Cancer carotenoids

Ebadi s Chapter 19 takes up the class of compounds known as carotenoids, which are known to reduce the risk of prostate cancer, breast cancer, and head and neck cancers. Carotenoids are pigments ranging from yellow to deep red, as found in many common vegetables and fruits, including carrots, leading to the present-day recommendation to consume colorful fruits and vegetables. 

In fact, recent publications show that carotenoid derivatives would participate in the modulation of transcription systems important in cancer and inflammatory processes [14]. And new large-populations studies again confirm the existence of a relationship between carotenoid intake and the probability of suffering certain cancers. For example, in the case of breast cancer, carotenoid intake would have an inverse relationship with cancer in premenopausal women (especially for smokers), but not in postmenopausal [15]. 

Several studies have investigated the role of dietary factors in prostate cancer risk, but results appear inconsistent. Significant effects have not been detected for dietary soya products certain vegetables, beans, fruit, rice and seaweed appear to be protective in some studies, while another has shown no protective effect from seaweed or vegetable consumption. In addition, a number of other risk factors have been shown to be associated with an increased risk of this cancer, including meat and dairy products and carotenoids. 

It is important to note that diet is a complex mixture that contain compounds with varying activity. Chemical stimulators of colon cancer growth include bile acids, 1,2-diglycerides and prostaglandins which stem from consumption of fat. In contrast, fruits and vegetables contain substances such as carotenoids, flavonoids and fibre, which may inhibit cancer cell growth, and the risk of colon cancer appears to be mirrored by the ratio of plant sterols to cholesterol in the... 

ZEiGLER R G (1991) Vegetables, fruits and carotenoids and the risk of cancer , ffwJC/w Nutr, 53, 251S-295S. 

Functional benefits of carotenoids vision, cancer and cardiovascular disease... 

It is well known that excessive intake of P-carotene may lead to carotenodermia (yellow skin), and it is undoubtedly the case that some carotenoid is directly lost via the skin or through photo-oxidation in the skin. As far as is known the carotenoids are not cytotoxic or genotoxic even at concentrations up to 10 times the normal plasma concentration which may cause carotenodermia. However, they are associated with amenorrhoea in girls who may be consuming bizarre diets and, in long-term supplementation studies, with an increase in lung cancer (The Alpha-tocopherol, Beta-carotene Cancer Prevention Study Group, 1994). 

ASTLEY s B, ELLIOTT R M, ARCHER D B and souTHON s (2002) Increased cellular carotenoid levels reduce the persistance of DNA single strand breaks following oxidative chaUange. Nutrition and Cancer. In press. 

J w, Jr. (1996) Cis-trans lycopene isomers, carotenoids and retinol in the human prostate. Cancer Epidemiol Biomarkers Prev. 5(10) 823-33. 

GIOVANNUCCI E, ASCHERIO A, RIMM E B, STAMPFER M J, COLDITZ G A and WILLETT W 0 (1995) Intake of carotenoids and retinol in relation to risk of prostate cancer. JNatl Cancer Inst. 87(23) 1767-76. 

SU L C, BUI M, KARDINAAL A, GCMEZ-ARACENA J, MARTIN-MORENO J, MARTIN B, THAMM M, SIMONSEN N, van t veer p, kck f, STRAIN s and KOHLMEiER L (1998) Differences between plasma and adipose tissue biomarkers of carotenoids and tocopherols. Cancer Epidemiol Biobarkers Prev 7(11) 1043-8. 

YEUM K J, AHN S H, RUPP DE PAIVA S A, LEE-KIM Y C, KRINSKY N I, and RUSSELL R M (1998) Correlation between carotenoid concentration in serum and normal breast adipose tissue of women with benign tumour or breast cancer , JNutr 128 (11) 1920-26. 

COOPER D A, ELDRiDGE A L and PETERS J c (1999) Dietary carotenoids and certain cancers, heart disease and age-related macular degeneration a review of recent research , iVMtr Rev, 57, 201-14. 

ZHANG L-x, CONNEY R V and BERTRAM J s (1991) Carotenoids enhance gap jrmctional communication and inhibit lipid peroxidation in C3H/1077/2 cells relationship to their cancer chemopreventative action . Carcinogenesis, 12, 2109-14. 

New research has demonstrated that carotenoids may also lend additional health benefits that may possibly reduce the risk of certain types of chronic diseases such as cancer and heart disease. Carotenoids are also important natural sources of orange, yellow, and red food coloring for the food and beverage industries. ... 

In animals, the major function of carotenoids is as a precursor to the formation of vitamin A. Carotenoids with provitamin A activity are essential components of the human diet, and there is considerable evidence that they are absorbed through the diet and often metabohzed into other compounds. Beyond their important role as a source of vitamin A for humans, dietary carotenoids, including those that are not provitamin A carotenoids, have been implicated as protecting against certain forms of cancer and cardiovascular disease. ... 

Many epidemiological studies have analyzed the correlations between different carotenoids and the various forms of cancer and a lot of conclusions converge toward protective effects of carotenoids. Many studies were carried out with (i-carotene. The SUVIMAX study, a primary intervention trial of the health effects of antioxidant vitamins and minerals, revealed that a supplementation of p-carotene (6 mg/day) was inversely correlated with total cancer risk. Intervention studies investigating the association between carotenoids and different types of cancers and cardiovascular diseases are reported in Table 3.1.2 and Table 3.1.3. 

Carotenoids and prostate cancer — Numerous epidemiological studies including prospective cohort and case-control studies have demonstrated the protective roles of lycopene, tomatoes, and tomato-derived products on prostate cancer risk other carotenoids showed no effects. " In two studies based on correlations between plasma levels or dietary intake of various carotenoids and prostate cancer risk, lycopene appeared inversely associated with prostate cancer but no association was reported for a-carotene, P-carotene, lutein, zeaxanthin, or p-cryptoxanthin. - Nevertheless, a protective role of all these carotenoids (provided by tomatoes, pumpkin, spinach, watermelon, and citrus fruits) against prostate cancer was recently reported by Jian et al. ... 

Summary of Supplementation Studies Examining Intake of Carotenoids and Incidence of Cancers... 

Carotenoids and breast cancer — Among seven case-control studies investigating the correlation between different carotenoid plasma levels or dietary intakes and breast cancer risk, five showed significant inverse associations with some carotenoids. - In most cases, this protective effect was due to 3-carotene and lutein. However, one (the Canadian National Breast Screening Study ) showed no association for all studied carotenoids including (I-carotene and lutein. More recently, another study even demonstrated a positive correlation between breast cancer risk and tissue and serum levels of P-carotenes and total carotenes. Nevertheless, these observational results must be confirmed by intervention studies to prove consistent. 

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