Antioxidants & Beta-Carotene
Observational epiderniologic data have consistently suggested that persons, e.g. in the Mediterranean area, who consume large amounts of antioxidant vitamins have a lower than average risk of cardiovascular disease.
The Naples group consumed more tomatoes and tomato juice, a higher proportion of monounsaturated fatty acids (from olive oil) and had a higher level of lipid antioxidant vitamin E and of beta-carotene.
Dietary habits leading to relatively low levels of oxidized lipoproteins might contribute to the lower risk of coronary artery disease in Southern Italy.
Antioxidants in the Mediterranean diet. Mancini-M; Parfitt-VJ; Rubba-P. Can-J-Cardiol. 1995 Oct; 1 1 Suppl G: 105G-109G.
Substantial evidence supports the theory that free radicals, especially oxygen radicals, are involved in the process of aging. Human organisms have two ways to fight them: an enzymatic way (superoxide dismutase, catalase..) and a chemical way with scavengers( e.g. vitamins, cysteine, methionine, gluthatione..).
A supply of beta carotene (15 or 3 0 mg/day), vitamin E (15 mg/day) and vitamin C (3 0 mg/day) involves an increase of singlet oxygen protection of erythrocytes. This protection appears after 15 days of treatment.
Increase of singlet oxygen protection of erythrocytes by vitamin E, vitamin C, and beta carotene intakes. Postaire-E; Regnault-C; Simonet-L; Rousset-G; Bejot-M. Biochem-Mol-Biol-Int. 1995 Feb; 35(2): 371-4.
Atherosclerosis & Beta Carotene
The oxidative modification of low density lipoprotein (LDL) may be an early step in atherogenesis. Furthermore, evidence of oxidized LDL has been found in vivo. Examined the roles that vitamin E, vitamin C and beta-carotene may play in reducing LDL oxidation.
Vitamin E has shown the most consistent effects with regard to LDL oxidation. Beta-carotene appears to have only a mild or no effect on oxidizability. Ascorbate, although it is not lipophilic, can also reduce LDL oxidative susceptibility.
Effect of vitamin E, vitamin C and beta-carotene on LDL oxidation and atherosclerosis. Jialal-I; Fuller-CJ. Can-J-Cardiol. 1995 Oct; I I Suppl G: 97G- I 03G.
Evidence that dietary antioxidants may prevent atherosclerotic disease is growing. The relationship between the intake of dietary and supplemental vitamin C, alpha-tocopherol, and provitamin A carotenoids and average carotid artery wall thickness was studied.
Intake was assessed by use of a 66-item semiquantitative food-frequency questionnaire. Carotid artery intima-media wall thickness was measured at multiple sites with B-mode ultrasound.
There was a significant inverse association between carotene intake and wall thickness in older men.
Data provide limited support for the hypothesis that dietary vitamin C and alpha-tocopherol may protect against atherosclerotic disease, especially in individuals > 55 years old.
Dietary antioxidants and carotid artery wall thickness. The ARIC Study. Atherosclerosis Risk in Communities Study. Kritchevsky-SB; Shimakawa-T; Tell-GS; Dennis-B; Carpenter-M; Eckfeldt-JH; Peacher-Ryan-H; Heiss-G. Circulation. 1995 Oct 15; 92(8): 2142-50.
Epidemiological studies strongly suggest that high intakes of foods rich in beta carotene, as well as those rich in vitamin E or vitamin C, reduce the risk of some but not all cancers and cardiovascular disease.
It is difficult to determine whether these antioxidant nutrients per se are the sole protective agents or whether other factors associated with foods containing them contribute to the foods' protective effects. With respect to vitamin E, a number of studies where dietary and supplementary vitamin E were clearly differentiated, a reduced risk of certain cancers or cardiovascular disease from supplemental vitamin E but not from dietary vitamin E was demonstrated. This provides strong presumptive evidence that high intakes of vitamin E per se provide a health benefit. Only a few intervention studies with specific nutrients are available and results are inconsistent.
Critical assessment of the epidemiological data concerning the impact of antioxidant nutrients on cancer and cardiovascular disease. Machlin-U. Crit-Rev-Food-Sci-Nutr. 1995; 35(1-2): 41-50.
Cancer & Beta-Carotene
Reviews the current knowledge on the cancer-preventive potential of beta-carotene, a precursor of vitamin A, and plentiful in fruits and vegetables, which has been studied widely as a promising chernopreventive agent in reducing the risk of cancer in humans.
Investigations have demonstrated that a diet rich in micronutrients such as vitamins, carotenoids and selenium, could prevent precancerous and neoplastic lesions of specific sites, particularly of the upper aerodigestive tract.
Beta-carotene, in vitro, can affect carcinogenesis, particularly in early stages, through an antigenotoxic action. Antioxidant functions, immunomodulatory effects and control of intercellular messages via gap junctions are possible action mechanisms of the ability of beta-carotene to block the carcinogenetic process. In vivo animal studies partially confirm these results; moreover, the association of the carotenoid with other microelements, such as vitamins E, C and glutathione often appears to be more effective than each agent used alone.
Beta-carotene appears an 'ideal' agent; its almost zero toxicity permits the long-term administration of the drug, a vital condition for its anti-cancer activity, with good patient compliance. Studies showed positive findings in specific cancer sites such as oral cavity, head and neck and colon; less consistent or negative are results on skin, lung and oesophagus cancer.
Effectiveness of beta-carotene in cancer chemoprevention. Toma-S; Losardo-PL; Vincent-M; Palumbo-R. Eur-J-Cancer-Prev. 1995 Jun; 4(3): 213-24.
Cancer of the Colon
Epiderniologic studies have shown that beta-carotene consumption is associated with a decreased incidence of colon cancer. The validity of this association has recently been questioned. It is not known if the rate of colonic cell proliferation differs among individuals with or without a history of colonic polyps or cancer and if proliferation changes in response to beta-carotene.
This study was intended to (a) determine whether differences exist in colonic cell proliferation in individuals with and without prior colonic polyps or tumors, (b) demonstrate that beta-carotene accumulates in colonic mucosa following dietary supplementation, and (c) determine whether mucosal beta-carotene accumulation influences colonic cell proliferation.
Colonic cell proliferation did not differ in samples obtained from individuals with and without prior colonic polyp(s) or cancer. Beta-carotene concentrations in serum and colonic tissue were significantly increased in groups receiving beta-carotene.
Dietary supplementation with beta-carotene for a period of 3 months does not alter colonic cell proliferation in individuals with a history of colonic polyps or cancer.
Effect of beta-carotene supplementation on indices of colonic cell proliferation. Frommel-TO; Mobarhan-S; Doria-M; Halline-AG; Luk-GD; Bowen-PE; Candel-A; Liao-Y. J-Natl-Cancer-Inst. 1995 Dec 6; 87(23): 1781-7.
Diabetes & Beta-Carotene
Evaluated serum retinol, retinol-binding protein (RBP), and beta-carotene levels to elucidate the retinoid metabolism in non-insulin-dependent diabetes mellitus (NIDDM).
The mean retinol levels by gender (1.83 mumol/L for females and 2.24 mumol/L for males) in diabetics were higher than those (1.31 mumol/L for females and 1.82 mumol/L for males) in control subjects.
The mean retinol/RBP ratios (0.95 for females and 0.97 for males) of diabetics were higher than those of the control subjects (0.60 for females and 0.64 for males) and of male patients having impaired glucose tolerance (0.55).
Lipid-lowering medication significantly decreased retinol, with decreasing apolipoprotein C-II but without a commensurate decrease in RBP. The retinol levels had a positive correlation with apolipoprotein C-II in all or normolipidemic patients with diabetes and control subjects. The high retinol/RBP ratio implies that an excessive or free retinol possibly exists in NIDDM. An alternative metabolism of retinol is inferred to underlie NIDDM without direct influences of cholesterol or triglyceride themselves.
High retinol/retinol-binding protein ratio in noninsulin-dependent diabetes mellitus. Sasaki-H; Iwasaki-T; Kato-S; Tada-N. Am-J-Med-Sci. 1995 Nov; 310(5): 177-82.
Diet & Beta-Carotene
New analytical data of Finnish foods were utilized in calculating the intakes of 8 different carotenoids, 6 retinoids, 4 tocopherols and tocotrienols in a Finnish population sample (5403 men and 4750 women) forming a basis for prospective studies on the associations of diet and chronic diseases.
Beta-carotene, lutein and lycopene, mainly provided by different vegetables, were the most abundant carotenoids. Alltrans retinol was a predominant retinoid compound. A major proportion of total vitamin A (85% in men and 74% in women) was attributed to dietary retinoids.
More specific measures for carotenoids and tocopherols would increase the accuracy of estimating health impacts of antioxidant vitamins in the study population.
Carotenoids, retinoids, tocopherols and tocotrienols in the diet; the Finnish Mobile Clinic Health Examination Survey. Jarvinen-R. Int-J-Vitam-Nutr-Res. 1995; 65(1): 24-30.
Jarvinen-R: Carotenoids, retinoids, tocopherols and tocotrienols in the diet; the Finnish Mobile Clinic Health Examination Survey.. Int-J-Vitam-Nutr-Res. 1995; 65(1): 24-30.
The heart is the most susceptible organ to premature aging and free radical oxidative stress. The combination of a healthy diet supplemented with antioxidants and phytonutrients may be useful in the prevention and promotion of optimum cardiovascular health.
Free radicals, oxidative stress, oxidized low density lipoprotein (LDL), and the heart: antioxidants and other strategies to limit cardiovascular damage. Sinatra-ST; DeMarco-J. Conn-Med. 1995 Oct; 59(10): 579-88.
To examine the resistance to oxidation of low-density lipoproteins (LDL) from patients with systemic sclerosis (SSc) and primary Raynaud's phenomenon (RP) compared with healthy controls.
LDL from patients with dcSSc and lcSSc were more susceptible to oxidation than were those from healthy control subjects or patients with RP. Suggest that free radicals play a role in the pathology of SSc.
Increased susceptibility to oxidation of low-density lipoproteins isolated from patients with systemic sclerosis. Bruckdorfer-KR; Hillary-JB; Bunce-T; Vancheeswaran-R; Black-CM. Arthritis-Rheum. 1995 Aug; 38(8): 1060-7.
Smokers & Beta-Carotene
Evaluate the effect of daily supplementation with foods high in vitamin C and beta carotene on plasma vitamin levels and oxidation of low-density lipoprotein (LDL) in cigarette smokers.
In habitual cigarette smokers, antioxidant vitamins, which can be feasibly provided from food, partly protected LDL from oxidation despite a diet rich in polyunsaturated fatty acids.
Dietary supplementation with orange and carrot juice in cigarette smokers lowers oxidation products in copper-oxidized low-density lipoproteins. Abbey-M; Noakes-M; Nestel-PJ. J-Am-Diet-Assoc. 1995 Jun; 95(6): 671-5.
Beta-carotene, a quencher of excited species such as singlet oxygen and free radicals, has been reported to protect against cutaneous photodamage, including sunburn acutely and photocarcinogenesis chronically.
Examines the effect of beta-carotene supplementation on the human sunburn response. Data suggest that oral beta-carotene supplementation is unlikely to modify the severity of cutaneous photodamage in normal individuals to a clinically meaningful degree.
Effect of beta-carotene supplementation on the human sunburn reaction. Garmyn-M; Ribaya-Mercado-JD; Russel-RM; Bhawan-J; Gilchrest-BA. Exp-Dermatol. 1995 Apr; 4(2): 104-11.
Supplementation & Beta-Carotene
Dietary antioxidants such as vitamin E, vitamin C, beta carotene and flavonoids may retard atherosclerosis by preventing low density lipoprotein oxidation.
High vitamin E levels may be associated with decreased cardiovascular disease. Beta carotene may be protective among smokers and the elderly. Few studies have been able to show that vitamin C has a protective effect. A handful of intervention studies have examined the effects of vitamin E and beta carotene with mixed results.
Increased intake of fruits and vegetables that are rich in antioxidants is recommended.
[Antioxidants and cardiovascular disorders--epidemiologic aspects. Should high risk patients receive supplementation?] Tonstad-S. Tidsskr-Nor-Laegeforen. 1995 Jan 20; 115(2): 227-9.
Higher levels of carotenoids and tocopherols are not consistently associated with less severe eye opacities in the general population.
Serum carotenoids and tocopherols and severity of nuclear and cortical opacities. Mares-Perlman-JA; Brady-WE; Klein-BE; Klein-R; Palta-M; Bowen-P; Stacewicz-Sapuntzakis-M. Invest-Ophthalmol-Vis-Sci. 1995 Feb; 36(2): 276-88.
Aging & Beta-Carotene
According to the Adult Treatment Panel of the National Cholesterol Education Program, age is a major risk factor for heart disease. To assess the relation between age and LDL oxidizability, copper-mediated LDL oxidation was studied
In the healthy elderly, LDL oxidation may not be a crucial mediator for atherogenesis.
Effect of aging on susceptibility of low-density lipoproteins to oxidation. Schmuck-A; Fuller-CJ; Devaraj-S; Jialal-I. Clin-Chem. 1995 Nov; 41(11): 1628-32.
Alcohol & Beta-Carotene
Compared the effect of 30 g alcohol/d for three menstrual cycles with three alcohol-free cycles on plasma carotenoid concentrations in 18 nonsmoking, premenopausal women. consumed approximately 6 mg total carotenoids/d under isoenergetic conditions.
Mean plasma alpha- and beta-carotene concentrations were significantly higher during the alcohol-intake
phase of the study. The paired difference in mean plasma lutein/zeaxanthin concentration was
significantly lower. 0
Effect of alcohol consumption on plasma carotenoid concentrations in premenopausal women: a controlled dietary study. Forman-MR; Beecher-GR; Lanza-E; Reichman-ME; Graubard-131; Campbell-WS; Marr-T; Yong-LC; Judd-JT; Taylor-PR. Am-J-Clin-Nutr. 1995 Jul; 62(l): 131-5.
Beta-Carotene & Breast Cancer
According to the study, consuming high levels of specific carotenoids and vitamins found in fruits and vegetables may reduce premenopausal breast cancer risk. Premenopausal women who consumed five or more servings per day of fruits and vegetables had a modestly lower risk of breast cancer than those who had less than two servings per day. Thus, lowering breast cancer risk may be associated with consuming fruit and vegetables high in specific carotenoids and vitamins.
Zhang S, Hunter DJ, Forman MR, Rosner BA, Speizer FE, Colditz GA, Manson JE, Hankinson SE, Willett WC: Dietary carotenoids and vitamins A, C, and E and risk of breast cancer, J Natl Cancer Inst 1999 Mar 17; 91 (6):
Cancer - Aerodigestive Tract Cancers
Cancer - Aerodigestive Tract Cancers
Increased mutagen sensitivity and decreased intake of antioxidant-rich fruits and vegetables have been associated with an increased risk of upper aerodigestive tract cancers.
Significant inverse correlations were found between mutagen sensitivity scores and the plasma levels of alpha-carotene, total carotenoids, and ascorbic acid. There were also significant inverse associations between monthly mean plasma levels of alpha-carotene, beta-carotene and total carotenoids and monthly mean chromosomal breaks. In contrast, there was a significant positive correlation between monthly mean plasma triglyceride level and mutagen sensitivity. Results suggest that mutagen sensitivity as assessed by the bleomycin assay may be influenced by plasma levels of certain nutrients and could potentially be modified by dietary interventions or micronutrient supplementation.
Correlations between mutagen sensitivity and plagma nutrient levels of healthy individuals. Kucuk-0; Pung-A; Franke-AA; Custer-LJ; Wilkens-LR; Le-Marchand-L; Higuchi-CM; Cooney-RV; Hsu-TC. Cancer-Epidemiol-Biomarkers-Prev. 1995 Apr-May; 4(3): 217-21.
High vegetable intake has been associated with a decreased risk for various human cancers in epidemiological studies. Carotenoids are plant compounds that may both possess chernopreventive activity and be useful biomarkers of vegetable and fruit intake.
The control diet consisted of commonly consumed foods and was essentially carotenoid free. High vegetable diets (carotenoid, cruciferous, and soy) consisted of the control diet plus carrots and spinach (carotenoid), broccoli and cauliflower (cruciferous), and tofu and FriChik (soy). Plasma carotenoid concentrations were highest on the carotenoid and cruciferous diets.
There were no differences between diets in plasma beta-cryptoxanthin and lycopene concentrations. These data indicate that plasma alpha-carotene, beta-carotene, and lutein may be useful biomarkers of carotenoid-rich food intake and that lutein may act as an intake biomarker of commonly consumed vegetables in the Cruciferae family.
It is feasible to monitor intake of some plant foods and of distinguishing among plant food groups.
Plasma carotenoids as biomarkers of vegetable intake: the University of Minnesota Cancer Prevention Research Unit Feeding Studies. Martini-MC; Campbell-DR; Gross-MD; Grandits-GA; Potter-JD; Slavin-JL. Cancer-Epidemiol-Biomarkers-Prev. 1995 Jul-Aug; 4(5): 491-6.
Cardiovascular Disease (Beta-Carotene)
Review prospective epidemiologic studies and randomized trials regarding the role of antioxidant vitamins (vitamins E and C and beta-carotene) in the prevention of cardiovascular disease
All three large epiderniologic cohort studies of vitamin E noted that high-level vitamin E intake or supplementation was associated with a significant reduction in cardiovascular disease (RRR range, 3 1 % to 65%), as measured by various fatal and nonfatal cardiovascular end points. To obtain these reductions, vitamin E supplementation must last at least 2 years. Less consistent reductions were seen in studies of beta-carotene (RRR range, -2% to 46%) and vitamin C (RRR range, -25 % to 5 1 %).
The true therapeutic benefit of vitamin E and other antioxidants in reducing fatal cardiovascular disease (a survival benefit as long as 5 years) is probably more modest than the epiderniologic data suggest. CONCLUSION: The epiderniologic data suggest that antioxidant vitamins reduce cardiovascular disease, with the clearest effect for vitamin E; however, completed randomized trials do not support this finding.
The antioxidant vitamins and cardiovascular disease. A critical review of epiderniologic and clinical trial data [see comments] Jha-P; Flather-M; Lonn-E; Farkouh-M; Yusuf-S. Ann-Intern-Med. 1995 Dec 1; 123(11): 860-72.
Case Study in Sweden
Case Study in Sweden
Based on these findings, lower breast cancer risks may be linked to diets high in beta-carotene. The relation between beta-carotene consumption and breast cancer risk was determined in a case-control study involving women screened for breast cancer in Sweden. Women who increased their intake of beta-carotene had a lower risk of breast cancer. Thus, the increasing intake of beta-carotene may reduce the risk of breast cancer.
Humaan AO, Holmberg L, Zack M, Mokdad AH, Ohlander EM, Wolk A, Byers T: Beta-carotene intake and risk of postmenopausal breast cancer, Epidemiology 1999 Jan; 10(1): 49-53
To determine whether patients with colon cancer metabolize beta-carotene differently from benign colon polyp patients groups of resected colon polyp patients or resected colon cancer patients were supplemented with placebo or beta-carotene (30 mg/day) taken with their morning meals for three months.
Serum samples at zero and three months of the study were analyzed blindly for retinoic acid and beta--carotene. The results showed that beta-carotene levels in the serum of colon polyp and colon cancer groups were 8- to 12-fold higher than in the untreated control or the placebo-treated groups.
Trans-retinoic acid levels in response to beta-carotene supplementation are different between treated cancer and benign patients because of different body demands for retinoic acid.
Serum retinoic acid levels in patients with resected benign and malignant colonic neoplasias on beta--carotene supplementation. Tang-G; Shiau-A; Russell-RM; Mobarhan-S. Nutr-Cancer. 1995; 23(3): 291--8.
Colorectal Adenomas & Beta-Carotene
Epiderniologic evidence of associations between the high intake of fat and low intake of dietary fiber, beta carotene, and other dietary constituents and the risk of colorectal neoplasia has been inconsistent and has not provided a sufficient basis for the dietary prevention of large-bowel cancer in humans.
Assessed the effects on the incidence of adenomas of reducing dietary fat to 25% of total calories and supplementing the diet with 25 g of wheat bran daily and a capsule of beta carotene (20 mg daily).
These interventions may reduce the transition from smaller to larger adenomas, a step that may critically define those adenomas most likely to progress to malignancy.
Randomized trial of intake of fat, fiber, and beta carotene to prevent colorectal adenomas. The Australian Polyp Prevention Project [see comments] MacLennan-R; Macrae-F; Bain-C; Battistutta-D; Chapuis-P; Gratten-H; Lambert-J; Newland-RC; Ngu-M; Russell-A; et-al. J-Nati-Cancer-Inst. 1995 Dec 6; 87(23): 1760-6.
Cystic Fibrosis & Beta-Carotene
Concentrations of carotenoids are low in patients with cystic fibrosis (CF) and are associated with essential fatty acid deficiency and increased markers of inflammation. Conducted single? and multiple?dose studies of beta?carotene supplementation in patients with CF. Dose?proportional increases in beta?carotene concentrations were found, although clearance was independent of dose. Large doses of beta?carotene were necessary to achieve normal plasma levels.
Single? and multiple?dose?response relationships of beta?carotene in cystic fibrosis. Homnick?DN; Spillers?CR; Cox?SR; Cox?JH; Yelton?LA; DeLoof?MJ; Oliver?LK; Ringer?TV. J?Pediatr. 1995 Sep; 127(3): 491?4.
Investigated the effect of correcting beta?carotene deficiency in cystic fibrosis (CF) patients on two parameters of lipid peroxidation.
CF patients (#34) were investigated before and after 3 months of oral beta?carotene supplementation. Beta?carotene concentrations increased in plasma and in LDL, without significant changes in alphatocopherol,
Data suggest that excess lipid peroxidation occurring in beta?carotene deficiency can be limited and normalized during efficient beta?carotene supplementation in CF patients.
Enhanced resistance to oxidation of low density lipoproteins and decreased lipid peroxide formation during beta?carotene supplementation in cystic fibrosis. Winklhofer?Roob?BM; Puhl?H; KhoschsorurG; van't?Hof?MA; Esterbauer?H; Shmerling?DH. Free?Radic?Biol?Med. 1995 May; 18(5): 849?59.
Restriction of energy intake (ER), without "malnutrition" of essential "nutrients", has repeatedly been demonstrated to increase longevity in rodents. In the antioxidant theory the lack of balance between the generation of free radicals and free radical scavenging was thought to be a main causal agent in the "aging" process. The antiaging effect induced by ER might be due to the lower rate of free-radical production and related damage induced by a lower "metabolic" rate. The antiaging effects of ER might also occur in humans.
Moderate ER over 10 weeks did not affect indicators of antioxidative capacity, "oxidative" "stress" and genotoxicity of humans.
Short-term moderate energy restriction does not affect indicators of oxidative stress and genotoxicity in humans. Velthuis-te-Wierik-EJ; van-Leeuwen-RE; Hendriks-HF; Verhagen-H; Loft-S; Poulsen-HE; Van-den-Berg-H. J-Nutr. 1995 Oct; 125(10): 2631-9.
This study indicated that a daily dose of Dunaliella beta-carotene might have a protective effect against exercise-induced asthma (EIA) in some patients due to its in vivo antioxidative effect. The alga Dunaliella bardawil contains a very high concentration of beta-carotene containing different physiochemical and antioxidative properties. The results concluded that out of 38 patients who ingested a daily dose of of beta-carotene for 1 week, 20 (53%) did not have EIA.
Neuman I, Nahum H, Ben-Amotz A: Prevention of exercise-induced asthma by a natural isomer mixture of beta-carotene, Ann Allergy Asthma Immunol 1999 Jun; 82(6): 549-53
Free Radicals & Beta-Carotene
Most of the degenerative diseases that afflict humanity have their origin in deleterious free radical reactions, including: ageing, asthma atherosclerosis, cancer, degenerative eye disease, diabetes, inflammatory joint disease and senile dementia.
Most free radical damage to cells involves oxygen free radicals or, more generally, activated oxygen species (AOS) which include non-radical species such as singlet oxygen and hydrogen peroxide as well as free radicals. The AOS can damage genetic material, cause lipid peroxidation in cell membranes, and inactivate membrane-bound enzymes.
Humans have antioxidant defences against AOS (antioxidants or free radical scavengers): including: ascorbic acid (vitamin C, alpha-tocopherol (vitamin E), beta-carotene, coenzyme Q 10, enzymes such as catalase and superoxide dismutase, and trace elements including selenium and zinc.
The eye has intense AOS activity, requiring high levels of antioxidants to protect its unsaturated fatty acids. Man is not genetically adapted to survive past middle age and antioxidant supplementation is needed to ensure a more healthy elderly population.
The role of free radicals in disease. Florence-TM. Aust-N-Z-J-Ophthalmol. 1995 Feb; 23(l): 3-7.
LDL Oxidation & Beta-Carotene
The inhibition of low density lipoprotein (LDL) oxidation has been postulated as one mechanism by which antioxidants may prevent the development of atherosclerosis. Available data on the ability of beta-carotene to inhibit LDL oxidation are conflicting. We examined the role of in vivo and in vitro supplementation with beta-carotene on oxidation of LDL.
Supplementation with beta-carotene in vivo and in vitro does not inhibit low density lipoprotein oxidation. Gaziano-JM; Hatta-A; Flynn-M; Johnson-EJ; Krinsky-NI; Ridker-PM; Hennekens-CH; Frei-B. Atherosclerosis. 1995 Jan 20; 112(2): 187-95
Leafy Vegetables (Indonesia)
There is little evidence to support the general assumption that dietary carotenoids can improve vitamin A status.
Examined an additional daily portion of dark-"green leafy vegetables", or a "wafer" enriched with beta-carotene, "iron", "vitamin C", and "folic acid", on vitamin A and iron status in women with low haemoglobin concentrations (< 130 g/L) who were breastfeeding a child
An additional daily portion of dark-green leafy vegetables did not improve vitamin A status, whereas a similar amount of beta-carotene from a simpler matrix produced a strong improvement. These results suggest that the approach to combating vitamin A deficiency by increases in the consumption of "provitamin A" carotenoids from vegetables should be re-examined.
Lack of improvement in vitamin A status with increased consumption of dark-green leafy vegetables. de-Pee-S; West-CE; Muhilal; Karyadi-D; Hautvast-JG. Lancet. 1995 Jul 8; 346(8967): 75-81.
Low-Density Lipoprotein (LDH)
Low-Density Lipoprotein (LDH)
This study showed that beta-carotene may function as an antioxidant by protecting low-density lipoprotein (LDL) from cell-mediated oxidation. In this study, individuals consuming beta-carotene daily for 4 weeks had increased their beta-carotene content in LDL by three to sixfold. Dietary supplementation of LDL with beta-carotene was more effective in inhibiting oxidation than the in vitro LDL. These results indicated that dietary supplementation with cartenoids may be a more effective means to reduce LDL oxidation.
Dugas TR, Morel DW, Harrison EH, Free Radic Biol Med 1999 May; 26(9-10): 1238-44
Myocardial Infarction & Beta-Carotene
To determine whether a "fat"- and energy-reduced diet rich in antioxidant vitamins C and E, "beta carotene", and "soluble" dietary "fiber" reduces free-radical stress and cardiac "enzyme" level but increases plasma "ascorbic acid" level 1 week after acute "myocardial" "infarction".
Plasma lipid peroxide level decreased significantly and the hypotheses were confirmed.
Antioxidant-rich foods may reduce myocardial "necrosis" and reperfusion injury induced by oxygen free radicals.
Effect of antioxidant-rich foods on plasma ascorbic acid, cardiac enzyme, and lipid peroxide levels in patients hospitalized with acute myocardial infarction. Singh-RB; Niaz-MA; Agarwal-P; Begom-R; Rastogi-SS. J-Am-Diet-Assoc. 1995 Jul; 95(7): 775-80.
Because antioxidants may play a role in the prevention of coronary "heart disease" by inhibiting the peroxidation of "polyunsaturated fatty acids" (PUFAs), the combined association of diet-derived antioxidants and PUFAs with acute myocardial infarction (MI) was investigated.
Findings support the hypothesis that beta-carotene plays a role in the protection of PUFAs against "oxidation" and subsequently in the protection against MI. No evidence was found that alpha-"tocopherol" or "selenium" may protect against MI at any level of PUFA intake.
Association between beta-carotene and acute myocardial infarction depends on "polyunsaturated fatty acid" status. The EURAMIC Study. European Study on Antioxidants, Myocardial Infarction, and "Cancer" of the Breast. Kardinaal-AF; Aro-A; Kark-JD; Riemersma-RA; van-'t-Veer-P; Gomez-Aracena-J; Kohlmeier-L; Ringstad-J; Martin-BC; Mazaev-VP; et-al. Arterioscler-Thromb-Vasc-Biol. 1995 Jun; 15(6): 726-32.
Oral Cancer & Beta-Carotene
Beta-carotene and other antioxidant nutrients, such as vitamin E, are well suited for widespread preventive use because they are nontoxic and easily given in supplement form.
Smokers have lower beta-carotene levels in plasma and oral mucosal cells than nonsmokers. Eight clinical trials have now shown that beta-carotene and vitamin E produce regression of oral leukoplakia. All available evidence supports a significant role for antioxidant nutrients in preventing oral cancer.
Emerging role of beta-carotene and antioxidant nutrients in prevention of oral cancer. Garewal-HS; Schantz-S. Arch-Otolaryngol-Head-Neck-Surg. 1995 Feb; 121(2): 141-4.
Pregnancy Mortality & Beta-Carotene
According to this study, undernourished Asian women at childbearing age might have a better chance of surviving pregnancy by taking either vitamin A or beta-carotene at recommended dietary amounts. This study was based on a controlled trial in rural southeast central plains of Nepal. Overall, vitamin A or beta-carotene reduced premenopausal mortality by 44% and pregnancy mortality by 40%. In conclusion, vitamin A or beta-carotene may prevent mortality among childbearing women.
West KP Jr, Katz J, Khatry SK, LeClerq SC, Pradhan EK, Shrestha SR, Connor PB, Dali SM, Christian P, Pokhrel RP, Sommer A: Double blind, cluster randomised trial of low dose supplementation with vitamin A or beta carotene on mortality related to pregnancy in Nepal. The NNIPS-2 Study Group, BMJ 1999 Feb 27; 318(7183): 570-5
Prostate Cancer & Beta-Carotene
Several human studies have observed a direct association between retinol (vitamin A) intake and risk of prostate cancer; other studies have found either an inverse association or no association of intake of beta--carotene (the major provitamin A) with risk of prostate cancer. Data regarding carotenoids other than beta-carotene in relation to prostate cancer risk are sparse.
Assessed dietary intake for a 1 -year period for a cohort of 47,894 eligible subjects initially free of diagnosed cancer.
Intakes of the carotenoids beta-carotene, alpha-carotene, lutein, and beta-cryptoxanthin were not associated with risk of non-stage Al prostate cancer; only lycopene intake was related to lower risk.
Of 46 vegetables and fruits or related products, four were significantly associated with lower prostate cancer risk; of the 4: tomato sauce, tomatoes, and pizza but not strawberries were primary sources of lycopene. Combined intake of tomatoes, tomato sauce, tomato juice, and pizza (which accounted for 82% of lycopene intake) was inversely associated with risk of prostate cancer).
Support recommendations to increase vegetable and fruit consumption to reduce cancer incidence but suggest that tomato-based foods may be especially beneficial regarding prostate cancer risk.
Intake of carotenoids and retinol in relation to risk of prostate cancer. Giovannucci-E; Ascherio-A; Rimm-EB; Stampfer-MJ; Colditz-GA; Willett-WC. J-Natl-Cancer-Inst. 1995 Dec 6; 87(23): 1767-76.
Stomach Cancer (Italy)
The proportions of gastric cancer cases attributable (or attributable risks, AR) to consumption of traditional foods (i.e., pasta, rice and "maize"), low intake of beta-carotene and vitamin C, short duration of use of an electric refrigerator, low educational level, and family history of gastric cancer were computed using data from a case-control study conducted in Northern Italy.
Increased consumption of vitamin C and beta-carotene, and reduced consumption of traditional foods, would help to avoid over 10,000 out of 14,000 "stomach"-cancer deaths in Italy every year. Consequently, stomach cancer, which is still the third leading cause of cancer death in Italy, would represent only about 2% of all cancer deaths.
Attributable risks for stomach cancer in northern Italy. La-Vecchia-C; D'Avanzo-B; Negri-E; Decarli-A; Benichou-J. Int-J-Cancer. 1995 Mar 16; 60(6): 748-52.
Micronutrients, such as beta-carotene and vitamins A and E, are potential chemopreventive agents; however, their concentrations in human target tissues are largely unknown. If they exert their action at the site of target tissues, the tissue concentrations of the micronutrients need to be determined.
Measured the concentrations of seven carotenoids, two retinoids, and two tocopherols in paired plasma, buccal mucosal cells (BMC), and "skin" samples from 96 healthy subjects (ages 26-82 yrs). The plasma-tissue, as well as the diet-plasma and diet-tissue relationships of the micronutrients, and the impact of various potential confounders on the micronutrient concentrations were evaluated.
Among the seven carotenoids examined, lycopene was unique, because its concentration was not lower in smokers or higher in supplement users but was inversely associated with "age".
Concentrations and plasma-tissue-diet relationships of carotenoids, retinoids, and tocopherols in humans. Peng-YM; Peng-YS; Lin-Y; Moon-T; Roe-DJ; Ritenbaugh-C. Nutr-Cancer. 1995; 23(3): 233-46.
Vitamins were considered as essential nutrients needed only in very small amounts to prevent deficiency syndromes. Many vitamins and their derivatives, however, are currently being used in the mainstream of medicine as therapeutic modalities.
Based on a literature review, recommendations for the use of vitamins for treatment and prevention include: topical vitamin A derivatives ("tretinoin") for the treatment of "acne" and age-related skin damage, oral vitamin A derivatives for severe cystic acne (isotretinoin) and "psoriasis" (etretinate), "vitamin D3" for the treatment and prevention of "osteoporosis" in postmenopausal females, topical "vitamin D" in psoriasis patients, and "niacin" for serum cholesterol reduction. "Folate" appears to decrease the incidence of neural tube defects if given in the preconception phase of "pregnancy". Finally, recent preliminary evidence suggests the possible benefit of antioxidants (vitamins C, E, and beta-carotene) in the prevention of atherosclerosis and cancer.
Vitamins as therapy in the 1990s. Swain-R; Kaplan-B. J-Am-Board-Fam-Pract. 1995 May-Jun; 8(3): 206-16.
Heart Disease & Inflammation
Heart Disease and Inflammation
Low levels of carotenoids may cause inflammation that may be associated with cardiovascular disease, according to this study conduced on 4,557 nonsmoking, middle-aged participants. Researchers measured serum carotenoid levels (alpha-carotene, beta-carotene, beta-cryptoxanthin, lycopene, and lutein/zeaxanthin), and compared these results with measurements of inflammatory markers (C-reactive protein, fibrinogen, and white blood cell count). Participants with low carotenoid levels exhibited high levels of inflammatory markers.
Kritchevsky SB, Bush AJ, Pahor M, Gross MD: Serum carotenoids and markers of inflammation in nonsmokers, Am J Epidemiol 2000 Dec 1;152(11):1065-71
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