Refined grains

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.)

Harvard researchers followed over 120,000 adults for 24-30 years, tracking their diet and health records. The scientists found that replacing 5% of daily calories from saturated fat (like butter, cream, and red meat) with whole grains is associated with a 9% lower risk of heart disease, but replacing saturated fat with refined grains or added sugars does not lower heart disease risk. Additionally, they found that replacing 5% of daily calories from refined grains and added sugars with whole grains or polyunsaturated fats (found in fish, nuts, seeds, and safflower oil) can also significantly reduce heart disease risk. The researchers concluded, “Our findings provide epidemiological evidence of the current dietary guidelines, which recommend both “replacing saturated fatty acids with monounsaturated and polyunsaturated fatty acids” and “replacing refined grains with whole grains.””
Journal of the American College of Cardiology. 2015 Oct;66(14):1538-48. (Li Y et al.)

It seems that comfort foods like refined sweets might not be so comforting in the long run. Scientists in New York analyzed the eating patterns of nearly 70,000 women without depression across the U.S. , then tracked their health records over three years to see how diet relates to developing depression. The researchers found that both refined grains and added sugars were significantly tied to a higher risk of developing depression over the three year study, while fiber, vegetables, fruit (excluding juice), and lactose (a sugar found in milk) was linked with a significantly lower risk of depression. A higher intake of whole grains was also related to a lower risk of depression, although this relationship was not statistically significant. Overall, foods that contributed to a high glycemic index diet were associated with increased odds of developing depression. 
American Journal of Clinical Nutrition. 2015 Jun 24. [Epub ahead of print] (Gangwisch JE et al.)

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.)

A study commissioned by the Australian Breakfast Cereal Manufacturers Forum analyzed 232 articles to investigate the health benefits and risks of eating cereal. The researchers found that while breakfast cereal consumption of any type is associated with diets higher in vitamins and minerals and lower in fat and a lower body mass index and less risk of being overweight or obese, whole grain breakfast cereal consumption provided even more benefits. Specifically, the study found that oat and barley based cereals can help lower cholesterol, and whole-grain or high-fiber breakfast cereals are associated with a lower risk of diabetes and higher intakes of protein, fiber, niacin, folate, calcium, and zinc. Additionally, the study found that those who eat breakfast cereal regularly have higher whole-grain consumption per day.
Advances in Nutrition. 2014 Sep 15;5(5):636S-73S, (Williams PG et al.)

A team of researchers at the Harvard School of Public Health conducted a meta-analysis of four studies on rice intake and type 2 diabetes, with a total of 352,384 participants. Asian (Chinese and Japanese) people, who ate white rice three to four times per day as compared to Western populations who ate white rice once or twice a week, had a much higher risk of type 2 diabetes.

3977 participants in the Age-Related Eye Disease Study were followed for 8 years by Chung-Jung Chiu and a team at Tufts University, who tracked the glycemic index of their diets and the development of age-related macular degeneration (AMD). The scientists concluded that seniors at risk of AMD may “benefit from consuming a smaller amount of refined carbohydrates.”
American Journal of Clinical Nutrition, October 2007; vol 86(4):1210-8

Nancy Keim and a team at the USDA ARS Western Human Nutrition Center studied 10 women age 20-45 who ate a whole grain diet for three days, then ate the same foods but with refined grains in place of whole grains. Blood samples at the end of each 3-day period showed that the refined grains diet caused a significant increase in triglycerides and a worrisome protein called “apolipoprotein CIII” (apoCIII), both of which have been associated with increased risk of heart disease. A larger study is underway.
Agricultural Research, March 2006, 20-21