Whole grains

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.)

Because colorectal cancer forms in the large intestine, diet is thought to be a potential risk factor. To see how food fits into the puzzle, scientists at Harvard analyzed the eating patterns and health markers of 137,217 adults for more than two decades. Those eating a healthy diet rich in fiber and whole grains were significantly less likely to develop a certain type of colorectal cancer (Fusobacterium nucleatum–positive, but not Fusobacterium nucleatum-negative) than those eating a “Western diet” rich in red meat, refined grains, and dessert. Fusobacterium nucleatum is a type of gut bacteria thought to contribute to colorectal cancer, as it’s often elevated in colorectal cancer patients. Based on their findings, the scientists suspect that the cancer-protective effect of fiber and whole grains may have to do with their role in improving the gut microbiome.
JAMA Oncology.  2017 Jan 26. [Epub ahead of print.] (Mehta RS)

Early exposure to whole grain foods can shape food preferences later in life, so researchers wonder if it may be worthwhile to start with infants. Infant cereals are one of the first solid foods given to babies to compliment breast milk or formula and are often made from refined grains like white rice or pearled barley. In this study, researchers in Spain worked with parents of 81 infants (4-24 months old) to test the acceptability of 30% whole grain infant cereals (made with whole wheat), compared with a popular refined infant cereal. (Whole wheat was chosen to comply with European infant legislation, to make sure that the amount of fiber was appropriate.) After trying each of the cereals for 3 days in a row, infants were just as likely to accept and finish the whole grain cereal as they were the refined cereal. The researchers concluded that infant cereals are an opportunity to expose young people to whole grains earlier in life, to build a taste for them.
Nutrients. 2017 Jan 13;9(1). pii: E65. (Haro-Vicente JF et al.)

Good dental hygiene is essential for healthy gums, but the foods we eat might help protect us against gum disease as well. To see how eating patterns relate to gum health. researchers analyzed national survey data from 6052 US adults. They found that people eating at least 1.5 servings of whole grains per day were significantly less likely to have severe gum disease than those not eating whole grains. Similarly, those eating fewer than 12 grams fiber per day were 27% more likely to have increasing severity of gum disease. However, fruit and vegetable intake was not significantly related to gum health.
The Journal of Nutrition. 2016 Dec;146(12):2530-2536. (Nielsen SJ et al.)   

Fat is essential to the diet, but certain fats are better than others. Scientists analyzed the eating patterns and health outcomes of more than 115,000 men and women in the Nurse’s Health Study and the Health Professionals Follow Up Study. The scientists found that those eating the most saturated fats (the types of fats found in red meat, butter, and milk) were more likely to get heart disease over the 24-28 year study period. In fact, replacing just 1% of calories from saturated fat with the same amount of calories from whole grains, polyunsaturated fats (found in fish, nuts, and seeds), or plant proteins (such as beans or nuts) is linked with a 6-8% lower risk of heart disease. The scientists conclude that “dietary recommendations for the prevention of coronary heart disease should continue to focus on replacing total saturated fat with more healthy sources of energy.”
British Medical Journal. 2016 Nov; 355:i5796. (G Zong et al.)

In a small study, researchers assigned overweight and obese adults in Ohio to one of two diets for 8 weeks, one with whole grains, one with refined grains. After going back to their normal diet for 10 weeks as a washout, the 33 participants then switched diets, serving as their own control. Both diet groups lost weight and body fat, and lowered their systolic blood pressure (the top number in a blood pressure reading), total cholesterol, and LDL (“bad”) cholesterol. The scientists also found that the whole grain diet reduced diastolic blood pressure (the bottom number in the blood pressure reading) by 5.8 mm Hg, “or an additional 4.2 mm Hg beyond any change attributable to weight loss.” According to the researchers, this improvement, which was 3-fold greater in the whole grain group than the refined grain group, “approximates to a 40% lower risk of dying from stroke and a 30% lower risk of dying from ischemic heart disease or other vascular causes.”  
The Journal of Nutrition. 2016 Oct 19. pii: jn230508. [Epub ahead of print] (Kirwan JP et al.)

Pre-diabetes can increase the risk of diabetes and heart disease, so understanding lifestyle factors is important. To see how diet relates to pre-diabetes, scientists analyzed the eating habits of 150 pre-diabetic adults in Iran, and 150 healthy, matched controls. Two distinct eating patterns emerged: the “vegetable, fruit, legume” pattern, with lots of plant foods including produce, whole grains, nuts, low fat dairy, and fish, and the “sweet, solid fat, meat, and mayonnaise” pattern, with lots desserts, red meat, fried potatoes, and solid fats. Those whose diets more aligned with the “vegetable, fruit, legume” pattern were significantly less likely to be pre-diabetic than those whose diets more closely resembled the “sweet, solid fat, meat, and mayonnaise” pattern.
British Journal of Nutrition. 2016 Sep;116(5):874-81. (Bagheri F et al.)