**3. Grains and human health**

Rice is rich in phytochemicals that are present in lipophilic, hydrophilic and insoluble forms. In reference [38], it was indicated that tocopherols, tocotrienols (Figure 4) and ץ-oryzanol, are major lipophilic fractions of whole grain rice and are beneficial to human health. It also contains tricin, ferulic acid, caffeic acid and methoxycinnamic acid which are hydrophilic phenolic compounds reported to have cancer protective potential. Barley grains contain DFs, β-glucans, arabinoxylans and polyphenols [39,40]. β-glucans and arabinoxylans present in barley are critical nutrients that determine wort viscosity, foam stability and beer filtration rates, thus playing a significant role in beer brewing process [41,42]. Barley β-glucans also plays health beneficial roles in the reduction of blood cholesterol level, glucose level and helps in weight loss by increasing satiety, thereby reducing susceptibility to heart disease and type-2 diabetes [40]. Oats and psyllium husk which contains fibres have also been implicated in the reduction of homocysteine, cholesterol and risk of CVD [43]. Millets are rich source of DF, phytochemi‐

cals, micronutrients, nutraceuticals, and could be rightly termed as nutricereals.

**Figure 4.** Tocopherols and tocotrienols in grains

174 Antioxidant-Antidiabetic Agents and Human Health

Dietary antioxidants are food compounds that impede the deleterious effects of reactive oxygen species, reactive nitrogen species, or both, on the normal physiological function in humans [44,27]. Dietary antioxidants include ascorbate, tocopherols, carotenoids and bioactive plant phenols. ROS; oxygen ions, free radicals, and peroxides and reactive nitrogen species (RNS); nitrous anhydride, peroxynitrite, and nitrogen dioxide radicals, causes oxidation, nitration, halogenation and deamination of biomolecules of all types, including lipids, proteins, carbohydrates, and nucleic acids, with the resultant formation of toxic and mutagenic products [45,46]. Biological systems control these oxidative factors by a variety of antioxidative mechanisms that restrict the reactivity of ROS and RNS and oxidation catalysts [20]. In human cells, *de novo* antioxidant production is much more limited and oxidative damage resulting from excess production of free radicals has been reported to initiate the pathogenesis of most chronic degenerative diseases such as brain stroke, diabetes mellitus, rheumatoid arthritis, Parkinson's disease, Alzheimer's disease, and cancer [27,28]. The production of ROS and RNS are speedily formed in cells as a consequence of disease processes (e.g. inflammation), tobacco smoke, environmental pollutants, ingestion of oxidized foods, ischemia, drugs, ethanol and radiations. If unchecked, such cellular event can promote a chain of chemical reactions that form free radicals, peroxides and secondary oxidation breakdown products which in turn reacts with and cause damage to cellular membranes, proteins and nucleic acids [20,23].

Phenolic compounds present in whole grains are known to be effective in protecting against CVDs and some cancer (Table 4). This protective effect is thought to be mediated through their action as antioxidants to prevent oxidative damage induced by ROS to some biomolecules (DNA, lipids and proteins) under pathological conditions [47]. In reference [48], it was reported that phenolic compounds could be responsible for chelating metals as well as inhibiting the free radicals capitation by limiting the action of the lipoxygenase enzyme. Phytate compounds on the other hand may exert antioxidant activity by complexing with iron, reducing the formation of free radicals and peroxidation of membranes, which could provide anticarcino‐ genic power. Lignans on their part are a group of dietary phytoestrogen found in a variety of plant foods like corn, oats, rye, wheat, flaxseeds, legumes, fruits and vegetables. These plant lignans when consumed are converted to the mammalian lignans, enterodiol and enterolac‐ tone which have strong antioxidant activity. β-glucan is mostly found in cell walls of oats, barley and wheat. Its major biological effects include lowering of blood cholesterol level, controlling blood sugar, promotion of weight management, encouraging the growth of beneficial gut microflora and enhancing the immune system. This is probably due to its high viscosity property as a soluble fibre to bind cholesterol and bile acids and facilitate their elimination from the body. It has been [93] indicated that β-glucan had an effect in controlling blood sugar in diabetes subjects, and was helpful in reducing the elevation in blood sugar levels after a meal. The authors further indicated that this is probably as a result of delaying gastric emptying, allowing dietary sugar to be absorbed more gradually, as well as by possibly increasing the tissue sensitivity to insulin. The United States Food and Drug Administration (FDA) is allowing whole grain barley products that can supply β-glucan at levels of 0.75 g per serving or 3 g per day to carry a claim that they reduce the risk of coronary heart disease [49].


high-fibre whole grain diet [71]. Available epidemiological evidence suggests that sorghum consumption reduces the risk of certain types of cancer in humans compared to other cereals [19]. Positive effects of sorghum and/or millet consumption on cancer have been document‐ ed. Sorghum consumption consistently correlated with low incidence of oesophageal cancer [72] in various parts of the world (including several parts of Africa, Russia, India, China and Iran) whereas wheat and corn consumption correlated with elevated incidence [19]. Sorghum containing tannins are widely reported to reduce caloric availability and hence weight gain in animals. However, withobesity as amajor andever-increasingprobleminthedeveloped world (withmore than60%ofAmericans reportedtobeoverweight),this attributeof sorghumtannins has the potential of mitigating the problem [19]. Although information on how sorghum phytochemicals affect human health is limited, overall epidemiological studies suggest that

Antioxidant-Rich Natural Grain Products and Human Health

http://dx.doi.org/10.5772/57169

177

sorghum possesses anti-carcinogenic properties when consumed regularly in the diet.

tional factors.

the risk of chronic diseases [76].

**4. Fortified antioxidant grain-based products**

Whole grains, oilseeds, nuts and legumes are rich in sterols and stanols. In humans, high intake of sterols or stanols is associated with lowering of serum and LDL cholesterol concentrations. Phytosterols compete with cholesterol for micelle formation in the intestinal lumen and inhibits cholesterol absorption [73],. Whole grains are good sources of health beneficial phytochemicals. These phytochemicals are in free soluble-conjugated and bound forms [74]. Most of them are bound to the cell wall materials and insoluble. This makes it difficult for these phytochemicals to be released during the upper gastrointestinal tract digestion. As a result of this, colonic digestion of such materials by microflora results in the release of the bulk of bound phytochemicals to exert their health benefits. Hence, the reduced risk of colon cancer associated with increased consumption of whole grain products. Higher beans consumption apart from being associated with reduced risk of diabetes and obesity, is inversely associated with prostate, breast and colon cancers [10]. This is due to the presence of elements which are able to retard the glycemic response, slowing the release of glucose into the blood [75]. This antioxidant and anticarcinogenic effect of beans has been attributed to the presence of phenolic and phytate acids, which were previously regarded as unwanted compounds with antinutri‐

Consuming whole grains and their products regularly is associated with risk reduction of developing chronic diseases such as CVDs, type 2 diabetes and some cancers. Therefore, dietary modification by increasing the consumption of wide variety of fruits, vegetables and whole grains daily is a practical strategy for consumers to optimize their health and reduce

Cereal extruded products are mainly composed of starches, and or vegetable proteins. The role of these constituents is mainly to impart structure, texture, bulk, mouth feel and other desired characteristics for finished products [77]. Infant cereals are one of the most common weaning foods. However, these foods in their natural form may lack some vital infant nutritional requirements for proper growth. The nutritional quality of raw cereal based infant

**Table 4.** Antioxidant compounds in cereals, human effects and methods of determination

According to [67], these antioxidant compounds may offer protection against heart disease, hormone-related breast and prostate cancers. Enterodiol and enterolactone inhibited colon cancer cell growth, induced cell cycle and apoptosis *in vitro* [68]. In a study conducted among post-menopausal women diagnosed with heart conditions, whole grains was associated with a slower build-up of artery-narrowing plaque among the post-menopausal women and in lowering the overall risk of mortality associated to CVDs [69,70]. Whole grains were also implicated in a 66% reduction in cancer in a study conducted in over 2000 people fed with a high-fibre whole grain diet [71]. Available epidemiological evidence suggests that sorghum consumption reduces the risk of certain types of cancer in humans compared to other cereals [19]. Positive effects of sorghum and/or millet consumption on cancer have been document‐ ed. Sorghum consumption consistently correlated with low incidence of oesophageal cancer [72] in various parts of the world (including several parts of Africa, Russia, India, China and Iran) whereas wheat and corn consumption correlated with elevated incidence [19]. Sorghum containing tannins are widely reported to reduce caloric availability and hence weight gain in animals. However, withobesity as amajor andever-increasingprobleminthedeveloped world (withmore than60%ofAmericans reportedtobeoverweight),this attributeof sorghumtannins has the potential of mitigating the problem [19]. Although information on how sorghum phytochemicals affect human health is limited, overall epidemiological studies suggest that sorghum possesses anti-carcinogenic properties when consumed regularly in the diet.

**Compounds**

Vitamins (Tocopherols and tocotrienols)

Phytosterols (Sitosterol, campesterol, stigmasterol, brassicasterol)

Phenolics (Lignans, phenolic acids, alkylresorcinols, avenathramide, coumarins)

Flavonoids (anthocyanidins, flavonols, flavanones)

Phytate (Inositol hexaphosphate) **Cereals/Parts Found**

Germ of all cereal

Aleurone, pericap and germ of rice, wheat, rye, oat and

Bran layer of most cereals e.g. barley, sorghum, rice, rye, wheat, millet and

of durum wheat.

Yellow lemon sorghum, aleurone of blue and red coloured maize.

Aleurone layer and scutellum cells of germ of most cereals.

grains.

176 Antioxidant-Antidiabetic Agents and Human Health

barley.

oat.

Carotenoids Yellow endosperm

**Method of Determination**

Gas chromatography

HPLC

analysis

HPLC, GC-MS

spectrometry, HPLC

spectrometry, HPLC, mass spectrometry

According to [67], these antioxidant compounds may offer protection against heart disease, hormone-related breast and prostate cancers. Enterodiol and enterolactone inhibited colon cancer cell growth, induced cell cycle and apoptosis *in vitro* [68]. In a study conducted among post-menopausal women diagnosed with heart conditions, whole grains was associated with a slower build-up of artery-narrowing plaque among the post-menopausal women and in lowering the overall risk of mortality associated to CVDs [69,70]. Whole grains were also implicated in a 66% reduction in cancer in a study conducted in over 2000 people fed with a

UV/Vis

and MS spectrometry

UV/Vis

HPLC, HPIC

**Table 4.** Antioxidant compounds in cereals, human effects and methods of determination

**Effects on Humans References**

Prevent CVDs. [53,54,55]

Believed to have anticancer activity; prevent oxidative stress, cholesterolemia, atherosclerosis and aging; anti-inflammatory and anti-

Prevent cataracts, age-related muscular degeneration, cancer and cardiovascular

Inhibitory effects on cancer, anti-inflammatory properties, reduce glycemia, combats complications of diabetes.

Gene regulation, antiinflammatory, prevents complications of diabetes, antineoplastic in breast, colon

irritant.

disease.

and liver.

[50,51,52]

[56,57,52,58]

[59,52,60]

[61,52,62,63]

[64,65,66]

Induction of immune responses; lowering of cholesterol levels; defence against oxidative stress; antimutagenic and anticancer.

> Whole grains, oilseeds, nuts and legumes are rich in sterols and stanols. In humans, high intake of sterols or stanols is associated with lowering of serum and LDL cholesterol concentrations. Phytosterols compete with cholesterol for micelle formation in the intestinal lumen and inhibits cholesterol absorption [73],. Whole grains are good sources of health beneficial phytochemicals. These phytochemicals are in free soluble-conjugated and bound forms [74]. Most of them are bound to the cell wall materials and insoluble. This makes it difficult for these phytochemicals to be released during the upper gastrointestinal tract digestion. As a result of this, colonic digestion of such materials by microflora results in the release of the bulk of bound phytochemicals to exert their health benefits. Hence, the reduced risk of colon cancer associated with increased consumption of whole grain products. Higher beans consumption apart from being associated with reduced risk of diabetes and obesity, is inversely associated with prostate, breast and colon cancers [10]. This is due to the presence of elements which are able to retard the glycemic response, slowing the release of glucose into the blood [75]. This antioxidant and anticarcinogenic effect of beans has been attributed to the presence of phenolic and phytate acids, which were previously regarded as unwanted compounds with antinutri‐ tional factors.

> Consuming whole grains and their products regularly is associated with risk reduction of developing chronic diseases such as CVDs, type 2 diabetes and some cancers. Therefore, dietary modification by increasing the consumption of wide variety of fruits, vegetables and whole grains daily is a practical strategy for consumers to optimize their health and reduce the risk of chronic diseases [76].
