California created models to analyze how greenhouse gas emissions and healthcare costs might change if we decrease red & processed meat and refined grains in our standard US diet, and shift to eat more beans and peas, whole grains, fruits, and vegetables. The researchers found that opting for the healthier diets can reduce risk of heart disease, colorectal cancer, and type 2 diabetes by 20-40%, saving the US $77-93 billion per year in healthcare. These shifts can also lower greenhouse gas emissions by 222-826 kg CO2, which is equivalent to 6-23% of the US Climate Action Plan’s target. Climatic Change. 2017 Mar 6. [Epub] (Hallstrom E et al.)

Grains have been at the core of traditional diets for millennia, but some misguided celebrities and fad diets have moved away from this tradition. Using national health survey data from 9,341 adults in Australia, researchers found that those avoiding core grain foods were significantly more likely to be overweight or obese than those who eat grains, despite consuming fewer calories, fruits, vegetables and less fiber than grain eaters. After adjusting for age, sex, and calorie intake, avoiding grains was also linked with a higher BMI and waist size.
Nutrients. 2017 Feb 18;9(2). pii: E157. (Fayet-Moore F et al.)

Whole grains are often associated with lower body weights, and new research is uncovering why. In a randomized trial, scientists assigned 81 healthy adults in Boston to diets with either whole grains or refined grains for 6 weeks, keeping all other foods and nutrients consistent between the groups. Although the diets were designed to be isocaloric (meaning that people were supposed to maintain their same body weight), the resting metabolic rate (how many calories your body burns at rest) became significantly higher (by 43 calories) in the whole grain group. In fact, the whole grain group significantly improved their metabolism over the 6-week study compared with the refined grains group, burning 92 more calories per day. The researchers suspect that this is partly due to the fact that the whole grain group excreted more energy in the stool, and had more frequent bowel movements.
American Journal of Clinical Nutrition. 2017 Feb 8. pii: ajcn139683. [Epub ahead of print.] (Karl JP et al.)

Researchers randomly assigned 81 healthy adults in Boston to diets with either whole grains or refined grains for 6 weeks, keeping all other foods and nutrients consistent between the groups. The researchers found that making all of your grains whole is linked with “modest, positive effects on gut micriobiota,” (due to higher concentrations of “good” gut microbes and short chain fatty acids – an indicator of colon health and dietary fiber breakdown) as well as increased stool weight and stool frequency.
American Journal of Clinical Nutrition. 2017 Feb 8. pii: ajcn146928. [Epub ahead of print.] (Vanegas SM et al.)