Whole Grains: Meaning, Structure and Effects

In this article we will discuss about the Whole Grains:- 1. Meaning of Whole Grain 2. Structure of Whole Grain 3. Whole Grains 4. Whole Grain Serving 5. Health Effects.

Contents:

1. Meaning of Whole Grain
2. Structure of Whole Grain
3. Whole Grains and Health
4. Definition of Whole Grain Serving
5. Health Effects of some Whole Grains

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1. Meaning of Whole Grain:

Grains are the most important food source of the Indian population. Asian Indians in India consume a high carbohydrate diet about 60-67% as com­pared to the Asian Indians settled in UK and USA. Foods made by the whole grains are the import source of fibres, trace minerals, and vitamins.

Diets containing whole grains are most essential in re­ducing the risk of coronary heart disease (CHD), type 2 diabetes mellitus (T2DM), certain types of cancers and obesity. In India the commonly used grains are wheat, rice, bajra, jowar etc. In USA, the most commonly consumed grains are wheat, rice, maize, oats, and rye.

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2. Structure of Whole Grain:

All grains have a protective hull, beneath which are the endosperm, bran, and germ. The germ con­tains the plant embryo.

The endosperm supplies food for the growing seedling. Surrounding the germ and the endosperm is the bran which protects the grain from the weather, insects, moulds, and bacte­ria.

About 50-75 per cent of the endosperm is starch which supplies major energy to the embryo during germination of the kernel.

The endosperm also con­tains storage proteins about 8-18 per cent, few vita­mins, minerals, and fibre. The germ is a minor con­tributor to the dry weight of most grains.

The whole grain is the entire grain seed of a plant. This seed is known as the kernel which is made up of the bran, the germ, and the endosperm.

The whole grains may be eaten whole, cracked, or flaked. These are, most often, milled into flour and used to make breads, cereals, pastas, and crackers etc.

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3. Whole Grains and Health:

i. Obesity:

(a) Grains rich in viscous soluble fibre tend to increase intraluminal viscosity, prolong gastric emptying time, and slow nutrient absorption in the small intestine.

(b) A healthy eating pattern, including the consumption of whole grains, is associ­ated with smaller gains in body mass in­dex (BMI).

(c) As per the data of UK researchers it was found that a higher intake of whole grains (about 3 servings/day) was associated with lower BMI and less central adiposity (abdominal fat).

ii. Insulin Resistance:

(a) People who eat three or more servings of whole grains a day, mainly from high fi­bre cereals, are less likely to develop in­sulin resistance and the metabolic syn­drome, common precursors of both T2DM and CHD.

(b) The dietary product (WG) favorably in­fluences metabolic risk factors (like insu­lin resistance) for T2DM independent from the amount of body weight lost dur­ing a hypo-energetic diet.

iii. Dyslipidemia:

(a) The most common symptoms of dyslipidemia in people with the metabolic syndrome and diabetes include elevated serum triglyceride (TG), low HDL choles­terol (HDL-C) and predominance of small dense LDL cholesterol (SDLDL-C).

(b) The healthy diet of consumption of bar­ley containing increased soluble fiber can reduce cardiovascular risk factors.

(c) Diets having abundant whole grains tend to decrease LDL cholesterol, triglycerides, blood pressure, and increase HDL choles­terol.

iv. Diabetes:

(a) German researchers had observed that those who ate cereal fiber the most had a 27 per cent lower risk of developing T2DM than those who ate the least.

(b) Whole grains containing magnesium, fiber, vitamin E, phytic acids, lectins, and phenolic compounds can contribute re­duction of T2DM, lowering of blood glu­cose and blood insulin levels.

The fiber from whole grains but not from fruit or vegetable sources can only exert the pro­tective effect in reducing risk for devel­oping T2DM.

(c) Some of the whole grain products can control blood glucose for up to ten hours. Bar­ley has the strongest effect in this regard.

v. Coronary Heart Disease:

(a) It has been strongly suggested that the regular consumption of whole grains sig­nificantly reduces the risk of CHD.

(b) It was also found that those eating two to six servings of whole grain cereal a week reduced their risk of heart failure by 22 per cent, while those eating whole grains daily reduced the risk by 28 per cent.

(c) It had been found that those with the high­est whole grain intake (about 40 g per day) cut CHD risk by almost 20 per cent, but even those eating just 25 g cut their CHD risk by 15 per cent.

vi. Hypertension:

(a) Higher whole grain intake is associated with a reduced risk of hypertension in middle-aged and older women. This sug­gests a potential role for increasing whole grain intake in the primary prevention of hypertension and its cardiovascular com­plications.

(b) The DASH diet consisting of whole grain products and other healthy foods can lower blood pressure.

vii. Polycystic Ovarian Syndrome (PCOS):

(a) It has been suggested that a diet low in saturated fat and high in fiber is recom­mended.

(b) Diet and exercise are the instructions for the overweight/obese women to lose weight. This diet includes an increase in fiber and a decrease in refined carbohy­drates.

viii. Non-alcoholic Fatty Liver Disease (NAFLD):

(a) Carbohydrates that are high in indigest­ible and fermentable fiber and low in glycemic index can be helpful in main­taining glucose, insulin, and free fatty acid concentrations in individuals with insu­lin resistance and non-alcoholic steatohepatitis (NASH).

(b) Fiber and certain starches found in whole grains ferment in the colon to help reduce transit time and improve gastrointestinal health.

(c) Whole grains also contain antioxidants that may help protect against oxidative damage which may play a role in cancer development.

(d) Other bioactive components in whole grains may affect hormone levels and lower the risk of hormone dependent cancers. But it is not yet clear between whole grain intake and breast cancer.

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4. Definition of Whole Grain Serving:

A serving of whole grain is defined as ½ cup cooked brown rice or other cooked grain, ½ cup cooked whole grain pasta, ½ cup cooked hot cereal such as oatmeal, 1 ounce uncooked whole grain pasta, brown rice or other grain, 1 slice 100 per cent whole grain bread, 1 very small 100 per cent whole grain muffin, and 1 cup 100 per cent whole grain ready to eat cereal.

One can count a serving of whole grain as 16 grams of whole grain ingredients.

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5. Health Effects of some Whole Grains:

(a) Barley:

The fiber in barley is definitely healthy. It may lower cholesterol more effectively than oat fiber.

(b) Oats:

Oats contain a special kind of fiber called beta glucan which is effective in lowering cho­lesterol. Oats have an antioxidant that protects blood vessels from the damaging effects of LDL cholesterol.

(c) Jowar:

It is a gluten-free grain and is very popu­lar among those with celiac disease.

(d) Ragi:

i. Ragi products are consumed in vari­ous states of the southern region.

ii. It is used to make flat breads (named bhakari), dosa, and rotis.

iii. Ragi grain is malted too and mixed with milk, water or yoguri and eaten at breakfast time.

iv. The sprouted ragi is used to make baby food. It is also useful for eld­erly people since it is easy to digest.

v. It contains high fiber, proteins, cal­cium, B complex vitamins and also vitamin E.

vi. It is rich in minerals and helps in low­ering cholesterol.

(e) Bajra (Whole):

It is used in the preparation of khichri in many parts of Rajasthan.

(f) Rice Bran Oil:

This oil is rich in vitamin E and it has also cholesterol lowering effects.

(g) Com (Maize) Oil:

It is a highly desired vegeta­ble oil owing to its high level of linolenic fatty acid and its excellent flavour.

(h) Fermented Cereal Products:

The term fermen­tation means the breakdown of carbohydrate like matter under aerobic or anaerobic condi­tions.

The organisms involved may be bacte­ria or moulds. The gas during fermentation pro­duces flavouring substances.

The vitamin B and C contents are also increased after fermen­tation. The commonly consumed fermented products in different parts of India are idli, dosa, dhokla, bread etc.