Whole grains, cereals and cereal products - nutritional profile, health
benefits and food labelling of whole grains

Humans have been enjoying grain foods for at least the past 10,000 years. Grain foods, which include cereals, are dietary staples for many cultures around the world and Australia is no exception. Cereals provide the average Australian with around one fifth of their daily nutrient requirements. Current research around the world is discovering the many and varied health benefits that wholegrain cereal foods can offer, particularly in reducing the risk of diseases such as coronary heart disease, cancer and diabetes Much of the attention for phytochemicals has focused on fruit (especially grapes and apples), vegetables (especially onions, broccoli, tomatoes) and legumes (especially soy).
Grains include wheat, barley, oat, rye, corn, rice, triticale.

Wholegrains include wholemeal or wholegrain breads or crispbreads, dark 'seedy' breads, wholegrain breakfast cereals, wheat germ, brown rice, puffed whole grains, bulgar, couscous, pop corn and oatmeal. Refined cereals include sweet rolls, cake, desserts, white bread, pasta, muffins, sweet or savoury biscuits, refined grain breakfast cereals, white rice, pancakes, waffles and pizza.

The US Food & Drug Administration permits food manufacturers to make a health claim on whole grain food products, as possibly reducing the risk of coronary heart disease and some cancers as long as the product contains 51% or more wholegrain ingredients by weight per reference amount, with dietary fibre 2.3g per 50g or 1.7g per 35g and the food must be low in fat.

Nutritional content of whole grain cereals

The kernels of grains (such as wheat, barley, oat, rye, corn, rice, triticale) consist of 3 major parts:
Bran- this is the outer layer of the grain (14-16% of wheat, 5-6% of corn)
Endosperm - this is the main part of the grain
Germ - this is the smallest part of the grain.

Wholegrains contain all three layers of the grain.

Whole grain cereals provide a rich source of many essential vitamins, minerals and phytochemicals. The typical cereal food is:
Low in saturated fat but is a source of polyunsatured fats, including omega 3 linolenic acid.
Cholesterol free
High in both soluble and insoluble fibre and resistant starch
An excellent source of carbohydrates
A significant source of protein
A good source of B-complex vitamins, including folate
A good source of many minerals - such as iron, magnesium, copper, phosphorus and zinc.
A good source of antioxidants, including vitamin E and selenium as well as phytochemicals including phytoestrogens, phytic acid, flavonoids and phytosterols (which can help lower blood cholesterol levels)

Refined Cereals

When grains are refined (for example to produce white flour), the bran and germ layers are generally removed, leaving only the endosperm. This 'refining' process can cause 66% loss of fibre, 92% loss of selenium, 62% loss of folate and up to 99.8% of phytochemicals from the grains. Some fibre, vitamins and minerals may be added back into refined cereal products (such as white bread) which compensates for losses due to refining, but its impossible to add the mix of phytochemicals that's lost in the processing. Sometimes, the fibre that is added back to refined products is derived from vegetable fibre (lupin, pea hulls). Some breads contain 'Hi- maize' which is a resistant starch from corn. It is unknown whether these breads have similar beneficial properties to breads high in cereal fibres. For example, 'Hi-maize' does not have the same laxative effect as wheat fibre. Refined cereals, such as white flour, generally have a higher glycaemic index (GI) than their wholegrain counterparts. This means that consuming refined cereals causes a sharp rise in blood sugars, demanding a strong response from the pancreas. A diet full of high glycaemic index foods has been linked to the development of diabetes and heart disease. Studies have also found that people who eat large amounts of refined cereals do so at the expense of more nutritious foods like fruits and vegetables. This increases the risk of certain diseases, such as some types of cancer.


A host of protective chemicals
Attention has now turned to wholegrain cereals as being a significant source of antioxidant phytochemicals, including phytoestrogens. Wholegrain cereals contain many different phytochemicals that researchers have linked to significant health benefits. These phytochemicals include:
Lignans - a phytoestrogen that can lower the risk of coronary heart disease and may
protect against hormonally-linked diseases such as breast and prostate cancer.They are mostly found in outer layers (such as wheat bran) and are high in flaxseed (linseed).
Phytic acid - reduces the glycaemic index of food, which is important for people with diabetes, and helps protect against the development of cancer cells in the colon.
It was previously thought to be a disadvantage because it binds iron and zinc and makes it unavailable for absorption. It is now known to act as an important antioxidant which protects the bowel wall from damaging chemical reactions involving iron. 
Saponins, phytosterols, squalene, oryzanol and tocotrienols - have been found to lower blood cholesterol.
Phenolic compounds - have antioxidant effects.

Other protective components include resistant starch, selenium, copper, zinc and digestive enzyme inhibitors. More research needs to focus on where the phytochemicals are located in grains ?taking a fibre supplement which tends to be a refined cereal product will be high in fibre but may be devoid of these pytochemicals and nutrients found in whole grain products (Slavin et al. AJCN 1999; 70(supp): 459-63). 

Coronary heart disease
A heart attack is almost always preceded by a condition called coronary heart disease. Over the years, fatty deposits or 'plaques' build up inside one or both of the coronary arteries (atherosclerosis). This constant silting narrows the artery, until a blood clot blocks the passage of blood altogether. Too much blood cholesterol contributes to atherosclerosis. Cereal fibre or whole grains appear to offer greater protection against the risk of heart attack than the fibre from fruits and vegetables. A study conducted on postmenopausal women found that eating at least one serve of wholegrains daily reduced the risk of heart and blood vessel disease by almost 30% compared to those who rarely ate wholegrains. Regularly eating cereals that are rich in soluble fibre, such as oats and psyllium, has been found to significantly reduce the amount of cholesterol circulating in the bloodstream. Eating just 3gm of soluble fibre from oatbran lowers the blood cholesterol by as much as two per cent. However, only a small part of the cardioprotective effect of grains can be explained by the cholesterol lowering effect of their soluble fibre content. Wholegrains should thus be preferred to fibre supplements.

Diabetes (type 2 or non-insulin dependent)
A study conducted by Harvard researchers in 2000 showed that eating one serving of whole grain cereal every day can lead to a reduced risk of developing type 2 diabetes by as much as 34%. This may be because wholegrains tend to be more slowly digested
reducing he need for large quantities of insulin to be released into the bloodstream. Cereal fibre, as opposed to other plant fibres, has been shown to be particularly protective against this condition. It is also preferable for people with established diabetes to consume wholegrain cereal products rather than refined cereals, due to the higher glycaemic index of refined cereal products.

Obesity
People who are obese tend to have energy-dense diets. High fibre foods, such as wholegrain breads and cereals, can be an effective part of any weight loss program. They take longer to digest and create a feeling of fullness, which discourages overeating. They also help to lower the energy density of the diet. Whole grains are also naturally low in saturated fat and contain beneficial polyunsaturated fatty acids, including the omega 3 fatty acid 'linolenic'.

Is white bread more 'fattening' than wholegrain bread?
A study published in the American Journal of Clinical Nutrition 2003; 78: 920-7 by Liu and colleagues concluded that weight gain in 74,091 US nurses between 1984 to 1996 was related to the intake of refined grain products (like white bread, white pasta). Women who consumed more fibre and whole grain products consistently weighed less than did women who consumed less wholegrains.

Bowel health
High fibre foods, such as wholegrain cereal products, increase movement of food through the digestive tract. The result is increased stool bulk, softer, larger stools and more frequent bowel action. This increased bowel action provides a good environment for beneficial bacteria, while at the same time decreasing levels of destructive bacteria and the build up of carcinogenic compounds. Wheat fibre can bind certain toxins, such as secondary bile acids, oxidised fatty acids and carcinogens, and remove them from the large bowel. This binding ability has not been found to the same degree with fruit and vegetable fibres.

A high fibre diet, especially when high in insoluble fibre, has been associated with decreased risk of developing colon cancer and diverticular disease (a condition where 'pouches' form in the wall of the intestine). Many wholegrains also contain resistant starch (a starch which resists digestion in the small intestine) which may provide similar benefits to fibre; along with some types of fibre, resistant starch can be fermented in the large bowel to produce 'short chain fatty acids' which appear to play a role in bowel health. Fermentation of fibre by bacteria also increases moisture content and lowers pH in the bowel, which helps prevent the solubility and close contact of some harmful substances with the intestinal wall.

Cancer
Wholegrains can reduce the risk of many different types of cancers, including those of the colon, stomach other digestive tract cancers, gallbladder, bladder, kidney and breast. A consistant protective effect has been observed when wholegrains are consumed 3-4 times a week. A Norwegian study found that people who ate the highest amount of wholegrains had a 21% reduced risk of death from cancer and 23% reduced risk of death from heart disease, compared with people who ate little or no whole grains. A study conducted by the Mayo Clinic in 2001 found that those who ate the highest amount of cereal fibre were less likely than those who ate little or no cereal fibre to develop cancer at the juncture between the oesophagus and the stomach.

Too many refined cereals pose health risks
When a cereal is processed to remove the bran and wheat germ, many of the vitamins, minerals and phytochemicals are lost. The refined cereal, such as white flour, generally has a higher glycaemic index than its wholegrain counterpart. This means that consuming refined cereals causes a sharp rise in blood sugars, demanding a strong response from the pancreas. A diet full of high glycaemic index foods has been linked to the development of diabetes. Studies have also found that people who eat large amounts of refined cereals do so at the expense of more nutritious foods like fruits and vegetables.
This increases the risk of certain diseases, such as some types of cancer.


How much?
Whole grain cereals of various kinds are recommended since they have different and important micronutrient and other phytochemical profiles of health relevance. Refined grains and cereals are not sufficiently nutrient dense for increasingly sedentary populations, who may not be able to eat enough food without energy (calorie) excess. At the same time, enough "food space" in the diet needs to be retained for other protective foods like fruit and vegetables, fish and for low fat meats and dairy products.

The Australian Nutrition Foundation's 'Healthy Eating Pyramid' has 3 food category tiers. The 'Eat Most' tier includes Vegetables, Fruits, Legumes and Cereals, followed by the 'Eat Moderately' tier of animal foods and at the top or 'Eat Least' are the fats and sugars. In other words, a variety of plant foods are recommended in large quantities as opposed to recommending a preference for cereals over other plant foods. Okinawa in Japan boasts the highest percentage of centenarians in the world - the Okinawan diet could be the key. The average Okinawan consumes at least seven servings of vegetables daily and an equal number of grains in the form of noodles, bread and rice.

The CSIRO (Australia), the AntiCancer Foundation South Australia, the Australian Guide to Healthy Eating and the Healthy Eating Club Pyramid/Dietary assessment tool also recommend at least 4-5 serves daily. It is also recommended that at least half of these serves should be wholegrain since the protective components (such as fibre, antioxidants and phytoestrogens) are found in the outer layers of grains. One serve is a 1 slice of bread, 1 cup pasta, rice or breakfast cereal.

Read the 'Grains and Cereals debate' article


Buying Cereals and Food Labels

Media release on food labelling of wholegrains by Sanitarium 2005

The new food standards code introduced in 2002 no longer has requirements for the specific composition standards for breads, which means manufacturers can choose to make bread with whatever percentage of the relevant flour they want. In the past "wholemeal bread" had to have 90% wholemeal flour and rye bread 30% rye flour. This is no longer the case. Use the mandatory percentage labelling to find out how much wholemeal or rye flour's been used in a bread.

When purchasing wholegrain products look for words like "wholegrain" "wholemeal". Grainy/seedy breads are more nutritious and have a lower GI than more refined breads. Some "multigrain breads" are made with white flour with various whole grains added. Look for "wholemeal wholegrain bread" made with wholemeal flour plus wholegrains - this bread has more fibre and nutrients and a lower glycaemic index than wholemeal, wholegrain or white breads. Sourdough breads have a lower GI, especially dark rye. These breads contain 'wild' yeast whereas other breads have specially cultured baker's yeast.

The Australian Consumers Association analysed 188 breakfast cereals, of which 65 were found to be nutritionally acceptable according to salt, fat, carbohydrate, sugar and fibre contents. Here are some of the cereals recommended (published in May 2003 issue of CHOICE magazine):

Sanitarium HI Bran Weet-Bix
Lowan Whole foods Soy Flakes with apricot & almond
Uncle Tobys Shredded Wheat
Nature's Source Strawberry & Yoghurt
Uncly Tobys Vita Brits and most other brands of Wheat Biscuits
Weight Watchers Tropicana
Kellogg's Mini-Wheats Whole wheat
Goldenvale Sultana Flakes
Sanitarium Fruit Bix Fruit & Nut
Vogel's Soy & Linseed Soy-tana Bran
Kellogg's Guardian
Carman's Muesli (natural)
Uncle Tobys Healthwise for bowel ORheart
Sanitarium Soy Delight Muesli
Uncle Tobys Fibre Plus
Home Brand Muesli Tropical
Norganic Crunchola Apple Blueberry
Freedom Foods Muesli (natural)
Uncle Tobys Weeties or Weeties fruit and nut
Goodness Muesli Mixed Berry
Weight Watchers Fruit & Fibre
Uncle Tobys Natural Swiss Muesli
Uncle Tobys Bran Plus
Farmland Muesli Apricot & Almond
No Frills Just Bran
Goodness Apple or Banana Magic
Kellogg's All-Bran
Vogel's Ultra Bran Soy & Linseed
Kellogg's Sultana Bran/Bran flakes
Uncle Tobys Crunchy Oat Bran with Fruit
Lowan Whole foods Wheat, rice, oat & soy multibran
Nu-Vit 4 fibre breakfast cereal

References

http://www.gograins.grdc.com.au

Jacobs DR, Meyer KA et al. Wholegrain intake may reduce the risk of ischemic heart disease death in postmenopausal women; the Iowa Women's Health Study. Am J Clin Nutr 1998; 68: 248-57.

Jacobs DR et al. Wholegrain intake and cancer - an expanded review and meta-analysis. Nutrition and Cancer an International Journal 1998; 30 (2): 85-96.

Salmeron J et al. Dietary Fibre, glycemic load and risk of NIDDM in women. J Am Med Assoc 1997; 277; 472-477.

Revision of the Dietary Guidelines for Australians - draft 2001 http://www.health.gov.au/nhmrc/publications/synopses/n4syn.htm

Article co-authored by Better Health Channel
(Australian -Victorian Government website)

Last Updated: September 2005