Introduction
In most healthy eating pyramids, fruits and vegetables are found at the bottom, as along with wholegrain cereals, they are the foods which should make the greatest contribution to our diet. Most fruits and vegetables are relatively low in calories, have a low glycemic index and are rich sources of micronutrients, dietary fibre and non-nutrient substances called phytochemicals which are thought to contribute towards their significant protective effect upon some of the most important diet-related diseases such as cardiovascular disease, cancer and many more.
We should be aiming to include at least 2 servings of fruit and 5 servings of vegetables in our diet each day. Although some varieties are thought to be more healthy than others, it is not known for sure which fruits and vegetables are the absolute best, which is why it is important to include a wide variety in our diet.
Although some of the potentially disease preventing substances in these foods have been identified, it is not know for sure which ones are responsible. Furthermore, there may be thousands of these phytochemical substances involved in their protective effects, many which may not have even been discovered yet. Consequently, dietary supplements make a poor substitute.
Some of the beneficial effects of fruits and vegetables as well as which ones are thought to be of the greatest benefit are discussed below.
Cancer
It has been suggested that a healthy diet can reduce the risk of cancer by at least 30-40%, [1] though some experts suggest that some of the more common cancers may potentially be reduced by up to 70%, purely through dietary strategies.[2] Studies suggest that one of the most important dietary factors thought to protect against cancer is a higher intake of fruits and vegetables. [2-4]
Not all cancers are associated with fruit and vegetable intake, however the risk of cancers of the mouth, esophagus, stomach, lung, colon and rectum are thought to be most likely affected. There is at least some good evidence however to suggest that fruits and veggies also protect against cancers of the pharynx, larynx, ovary, pancreas bladder and kidney. [5-8]
Studies which look only at total intake however may not always take into consideration that certain types of fruits and vegetable are thought to possess more powerful cancer protective properties than others. [9] For example, specific fruits like pomegranate and tomatoes may also decrease the risk of prostate cancer, even though ‘total' fruit intake may not. Some of these specific examples are discussed further on.
Cardiovascular Disease (CVD)
Large, well designed population studies have found that higher intakes of fruits and vegetables can decrease the risk of heart disease by approximately 20-30%.[10] Although the exact mechanism behind their protective effects vary and are not fully understood, fruits and vegetables are rich in soluble fibre, potassium, folic acid and phytochemicals which can lower blood cholesterol, blood pressure, homocysteine levels as well as protect against LDL-cholesterol oxidation. Various fruits and vegetables may also relax blood vessels, decrease platelet aggregation (blood stickiness) and reduce inflammation. [11]
Eye related problems.
Population studies have found that higher intakes of fruit and vegetables can decrease the risk of age related eye problems such as cataracts macular degeneration.[12-16] It is thought that certain dietary antioxidants protect against free radical damage involved in the pathogenesis of these diseases. The carotenoids lutein and zeaxanthin may be at least in part responsible, as they tend to accumulate in tissues of the eye. [17]
Other Diseases
Because fruits and vegetables are rich in fibre, they are able to prevent bowel problems such as constipation and diverticulosis. [18,19]
In addition to gastrointestinal problems, because age-related memory problems such as senile dementia and Alzheimer's disease are hypothesized to be attributed at least in part to oxidative damage, higher intake of certain plant foods are though to decrease the risk of these problems, presumably due to their antioxidant effects. Some evidence from laboratory investigations suggest that berries [20,21] tomatoes [22] and apples [23] may offer some protection, however evidence from human studies is lacking.
Recommendations
The National Health and Medical Research Council, a division of the Department of Health and Ageing, has recommended that Australians consume at least 2 servings of fruit and 5 servings of vegetables per day. [24] A standard serving of fruit is equivalent to 1 medium piece of fruit (for example, an apple) or 2 small pieces (example, apricots). A standard serving of vegetables would equate to approximately enough to fill half to 1 cup. Servings for children should be adjusted appropriately. Processed and packaged fruit and vegetable foods do lose some nutrients, so they are generally considered approximately half of that if they were fresh. Fruits and Veggies should be washed under the tap before Ppreparation and consumption. For more information on what defines standard servings of fruit and vegetables, visit healthyactive.gov.au.
A Major Problem
The National Nutrition Survey published by the Australian Institute of Health and Welfare, found that a significant proportions of Australians do not meet the recommended intakes for fruit and vegetable consumption. [25] The Survey found that only 60% of women and less than 50% of men consumed two or more serves of fruit per day, and about 35% of women and less than 30% of men consumed four or more serves of vegetables. Among children, just 56% of boys and 62% of girls ate fruit on the day before the interview.
This is a major problem in terms of public health, as a significant portion of chronic, age-related diseases could be prevented if more people obtained adequate fruit and vegetable intake. One of the major reasons that adults intake is poor, is probably because they do not acquire a taste for these foods throughout childhood. Because dietary habits are often developed through childhood, it is absolutely crucial that parents and schools promote fruit and vegetable consumption throughout childhood, so that children acquire a taste for these foods and continue to eat them throughout their adult life.
The issue of developing healthy dietary habits through childhood is the reason that a great portion of nutrition related health promotion programs target schools and parents. [26-28] Recently, some schools have adopted a ‘fruit break'; a short break in the middle of the school day where children eat a serving of fruit. [29]
I have worked with schools and dealt with teachers and parents regarding this very important issue. From the feedback I have received, a lot of parents do not understand or grossly underestimate the importance of developing good eating practices during childhood. Moreover, a lot of parents and teachers are reluctant to consider these issues worthwhile trying to address.
The majority of feedback I have received from parents who participated in healthy eating programs (involving attending seminars and cooking workshops) suggests that once they are adequately informed enough to understand the importance of this issue, they are more likely to implement appropriate changes and encourage healthy eating among their family. After equipping parents with the appropriate knowledge and skills, getting them to care enough to want to make a difference was not difficult. The difficult part was getting them to care enough to turn up in the first place.
If you are a parent of school aged children and have concerns regarding this issue, please approach your school and advise them to contact Nutrition Australia, who can arrange for consultant nutritionists to work with your school to devise an appropriate heath promotion program.
Which are the best?
As mentioned previously, ‘total' fruit and vegetable intake may not always show protective results in population studies, because some plant foods are probably more healthy than others. It is important to emphasize however that no one ‘super food' contains all the nutrients and phytochemicals necessary to fight dietary related diseases. Furthermore, different fruits and vegetables contain different amounts and classes of protective substances; the most protective of which are not known. Consequently, it is very important to obtain a wide variety of fruits and vegetables, rather than simply relying on only a small handful. Obtaining a wide variety ensures a higher probability of obtaining the best disease-fighting substances. [2]
Having said this however, there is some evidence from population studies and especially from laboratory studies to suggest that certain fruits and vegetables are perhaps healthier than others. They are briefly discussed below.
Carotenoid-Rich Fruits and Vegetables
Higher intake of dark green leafy vegetables such as spinach as well as bright red, orange and yellow colored fruits and vegetables such as and carrots, appear to be especially protective against cancers such as lung cancer [30,31] and colon cancer, [32] whilst dark red coloured varieties such as tomatoes appear to be protective against prostate cancer. [33,34]
Some of the substances which give these foods their colour (pigment) called carotenoids (such as Astaxanthin, Cryptoxanthin, Lutein, Zeaxanthin alpha-carotene, beta-carotene and lycopene ) are thought to be at least in part responsible for their chemo-protective effect. [35-37]
Because large clinical trials have found no protection among people given supplements of specific carotenoids such as beta-carotene, it is important to note that the protective effect more than likely comes from the combination of many phytochemicals and fibres found in these foods; of which carotenoids make only a small portion.[38]
Higher intake of cruciferous vegetables has also been found to be protective against cancers of the digestive tract and lung. [39-41] These vegetables, sometimes referred to as the ‘brassica' family, include broccoli, cabbage, Brussels sprouts and cauliflower, which contain a class of phytochemicals called Glucosinolates that break down to form isothiocyanates and indoles. These metabolites possess several anti-carcinogenic mechanisms; most notably their ability to induce phase II conjugating enzymes. [42,43]
Vegetables from the allium family such as garlic, onion and leeks are also significantly associated with a reduction in the risk of certain cancers, particularly gastric and colorectal cancer. [44] These vegetables contain a class of sulphur containing substances such as allium, which possess a range of cancer fighting mechanisms including the ability to protect against DNA and chromosomal damage, potent antioxidant activity as well as the ability to detoxify or deactivate carcinogens (cancer-causing substances) by acting on certain enzymes involved with their metabolism . [45]
Allium vegetables such as garlic may also defend against CVD. Animal studies have found that garlic can protect against atherosclerosis, whilst clinical trials have found that garlic may lower blood pressure as well as total, LDL cholesterol and triglyceride levels. Furthermore, garlic improves fibinolytic activity, and protects against LDL-cholesterol oxidation; [46] all factors thought to contribute towards its cardio-protective properties. More detailed information on the health benefits of garlic can be found here.
Some population studies have observed a decrease in the risk of CVD, asthma, diabetes and certain cancers among higher consumers of apples. Apples are a rich source of phytochemicals such as quercetin, catechin, phloridzin and chlorogenic acid, though which substances are responsible for these disease protective effects are not known. [47]
Apples may protect against CVD due to their ability to lower cholesterol levels and inhibit LDL oxidation, whilst their potent antioxidant and anti-mutagenic effects are thought to be responsible for their cancer preventive effects. [48]
Citrus fruits include oranges, lemons, limes, pineapples and grapefruit. These fruits are a rich source of soluble fibre, poatassium, folic acid, vitamin C, carotenoids and other phytochemicals such as limonoids [49,50] and tangeretin [51] which have all been thought to contribute towards their protective effect on CVD and cancer. Laboratory studies have found that flavanone and flavone O- and C-glycosides and methoxylated flavones found in citrus fruits, possess anti-inflammatory and anti-carcinogenic actions, thought to be due to the way that they interact with certain regulatory enzymes involved in cell activation and receptor binding. [52] Recent clinical trials have revealed that red grapefruit juice, rich in the phytochemical naringin, may favorably affect serum lipid levels,[53]however grapefruit may also interact with certain medications.
Berries are rich in anthocyanadins and quercetin. Additionally, blueberries are rich in chlorogenic acid, cranberries are rich in benzoic acid, whilst strawberries are rich in ellagic acid and kaempferol . These foods are thought to protect against CVD by improving arterial relaxation, capillary permeability and decrease platelet aggregation. They may help to defend against age related memory loss (dementia) and macular degeneration due to their antioxidant activity. [54,55] Laboratory investigations also suggest that they may possess anti-carcinogenic activity. [55,56] Cranberries may also help defend against urinary tract infections.[54]
Grapes are a rich source of fllavonoids such as delphinidin, quercetin and resveratrol, as well as other procyanadins and anthocyanadins;[57] levels of which are particularly high in the skins and seeds. [58] Grapes may protect against CVD by improving cholesterol levels and decreasing LDL oxidation as well as exerting beneficial effects on blood clotting and nitric oxide metablolism. [59] Furthermore, resveratrol has demonstrated a significant anti-cancer action in laboratory studies. [60]
Turmeric, the main ingredient in curry, is rich in the phytochemical curcumin which has been shown to possess a wide range of protective mechanisms, specifically in regards to cancer protection; an effect which has been observed in preliminary population studies. Curcumin may protect against various diseases such as cancer due its anti-inflammatory, anti-angiogenic and antioxidant mechanisms.[61]
Pomegranate polyphenols (including ellagitannins and anthocyanins) have demonstrated significant cardio-protective effects in laboratory studies; inhibiting the progression of atherosclerosis in animals, presumably by protecting against LDL cholesterol oxidation [62] and protecting the blood vessels by improving expression of endothelial nitric oxide. [63] Clinical trials have shown that consumption of pomegranate juice may protect against CVD by lowering serum cholesterol levels, [64] decreasing systolic blood pressure and most importantly, protecting against atherosclerosis by improving intima-media thickness of the arteries.[65]
Pomegranate is also thought to protect against cancer; demonstrating significant protection against prostate cancer in laboratory studies, [66] presumably by modulating cellular transcription factors and signaling proteins. [67] Preliminary results from recent clinical trials found that giving pomegranate juice to prostate cancer patients increased the PSA doubling time from 14 to 26 months after surgery, increased cancer cell death and decreases cancer cell proliferation.[68]
Laboratory investigations suggest that kiwifruit phytochemicals may possess a range of beneficial effects on cardiovascular health [69] as well as possessing anti-cancer effects by protecting against oxidative DNA damage.[70] Clinical trials have shown that consuming 2-3 kiwifruit daily can have a blood thinning effect and lower serum triglyceride levels, thus suggesting a cardio-protective role. [71]
Variety
It is important to note however that because it is not known precisely which of these foods the absolute best are, it is important to obtain a wide variety as part of a healthy diet. Many other fruits and vegetables are rich sources of micronutrients, phytochemicals and fibre. The majority of these foods also have a low glycaemic index (G.I), making them useful in the fight against diabetes by lowering blood sugar levels. Exceptions to this rule however include watermelon, pumpkin and white potatoes, which all have a high G.I. [72]
Juicing
At least part of the reason why higher intakes of plant foods offer protection against cancer and CVD is due to their fibre content; one of the most important components. Population studies have provided an abundance of evidence to show that higher intakes of dietary fibre decreas the risk of certain cancers, particularly colorectal cancer, [73] whilst clinical trials show that soluble fibres from fruits and vegetables can lower serum cholesterol levels. [74]
Additionally, the skins and seeds of certain fruits such as apples and grapes are the richest source of phytochemicas thought to offer disease protective effects. Because most of the skin and fibrous material is filtered out during the production of juices, consuming fruit and vegetable juice, whilst providing some nutrients and phytochemicals, is generally considered a poor substitute for eating them whole. Furthermore, some fruit juices can contain high concentrations of sugar,[75] contributing towards total caloric intake which, if not utilized as energy, will contribute towards weight gain.
Supplements
When I give seminars on nutrition-related topics, I often ask the audience why they think that fruit and vegetables are so important and how they decrease the risk of serious diseases. Inevitably, I will either be told that it is because they are a good source of vitamins and minerals, or a good source of antioxidants.
This is certainly true, however as I explain to them, these substances can also be consumed as a supplement, yet do not offer the same protection. In regards to micronutrients [vitamins and minerals] it is true that fruits and vegetables are generally good sources of certain vitamins such as vitamins A, C and folic acid, as well as minerals such as potassium; all important in protecting against cardiovascular disease. It is the phytochemicals and the fibres however which are more likely to be responsible for their disease preventing effects.
Anti-oxidants
Whilst many of these substances to possess an anti-oxidant action, I believe that the importance of ‘anti-oxidants' are significant over-played by the media and popular press. Vitamins such as vitamins C, E and beta carotene act as anti-oxidants, yet supplemental doses do not decrease the risk of diseases they are thought o protect against such as CVD and cancer.
It is important to understand firstly, that whilst anti-oxidants protect against lipid oxidation and free radicals, the pathogenesis of CVD and Cancer involves a lot more than these factors. [76] Consequently, substances that provide only an anti-oxidant effect will have very limited protection against such diseases.
To give an example, it is known that large supplemental doses of the antioxidant vitamin alpha-tocopherol (vitamin E) decreases the susceptibility to low-density lipoprotein (LDL) ‘bad' cholesterol oxidation (which is a significant contributing factor in the pathogenesis of coronary heart disease). [77] Population studies have revealed that diets high in vitamin E rich foods such as nuts, [78] olive oil [79] and whole grain cereal foods [80] significantly decrease the risk of heart disease. Despite these observations, large well-designed clinical trials have generally failed to find any reduction in the incidence of heart attacks between subjects given vitamin E supplements, and those given a placebo over several years. [81]
To give another example, this time using cancer as the model; it is well known that tea, particularly green tea , possesses a very potent antioxidant action (far greater than that of vitamin E, and far greater than that of most fruits and vegetables).[82] Most well designed population studies however have failed to find the same reduction in the risk of cancer among higher green tea drinkers as higher consumers of fruits and veggies, despite the huge difference in anti-oxidant activity.[83-87]
Whilst many of the phytochemicals found in fruits and vegetables do have an anti-oxidant action, they also possess a plethora of disease preventing mechanisms which substances such as anti-oxidant vitamins do not. They are frequently able to inhibit cholesterol synthesis in the liver as well as interfering with enzymes involved in carcinogenesis, thus contributing towards their cardio-protective and chemo-protective mechanisms. [9, 36,37,43,54,59,88]
As a result, taking vitamin supplements, even those with an anti-oxidant action, will do little to protect against these serious diseases compared with ensuring adequate intake of fruits and vegetables. The results from the National Nutrition Survey tell us that the average intake of vitamins and minerals exceed the recommended dietary intake levels, however the average fruit and vegetable intake needs significant improvement. [25]
Phytochemical Supplements
Mentioned under the headings of each fruit and vegetables discussed, are some of the phytochemicals they contain, thought to contribute towards their disease preventing effects. As a result of this preliminary knowledge, some supplement companies may even include some of these phytochemicals in their products in the hope of leading consumers to believe that they will offer the same protection that eating fruits and vegetables would have.
It is important to understand that the phytochemicals mentioned are only a very small handful of those contained in these foods. To give an example, I mentioned that Allicin was an important phytchemical found in garlic thought o contruibute towards its healthy effects. In actual fact, garlic contains many more phytoechamials which are chemically very similar, however simply don't get mentioned as much or have not been studied in as much detail. They include , S-allyl cysteine and diallyl-di-sulfide which have been shown to be able to inhibit cholesterol synthesis in the liver, [89, 90] Ethyl acetate increases fibrinolytic activity whilst decreasing LDL cholesterol and triglyceride levels. [91] Adenosine and polysulfides have been identified has having anti-platelet activity. [92] Ajoene (a product of allicin decomposition ) inhibits the activity of phorbol myristate acetate (PMA) – a chemical used to promote tumours., [93] plus other organosulphides found in garlic which may contribute towards its favourable health effects include diallyl disulphide, dimethyl-, methyl alIyI sulphides, dimethyl-, dipropyl- allyl propyl- and methyl allyl disulphides, dimethyl-, diallyl- and methylallyl trisulfides, methyl propyl trisulphide, diallyl thi-sulphinate, and sulphur dioxide. [94,95]
Likewise, all the fruits and vegetables discussed above contain vast numbers of differing phytochemicals, only a handful of which have been studied and even smaller numbers of them included in supplements. Put simply, many of the protective substances in these foods may not have even been discovered yet, and even if they had, there would be too many to simply it into a pill, powder or potion.
After after one particular lecture, an audience meber approached me later on, telling me that she took a supplement sold by a Multilevel Marketing distributor, and after reading the label, ensured me that it contained ‘everything'. Consumers should not be fooled by reading the labels of some supplements which may contain some of these phytochemicals as well as the usual vitamins and minerals. As I assured this person, absolutely no supplement contains ‘everything', nor would it even come close.
The bottom line is that if you want the protective effects that fruit and vegetable consumption have, there is no other way than to eat them. Jjuices are a poor substitute, phytochemical supplements an even poorer substitute, and vitamin supplements poorer still. More information on the topic of supplements can be found here.
Article by Stuart J. Adams: Nutritionist, Author and Speaker
Photography by Chi Tan: Psychologist and Photographer
REFERENES
[1] World Cancer Research Fund (WCRF) and American Institute for Cancer Research (AICR) 1997. Food, nutrition and the prevention of cancer: a global perspective . New York : AICR.
[2] Donaldson MS . Nutrition and cancer: a review of the evidence for an anti-cancer diet. Nutr J. 2004 Oct 20;3:19.
[3] Mathers C, Vos T & Stevenson C 1999. The burden of disease and injury in Australia . Canberra : Australian Institute of Health and Welfare.
[4] Riboli E, Norat T. Epidemiologic evidence of the protective effect of fruit and vegetables on cancer risk.Am J Clin Nutr. 2003;78:559S-569S.
[5] World Cancer Research Fund (WCRF) and American Institute for Cancer Research (AICR) 1997. Food, nutrition and the prevention of cancer: a global perspective . New York : AICR.
[6] World Health Organization (WHO) & Food and Agriculture Organization (FAO) 2003. Diet, nutrition and the prevention of chronic diseases: report of a joint WHO/FAO expert consultation . WHO Technical Report Series916. Geneva : WHO.
[7] United Kingdom Department of Health (UKDH) 1998. Nutritional aspects of the development of cancer. Report of the Working Group on Diet and Cancer of the Committee on the Medical Aspects of the FoodSupply . Norwich : The Stationery Office.
[8] Vainio H, Bianchini F. IARC Handbooks of Cancer Prevention: Fruit and Vegetables. Vol. 8. Lyon , France , 2003.
[9] Nishino H, Tokuda H, Satomi Y, Masuda M, Onozuka M, Yamaguchi S, Takayasu J, Tsuruta J, Takemura M, Ii T, Ichiishi E, Kuchide S, Okuda M, Murakoshi M. Cancer Chemoprevention by Phytochemicals and their Related Compounds. Asian Pac J Cancer Prev. 2000;1(1):49-55.
[10]Ovesen LF. Increased consumption of fruits and vegetables reduces the risk of ischemic heart diseaseUgeskr Laeger. 2005 Jun 20;167(25-31):2742-7
[11] Lampe JW. Health effects of vegetables and fruit: assessing mechanisms of action in human experimental studies. Am J Clin Nutr. 1999 Sep;70(3 Suppl):475S-490S.
[12] Vaicaitiene R , Luksiene DK , Paunksnis A , Cerniauskiene LR , Domarkiene S , Cimbalas A . Age-related maculopathy and consumption of fresh vegetables and fruits in urban elderly. Medicina ( Kaunas ). 2003;39(12):1231-6.
[13] Cho E , Seddon JM , Rosner B , Willett WC , Hankinson SE . Prospective study of intake of fruits, vegetables, vitamins, and carotenoids and risk of age-related maculopathy. Arch Ophthalmol. 2004 Jun;122(6):883-92.
[14] . Brown L, Rimm EB, Seddon JM, et al. A prospective study of carotenoid intake and risk of cataract extraction in US men. Am J Clin Nutr 1999; 70:517-24.
[15] Moeller SM, Taylor A, Tucker KL, et al. Overall adherence to the dietary guidelines for americans is associated with reduced prevalence of early age-related nuclear lens opacities in women. J Nutr 2004; 134:1812-9.
[16] Krinsky NI, Landrum JT, Bone RA. Biologic mechanisms of the protective role of lutein and zeaxanthin in the eye. Annu Rev Nutr 2003; 23:171-201.
[17] Stringham JM , Hammond BR Jr . Dietary lutein and zeaxanthin: possible effects on visual function. Nutr Rev. 2005 Feb;63(2):59-64.
[18] Lembo A, Camilleri M. Chronic constipation. N Engl J Med 2003; 349:1360-8.
[19] Aldoori WH, Giovannucci EL, Rockett HR, Sampson L, Rimm EB, Willett WC. A prospective study of dietary fiber types and symptomatic diverticular disease in men. J Nutr 1998; 128:714-9.
[20] Joseph JA, Fisher DR, Carey AN. Fruit extracts antagonize Abeta- or DA-induced deficits in Ca2+ flux in M1-transfected COS-7 cells. J Alzheimers Dis. 2004 Aug;6(4):403-11; discussion 443-9.
[21] Joseph JA, Denisova NA, Arendash G, et al. Blueberry supplementation enhances signaling and prevents behavioral deficits in an Alzheimer disease model. Nutr Neurosci. 2003;6(3):153-162.
[22] Suganuma H, Hirano T, Arimoto Y, Inakuma T. Effect of tomato intake on striatal monoamine level in a mouse model of experimental Parkinson's disease. J Nutr Sci Vitaminol ( Tokyo ). 2002;48(3):251-254.
[23] Tchantchou F , Graves M , Ortiz D , Rogers E , Shea TB . Dietary supplementation with apple juice concentrate alleviates the compensatory increase in glutathione synthase transcription and activity that accompanies dietary- and genetically-induced oxidative stress. J Nutr Health Aging. 2004;8(6):492-6.
[24] NHMRC, Dietary Guidelines for all Australians. Publications available at: http://www.nhmrc.gov.au/publications/synopses/dietsyn.htm
[25] McLennan W, Podger A. National Nutrition Survey. Nutrient intakes and physical measurements. Australia 1995. Canberra : Australian Bureau of Statistics, 1998. (Catalogue No. 4805.0.)
[26] North Coast Area Health Service; Tooty Fruity Vegie. Available at http://www.ncahs.nsw.gov.au/tooty-fruity/
[27] Nutrition Australia – Lets Get Fruity. Available at http://www.nutritionaustralia.org/newtemplate%2Dfruity.asp
[28] Dep Health and Ageing. Go for 2 fruit and 5 veg. Available at http://healthyactive.gov.au/2and5/index.htm
[29] Healthy eating rewards, Newcastle Herald 21/6/05.
[30] Mannisto S, Smith-Warner SA, Spiegelman D, Albanes D, Anderson K, van den Brandt PA, Cerhan JR, Colditz G, Feskanich D, Freudenheim JL, Giovannucci E, Goldbohm RA, Graham S, Miller AB, Rohan TE, Virtamo J, Willett WC, Hunter DJ. Dietary carotenoids and risk of lung cancer in a pooled analysis of seven cohort studies. Cancer Epidemiol Biomarkers Prev. 2004 Jan;13(1):40-8.
[31] Smith-Warner SA, Spiegelman D, Yaun SS, Albanes D, Beeson WL, van den Brandt PA, Feskanich D, Folsom AR, Fraser GE, Freudenheim JL, Giovannucci E, Goldbohm RA, Graham S, Kushi LH, Miller AB, Pietinen P, Rohan TE, Speizer FE, Willett WC, Hunter DJ. Fruits, vegetables and lung cancer: a pooled analysis of cohort studies. Int J Cancer. 2003 Dec 20;107(6):1001-11.
[32] Slattery ML, Benson J, Curtin K, Ma KN, Schaeffer D, Potter JD. Carotenoids and colon cancer.Am J Clin Nutr. 2000 Feb;71(2):575-82.
[33] Giovannucci E . Tomato products, lycopene, and prostate cancer: a review of the epidemiological literature. J Nutr. 2005 Aug;135(8):2030S-1S.
[34] Campbell JK, Canene-Adams K, Lindshield BL, Boileau TW, Clinton SK , Erdman JW Jr. Tomato phytochemicals and prostate cancer risk. J Nutr. 2004 Dec;134(12 Suppl):3486S-3492S
[35] Nishino H , Murakoshi M , Mou XY , Wada S , Masuda M , Ohsaka Y , Satomi Y , Jinno K . Cancer prevention by phytochemicals. Oncology. 2005;69 Suppl 1:38-40. Epub 2005 Sep 19.
[36] LANDRUM, J.T.,BONE, R.A. and HERRERO, C. Astaxanthin, Cryptoxanthin, Lutein, and Zeaxanthin. In. Phytochemicals in Nutrition and Health., CRC Press LLC. 2002
[37] Burri, B.J. Lycopene and Human Health. In. Phytochemicals in Nutrition and Health., CRC Press LLC. 2002
[38] Neuhouser ML, Patterson RE, Thornquist MD, Omenn GS, King IB, Goodman GE. Fruits and vegetables are associated with lower lung cancer risk only in the placebo arm of the beta-carotene and retinol efficacy trial (CARET). Cancer Epidemiol Biomarkers Prev. 2003 Apr;12(4):350-8.
[39] Seow A, Vainio H, Yu MC. Effect of glutathione-S-transferase polymorphisms on the cancer preventive potential of isothiocyanates: An epidemiological perspective. Mutat Res. 2005 Dec 30;592(1-2):58-67. Epub 2005 Jul 12.
[40]Verhoeven DT, Goldbohm RA, van Poppel G, Verhagen H, van den Brandt PA. Epidemiological studies on brassica vegetables and cancer risk. Cancer Epidemiol Biomarkers Prev. 1996 Sep;5(9):733-48.
[41] Murillo G , Mehta RG . Cruciferous vegetables and cancer prevention. Nutr Cancer. 2001;41(1-2):17-28.
[42] Lynn A , Collins A , Fuller Z , Hillman K , Ratcliffe B . Cruciferous vegetables and colo-rectal cancer. Proc Nutr Soc. 2006 Feb;65(1):135-44.
[43] Chung, F.L. Dietary Isothiocyanates: Roles in Cancer Prevention and Metabolism in Rodents and Humans In; Phytochemicals in Nutrition and Health., CRC Press LLC. 2002
[44] Sengupta A, Ghosh S, Bhattacharjee S. Allium vegetables in cancer prevention: an overview. Asian Pac J Cancer Prev. 2004 Jul-Sep;5(3):237-45
[45] Khanum F, Anilakumar KR, Viswanathan KR. Anticarcinogenic properties of garlic: a review. Crit Rev Food Sci Nutr. 2004;44(6):479-88.
[46] Rahman K, Lowe GM. Garlic and CVD: a critical review.
J Nutr. 2006 Mar;136(3):736S-40S.
[47]Kahle K , Kraus M , Richling E . Polyphenol profiles of apple juices. Mol Nutr Food Res. 2005 Aug;49(8):797-806.
[48] Boyer J , Liu RH . Apple phytochemicals and their health benefits. Nutr J. 2004;3:5
[49] Silalahi J . Anticancer and health protective properties of citrus fruit components. Asia Pac J Clin Nutr. 2002;11(1):79-84.
[51] Brack ME , Boterberg T , Depypere HT , Stove C , Leclercq G , Mareel MM . The citrus methoxyflavone tangeretin affects human cell-cell interactions. Adv Exp Med Biol. 2002;505:135-9.
[52]Manthey JA , Grohmann K , Guthrie N . Biological properties of citrus flavonoids pertaining to cancer and inflammation. Curr Med Chem. 2001 Feb;8(2):135-53.
[53] Gorinstein S , Caspi A , Libman I , Lerner HT , Huang D , Leontowicz H , Leontowicz M , Tashma Z , Katrich E , Feng S , Trakhtenberg S . Red grapefruit positively influences serum triglyceride level in patients suffering from coronary atherosclerosis: studies in vitro and in humans. J Agric Food Chem. 2006 Mar 8;54(5):1887-92.
[54] Camire , M.E. Phytochemicals in the Vaccinium Family: Bilberries, Blueberries, and Cranberries. In; Phytochemicals in Nutrition and Health., CRC Press LLC. 2002
[55] Hannum SM Potential impact of strawberries on human health: a review of the science. Crit Rev Food Sci Nutr. 2004;44(1):1-17.
[56] [Juranic Z, Zizak Z. Biological activities of berries: From antioxidant capacity to anti-cancer effects.Biofactors. 2005;23(4):207-11.],
[57] Sovak M. Grape Extract, Resveratrol, and Its Analogs: A Review. J Med Food. 2001 Summer;4(2):93-105.
[58] Monagas M , Hernandez-Ledesma B , Gomez-Cordoves C , Bartolome B . Commercial Dietary Ingredients from Vitis vinifera L. Leaves and Grape Skins: Antioxidant and Chemical Characterization. J Agric Food Chem. 2006;54:319-327.
[59] Dubick, M.A. Wine Polyphenols and Protection from Atherosclerosis and Ischemic Heart Disease: Drink To Your Health?; In Phytochemicals in Nutrition and Health., CRC Press LLC. 2002
[60] Ulrich S, Wolter F, Stein JM. Molecular mechanisms of the chemopreventive effects of resveratrol and its analogs in carcinogenesis. Mol Nutr Food Res. 2005 May;49(5):452-61
[61] Maheshwari RK , Singh AK , Gaddipati J , Srimal RC . Multiple biological activities of curcumin: A short review. Life Sci. 2006 Mar 27;78(18):2081-7. Epub 2006 Jan 18.
[62] Aviram M, Dornfeld L, Kaplan M, Coleman R, Gaitini D, Nitecki S, Hofman A, Rosenblat M, Volkova N, Presser D, Attias J, Hayek T, Fuhrman B. Pomegranate juice flavonoids inhibit low-density lipoprotein oxidation and CVDs: studies in atherosclerotic mice and in humans. Drugs Exp Clin Res. 2002;28(2-3):49-62.
[63] de Nigris F, Williams-Ignarro S, Lerman LO, Crimi E, Botti C, Mansueto G, D'Armiento FP, De Rosa G, Sica V, Ignarro LJ, Napoli C. Beneficial effects of pomegranate juice on oxidation-sensitive genes and endothelial nitric oxide synthase activity at sites of perturbed shear stress.Proc Natl Acad Sci U S A. 2005 Mar 29;102(13):4896-901. Epub 2005 Mar 21.
[64] Esmaillzadeh A, Tahbaz F, Gaieni I, Alavi-Majd H, Azadbakht L. Concentrated pomegranate juice improves lipid profiles in diabetic patients with hyperlipidemia. J Med Food. 2004 Fall;7(3):305-8.
[65] Aviram M, Rosenblat M, Gaitini D, Nitecki S, Hoffman A, Dornfeld L, Volkova N, Presser D, Attias J, Liker H, Hayek T. Pomegranate juice consumption for 3 years by patients with carotid artery stenosis reduces common carotid intima-media thickness, blood pressure and LDL oxidation.Clin Nutr. 2004 Jun;23(3):423-33.
[66] Malik A, Mukhtar H. Prostate cancer prevention through pomegranate fruit. Cell Cycle. 2006 Feb;5(4):371-3. Epub 2006 Feb 15.
[67] Adams LS, Seeram NP, Aggarwal BB, Takada Y, Sand D, Heber D. Pomegranate juice, total pomegranate ellagitannins, and punicalagin suppress inflammatory cell signaling in colon cancer cells. J Agric Food Chem. 2006 Feb 8;54(3):980-5.
[68] Pantuck AJ, Zomorodian N, Belldegrun AS. Phase-II Study of pomegranate juice for men with prostate cancer and increasing PSA. Curr Urol Rep. 2006 Jan;7(1):7.
[69] Jung KA, Song TC, Han D, Kim IH, Kim YE, Lee CH. Cardiovascular protective properties of kiwifruit extracts in vitro. Biol Pharm Bull. 2005 Sep;28(9):1782-5.
[70] Collins BH, Horska A, Hotten PM, Riddoch C, Collins AR. Kiwifruit protects against oxidative DNA damage in human cells and in vitro. Nutr Cancer. 2001;39(1):148-53.
[71] Duttaroy AK , Jorgensen A . Effects of kiwi fruit consumption on platelet aggregation and plasma lipids in healthy human volunteers. Platelets. 2004 Aug;15(5):287-92.
[72] Foster-Powell K, Holt SH, Brand-Miller JC. International table of glycemic index and glycemic load values: 2002.Am J Clin Nutr. 2002 Jul;76(1):5-56.
[73] Park Y, Hunter DJ, Spiegelman D, Bergkvist L, Berrino F, van den Brandt PA, Buring JE, Colditz GA, Freudenheim JL, Fuchs CS, Giovannucci E, Goldbohm RA, Graham S, Harnack L, Hartman AM, Jacobs DR Jr, Kato I, Krogh V, Leitzmann MF, McCullough ML, Miller AB, Pietinen P, Rohan TE, Schatzkin A, Willett WC, Wolk A, Zeleniuch-Jacquotte A, Zhang SM, Smith-Warner SA. Dietary fiber intake and risk of colorectal cancer: a pooled analysis of prospective cohort studies. JAMA. 2005 Dec 14;294(22):2849-57.
[74] Mia MA, Siddiqui MN , Haque MS, Islam MN , Rukunzzaman M, Deb K. Dietary fibre and coronary heart disease. Mymensingh Med J. 2002 Jul;11(2):133-5.
[75] USDA National Nutrient Database for Standard Reference, Release 16-1 USDA National Nutrient Database for Standard Reference, Release 16-1 Sugars, total (g).Content of Selected Foods per Common Measure, sorted alphabetical
[76] Underwood, J.C.E. Gneral and systemic pathology, 4 th Ed. 2004; Churchill Livingston, London
[77] Porkkala-Sarataho EK, Nyyssonen MK, Kaikkonen JE, Poulsen HE, Hayn EM, Salonen RM, Salonen JT . A randomized, single-blind, placebo-controlled trial of the effects of 200 mg alpha-tocopherol on the oxidation resistance of atherogenic lipoproteins. Am J Clin Nutr . 1998;68:1034-1041
[78] Kris-Etherton PM , Zhao G , Binkoski AE , Coval SM , Etherton TD . The effects of nuts on coronary heart disease risk. Nutr Rev. 2001;59:103-111.
[79] Panagiotakos DB, Pitsavos C, Polychronopoulos E, Chrysohoou C, Zampelas A, Trichopoulou A. Can a Mediterranean diet moderate the development and clinical progression of coronary heart disease? A systematic review Med Sci Monit. 2004;10: 193-198
[80] Liu, S. Intake of refined carbohydrates and whole grain foods in relation to risk of type 2 diabetes mellitus and coronary heart disease. J Am Coll Nutr. 2002;21:298-306.
[81]Jialal I , Devaraj S . Scientific evidence to support a vitamin E and heart disease health claim: research needs. J Nutr. 2005;135:348-53.
[82] Prior RL, Cao G. Antioxidant capacity and polyphenolic components of teas: implications for altering in vivo antioxidant status. Proc Soc Exp Biol Med. 1999;220:255-261.
[83]Seely D , Mills EJ , Wu P , Verma S , Guyatt GH . The effects of green tea consumption on incidence of breast cancer and recurrence of breast cancer: a systematic review and meta-analysis. Integr Cancer Ther. 2005;4:144-155.
[84] Hoshiyama Y, Kawaguchi T, Miura Y, Mizoue T, Tokui N, Yatsuya H, Sakata K, Kondo T, Kikuchi S, Toyoshima H, Hayakawa N, Tamakoshi A, Yoshimura T; JACC Study Group. Green tea and stomach cancer--a short review of prospective studies.J Epidemiol. 2005;15:S109-112.
[85] Borrelli F, Capasso R, Russo A, Ernst E. Systematic review: green tea and gastrointestinal cancer risk. Aliment Pharmacol Ther. 2004;19:497-510.
[86] Arab L, Il'yasova D. The epidemiology of tea consumption and colorectal cancer incidence. J Nutr. 2003;133:3310S-3318S.
[87]Sun CL, Yuan JM, Koh WP, Yu MC. Green tea, black tea and breast cancer risk: a meta-analysis of epidemiological studies. Carcinogenesis. 2005 Nov 25;
[88] Newmark, H.L., and Yang, C.S. Phytochemical Pharmacokinetics. In Phytochemicals in Nutrition and Health., CRC Press LLC. 2002
[89] Yu-Yan, Yeh.; Liu, L. Cholesterol lowering effect of garlic extracts and organosulfur compounds: Human and animal studies. J Nutr 2001; 131 :989S–993S.
[90] Gebhardt R, Beck H. Differential inhibitory effects of garlic-derived organosulfur compounds on cholesterol biosynthesis in primary rat hepatocyte culture . Lipids 1996; 31 :1269–1276
[91] Bordia A, Verma SK , Srivastava KC. Effect of garlic (Allium sativum) on blood lipids, blood sugar, fibrinogen and fibrinolytic activity in patients with coronary artery disease. Prostaglandins Leukot Essent Fatty Acids 1998; 58 :257–263.
[92] Makheja AN, Bailey JM: Antiplatelet constituents of garlic and onion . Agents Actions 1990, 29: 360-363.
[93] Belman, S., Block, E., Perchellet, J.P., Perchellet, E.M., and Fischer, S.M. 1987. Onion and garlic oils inhibit promotion whereas the oils enhance the conversion of papillomas to carcinomas. Proc. Am. Asso. Cancer. Res., 28:166.
[94] Delaquis, P. and Mazza G. 1998. Functional vegetable products. In: Fitnetional Foods: Biochemical & processing aspects. Mazza, G. Ed. pp. 193-200.Technomic publishing Co. INC.
[95] Abraham, K.O., Shankaranarayana, M.L., Raghavan, B., and Nataraja. C.P. 1976. Alliums-varieties, chemistry, and analysis Lebensm-Wiss. U. Teclmol 9:193-200.
