Go for the Grain

By: 

Kerry Torrens BSc, DipION, Nutritional therapist and health writer

Issue: 
Spring
Year of publication: 
2010

A dietary staple for some 10,000 years, grains are the seeds of cereal crops and include wheat, rye, rice, millet, oats, maize and barley as well as the less common varieties, sorghum and teff. Frequently cited as a cause of food sensitivity, grains – especially those containing gluten – have been much maligned of late. However, the evidence supporting their contribution to disease prevention is growing and so too is our appreciation for their versatile and useful inclusion in our diets. There is clear scientific evidence supporting the role of grains, especially whole-grains, in the reduced risk of chronic diseases such as hear t disease, type II diabetes and cancer.

In the case of heart disease, studies suggest that those who regularly consume three or more portions of whole-grains each day enjoy a 20-  40% reduction in the risk of what is currently the UK’s biggest killer. Such figures make impressive reading and extol benefits which exceed even those reported for fruit and vegetables. Nevertheless, the underlying mechanism which bestows these benefits remains elusive although it is known that whole-grains possess strong antioxidant activity, are a source of vitamins, especially the B complex and vitamin E, supply minerals including magnesium as well as fatty acids and protein.

It is the bran and germ of the grain which supply much of this nutritional arsenal as well as being a source of valuable phyto-chemicals. The latter include hormonally-active phenols such as lignans which protect against oestrogen-dependent conditions including breast cancer. These valuable lignans are concentrated in the outer layer of the grain and are especially rich in whole-grain wheat, oats and rye. Lignans also provide protection from heart disease by helping to control lipid and glucose levels which serve to reduce blood pressure and inflammation.

 Although lignans are common to many plant foods, certain other phyto- chemicals such as avenanthramides and avenalumic acid are unique to grains. These compounds are responsible, at least in part, for the grains’ high antioxidant content and diverse activity which supports many of their wide-reaching benefits. For instance, soluble antioxidants such as avenanthramides as well as phenols are absorbed by endothelial cells in the colon where they provide invaluable protection, but thanks to their solubility they also enter the portal circulation where they supply sustained protection throughout the entire digestive system.

As well as being a potent source of antioxidants, grains are rich in fermentable fibre which reaches the colon undigested and is acted on by gut microflora forming protective short chain fatty acids (SCFA) including butyrate.

These SCFA not only act as fuel for the colonic mucosa but help lower cholesterol, reduce the risk of cancer and improve intestinal transit. Rye, barley and wheat supply a type of this fibre called inulin which has the added advantage of influencing the microflora itself, promoting the growth of bifidobacteria and reducing that of Escherichia coli, clostridia and bacteroides. As well as this indigestible form of fibre about a third of the fibre supplied by oats, rye and barley is soluble which helps lower cholesterol and improves glucose response making wholegrains low in Glycaemic Index (GI) and an important dietary inclusion for those with blood sugar issues.

 Despite their many nutritional highlights, whole-grains contain antinutrients such as digestive enzyme inhibitors, phytic acid, saponins and lectins. Surprisingly, studies reveal that even these compounds have beneficial effects on our health such as reducing the risk of colon and breast cancer, lowering blood glucose, insulin and cholesterol levels.

 Although, most of us are familiar with the term “whole-grain”, it continues to confuse the vast majority of consumers. In essence it refers to a product or ingredient which comprises all three sections of the grain, that being the endosperm, germ (starch) and bran; in this “whole” form it may be eaten whole, cracked, split, flaked or ground. With surveys suggesting that Britons consume less than one serving of wholegrains per day it is clear that the majority of us prefer grains that have been refined through milling. These products have a softer texture, are considered more palatable and offer an extended shelflife. However, despite these perceived advantages refined flour, being depleted in both the bran and germ, results in a product which is without doubt inferior in nutritional quality and contribution.

THE BOTTOM LINE

Refined products are not only depleted in dietary fibre but also vitamins, minerals, lignans and other important phytochemicals which act alone or collectively to contribute towards our improved health. Although individuals with the autoimmune condition Coeliac disease need to avoid those grains which contain gluten, the majority of us would benefit greatly from a wider dietary inclusion and should aim to consume three or more portions of whole-grains daily.

How to increase your intake …

Breakfast on porridge oats, whole-wheat cereal, puffed whole-grains or muesli

Snack on pop-corn, oat cakes or rye crispbreads

Accompany main meals with brown rice, whole-wheat pasta, bulgur wheat or quinoa

Replace white flour in recipes for bread, pancakes, muffins and cakes with whole-wheat or spelt flour

Add brown rice, barley or quinoa to soups and casseroles

Keywords: 
FOOD, bran, germ, lignan, whole-grain, fibre, SCFA,
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