Whole grains are important to our brain health today, but new evidence suggests that they were also vital to our brain development millions of years ago. Researchers in Europe and Australia examined diet’s role in the development of early humans, and found that carbohydrates (such as whole grains, root vegetables, and other starchy plant foods) were “necessary to accommodate the increased metabolic demands of a growing brain.” While most depictions of early human foods emphasize hunter-gatherer diets full of meat, the scientists argue that cooked starches permitted “the acceleration in brain size increase from the Middle Pleistocene onward.”
The Quarterly Review of Biology. 2015 Sept;90(3):251-268. (Hardy K et al.)

Even modest reductions in cholesterol are thought to help prevent heart disease, so heart healthy diets are an important area of research. To determine the link between whole grains and cholesterol, scientists analyzed the results of 24 randomized controlled trials (totaling 2,275 participants). They found that eating whole grains is associated with lower LDL (“bad”) cholesterol and total cholesterol, with no significant effect on HDL (“good”) cholesterol or triglycerides (a type of fat in the blood). Whole grain oats specifically seemed to be linked with the greatest cholesterol lowering effects compared to other whole grain foods. The length of the study was also associated with positive changes in cholesterol, indicating health benefits are greater for those who make whole grains a regular part of their daily lifestyle.
The American Journal of Clinical Nutrition. 2015 Sept;102(3):556-72. (Hollaender PLB et al.)

It is estimated that up to 80% of strokes can be prevented, so food choices to protect against strokes are an important area of research. Scientists in China analyzed six large prospective studies following over 247,000 people to see how whole grain intake related to stroke risk. Those eating the most whole grains had a 14% lower risk of stroke than those eating the least whole grains. The authors concluded that “higher whole grain intake has a protective effect on stroke.”
International Journal of Clinical and Experimental Medicine. 2015 Sep 15;8(9):16978-83 (Fang L et al.)

Complications from diabetes can lead to serious health problems, including vision impairment, blindness, and kidney damage. Using data from the PREDIMED study (where adults at risk for heart disease were assigned to either a low fat diet, a Mediterranean diet with olive oil, or a Mediterranean diet with nuts), researchers analyzed data from over 3,600 Spanish adults with type 2 diabetes, to see how diet affects the risk of diabetic nephropathy (kidney damage from diabetes) or diabetic retinopathy (eye damage from diabetes). Those following a Mediterranean diet with olive oil had a 43% lower risk of diabetic retinopathy compared to the low fat control group, and those following a Mediterranean diet with nuts had a non-significant 38% lower risk of diabetic retinopathy. There were no significant changes in the risk for diabetic nephropathy.
Diabetes Care. 2015 Sept 13. [Epub ahead of print] (Diaz-Lopez A et al.)

Fish is well known for its place in many of the healthiest diets around the world. To determine the link between eating fish and depression risk, Chinese scientists reviewed 26 studies of over 150,000 people. The researchers concluded that “high fish consumption can reduce the risk of depression.”  
Journal of Epidemiology and Community Health. 2015 Sep 10. pii: jech-2015-206278. [Epub ahead of print.] (Li Fu et al.)

Congenital heart defects (heart problems that occur before birth) affect nearly 1% of newborns in America. In a study of over 19,000 American women, researchers compared mothers of babies with congenital heart defects to mothers of babies without this condition. Scientists analyzed the mothers’ diets in the year before pregnancy using both the Mediterranean Diet Score and the Diet Quality Index for Pregnancy. Babies whose moms’ diets ranked healthy on both scores were significantly less likely to suffer from certain specific subgroups of congenital heart defects, such as tetralogy of Fallot (a defect in heart structure which causes oxygen poor blood to flow throughout the body), but not all heart defects. The relationship between diet and congenital heart defects was stronger with the Diet Quality Index for Pregnancy than with the Mediterranean Diet.
Archives of Disease in Childhood. Fetal and Neonatal Edition. 2015 August 24. pii: fetalneonatal-2014-308013. [Epub ahead of print.] (Botto LD et al.) 

Whole grains are well known for their fiber; however, fiber is not the only benefit of a diet rich in whole grains. This study uses nutritional metabolomics (a field of that looks at how different foods affect metabolism) to explore how the different compounds in whole grains may affect metabolism, and suggests scientific reasons behind the health benefits of whole grains, beyond just their fiber content. Specifically, this analysis suggests that whole grains may have positive effects on insulin sensitivity and protein metabolism, and may contain other beneficial compounds, such as glycine betaine.
Proceedings of the Nutrition Society. 2015 Aug;74(3):320-7. doi: 10.1017/S0029665114001542. Epub 2014 Oct 23. (Ross AB et al.)

Phytates are compounds found in many plant foods, especially in beans and whole grains. Although phytates are linked with health benefits, they can also block the absorption of non-heme iron (the type of iron found in beans and other plant sources). To see how eating these phytate-rich foods affects nutrition status, scientists in Iowa assigned 28 non-anemic young women to either a high phytate (lots of whole grains, beans, nuts, and tofu) or low phytate (refined grains, eggs, and cheese, avoiding high phytate foods) diet for eight weeks, then tested their iron levels. After consuming a high phytate diet for 8 weeks, there was a 41% increase in serum iron response (measured by area under the curve). This indicates that “habitual consumption of [a high phytate] diet can reduce the negative effect of phytate on non-heme iron absorption among young women with sub-optimal iron stores.”
Journal of Nutrition. 2015 Aug;145(8):1735-9. (Armah SM et al.)

Palmitic acid (found in palm oil, shortening, butter, and red meat) is a type of saturated fat prevalent in the Western diet, while oleic acid (found in olive oil) is a type of monounsaturated fat prevalent in the Mediterranean diet. In a small study, researchers at the University of Vermont fed 16 adults either a diet high in palmitic acid or a diet high in oleic acid and low in palmitic acid to see how food choices affect the inflammatory response of various cells. All adults spent 3 weeks in each diet group, serving as their own control.  Although insulin sensitivity was not affected in this experiment, the scientists found that changing the diet to include more oleic acid and less palmitic acid was able to lower activation of certain cell signaling proteins (including TLR4 and NLRP3) that are associated with inflammation, oxidation and poor insulin signaling. These results suggest that shifting from a Western diet to a Mediterranean style diet (with greater proportions of oleic acid) may help fight inflammation.
Journal of Nutritional Biochemistry. 2015 Aug 1. pii: S0955-2863(15)00178-3. (Kien CL et al.)

Whole grains (like rye, oats, and whole wheat) have a strong history in traditional Scandinavian cuisine, but as in other regions, the food landscape is changing and refined grains have replaced some traditional foods. To see how eating whole grains relates to mortality, researchers analyzed the diets of over 120,000 people in Denmark, Norway, and Sweden.  The scientists found that those who ate the most whole grains had significantly lower risk of death from all causes. When analyzing individual whole grains, the researchers found significantly lower mortality rates in those who ate the most whole grain breakfast cereals, whole grain bread, oats, rye (only statistically significant for men), and whole wheat. These findings support existing evidence that whole grains may contribute to longevity.
British Journal of Nutrition. 2015 July 23:1-16. (Johnsen NF et al.) [Epub ahead of print]

In a small Italian study, researchers assigned 25 healthy adults to a Mediterranean meal (pasta, chicken breast, salad, bread, and an apple) prepared either with or without olive oil, then measured their cholesterol and blood sugar. After 30 days, the participants switched groups and ate the other meal, serving as their own control. The scientists found that 2 hours after eating, the meal without olive oil was associated with higher glucose and insulin levels, as well as higher “bad cholesterol” (LDL-C). In the second part of the experiment, the participants were assigned to a Mediterranean meal prepared with either olive oil or corn oil, switching groups after a 30 day washout period. Their blood sugar and cholesterol was tested after the meals as well. Two hours after eating, the meals with olive oil were associated with a lower increase in blood sugar and improved markers of blood sugar control (such as lower DPP, and higher GLP1 & GIP), as well as a smaller increase in “bad cholesterol” (LDL-C and oxidized LDL). These experiments indicate that meals with olive oil can help regulate blood sugar, and may help improve cholesterol.
Nutrition & Diabetes. 2015 July 20;5:e172. [Epub ahead of print.] (Violi F et al.)

Evidence is mounting that the healthiest diets are built around a variety of minimally processed, whole foods, and can’t be reduced to specific nutrients. To determine saturated fat’s role in heart disease risk, researchers from California reviewed the existing literature about saturated fats, polyunsaturated fats, carbohydrates, and heart disease. The scientists found that when saturated fat (found mostly in red meat and milk fat) is replaced with polyunsaturated fat (found mostly in nuts, seeds, and fish), heart disease risk decreases. However, when saturated fat is replaced with sugary refined carbohydrates, heart disease risk remains the same, if not worsens. The researchers also note a small, yet growing body of research that dairy fat (especially in fermented dairy, like yogurt), may be neutral (or even decrease risk) for heart disease. The researchers concluded that “overall dietary patterns emphasizing vegetables, fish, nuts, and whole versus processed grains form the basis of heart-healthy eating, and should supersede a focus on macronutrient composition.”
Annual Review of Nutrition. 2015 July 17;35:517-43. (Siri-Tarino PW et al.) [Epub]