Refined grains

White rice has displaced many traditional whole grains across Asia, so researchers wonder how white rice might relate to diabetes risk. In a study of 45,411 Chinese adults followed for 11 years, researchers found that replacing white rice with white bread and whole grain bread can reduce type 2 diabetes risk by 10% and 18% respectively, and that replacing white rice with noodles, red meat, or poultry might actually increase diabetes risk. Rice intake itself was not associated with higher type 2 diabetes. The authors conclude that “recommendations to reduce high white rice consumption in Asian populations for the prevention of [type 2 diabetes] may only be effective if substitute foods are considered carefully.”
European Journal of Nutrition. 2018 Dec 10. doi: 10.1007/s00394-018-1879-7. [Epub ahead of print] (Seah JYH et al.)

For decades, experts have debated the merits of a low-fat versus a low-carb diet. In this review, nutrition scientists of widely varying perspectives detailed evidence supporting both low-fat and low-carb diets, as well as points of consensus they could agree on. The experts agreed that carbohydrate quality (whole grains and low Glycemic Index foods over refined grains and sugars) and fat quality (unsaturated fats over trans fats and saturated fats) are much more important than the amount of carbohydrates or fat in the diet.
Science. 2018 Nov 16;362(6416):764-770. doi: 10.1126/science.aau2096. (Ludwig DS et al.)

Many parents buy gluten-free foods for their kids because they think that those foods are healthier. But unless you have a medically-diagnosed reason to avoid gluten (such as celiac disease), evidence suggests otherwise. Researchers in Canada went to 2 major supermarket chains and purchased all foods marketed to kids (with the exception of candy, soda, and a few other “junk foods”) – 374 products total. They then analyzed the nutrition labels of the foods, to see how products marketed as gluten free stacked up to those not marketed as gluten free. For a more direct comparison, they then identified 43 gluten-free foods marketed to kids that had a non-gluten-free counterpart, and compared nutrition between the matched products. Overall, nutrition was poor among all kids’ products, gluten-free or not, and there were few significant differences. Specifically, products marketed as gluten-free had slightly lower levels of sodium, but slightly higher levels of added sugar. Additionally, a higher proportion of gluten-free products had high levels of trans fat. The researchers concluded that “[gluten-free] supermarket foods that are targeted at children are not nutritionally superior to regular child targeted foods and may be of greater potential concern because of their sugar content,” adding that “parents who substitute [gluten-free] products for their product equivalents (assuming [gluten-free] products to be healthier) are mistaken.”
Pediatrics. 2018 Aug;142(2). pii: e20180525. (Elliott C et al.)

Sugar build up between your teeth can cause cavities and other dental problems, but certain food choices can have a protective effect. To see how different carbohydrates play a role, researchers analyzed 28 studies comparing rapidly digestible starches (refined grains) to slowly digestible starches (whole grains). Some evidence suggests that whole grains lower the risk of oral cancer and gum infection (periodontitis), and that refined grains may significantly increase cavities, but more research is needed. The researchers conclude that “the best available evidence suggests that only [rapidly digestible starches] adversely affects oral health.”
Journal of Dental Research.  2018 Aug 3. [Epub ahead of print.] (Halvorsrud K et al.)

Though many Paleo dieters believe that bread is a relatively “new” foodstuff, archeological evidence paints a different picture of what ancient diets were like for our hunting and gathering ancestors. Archeologists analyzed the remains of ancient fireplaces in what is today Jordan, and found the oldest empirical evidence of bread-like products from 14,400 years ago. These ancient flatbreads existed 4,000 years before Neolithic agriculture, and challenge previous assumptions about grains’ role (or lack thereof) in ancient, Epipaleolithic diets.
Proceedings of the National Academy of Sciences. 2018 Jul 31;115(31):7925-7930. (Arranz-Otaegui A et al.)

While some processing methods can improve the nutrition of food, some can also detract from it. To see how the nutrients in corn are impacted as corn is processed into cornflakes breakfast cereal, researchers analyzed the nutrient content at 5 points throughout the process (whole kernel, flaked grit, cooked grit, baked grit, and toasted cornflake). The scientists found that a large drop-off in phenolic acid (healthy phytochemicals that have antioxidant properties) occurred after the whole kernel was milled into flaked grits, when the bran and germ were removed. Smaller losses occurred at other points in the processing method as well, but were not as staggering.
Journal of Visualized Experiments. 2018 Jun 16;(136). (Butts-Wilmsmeyer C et al.)

Visceral fat is a dangerous type of abdominal fat that can surround vital organs like the liver. To see if grain choices might play a role in this fat distribution, researchers randomly assigned 50 Japanese men with a BMI of 23 or greater (midway through the “healthy weight” range or heavier) to a diet with whole grain bread or white bread for 12 weeks, and had their visceral fat estimated using tomography scans. After the 12-week study, the whole grain group lost 4 cm of visceral fat around their middle, while the white bread group showed no significant changes.
Plant Foods and Human Nutrition. 2018 Apr 18. [Epub ahead of print.] (Kikuchi Y et al.)

Refined wheat and rice noodles are common staple foods throughout Asia today, so replacing some of these foods with whole grain versions could go a long way in improving health. To test the impact, researchers randomly assigned 84 healthy adults (some with mildly high cholesterol) in Taiwan to an oat noodle group or a refined wheat noodle group, providing them with 100 grams (about 1 ½ cups cooked) of their respective noodles across 1 or 2 meals each day for 10 weeks. After the 10-week study, the oat group reduced their total cholesterol by 17% and LDL-c (“bad”) cholesterol by 19% compared with the wheat noodle group. The oat noodle group also significantly lowered their blood pressure by 7-11%, but the wheat noodle group did not. The benefits tended to be stronger in people who started the study with slightly high cholesterol, but the results were still statistically significant for the group as a whole.
Journal of Food and Drug Analysis. 2018 April. [Epub ahead of print.] (Liao MY et al.)

It’s important to get your fiber from a variety of foods, since different sources of fiber are associated with different health benefits. Researchers analyzed the eating patterns of 2,135 patients with breast cancer and 2,571 controls to see how different foods and fibers might relate to breast cancer risk. Those eating the most fiber (more than 26.5 grams per day) were 25% less likely to have breast cancer than those eating less than 15.2 grams of fiber per day. Similarly, those eating the most beans (more than 3.9 oz per day) and grains (more than 13.8 oz per day, of both whole and refined grains) were 19% and 18% less likely to have breast cancer, respectively, than those eating the least amount of beans and grains.
Cancer Medicine. 2018 Mar 23. [Epub ahead of print] (Sangaramoorthy M et al.)

In the US, most refined grains are enriched with high levels of folic acid, to help prevent neural tube defects in children, such as spina bifida. However, new research raises questions about the benefits of high levels of synthetic folate in children. In a study of 1,394 children, the kids who developed food allergies were found to have higher levels of UMFA, which is a derivative of synthetic folate. The authors conclude that “more research is needed to conclude whether mothers should consider consuming different sources of folate, like leafy green vegetables, citrus fruits, beans or lentils instead of synthetic forms of folate.” (Note that findings presented at meetings are typically viewed as preliminary until they’ve been published in a peer-reviewed journal.)
Presented at American Academy of Allergy, Asthma, & Immunology Annual Meeting. Orlando, Florida. March 2-5, 2018.