If you ask most consumers if whole grains are good for them, the answer would be a definitive 'yes'. But just what does the term wholegrain mean? Are all wholegrains packed the same and what regulations govern wholegrain and fibre claims?
What does wholegrain mean?
Wholegrains contain all parts of the grain kernel -- the bran, endosperm and germ. The bran is the tough outer layer of the grain kernel and contains fibre and protein. It also contains B vitamins, minerals and and phytochemicals (chemical compounds found naturally in plants which appear to provide health benefits). The endosperm, the largest layer, contains mostly carbohydrates and protein while the germ provides carbohydrates, vitamins, minerals and phytochemicals.
All grains are whole before milling but some grains are refined which removes the bran and the endosperm portions -- (and thereby the fibre and a lot of the vitamins and minerals). In some foods, nutrients lost through refining (such as vitamins and minerals) are added back to the product. Bran is sometimes added back to increase the dietary fibre content.
Types of whole grains
Whole wheat, Wholegrain corn, Whole oats/oatmeal, Popcorn, Brown rice, Whole rye, Wholegrain barley, Wild rice, Buckwheat, Millet, Quinoa and Sorghum.
Are all wholegrains high in fibre?
Though most people think a wholegrain product must be high in fibre, it is not always the case. The fibre content of the whole grains can vary greatly. Some whole grains contain a lot of fibre (such as wholegrain wheat) while others contain very little (such as brown rice).
The easiest way to confirm that a food provides the benefits of wholegrain and fibre is to check the nutrition facts table on the side of the pack. Choose foods that list a wholegrain as the first ingredient and provide at least 2 to 3 grams of fibre per serving.
Benefits of wholegrains
Weight control:
Whole grains can help with the control of body weight. Wholegrain foods require more chewing and have a low energy density so they help people to feel full for longer. Grains that are high in soluble fibre (such as barley, oats and psyllium) slow gastric emptying which can also help stop those between meal snacks.
A study of men conducted over 8 years showed that the more wholegrains the people ate, the less weight they gained during the course of the study.
Cardiovascular disease
Many scientific studies have shown a reduced risk of cardiovascular disease with an increased intake of wholegrains. The most recent study conducted at Pennysylvania University in 2008 compared the effects of wholegrains versus refined grains in a reduced calorie diet. Fifty obese men and women who had metabolic syndrome and hence were at an increased risk of heart disease participated in the study.
All lost weight regardless of the type of grain eaten, though those on the wholegrain diet had additional health benefits. They were shown to have reduced levels of abdominal fat (belly fat) and lowered their blood levels of CRP compared to the refined grain eaters. CRP is a blood protein which increases when there is chronic inflammation of blood vessels.
High levels of abdominal fat and CRP are both linked to the increased risk of heart attack and stroke.
It appears that the combination of compounds in grains rather than any one component is responsible for the protective effect.
One study which examined the effects of wholegrains compared to the various factions of the grains (wholegrains versus bran versus germ) concluded that wholegrain intake appears to lower the risk of coronary heart disease and that the fibre-rich bran component may be a key in the protective effect.
So convincing is the evidence about a link between wholegrain intake and reduced risk of heart disease that the US FDA allows a health claim related to this. In recognition of the fact that it is the whole nutrient profile of the food that reduces risk and not just one component of the grain, the claim is qualified. Products making this claim must be at least 51% wholegrain, have at least 2.3g of fibre per 50 g (4.6 fibre per 100 g) and below in fat.
Whole grain, fibre and
blood glucose
Studies consistently show that the risk of developing Type 2 diabetes mellitus is decreased with an increased intake of wholegrains. Intake of fibre from cereals has also been found to be inversely related to type 2 diabetes. In a long-term study of almost 90,000 women, researchers found that those with higher intakes of cereal fibre had about a 30% lower risk of developing type 2 diabetes, compared to those with the lowest intakes.
Wholegrains, fibre and cancer
Wholegrains also appear to offer benefits in helping reduce the risk of cancer. Wholegrains may be protective because of their effects in the large bowel, their anti-oxidant content, effects on blood sugar levels, weight loss effects etc. Two large epidemiological studies found that fibre was particularly important in reducing the risk of colon cancer.
(Courtesy Food Facts Asia) |
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