Consuming grains is important for our overall health

What is a whole grain?

A wholegrain kernel is made up of an endosperm, germ and bran (1). The bran is a rich source of fibre and the inner germ is packed full of vitamins, minerals, lignans and phytochemicals (1). Sources of whole grains, meaning the grain contains the endosperm, germ and brain include whole wheat, brown rice, oats, rye and barely (1). A process called grain-refining, removes the bran and germ, leaving only the starch rich endosperm (1). This means majority of the vitamins, minerals and fibre are removed, leaving very little nutritional value for the consumer (1). White bread, pasta, rice and cereals are all examples of grains that have been heavily refined, and regular consumption can lead to type 2 diabetes, cardiovascular disease, obesity and colorectal cancer (1).

 

Health benefits of consuming whole grains

High in fibre
Consuming whole grains are a great source of dietary fibre. Whole grains contain either soluble or insoluble fibre (2).  When soluble fibre is consumed, if forms a thick gel like substance, producing many beneficial effects such as slowing the emptying of our stomach, making us feel fuller for longer, assists in reducing cholesterol levels and helping to stabilise blood sugar levels (2). Insoluble fibre absorbs water in the digestive system which helps to regulate bowel movements and maintain a healthy environment in the gut (2).

 

Prebiotic
Many whole grains that contain insoluble fibre produce prebiotic effects on the digestive system (3). Soluble fibres causes fermentation in the gut, this then produces prebiotics and short chain fatty acids which allow the growth of healthy bacteria and provide fuel for the microbiome (3).

 

Control blood sugar levels
Whole grains are a form of complex carbohydrates and generally have a low glycaemic index (GI) (4). This means that when the carbohydrates are consumed, they are converted into sugar and released slowly into the blood, causing sustained energy levels and preventing high spikes of blood glucose levels which is seen in those with type 2 diabetes (4).

 

Reduce risk of cardiovascular disease
Consuming whole grains increases your daily intake of dietary fibre and phytochemicals such as polyphenols and phytosterols that are associated with a lower risk of developing cardiovascular disease and coronary heart disease (5). This is achieved by insoluble fibre fermenting in the large intestine, producing short chain fatty acids which aid in reducing circulating cholesterol levels (5). Grains also contain antioxidants and phytosterols which are great for regulating blood pressure and supporting heart health (5).

Assist in weight management / reduce the risk of obesity
Complex carbohydrates found in whole grains are more satisfying and keep us feeling fuller for longer compared to simple carbohydrates which only satisfies for a short period of time, and therefore wanting to consume more food (6). Soluble fibre contributes towards less weight gain and helps with weight management due to the gel-forming substance that is formed (6). This substance slows the emptying of the stomach and the transit time of food through the digestive system, thus feeling more satisfied (6).

 

Sources of grains: 

Whole grains containing gluten

Barley

Farro

Rye

Semolina

Wheat (including spelt)

 

Gluten free whole grains

Amaranth

Brown/wild rice

Buckwheat

Chia

Corn

Freekah

Millet

Oats (can be contaminated with gluten during processing)

Quinoa

 

 

Reference List

1.           McRae MP. Health Benefits of Dietary Whole Grains: An Umbrella Review of Meta-analyses. J Chiropr Med. 2017 Mar;16(1):10–8.

2.           Dhingra D, Michael M, Rajput H, Patil RT. Dietary fibre in foods: a review. J Food Sci Technol. 2012 Jun;49(3):255–66.

3.           Slavin J. Fiber and prebiotics: mechanisms and health benefits. Nutrients. 2013 Apr 22;5(4):1417–35.

4.           Chen C, Zeng Y, Xu J, Zheng H, Liu J, Fan R, et al. Therapeutic effects of soluble dietary fiber consumption on type 2 diabetes mellitus. Exp Ther Med. 2016 Aug;12(2):1232–42.

5.           Threapleton DE, Greenwood DC, Evans CEL, Cleghorn CL, Nykjaer C, Woodhead C, et al. Dietary fibre intake and risk of cardiovascular disease: systematic review and meta-analysis. BMJ. 2013 Dec 19;347:f6879.

6.           Bozzetto L, Costabile G, Della Pepa G, Ciciola P, Vetrani C, Vitale M, et al. Dietary Fibre as a Unifying Remedy for the Whole Spectrum of Obesity-Associated Cardiovascular Risk. Nutrients. 2018 Jul 21;10(7):943.

Casey Luttrell