Being overweight or obese is linked with higher levels of systemic inflammation, which is now recognised as an underlying risk factor of heart disease and diabetes in the long term. A recently published study reinforces the benefits of children consuming whole grains finding that a whole grain-rich diet lowered biomarkers of inflammation in overweight and obese children.(1) With one in four Australian children currently overweight or obese, and likely to be experiencing high levels of inflammation, this is another potential benefit from enjoying whole grain foods more often.
Whole grain foods contain a number of bioactive components which may work to reduce inflammation including vitamins B and E, magnesium, selenium, zinc, fibre and other phytonutrients.(1) Being such nutrient dense foods, researchers have been keen to investigate the impact of whole grains on inflammation, however until now studies had focused on adults not children.
This recent study included 44 overweight or obese Iranian girls aged 8–15 years who were randomly assigned to either a group which was encouraged to obtain half of their daily grain serves from whole grain foods for six weeks or a control group who were instructed to eat refined grain foods only, and avoid whole grain foods. After the initial six week period each participant was then instructed to avoid whole grain foods during a four week ‘washout period’ before crossing over to the alternate group for an additional six weeks.
While participants were assigned to the whole grain arm of the study they ate an average of 98 grams of whole grain foods each day from a wide variety of whole grain foods, which was one half of their total grain food intake. Converted to serves this equates to around 3 serves of whole grain foods each day, where one serve is equal to 1 slice of bread, 2/3 cup of flaked breakfast cereal or ½ cup cooked brown rice, oats.
Based on the blood measurements taken at the end of the six week diets, the authors found that consumption of whole grain foods significantly reduced levels of inflammatory biomarkers including C-reactive protein (CRP) and leptin in overweight and obese children.
What have other studies reported?
Previously observational studies have indicated an association between diets high in whole grains and lower CRP levels, a marker of inflammation.(2, 3) While this most recent study in overweight children found that a whole grain rich diet significantly reduced markers of inflammation, other intervention studies in adults have not yet clearly demonstrated this effect.(2, 3) Where possible it is also important that associations identified in observational studies are then compared with interventional studies to allow an interpretation of cause and effect.
What to make of this?
There are limited studies on this topic and, as is the case in many areas of nutrition science, “more research is needed” before conclusions can be drawn about the mechanisms by which whole grains may protect health and potentially lower inflammation.
Despite this gap, observational studies consistently link higher intakes of whole grains with reduced risk of heart disease, diabetes, obesity and some cancers.(4, 5) Whilst more research is needed, Australians should heed the Australian Dietary Guidelines and aim to make at least half their grain foods choices whole grain or high fibre within a balanced diet.
References:
- Hajihashemi P, Azadbakht L, Hashemipor M, Kelishadi R, Esmaillzadeh A. Whole-grain intake favorably affects markers of systemic inflammation in obese children: A randomized controlled crossover clinical trial. Molecular nutrition & food research. 2014;58(6):1301-8.
- Lefevre M, Jonnalagadda S. Effect of whole grains on markers of subclinical inflammation. Nutrition reviews. 2012;70(7):387-96.
- Buyken AE, Goletzke J, Joslowski G, Felbick A, Cheng G, Herder C, et al. Association between carbohydrate quality and inflammatory markers: systematic review of observational and interventional studies. The American journal of clinical nutrition. 2014;99(4):813-33.
- NHMRC. Australian Dietary Guidelines Providing the scientific evidence for healthier Australian diets. 2013 Accessed online January 2014.
- GLNC. The Grains & Legumes Health Report. Grains & Legumes Nutrition Council, 2010.
