**2.1 Body composition**

Nutrition transitions, taking place in developing countries since the 20th century, toward more energy-dense foods, associated with insufficient physical activity, resulted in pandemic prevalence of overweight and obesity (Popkin, 1995). Overweight and obesity are metabolic disorders and the leading causes of NCDs. Worldwide, 4.8% of all deaths and 2.3% of DALYs are attributable to overweight and obesity (WHO, 2009a).

Overweight and obesity are associated with increased risk of some cancer localizations (Calle et al., 2003; Lagergren, 2011; Fontham & Su, 2008; Stoll, 2002; Ma et al., 2008). Visceral adiposity and central obesity are risk factors for some cancers (AICR & WCRF, 2009). Fat mapping (adipotopography) is an emerging biomedical field dealing with localization and amount of intra-abdominal adipose tissue [IAAT] in the human body. Subjects with higher amount of intra-abdominal adipose tissue are at greater risk for insulin resistance, diabetes and cancer (Thomas et al., 2011). The recommended body-mass index [BMI] for cancer risk reduction is 21.5 kg/m2 on a population scale, and between 18.5 kg/m2 and 25.0 kg/m2 on individual level (AICR & WCRF, 2009; Food and Agriculture Organization of the United Nations [FAO], 2004). Individuals with BMI within the physiological range, but with highrisk waist circumference [WC], are classified as thin-on-the-outside, fat-on-the-inside [TOFI]

Scientists around the world declared war on cancer (Waldorp, 2011). Preventive medicine has been recognized as the most promising field in reducing the risk of malignant diseases development. As diet and lifestyle are believed to be the most important external factors implicated in cancer development, nutrition care process [NCP] (American Dietetic Association [ADA], 2006a, 2008) and medical nutrition prevention [MNP] are considered the most important tools in cancer risk management (Key et al., 2004; Béliveau & Gingras, 2007). NCP and MNP can be used to reduce the potential of nutrition misinformation to increase the cancer risks in populations and individuals who are inadequately educated about

Registered dietitians are well aware of dietary reference values and safe upper limits for nutrients intake in different population groups, but these recommendations neglect genetic differences in population subgroups. Therefore, special scientific disciplines - nutrigenetics and nutrigenomics - study the effects of different foods and food constituents on gene expression (Fenech et al., 2011). There is a distinct difference between nutrigenetics and nutrigenomics. Nutrigenetics studies effects of genetic variations on body response to diet and nutrition, while nutrigenomics studies health effects of gene alterations influenced by food constituents (Milner, 2006a). Both disciplines aim to determine the optimal nutrient intake and nutrient combinations (called nutriom) in order to sustain the genome and support the physiological processes of gene expression, metabolism and cell functioning. These findings are expected to be used in cancer risk reduction in dietetic practice (Milner,

**2. Risk factors related to lifestyle and the possibility of cancer prevention** 

Many lifestyle factors are related to cancer risks, but at the same time they are highly

Nutrition transitions, taking place in developing countries since the 20th century, toward more energy-dense foods, associated with insufficient physical activity, resulted in pandemic prevalence of overweight and obesity (Popkin, 1995). Overweight and obesity are metabolic disorders and the leading causes of NCDs. Worldwide, 4.8% of all deaths and

Overweight and obesity are associated with increased risk of some cancer localizations (Calle et al., 2003; Lagergren, 2011; Fontham & Su, 2008; Stoll, 2002; Ma et al., 2008). Visceral adiposity and central obesity are risk factors for some cancers (AICR & WCRF, 2009). Fat mapping (adipotopography) is an emerging biomedical field dealing with localization and amount of intra-abdominal adipose tissue [IAAT] in the human body. Subjects with higher amount of intra-abdominal adipose tissue are at greater risk for insulin resistance, diabetes and cancer (Thomas et al., 2011). The recommended body-mass index [BMI] for cancer risk reduction is 21.5 kg/m2 on a population scale, and between 18.5 kg/m2 and 25.0 kg/m2 on individual level (AICR & WCRF, 2009; Food and Agriculture Organization of the United Nations [FAO], 2004). Individuals with BMI within the physiological range, but with highrisk waist circumference [WC], are classified as thin-on-the-outside, fat-on-the-inside [TOFI]

2.3% of DALYs are attributable to overweight and obesity (WHO, 2009a).

healthy food and lifestyle choices (ADA, 2006b).

2006a).

preventable or modifiable.

**2.1 Body composition** 

phenotype (Thomas et al., 2011) and they are at greater risk of certain cancer localizations. TOFI is a pathological phenomenon, synonymous with "metabolically obese", whereas thin-on-the-outside, thin-on-the-inside [TOTI] is an acronym for healthy adipose tissue distribution (Thomas et al., 2011).

TOFI phenotype may be used to explain the rising incidence of cancers in developing countries. Rapid economic growth and social transitions happening in these countries affect dietary and other lifestyle choices. Energy-dense foods become easily accessible to consumers, while the level of physical activity decreases, promoting overweight and obesity (Popkin, 2001).

Higher amount of IAAT or visceral adiposity is usually related to increased serum levels of insulin-like growth factor [IGF-1], insulin, leptin, sex hormones and adipocytokines (tumor necrosis factor-alpha [TNF-α], interleukin-6 [IL-6], C-reactive protein [CRP], adiponectin, resistin, visfatin, apelin), all known as cancer and type 2 diabetes risk factors (Donohoe et al., 2011; Bon, 2008; Redinger, 2008). Epidemiological studies show that type 2 diabetes patients are at higher risk for developing many types of cancer. There is an ongoing effort in research of shared risk factors for cancer and type 2 diabetes supported by the American Diabetes Association and the American Cancer Society. This research strives to find a biological link between cancer and type 2 diabetes, as well as to explain whether diabetes mellitus therapy affects the risk for cancer development (Giovannucci et al., 2010).

Taller individuals are more likely to get cancer, due to cells being stimulated by IGF-1 and growth hormone continuously, increasing the possibility of DNA replication error, some of which may lead to malignant alterations (Hernandez et al., 2009).

Overweight and obesity are usually the result of external factors, and are therefore, preventable and treatable (WHO, 2005, 2008a) risk factors for some cancers (Table 1).


Table 1. Estimated percentage of cancers that could be prevented by healthy diet, regular physical activity and healthy weight in selected countries based on the conclusions of the 2007 WCRF/AICR Diet and Cancer Report (n/a – exposure data not available). Adapted from AICR & WCRF, 2009.

Lifestyle Changes May Prevent Cancer 155

Europidsa In the USA, the ATP III values (102 cm male, 88 cm female are likely to continue to be used for clinical purposes)

South Asians Based on Chinese, Malay and Asian-Indian population

Eastern Mediterranean and Middle East (Arab) populations

better comparisons). Table adapted from IDF, 2006.

2. Choosing low energy and low fat foods,

for dietitians to practice personalized nutrition.

3. Eating breakfast regularly, 4. Monitoring body mass,

(Grace, 2011):

**Country/Ethnic group Gender Waist circumference** 

Japanese Use South Asian recommendations until

Sub-Saharan Africans Use European recommendations until more

Ethnic South and Central Americans Use South Asian recommendations until

Table 3. Cut-off values of waist circumference by gender and ethnicity excluding children younger than 6 years (a. In future epidemiological studies of populations of Europid origin, prevalence should be given using both European and North American cut-points to allow

Key recommendations for long term maintenance of healthy body mass are as follows

Nutrition is the source of life. Healthy diet with optimal nutrients intake prevents nutrient deficiency and helps to maintain or improve health. Types of nutrients and their amounts sufficient for sustaining life and maintaining good health are well known and recommendations for nutrients intake are given according to age, gender, pregnancy or lactation (Smolin & Grosvenor, 2010). A number of factors (e.g. genetic background, physical activity level) affect individual's optimal nutrients intake, so it is still not possible

The inter-individual variability of responses to different food constituents is being scrutinized (Simopoulos & Milner, 2010). The scientific position that genetic predisposition to complex diseases is a result of small variations of a large number of genes and their ability to interact with specific ecological factors is strongly supported in available literature. Therefore, results of nutrigenomic and nutrigenetic research could, through practical and clinical use of new knowledge, reduce the risk for malignant alterations and help control the burden of cancer as the second most common cause of death in the world (Kinsella & He, 2009; WHO, 2011c). It is expected that nutrigenetics and nutrigenomics will shed some light

1. Being physically active (at least 60 minutes of moderate physical activity daily),

5. Catching body mass gain before it turns into overweight or obesity, 6. Establishing a consistent healthy diet and proper lifestyle choices.

**2.2 Cancer protective diet versus diet-related cancer risk** 

Male > 94 cm

Female > 80 cm

Male > 90 cm Female > 80 cm

more specific data are available

more specific data are available

specific data are available

Use European recommendations until more specific data are available

According to Fair & Montgomery, "nutritional energy intake is a modifiable factor in the energy balance-cancer linkage". Animal studies showed that reduction of energy intake by 10.0 to 40.0% decreases cell proliferation, by increasing apoptosis due to insufficient angiogenesis (Fair & Montgomery, 2009). Although known to have anticarcinogenic potential, decreased energy intake alone cannot reduce the risk of cancer, since energy expenditure depends highly on the physical activity level. Regular physical activity helps weight loss, reduction of IAAT, serum insulin, IGF-1 and adipocytokines levels, hence reducing the risk of cancer (WHO, 2008a).

Body mass reduction and maintenance of healthy body mass calls for accurate determination of daily energy requirements (Table 2), depending on age, gender and physical activity levels (U.S. Department of Agriculture [USDA] & U.S. Department of Health and Human Services, 2011).


Table 2. Estimated calorie needs per day by age, gender and physical activity level (a. The calorie ranges accommodate needs of different ages within the group. Children and adolescents need more calories at older ages, and adults need less calories at older ages.; b. Not including pregnant and breastfeeding females.) Adapted from: U.S. Department of Agriculture [USDA] & U.S. Department of Health and Human Services, 2011.

High waist circumference (WC) values increase the cancer risks, and they are undoubtedly related to all-cause mortality in middle aged men and women (Bigaard et al., 2005). Health risks of high waist circumference values in adolescence and young adulthood are similar to those of middle aged individuals. Efforts are being made to standardize WC reference data in accordance with age, gender, body height and ethnicity. Standardization of WC by BMI, site of waist measurement, meal timing and phase of respiration are suggested (Wang, 2006). According to Wang the "unit for WC standardization that investigators will accept logically and mathematically and that would increase the use of WC measurement in the clinical field" should be similar to the percentile system used in children's growth rate nomograms, or T-score used in bone density evaluation (Wang, 2006). Cut-off values of WC by gender and ethnicity are shown in table 3.

According to Fair & Montgomery, "nutritional energy intake is a modifiable factor in the energy balance-cancer linkage". Animal studies showed that reduction of energy intake by 10.0 to 40.0% decreases cell proliferation, by increasing apoptosis due to insufficient angiogenesis (Fair & Montgomery, 2009). Although known to have anticarcinogenic potential, decreased energy intake alone cannot reduce the risk of cancer, since energy expenditure depends highly on the physical activity level. Regular physical activity helps weight loss, reduction of IAAT, serum insulin, IGF-1 and adipocytokines levels, hence

Body mass reduction and maintenance of healthy body mass calls for accurate determination of daily energy requirements (Table 2), depending on age, gender and physical activity levels (U.S. Department of Agriculture [USDA] & U.S. Department of

> **Sedentary [kcal/day]**

Child (female and male) 2-3 1000-1200a 1000-1400a 1000-1400a Femaleb 4-8 1200-1400 1400-1600 1400-1600 9-13 1400-1600 1600-2000 1800-2400 14-18 1800 2000 2400 19-30 1800-2000 2000-2200 2400 31-50 1800 2000 2200 51+ 1600 1800 2000-2200 Male 4-8 1200-1400 1400-1600 1600-2000 9-13 1600-1800 1800-2200 2000-2600 14-18 2000-2400 2400-2800 2800-3200 19-30 2400-2600 2600-2800 3000 31-50 2200-2400 2400-2600 2800-3000 51+ 2000-2200 2200-2400 2400-2800

Table 2. Estimated calorie needs per day by age, gender and physical activity level (a. The calorie ranges accommodate needs of different ages within the group. Children and adolescents need more calories at older ages, and adults need less calories at older ages.; b. Not including pregnant and breastfeeding females.) Adapted from: U.S. Department of

High waist circumference (WC) values increase the cancer risks, and they are undoubtedly related to all-cause mortality in middle aged men and women (Bigaard et al., 2005). Health risks of high waist circumference values in adolescence and young adulthood are similar to those of middle aged individuals. Efforts are being made to standardize WC reference data in accordance with age, gender, body height and ethnicity. Standardization of WC by BMI, site of waist measurement, meal timing and phase of respiration are suggested (Wang, 2006). According to Wang the "unit for WC standardization that investigators will accept logically and mathematically and that would increase the use of WC measurement in the clinical field" should be similar to the percentile system used in children's growth rate nomograms, or T-score used in bone density evaluation (Wang, 2006). Cut-off values of WC

Agriculture [USDA] & U.S. Department of Health and Human Services, 2011.

**Physical Activity Level** 

**Moderately active** 

**[kcal/day] Active [kcal/day]** 

reducing the risk of cancer (WHO, 2008a).

Health and Human Services, 2011).

**Gender Age** 

by gender and ethnicity are shown in table 3.

**[years]** 


Table 3. Cut-off values of waist circumference by gender and ethnicity excluding children younger than 6 years (a. In future epidemiological studies of populations of Europid origin, prevalence should be given using both European and North American cut-points to allow better comparisons). Table adapted from IDF, 2006.

Key recommendations for long term maintenance of healthy body mass are as follows (Grace, 2011):


#### **2.2 Cancer protective diet versus diet-related cancer risk**

Nutrition is the source of life. Healthy diet with optimal nutrients intake prevents nutrient deficiency and helps to maintain or improve health. Types of nutrients and their amounts sufficient for sustaining life and maintaining good health are well known and recommendations for nutrients intake are given according to age, gender, pregnancy or lactation (Smolin & Grosvenor, 2010). A number of factors (e.g. genetic background, physical activity level) affect individual's optimal nutrients intake, so it is still not possible for dietitians to practice personalized nutrition.

The inter-individual variability of responses to different food constituents is being scrutinized (Simopoulos & Milner, 2010). The scientific position that genetic predisposition to complex diseases is a result of small variations of a large number of genes and their ability to interact with specific ecological factors is strongly supported in available literature. Therefore, results of nutrigenomic and nutrigenetic research could, through practical and clinical use of new knowledge, reduce the risk for malignant alterations and help control the burden of cancer as the second most common cause of death in the world (Kinsella & He, 2009; WHO, 2011c). It is expected that nutrigenetics and nutrigenomics will shed some light

Lifestyle Changes May Prevent Cancer 157

**Moderate Evidence Probable** 

Mouth (f&v) Pharynx (f&v) Larynx (f&v) Oesophagus (f&v) Stomach (f&v) Lung (f)

Oesophagus (f&v) Stomach (f) Colon & rectum (v)

Oral Cavity (f&v) Oesophagus (f&v) Stomach (f&v) Colon & rectum (f&v)

> Larynx (f&v) Pancreas (f&v) Breast (f&v) Bladder (f&v)

Colon & rectum (v) Breast (f&v)

**Lower Evidence Possible / Limited** 

Nasopharynx (f&v) Colon & rectum (f&v) Pancreas (f) Liver (f) Lung (v) Ovary (v) Endometrium (v)

Mouth (f&v) Pharynx (f&v) Larynx (f&v) Kidney (f&v) Colon & rectum (f) Bladder (f) Stomach (v) Lung (v) Ovary (v)

Ovaries (f&v) Cervix (f&v) Endometrium (f&v) Thyroid (f&v) Liver (v) Prostate (v) Kidney (v)

Organisation Review **Highest Evidence** 

WCRF/AICR (2007)

IARC (2003)

WHO/FAO (2003)

WCRF/AICR (1997)

**Convincing** 

COMA (1998) Oesophagus (f&v) Stomach (f&v)

Mouth (f&v) Pharynx (f&v) Oesophagus (f&v) Stomach (f&v) Colon & rectum (v) Lung (f&v)

Australia (www.cancer.org.au) (Cancer Council Australia, 2007).

Australia, 2007; Slimani & Margetts, 2009; Novaković et al., 2010).

Table 4. Conclusions from the major cancer prevention reports regarding the cancer protective effect of fruit (f) and vegetables (v). Used with permission of Cancer Council

Fruits and vegetables contain dietary fibers, vitamins, minerals and other bioactive molecules, as well as a large percentage of water which makes them low-energy foods. Replacing high-energy dense foods with fruits and vegetables may lead to body mass reduction and, consequently, to cancer risk reduction (Willet, 2010; Cancer Council

Nutritional and health benefits of indigestible oligosaccharides contained in fruits and vegetables are being pointed out in scientific journals. Oligosaccharides are dietary fibers which are generally highly fermentable. Some oligosaccharides, namely fructooligosaccharides, inulin and lactulose are valued for their prebiotic properties (Gray, 2006; Roberfroid et al., 2010; Mujal et al., 2009). High-energy dense nutrition is low in indigestible oligosaccharides and other dietary fibers. Chronic high fat intake and low dietary fiber intake may lead to gut microflora changes, specifically to Bifidobacterium spp. number decrease (Cani & Delzenne, 2009). Altered microflora may play an important role in obesity initiation and homeostasis perturbation (Cani et al., 2007a; Cani et al., 2009;

on the complex relations between nutritional molecules, genetic variations and the biological system, thus facilitating the concept of personalized nutrition. Development of nutrition guides intended for individual use depends on agricultural production and food availability (Simopoulos & Milner, 2010).

At this moment, only population-based nutrition guides exist. They first appeared in early 20th century (USDA, 2002). The first significant guide was the Exchange List for Meal Planning (American Diabetic Association & ADA, 2003) and it was followed by globally accepted MyPyramid (USDA, 2011a). In June 2011, USDA published the enhanced version of nutrition guide called ChooseMyPlate (USDA, 2011b), based on Dietary Guidelines for Americans, published earlier in 2011 (USDA & U.S. Department of Health and Human Services, 2011). The use of nutritional guides is still encouraged in dietetics practice, because they can help manage cancer risks by changing diet and lifestyle.

No specific food can be labelled as anticarcinogenic, but certain food constituents have the potential to reduce cancer risks (WCRF & AICR, 2007; WHO, 2003). Diet rich in fresh vegetables, fruits and low in red and processed meat has been referred to as chemoprotective, while foods with high glycemic indices and sweetened beverages have been linked to hyperinsulinemia, overweight, obesity and increased cancer risks (WCRF & AICR, 2007; Kushi et al., 2006).

#### **2.2.1 Grains and grain products**

The amount of nutrients in cereals and cereal products depends on the degree of refinement and processing. Dietary fibers, antioxidants, phenols, lignans and phytoestrogens, present in whole grain products may reduce the risk for some types of cancer (Schatzkin et al., 2007). Dietary fibers are defined as partially or completely indigestible carbohydrates consisting of 3 or more monosaccharide units (Gray, 2006). "Isolated indigestible carbohydrates shown to have beneficial physiological effects in humans" are called functional fibers (Institute of Medicine, 2005). The fiber content of carbohydrates, determines the food's glycemic index [GI] (Smolin & Grosvenor, 2010; Gray, 2006; Barclay, 2008). Foods labelled with "low GI" on nutrition claims (good sources of dietary fibers) are recommended for risk reduction of certain cancers (Barclay, 2008; Buttriss & Stokes, 2008). Nutrition (and health) claims have enormous potential for chronic diseases risk reduction and health promotion and improvement, but better education of consumers on this issue is necessary (Buttriss & Stokes, 2008; Jovičić et al., 2010; Bonsmann et al., 2010). Key recommendation concerning grains and grain products category is to pay attention to the GI and dietary fiber content per 100 g or per serving of foods.

#### **2.2.2 Fruits and vegetables**

During the last decade of the 20th century, scientists started emphasizing that high intake of fruits and vegetables may reduce cancer risks. That is why the "5-A-Day" program was developed by the American National Cancer Institute (Havas et al., 1994), but later studies failed to back up the optimistic findings from the 90s (Boffeta et al., 2010; Willet, 2010; Cancer Council Australia, 2007). There is an ongoing effort to find specific fruits and vegetables and their constituents (or their interactions) that are responsible for cancer risk reduction (Table 4).

on the complex relations between nutritional molecules, genetic variations and the biological system, thus facilitating the concept of personalized nutrition. Development of nutrition guides intended for individual use depends on agricultural production and food

At this moment, only population-based nutrition guides exist. They first appeared in early 20th century (USDA, 2002). The first significant guide was the Exchange List for Meal Planning (American Diabetic Association & ADA, 2003) and it was followed by globally accepted MyPyramid (USDA, 2011a). In June 2011, USDA published the enhanced version of nutrition guide called ChooseMyPlate (USDA, 2011b), based on Dietary Guidelines for Americans, published earlier in 2011 (USDA & U.S. Department of Health and Human Services, 2011). The use of nutritional guides is still encouraged in dietetics practice, because

No specific food can be labelled as anticarcinogenic, but certain food constituents have the potential to reduce cancer risks (WCRF & AICR, 2007; WHO, 2003). Diet rich in fresh vegetables, fruits and low in red and processed meat has been referred to as chemoprotective, while foods with high glycemic indices and sweetened beverages have been linked to hyperinsulinemia, overweight, obesity and increased cancer risks (WCRF &

The amount of nutrients in cereals and cereal products depends on the degree of refinement and processing. Dietary fibers, antioxidants, phenols, lignans and phytoestrogens, present in whole grain products may reduce the risk for some types of cancer (Schatzkin et al., 2007). Dietary fibers are defined as partially or completely indigestible carbohydrates consisting of 3 or more monosaccharide units (Gray, 2006). "Isolated indigestible carbohydrates shown to have beneficial physiological effects in humans" are called functional fibers (Institute of Medicine, 2005). The fiber content of carbohydrates, determines the food's glycemic index [GI] (Smolin & Grosvenor, 2010; Gray, 2006; Barclay, 2008). Foods labelled with "low GI" on nutrition claims (good sources of dietary fibers) are recommended for risk reduction of certain cancers (Barclay, 2008; Buttriss & Stokes, 2008). Nutrition (and health) claims have enormous potential for chronic diseases risk reduction and health promotion and improvement, but better education of consumers on this issue is necessary (Buttriss & Stokes, 2008; Jovičić et al., 2010; Bonsmann et al., 2010). Key recommendation concerning grains and grain products category is to pay attention to the GI and dietary fiber content per

During the last decade of the 20th century, scientists started emphasizing that high intake of fruits and vegetables may reduce cancer risks. That is why the "5-A-Day" program was developed by the American National Cancer Institute (Havas et al., 1994), but later studies failed to back up the optimistic findings from the 90s (Boffeta et al., 2010; Willet, 2010; Cancer Council Australia, 2007). There is an ongoing effort to find specific fruits and vegetables and their constituents (or their interactions) that are responsible for cancer risk

availability (Simopoulos & Milner, 2010).

AICR, 2007; Kushi et al., 2006).

100 g or per serving of foods.

**2.2.2 Fruits and vegetables** 

reduction (Table 4).

**2.2.1 Grains and grain products** 

they can help manage cancer risks by changing diet and lifestyle.


Table 4. Conclusions from the major cancer prevention reports regarding the cancer protective effect of fruit (f) and vegetables (v). Used with permission of Cancer Council Australia (www.cancer.org.au) (Cancer Council Australia, 2007).

Fruits and vegetables contain dietary fibers, vitamins, minerals and other bioactive molecules, as well as a large percentage of water which makes them low-energy foods. Replacing high-energy dense foods with fruits and vegetables may lead to body mass reduction and, consequently, to cancer risk reduction (Willet, 2010; Cancer Council Australia, 2007; Slimani & Margetts, 2009; Novaković et al., 2010).

Nutritional and health benefits of indigestible oligosaccharides contained in fruits and vegetables are being pointed out in scientific journals. Oligosaccharides are dietary fibers which are generally highly fermentable. Some oligosaccharides, namely fructooligosaccharides, inulin and lactulose are valued for their prebiotic properties (Gray, 2006; Roberfroid et al., 2010; Mujal et al., 2009). High-energy dense nutrition is low in indigestible oligosaccharides and other dietary fibers. Chronic high fat intake and low dietary fiber intake may lead to gut microflora changes, specifically to Bifidobacterium spp. number decrease (Cani & Delzenne, 2009). Altered microflora may play an important role in obesity initiation and homeostasis perturbation (Cani et al., 2007a; Cani et al., 2009;

Lifestyle Changes May Prevent Cancer 159

but foods from this group are rich sources of fats, oils and other substances that might affect

The majority of case-control studies suggested a positive link between meat consumption

Globally, meat and meat products account for 8.0% of the daily energy intake (FAO, 2011). On account of essential amino acids, fatty acids, vitamin B12, folates, iron, copper and zinc content, meat should be consumed on a daily basis. The amount and the percentage of fat in consumed meat, as well as the type of processing correlate with the incidence of colorectal malignancies (Gonzalez, 2006; Chan et al., 2011; Cross & Sinha, 2004). Risk factors associated with consumption of meat and meat products include nitrates, nitrites, N-nitroso compounds, heterocyclic amines and polycyclic aromatic carbohydrates. Iron is also considered to be a risk factor, because of its prooxidative properties (WCRF & AICR, 2007; Cross & Sinha, 2004; Eichholzer & Gutzwiller, 1998; Lanou & Svenson, 2010; Butler et al., 2003; Zheng et al., 2009). The overall evidence supports limiting red and processed meat intake in order to reduce the risk of colorectal cancer (WCRF & AICR, 2007; Key et al., 2004;

Dietary fatty acid composition plays a role in the process of carcinogenesis and tumor proliferation (WCRF & AICR, 2007; Fenech et al., 2011; WHO, 2008a; FAO, 2004; USDA & U.S. Department of Health and Human Services, 2011; Chan & Giovannucci, 2010; Hu et al., 2011a). The single most prominent issue responsible for global increase of total dietary fat and saturated fatty acids intake is the process of hydrogenation of oils (USDA & U.S. Department of Health and Human Services, 2011; Van Stuyvenberg, 1969). Total hydrogenation transforms unsaturated fatty acids from fish oil and plant oils to saturated fatty acids, while partial hydrogenation produces unsaturated trans-fatty acids. When consumed, trans-fatty acids act as saturated (USDA & U.S. Department of Health and Human Services, 2011; Van Stuyvenberg, 1969). WCRF (WCRF & AICR, 2007) and North Carolina Colon Cancer Study (Vinikoor et al., 2009) claim that specific effects of trans-fatty acids on cancer risk is not known, since positive correlation linking trans-fatty acids intake and overall cancer prevalence was detected using mailed food questionnaires (Hu et al.,

Data on health effects of fatty fish intake, the correlation between fatty fish intake and gastric cancer (Wu et al., 2011), breast cancer (Terry et al., 2003; Murff et al., 2011), prostate cancer (Terry et al., 2003; Allen et al., 2004) and colorectal cancer (Aune et al., 2009a; Vinikoor et al., 2009; Daniel et al., 2009) are inconsistent (Daniel et al., 2009). Long-chain polyunsaturated fatty acids from fish are seen as promising nutrients in cancer prevention, but currently there is not enough supportive scientific evidence. On the other hand, intake of α-linolenic acid might be a risk factor for cancer (Daniel et al., 2009; Colquhoun et al., 2009). New studies, both experimental and epidemiological, are necessary to shed more

The link between eggs consumption and cancer has not been researched as extensively. Currently, the evidence suggest that eggs intake may be linked to increase in colon, rectal, bladder and ovarian cancer risks, putting into consideration the use of dietary alternatives

to eggs (Zhang et al., 2003; Radosavljević et al., 2005; Aune et al., 2009).

and colorectal cancer risk (WCRF & AICR, 2007; Gonzalez, 2006; Chan et al., 2011).

cancer risks (Smolin & Grosvenor, 2010; USDA, 2011b).

Béliveau & Gingras, 2007; Kushi, 2006).

2011b).

light on these findings.

Heilbronn & Campbell, 2008). Lipopolysaccharides [LPS] from Gram negative bacteria (in altered gut microflora) promote secretion of inflammatory cytokines. LPS pass through intestinal wall, travel by chylomicrons to target organs where they promote inflammationinduced metabolic disorders (obesity, insulin resistance, macrophage infiltration into adipose tissue, liver steatosis). Bifidobacterium spp. as an important actor in healthy gut microflora, decreases the levels of intestinal endotoxins and enhances mucosal barrier function (Tuohy et al., 2005). Increasing the intake of prebiotics may be a beneficial strategy in keeping the number of Bifidobacterium spp. optimal and gut microflora healthy and functional, reducing low-grade inflammation (Tohuy et al., 2005; Cani et al., 2007b). According to Goodlad et al. "prebiotic dietary fibers may also modulate other targets prone to influence metabolic disorders associated with obesity, such as gut peptides" (Goodlad et al., 1987). Decreasing low-grade inflammation and beneficially influencing the body mass, prebiotics (together with probiotics) may be a factor in cancer risk reduction (Grey, 2006; Tuohy et al., 2005; Cani et al., 2007a; Goodlad et al., 1987; World Gastroenterology Organisation, 2008; Donaldson, 2004; Yan & Polk, 2010). Jain et al. indicated that certain synbiotics (combinations of prebiotics and probiotics) are more efficient in vivo than in either treatment alone, but that more research is needed to identify the most potent synbiotics (Jain et al., 2010).

#### **2.2.3 Milk and dairy products**

Milk and dairy products are sources of many essential nutrients, e.g. amino acids, fatty acids, lactose, vitamin D, vitamin A, vitamin B12, calcium, potassium and they are prerequisites for growth and development, as well as for optimal bone health (USDA & U.S. Department of Health and Human Services, 2011; Smolin & Grosvenor, 2010). The strength of evidence suggesting that intake of milk and dairy products is associated with reduced cardiovascular and type 2 diabetes risks and blood pressure lowering is moderate (Smolin & Grosvenor, 2010; Huth & al., 2006). A large number of epidemiological studies were conducted in order to explore the relations between milk and dairy products consumption and cancer risks, but the results were largely equivocal (Huth & al., 2006; Quigley, 2011; Järvinen, 2011; Van der Pols et al., 2007). Chronic excessive intake of dairy fat can promote development of malignancies, but certain fatty acids from milk, like conjugated linoleic acid [CLA] can inhibit cancer growth. Vitamin D3 may reduce the risk of prostate cancer. Calcium from milk and dairy products may have protective properties against colon cancer, while bovine lactoferrin from whey may inhibit colon carcinogenesis (Tsuda et al., 2000; Aune et al., 2011).

The aforementioned contradictory results do not undermine the importance of milk and dairy products in daily diet. Dietary Guidelines for Americans, 2010 recommendations for dairy intake are in accordance with cancer risk reduction (USDA & U.S. Department of Health and Human Services, 2011; Smolin & Grosvenor, 2010).

#### **2.2.4 Protein foods**

ChooseMyPlate nutrition guide classifies meat, fish, eggs and their products, legumes, nuts and seeds as protein foods (USDA, 2011b). Proteins have not been linked with increase in obesity, diabetes or cancer risks (WHO, 2007a; Joslin Diabetes Center & Joslin Clinic, 2007),

Heilbronn & Campbell, 2008). Lipopolysaccharides [LPS] from Gram negative bacteria (in altered gut microflora) promote secretion of inflammatory cytokines. LPS pass through intestinal wall, travel by chylomicrons to target organs where they promote inflammationinduced metabolic disorders (obesity, insulin resistance, macrophage infiltration into adipose tissue, liver steatosis). Bifidobacterium spp. as an important actor in healthy gut microflora, decreases the levels of intestinal endotoxins and enhances mucosal barrier function (Tuohy et al., 2005). Increasing the intake of prebiotics may be a beneficial strategy in keeping the number of Bifidobacterium spp. optimal and gut microflora healthy and functional, reducing low-grade inflammation (Tohuy et al., 2005; Cani et al., 2007b). According to Goodlad et al. "prebiotic dietary fibers may also modulate other targets prone to influence metabolic disorders associated with obesity, such as gut peptides" (Goodlad et al., 1987). Decreasing low-grade inflammation and beneficially influencing the body mass, prebiotics (together with probiotics) may be a factor in cancer risk reduction (Grey, 2006; Tuohy et al., 2005; Cani et al., 2007a; Goodlad et al., 1987; World Gastroenterology Organisation, 2008; Donaldson, 2004; Yan & Polk, 2010). Jain et al. indicated that certain synbiotics (combinations of prebiotics and probiotics) are more efficient in vivo than in either treatment alone, but that more research is needed to identify the most potent

Milk and dairy products are sources of many essential nutrients, e.g. amino acids, fatty acids, lactose, vitamin D, vitamin A, vitamin B12, calcium, potassium and they are prerequisites for growth and development, as well as for optimal bone health (USDA & U.S. Department of Health and Human Services, 2011; Smolin & Grosvenor, 2010). The strength of evidence suggesting that intake of milk and dairy products is associated with reduced cardiovascular and type 2 diabetes risks and blood pressure lowering is moderate (Smolin & Grosvenor, 2010; Huth & al., 2006). A large number of epidemiological studies were conducted in order to explore the relations between milk and dairy products consumption and cancer risks, but the results were largely equivocal (Huth & al., 2006; Quigley, 2011; Järvinen, 2011; Van der Pols et al., 2007). Chronic excessive intake of dairy fat can promote development of malignancies, but certain fatty acids from milk, like conjugated linoleic acid [CLA] can inhibit cancer growth. Vitamin D3 may reduce the risk of prostate cancer. Calcium from milk and dairy products may have protective properties against colon cancer, while bovine lactoferrin from whey may inhibit colon carcinogenesis (Tsuda et al., 2000;

The aforementioned contradictory results do not undermine the importance of milk and dairy products in daily diet. Dietary Guidelines for Americans, 2010 recommendations for dairy intake are in accordance with cancer risk reduction (USDA & U.S. Department of

ChooseMyPlate nutrition guide classifies meat, fish, eggs and their products, legumes, nuts and seeds as protein foods (USDA, 2011b). Proteins have not been linked with increase in obesity, diabetes or cancer risks (WHO, 2007a; Joslin Diabetes Center & Joslin Clinic, 2007),

Health and Human Services, 2011; Smolin & Grosvenor, 2010).

synbiotics (Jain et al., 2010).

Aune et al., 2011).

**2.2.4 Protein foods** 

**2.2.3 Milk and dairy products** 

but foods from this group are rich sources of fats, oils and other substances that might affect cancer risks (Smolin & Grosvenor, 2010; USDA, 2011b).

The majority of case-control studies suggested a positive link between meat consumption and colorectal cancer risk (WCRF & AICR, 2007; Gonzalez, 2006; Chan et al., 2011).

Globally, meat and meat products account for 8.0% of the daily energy intake (FAO, 2011). On account of essential amino acids, fatty acids, vitamin B12, folates, iron, copper and zinc content, meat should be consumed on a daily basis. The amount and the percentage of fat in consumed meat, as well as the type of processing correlate with the incidence of colorectal malignancies (Gonzalez, 2006; Chan et al., 2011; Cross & Sinha, 2004). Risk factors associated with consumption of meat and meat products include nitrates, nitrites, N-nitroso compounds, heterocyclic amines and polycyclic aromatic carbohydrates. Iron is also considered to be a risk factor, because of its prooxidative properties (WCRF & AICR, 2007; Cross & Sinha, 2004; Eichholzer & Gutzwiller, 1998; Lanou & Svenson, 2010; Butler et al., 2003; Zheng et al., 2009). The overall evidence supports limiting red and processed meat intake in order to reduce the risk of colorectal cancer (WCRF & AICR, 2007; Key et al., 2004; Béliveau & Gingras, 2007; Kushi, 2006).

Dietary fatty acid composition plays a role in the process of carcinogenesis and tumor proliferation (WCRF & AICR, 2007; Fenech et al., 2011; WHO, 2008a; FAO, 2004; USDA & U.S. Department of Health and Human Services, 2011; Chan & Giovannucci, 2010; Hu et al., 2011a). The single most prominent issue responsible for global increase of total dietary fat and saturated fatty acids intake is the process of hydrogenation of oils (USDA & U.S. Department of Health and Human Services, 2011; Van Stuyvenberg, 1969). Total hydrogenation transforms unsaturated fatty acids from fish oil and plant oils to saturated fatty acids, while partial hydrogenation produces unsaturated trans-fatty acids. When consumed, trans-fatty acids act as saturated (USDA & U.S. Department of Health and Human Services, 2011; Van Stuyvenberg, 1969). WCRF (WCRF & AICR, 2007) and North Carolina Colon Cancer Study (Vinikoor et al., 2009) claim that specific effects of trans-fatty acids on cancer risk is not known, since positive correlation linking trans-fatty acids intake and overall cancer prevalence was detected using mailed food questionnaires (Hu et al., 2011b).

Data on health effects of fatty fish intake, the correlation between fatty fish intake and gastric cancer (Wu et al., 2011), breast cancer (Terry et al., 2003; Murff et al., 2011), prostate cancer (Terry et al., 2003; Allen et al., 2004) and colorectal cancer (Aune et al., 2009a; Vinikoor et al., 2009; Daniel et al., 2009) are inconsistent (Daniel et al., 2009). Long-chain polyunsaturated fatty acids from fish are seen as promising nutrients in cancer prevention, but currently there is not enough supportive scientific evidence. On the other hand, intake of α-linolenic acid might be a risk factor for cancer (Daniel et al., 2009; Colquhoun et al., 2009). New studies, both experimental and epidemiological, are necessary to shed more light on these findings.

The link between eggs consumption and cancer has not been researched as extensively. Currently, the evidence suggest that eggs intake may be linked to increase in colon, rectal, bladder and ovarian cancer risks, putting into consideration the use of dietary alternatives to eggs (Zhang et al., 2003; Radosavljević et al., 2005; Aune et al., 2009).

Lifestyle Changes May Prevent Cancer 161

in phytochemicals has grown substantially over the years and it has not lessen, although screening for potential chemopreventive molecules requires a systematic and wide-range approach (Tan et al., 2011; Milner, 2004). In order to reduce the risk of cancer in human population, many experiments studying herbs and spices and their effects on carcinogenesis were conducted on animals. The possibility of using herbs and spices as substitutes for unhealthy food constituents (e.g added sugars, added fat, table salt) can contribute to

If phytochemicals are added to foods, such foods become functional. Functional foods are foods that provide healthy benefits beyond basic nutrition, when consumed as part of a varied diet on a regular basis, at effective levels (ADA, 2009; Howlett, 2008). According to some authors, health effects of consuming functional foods containing bioactive substances or pharmaceuticals may be as beneficial as consumption of those substances from their natural sources (Howlett, 2008). Other authors claim that chemopreventive properties of fruits and vegetables are a result of synergistic and additive effects of phytochemicals acting together in their natural environment, and therefore, cannot be imitated by functional foods

Global use of dietary supplements containing vitamins, minerals and other bioactive compounds, although already enormous, is still on the rise. Dietary supplements can reduce the risk of deficiencies and promote optimal health, but should not be considered substitutes for a well-balanced, healthy diet (Mason, 2007). Evidence supporting the use of dietary supplements in cancer risk reduction are scarce, so population-based recommendation is to increase the percentage of people who are achieving optimal nutrition without the use of dietary supplements (WCRF & AICR, 2007; Myung et al., 2009). Determination of oxidative stress-based biomarkers should be regarded as "indication" for using antioxidant

Mediterranean diet is considered to be protective against cancers, opposite to USA and Northern Europe diet patterns. Adoption of Mediterranean eating pattern in USA and Northern Europe may help cancer risk reduction (Simopoulos, 2001; Verberne et al., 2010).

Regular physical activity, besides leading to fitness, provides many health benefits (Warburton et al., 2006; Miles, 2007). Physical activity increases overall well-being, and if regular, improves quality of life, helps body mass maintenance and therefore, reduces cancer risks (WCRF & AICR, 2007; WHO, 2003, 2005, 2008a, 2009b; AICR & WCRF, 2009). Cancer risks in regularly physically active are up to 40.0% lower than among physically

Insufficient physical activity is considered to be the fourth leading risk factor in overall mortality. WHO holds insufficient physical activity responsible for 6.0% of global deaths (WHO, 2009a). Dropping levels of physical activity worldwide are in part responsible for rising prevalence of NCDs, including cardiovascular diseases, diabetes and cancer (WCRF & AICR, 2007; WHO, 2005, 2009a; Fair & Montgomery, 2009; AICR & WCRF, 2009; Newton & Galvão, 2008; Tucker et al., 2011; Hardman et al., 2011; Wannamethee et al., 2001). Insufficient physical activity accounts for 21.0-25.0% of breast and colon cancer burden

supplements (Ziech et al., 2010), although this is not financially viable yet.

chemopreventive potential of herbs and spices (Tapsell et al., 2006).

(Tapsell et al., 2006; Liu, 2003; Milner, 2006b).

**2.3 Physical activity** 

(WHO, 2009a, 2010a)

inactive (Newton & Galvão, 2008).

Legumes are known to be beneficial in cardiovascular and type 2 diabetes risk reduction, but there is limited evidence that legumes consumption may reduce the risk of stomach, colorectal, and kidney cancer. Further investigations of these complex relations are still waited upon (Kolonel et al., 2000; Aune et al., 2009b).

Effects of nuts and seeds intake on cancer risks are limited and inconclusive (WCRF & AICR, 2007).

Aflatoxin contamination of fungus-contaminated crops and legumes remains a serious food safety problem, as aflatoxin is known to be a risk for liver cancer (Goldman & Shields, 2003; Wogan et al., 2004).
