Onions Abstracts 1

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Onions and platelet aggregation.
            (Baghurst et al., 1977) Download
Four men and five women between 23 and 40 years old were given, in randomised order, three morning test meals at weekly intervals after an overnight fast. The control low-fat meal (grapefruit, cornflakes, skimmed milk, bread, and marmalade) supplied approximately 1000 kcal (4-2 MJ); the high-fat meal (cream, bacon, sausages, bread, butter, and fruit) contained 160 g of saturated fat and 2000 kcal (8-4 MJ); the third type of meal was the same as the high fat one but with the addition of 75g fried onions. The rate of platelet aggregation was significantly greater (p<0.02) after the fat meal, compared with the control, but when onion was included in the fat meal the results were not significantly different from the control values. Neither the high fat nor the onion meal had any significant effect on the extent of platelet aggregation.

Absorption and DNA protective effects of flavonoid glycosides from an onion meal.
            (Boyle et al., 2000) Download
BACKGROUND:  It is widely believed that antioxidant micronutrients obtained from fruit and vegetables afford significant protection against cancer and heart disease, as well as ageing. Flavonoids are potential antioxidants found in foods such as onions; information on their effectiveness in vivo is so far lacking. AIMS:  To determine uptake as well as in vivo antioxidant effects of flavonoids from foods. METHODS:  Six healthy non-obese normocholesterolaemic female volunteers in the age range 20-44 years participated in a randomised two-phase crossover supplementation trial to compare the antioxidant effects associated with (a) a meal of fried onions and (b) a meal of fried onions and fresh cherry tomatoes. Plasma flavonoids, lymphocyte DNA damage, plasma ascorbic acid, tocopherols and carotenoids, urinary malondialdehyde and 8-hydroxy-2'-deoxyguanosine were determined to assess flavonoid absorption and antioxidant efficacy. RESULTS:  Flavonoid glucosides (quercetin-3-glucoside and isorhamnetin-4-glucoside) were significantly elevated in plasma following ingestion of the onion meal and the increases were associated with an increased resistance of lymphocyte DNA to DNA strand breakage. A significant decrease in the level of urinary 8-hydroxy-2'-deoxyguanosine was evident at 4 h following ingestion of the onion meal. After the combined tomato and onion meal, only quercetin was detected in plasma. Endogenous base oxidation was decreased but resistance to strand breakage was unchanged. There was no significant change in the excretion of urinary malondialdehyde following either meal. CONCLUSION:  Both meals--onions, and onions together with tomatoes--led to transient decreases in biomarkers of oxidative stress, although the particular biomarkers affected differ. It is possible that the differences in patterns of response reflect the different uptakes of flavonoids but the underlying mechanism is not understood.

Effects of a quercetin-rich onion skin extract on 24 h ambulatory blood pressure and endothelial function in overweight-to-obese patients with (pre-)hypertension: a randomised double-blinded placebo-controlled cross-over trial.
            (Brüll et al., 2015) Download
The polyphenol quercetin may prevent CVD due to its antihypertensive and vasorelaxant properties. We investigated the effects of quercetin after regular intake on blood pressure (BP) in overweight-to-obese patients with pre-hypertension and stage I hypertension. In addition, the potential mechanisms responsible for the hypothesised effect of quercetin on BP were explored. Subjects (n 70) were randomised to receive 162 mg/d quercetin from onion skin extract powder or placebo in a double-blinded, placebo-controlled cross-over trial with 6-week treatment periods separated by a 6-week washout period. Before and after the intervention, ambulatory blood pressure (ABP) and office BP were measured; urine and blood samples were collected; and endothelial function was measured by EndoPAT technology. In the total group, quercetin did not significantly affect 24 h ABP parameters and office BP. In the subgroup of hypertensives, quercetin decreased 24 h systolic BP by -3·6 mmHg (P=0·022) when compared with placebo (mean treatment difference, -3·9 mmHg; P=0·049). In addition, quercetin significantly decreased day-time and night-time systolic BP in hypertensives, but without a significant effect in inter-group comparison. In the total group and also in the subgroup of hypertensives, vasoactive biomarkers including endothelin-1, soluble endothelial-derived adhesion molecules, asymmetric dimethylarginine, angiotensin-converting enzyme activity, endothelial function, parameters of oxidation, inflammation, lipid and glucose metabolism were not affected by quercetin. In conclusion, supplementation with 162 mg/d quercetin from onion skin extract lowers ABP in patients with hypertension, suggesting a cardioprotective effect of quercetin. The mechanisms responsible for the BP-lowering effect remain unclear.

Cardioprotective Efficacy of Red Wine Extract of Onion in Healthy Hypercholesterolemic Subjects.
            (Chiu et al., 2016) Download
The objective of this study was to evaluate the efficacy of the red wine extract of onion (RO) and red wine (RW) on alleviating the risk factors of cardiovascular disease. During in vitro studies, various antioxidant activities [trolox equivalent antioxidant capacity (TEAC), DPPH, and H2 O2 scavenging ability] of RO and RW group were evaluated. Both RO and RW showed the maximum antioxidant capacity. During in vivo studies, 23 healthy hypercholesterolemic volunteers were randomly selected and assigned into two groups, who drunk 250 mL of RO (n = 11) or RW (n = 10) for 10 weeks. No significant changes were observed in anthropometric parameters (body weight, height, body mass, and BMI) in each group. Both RW and RO extracts elevated (p < 0.05) antioxidant activity and thereby prolonging the lag time of low-density lipoprotein oxidation. However, RO extract intake substantially suppressed (p < 0.05) the total cholesterol and low-density lipoprotein cholesterol levels when equivalence with RW thus, indicating its additional hypocholesterolemic effect. The inflammatory markers such as factor VII were also positively modulated by RO extract. Results indicated that RO extract consumption rendered better cardio protective effect than RW by altering cholesterol, improving antioxidation and suppressing inflammatory marker levels and thereby, attenuating the cardiovascular disease incidence.

Effect of onion peel extract on endothelial function and endothelial progenitor cells in overweight and obese individuals.
            (Choi et al., 2015) Download
OBJECTIVES:  Acute or chronic intake of polyphenol-rich foods has been reported to improve endothelial function. Quercetin, found abundantly in onion, is a potent antioxidant flavonoid. The aim of this study was to investigate whether consumption of onion peel extract (OPE) improves endothelial function in healthy overweight and obese individuals. METHODS:  This was a randomized double-blind, placebo-controlled study. Seventy-two healthy overweight and obese participants were randomly assigned to receive a red, soft capsule of OPE (100 mg quercetin/d, 50 mg quercetin twice daily; n = 36 participants) or an identical placebo capsule (n = 36) for 12 wk. Endothelial function, defined by flow-mediated dilation (FMD), circulating endothelial progenitor cells (EPCs) by flow cytometry, and laboratory test were determined at baseline and after treatment. RESULTS:  Baseline characteristics and laboratory findings did not significantly differ between the two groups. Compared with baseline values, the OPE group showed significantly improved FMD at 12 wk (from 12.5 ± 5.2 to 15.2 ± 6.1; P = 0.002), whereas the placebo group showed no difference. Nitroglycerin-mediated dilation did not change in either group. EPC counts (44.2 ± 25.6 versus 52.3 ± 18.6; P = 0.005) and the percentage of EPCs were significantly increased in the OPE group. When FMD was divided into quartiles, rate of patients with endothelial dysfunction defined as lowest quartile (cutoff value, 8.6%) of FMD improved from 26% to 9% by OPE. CONCLUSION:  Medium-term administration of OPE an improvement in FMD and circulating EPCs.


 

The ability of onion extract gel to improve the cosmetic appearance of postsurgical scars.
            (Draelos, 2008) Download
Superior wound healing with excellent cosmesis is critical in superficial dermal wounds created when cosmetically unacceptable lesions are removed from the body. Dermatologists frequently remove seborrheic keratoses, nevi, and angiomas from the body with a superficial shave excision. The excision is designed to minimize dermal scarring while removing the unsightly skin growth. This study was undertaken to evaluate the ability of an onion extract gel to improve the appearance of scars following excision. Sixty subjects with symmetrical seborrheic keratoses at least 8 mm in diameter on the right and left upper chest were enrolled. The lesions were removed with a scalpel shave, following local anesthesia with 2% lidocaine plus epinephrine. The surgical sites were allowed to heal for 2 to 3 weeks, at which time the subjects returned to the research center for randomization to either the onion gel treatment group or the no-treatment group. Forty-seven subjects in the active treatment group were further randomized as to the site of study product application. Thirteen control subjects applied nothing to either side. Subjects returned to the study center at weeks 2, 4, 6, and 10 for photography, subject evaluations, and investigator assessments. The study showed that the onion extract gel significantly improved scar softness, redness, texture, and global appearance at the excision site at study weeks 4, 6, and 10 as assessed by the blinded investigator.

Effects of raw red onion consumption on metabolic features in overweight or obese women with polycystic ovary syndrome: a randomized controlled clinical trial.
            (Ebrahimi-Mamaghani et al., 2014) Download
AIM:  We aimed to evaluate the effects of raw red onion consumption on metabolic features in overweight and obese women with polycystic ovary syndrome. MATERIAL AND METHODS:  In this randomized controlled clinical trial, the patients (n=54) were randomly allocated to the intervention group as 'high-onion' (raw red onions: 2 × 40-50 g/day if overweight and 2 × 50-60 g/day if obese) or to the control group as 'low-onion' (raw red onions: 2 × 10-15 g/day) along with limited liliaceous vegetables for 8 weeks. Body mass index, dietary record, and metabolic parameters (fasting blood sugar, triglycerides, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and lipoprotein (a)) were evaluated in the follicular phase of the menstrual cycle at baseline and after 8 weeks. Hormonal variables (progesterone, prolactin, and 17-OH progesterone) were also measured at baseline. RESULTS:  Onion significantly decreased the levels of total cholesterol within each group; however, these changes were stronger in the high-onion group (weighted mean differences [WMD]: -5.60 [95% confidence interval [CI]: -9.16, -2.03]; P=0.003) than in the low-onion group (WMD: -6.42 [95%CI: -11.97, -0.87]; P=0.025). Similarly, low-density lipoprotein cholesterol decreased significantly (WMD: -5.13 [95%CI: -9.46, -0.81); P=0.022) in the high-onion group, and (WMD: -2.90 [95%CI -5.57, -0.21]; P=0.035) in the low-onion group after treatment. The levels of fasting blood sugar, triglycerides, high-density lipoprotein cholesterol and lipoprotein (a) did not differ significantly after 8-week onion treatment. Adjustment for confounders did not make any significant changes in any of the parameters in post-treatment levels. CONCLUSION:  Raw red onion consumption appears to be effective as a cholesterol-lowering food agent in women with polycystic ovary syndrome. However, further investigation is warranted.

Inhibition of the glycaemic response by onion: a comparison between lactose-tolerant and lactose-intolerant adults.
            (Hoffman et al., 2016) Download
This pilot study compared inhibition of the glycaemic response to glucose by a dietary source of quercetin glucosides (onion) in lactose-tolerant adults (n=12) and lactose-intolerant adults (n=12). We hypothesised that lactose-intolerant people (who do not express lactase) will retain intact quercetin glucosides that can inhibit glucose uptake via the glucose transporter SGLT1, whereas lactose-tolerant people (who do express lactase) will hydrolyse quercetin glucosides to free quercetin that does not inhibit glucose uptake. In a glucose tolerance test, reduction in peak glucose levels by an onion meal was higher in lactose-intolerant people than in lactose-tolerant people (44.2 versus 19.3%, P=0.04). Incremental area under the blood glucose curve was reduced more in lactose-intolerant people, but was not statistically significant (54.5 versus 42.1%, P=0.42). A diet containing quercetin glucosides may be of greater benefit for glycaemic control in lactose-intolerant people than in lactose-tolerant people.

Effects of Fresh Yellow Onion Consumption on CEA, CA125 and Hepatic Enzymes in Breast Cancer Patients: A Double- Blind Randomized Controlled Clinical Trial.
            (Jafarpour-Sadegh et al., 2015) Download
Onion (Allium cepa) consumption has been remarked in folk medicine which has not been noted to be administered so far as an adjunct to conventional doxorubicin-based chemotherapy in breast cancer patients. To our knowledge, this is the first study aimed to investigate the effects of consuming fresh yellow onions on hepatic enzymes and cancer specific antigens compared with a low-onion containing diet among breast cancer (BC) participants treated with doxorubicin. This parallel design randomized controlled clinical trial was conducted on 56 BC patients whose malignancy was confirmed with histopathological examination. Subjects were assigned in a stratified-random allocation into either group received body mass index dependent 100-160 g/d of onion as high onion group (HO; n=28) or 30-40 g/d small onion in low onion group (LO; n=28) for eight weeks intervention. Participants, care givers and laboratory assessor were blinded to the assignments (IRCT registry no: IRCT2012103111335N1). The compliance of participants in the analysis was appropriate (87.9%). Comparing changes throughout pre- and post-dose treatments indicated significant controls on carcinoembryonic antigen, cancer antigen-125 and alkaline phosphatase levels in the HO group (P<0.05). Our findings for the first time showed that regular onion administration could be effective for hepatic enzyme conveying adjuvant chemotherapy relevant toxicity and reducing the tumor markers in BC during doxorubicin-based chemotherapy.

Consumption of Fresh Yellow Onion Ameliorates Hyperglycemia and Insulin Resistance in Breast Cancer Patients During Doxorubicin-Based Chemotherapy: A Randomized Controlled Clinical Trial.
            (Jafarpour-Sadegh et al., 2017) Download
PURPOSE:  Doxorubicin has been found to be associated with insulin resistance in animal models. Onion, a so-called functional food, is noted to affect the insulin signaling pathway of diabetes in vitro. To our knowledge, this is the first study to investigate the effects of consuming fresh yellow onions on insulin-related indices compared with a low-onion-containing diet among breast cancer (BC) patients treated with doxorubicin. METHODS:  This parallel-design, randomized, triple-blind, controlled clinical trial was conducted on 56 eligible BC patients (aged 30-63 years), diagnosed with invasive ductal carcinoma. Following their second cycle of chemotherapy, subjects were assigned in a stratified-random allocation to receive body mass index-dependent 100 to 160 g/d of onion as high onion group (HO; n = 28) or 30 to 40 g/d small onions in low onion group (LO; n = 28) for 8 weeks intervention. Participants, care givers, and those who assessed laboratory analyses were blinded to the assignments (IRCT Registry No.: IRCT2012103111335N1). RESULTS:  The compliance level of participants in the analysis was as high as 87.85%. A total of 23 available cases was analyzed in each group. The daily use of HO resulted in a significant decrease in serum fasting blood glucose and insulin levels in comparison with LO, over the period of study ( P < .001). Posttreatment with HO showed a significant decrease in homeostasis model of assessment-insulin resistance relative to changes in the LO group ( P < .05). A comparison of the changes that occurred throughout pre- and postdose treatments indicated improved quantitative insulin sensitivity check index ( P < .05) and controls on C-peptide in the HO group ( P < .05). CONCLUSIONS:  The present study demonstrated the effectiveness of onion to ameliorate hyperglycemia and insulin resistance in BC during doxorubicin-based chemotherapy.

Consumption of onion juice modulates oxidative stress and attenuates the risk of bone disorders in middle-aged and post-menopausal healthy subjects.
            (Law et al., 2016) Download
Osteoporosis is a chronic inflammatory condition that is characterized by the loss of bone mineral density (BMD). The current study was undertaken to evaluate the impact of onion juice intake on the bone mineral density (BMD) and bone loss in corroboration with antioxidant effects in human (in vivo) as well as inhibitory effects on the differentiation of osteoclasts in the cell line (in vitro). For in vitro studies, the RAW 264.7 (osteoclast progenitor) cells were used to examine the anti-osteoclastogenic effect of onion. In the case of in vivo studies, twenty-four subjects were divided into two groups and advised to intake 100 mL of onion juice or placebo for 8 weeks. Anthropometric measurements and blood samples were collected at the initial, 2(nd), 6(th), 8(th) and 10(th) week. The result of in vitro studies indicated that onion extract would effectively inhibit the osteoclastogenesis and its differentiation. Significant changes in the levels of alkaline phosphatase (ALP), free radicals, total antioxidant capacity (TEAC) and various antioxidants were observed in onion administered subjects. The BMD of three postmenopausal women was also found to be mildly improved on supplementation with onion juice. Onion juice consumption showed a positive modulatory effect on the bone loss and BMD by improving antioxidant activities and thus can be recommended for treating various bone-related disorders, especially osteoporosis.

The association between onion consumption and bone density in perimenopausal and postmenopausal non-Hispanic white women 50 years and older.
            (Matheson et al., 2009) Download
OBJECTIVE:  The aim of this study was to determine whether frequent onion consumption is associated with increased bone density in perimenopausal and postmenopausal non-Hispanic white women 50 years and older. METHODS:  An analysis of the National Health and Nutrition Examination Survey 2003-2004 was performed. Perimenopausal and postmenopausal non-Hispanic white female participants (unweighted N = 507; weighted N = 35.7 million) were divided into those who consumed onions less than once a month, twice a month to twice a week, three to six times a week, and once a day or more based on self-reported dietary history. All study participants underwent total body dual-energy x-ray absorptiometry. RESULTS:  After controlling for age, body mass index, daily calcium intake, serum vitamin D, serum parathyroid hormone, estrogen use, smoking status, and exercise status, bone density increased as the frequency of onion consumption increased. Individuals who consumed onions once a day or more had an overall bone density that was 5% greater than individuals who consumed onions once a month or less (P < 0.03). CONCLUSIONS:  Onion consumption seems to have a beneficial effect on bone density in perimenopausal and postmenopausal non-Hispanic white women 50 years and older. Furthermore, older women who consume onions most frequently may decrease their risk of hip fracture by more than 20% versus those who never consume onions.


 

Effect of onions on blood fibrinolytic activity.
            (Menon et al., 1968) Download
Twenty-two convalescent patients at rest were given a fat-enriched breakfast with and without the addition of 60 g. of fried or boiled onions. Both forms of onions were found to prevent the expected decrease in fibrinolytic activity, and indeed the latter was actually increased.

Onion juice (Allium cepa L.), a new topical treatment for alopecia areata.
            (Sharquie and Al-Obaidi, 2002) Download
Alopecia areata is a patchy, non-scarring hair loss condition. Any hair-bearing surface may be involved, and different modalities of treatment have been used to induce hair regrowth. This study was designed to test the effectiveness of topical crude onion juice in the treatment of patchy alopecia areata in comparison with tap water. The patients were divided into two groups. The first group [onion juice treated] consisted of 23 patients, 16 males (69.5%) and 7 females (30.5%). Their ages ranged between 5-42 years with a mean of 22.7 years. The second group [control; tap-water-treated] consisted of 15 patients, 8 males (53.3%) and 7 females (46.6%). Their ages ranged between 3-35 years with a mean of 18.3 years. The two groups were advised to apply the treatment twice daily for two months. Re-growth of terminal coarse hairs started after two weeks of treatment with crude onion juice. At four weeks, hair re-growth was seen in 17 patients (73.9%), and, at six weeks, the hair re-growth was observed in 20 patients (86.9%) and was significantly higher among males (93.7%) compared to females (71.4%) P<0.0001. In the tap-water treated-control group, hair re-growth was apparent in only 2 patients (13%) at 8 weeks of treatment with no sex difference. The present study showed that the use of crude onion juice gave significantly higher results with regard to hair re-growth than did tap water (P<0.0001), and that it can be an effective topical therapy for patchy alopecia areata.

Consumption of large amounts of Allium vegetables reduces risk for gastric cancer in a meta-analysis.
            (Zhou et al., 2011) Download
BACKGROUND & AIMS:  The chemopreventive effects of Allium vegetables (onions, garlic, shallots, leeks, chives, and so forth) have been studied extensively, although their effect on gastric cancer risk is controversial. We performed a meta-analysis of cohort and case-control studies to analyze this association. METHODS:  We searched MEDLINE for studies of Allium vegetable consumption and gastric cancer that were published in any language, from January 1, 1966, to September 1, 2010. We analyzed 19 case-control and 2 cohort studies, of 543,220 subjects. We pooled the relative risks from individual studies using a random-effects model and performed dose-response, heterogeneity, and publication bias analyses. RESULTS:  In a pooled analysis of all studies, consumption of large amounts of Allium vegetables (in a comparison of the highest and lowest consumption groups) reduced the risk for gastric cancer (odds ratio, 0.54; 95% confidence interval, 0.43-0.65). Specific analyses for onion, garlic, leek, Chinese chive, scallion, garlic stalk, and Welsh onion yielded similar results, except for onion leaf. The estimated summary odds ratio for an increment of 20 g/day of Allium vegetables consumed (approximately the average weight of 1 garlic bulb) was 0.91 (95% confidence interval, 0.88-0.94), based on case-control studies from the dose-response meta-analysis. CONCLUSIONS:  In a meta-analysis, consumption of high levels of Allium vegetables reduced the risk for gastric cancer risk. Because of potential confounding factors and exposure misclassification, further studies are required to establish this association.

 


References

Baghurst, KI, MJ Raj, and AS Truswell (1977), ‘Onions and platelet aggregation.’, Lancet, 1 (8002), 101. PubMed: 63702
Boyle, SP, et al. (2000), ‘Absorption and DNA protective effects of flavonoid glycosides from an onion meal.’, Eur J Nutr, 39 (5), 213-23. PubMed: 11131368
Brüll, V, et al. (2015), ‘Effects of a quercetin-rich onion skin extract on 24 h ambulatory blood pressure and endothelial function in overweight-to-obese patients with (pre-)hypertension: a randomised double-blinded placebo-controlled cross-over trial.’, Br J Nutr, 114 (8), 1263-77. PubMed: 26328470
Chiu, HF, et al. (2016), ‘Cardioprotective Efficacy of Red Wine Extract of Onion in Healthy Hypercholesterolemic Subjects.’, Phytother Res, 30 (3), 380-85. PubMed: 26631904
Choi, EY, et al. (2015), ‘Effect of onion peel extract on endothelial function and endothelial progenitor cells in overweight and obese individuals.’, Nutrition, 31 (9), 1131-35. PubMed: 26233871
Draelos, ZD (2008), ‘The ability of onion extract gel to improve the cosmetic appearance of postsurgical scars.’, J Cosmet Dermatol, 7 (2), 101-4. PubMed: 18482012
Ebrahimi-Mamaghani, M, et al. (2014), ‘Effects of raw red onion consumption on metabolic features in overweight or obese women with polycystic ovary syndrome: a randomized controlled clinical trial.’, J Obstet Gynaecol Res, 40 (4), 1067-76. PubMed: 24612081
Hoffman, R, G Ranjbar, and AM Madden (2016), ‘Inhibition of the glycaemic response by onion: a comparison between lactose-tolerant and lactose-intolerant adults.’, Eur J Clin Nutr, 70 (9), 1089-91. PubMed: 27026422
Jafarpour-Sadegh, F, et al. (2015), ‘Effects of Fresh Yellow Onion Consumption on CEA, CA125 and Hepatic Enzymes in Breast Cancer Patients: A Double- Blind Randomized Controlled Clinical Trial.’, Asian Pac J Cancer Prev, 16 (17), 7517-22. PubMed: 26625755
Jafarpour-Sadegh, F, et al. (2017), ‘Consumption of Fresh Yellow Onion Ameliorates Hyperglycemia and Insulin Resistance in Breast Cancer Patients During Doxorubicin-Based Chemotherapy: A Randomized Controlled Clinical Trial.’, Integr Cancer Ther, 16 (3), 276-89. PubMed: 27352956
Law, YY, et al. (2016), ‘Consumption of onion juice modulates oxidative stress and attenuates the risk of bone disorders in middle-aged and post-menopausal healthy subjects.’, Food Funct, 7 (2), 902-12. PubMed: 26686359
Matheson, EM, AG Mainous, and MA Carnemolla (2009), ‘The association between onion consumption and bone density in perimenopausal and postmenopausal non-Hispanic white women 50 years and older.’, Menopause, 16 (4), 756-59. PubMed: 19240657
Menon, IS, et al. (1968), ‘Effect of onions on blood fibrinolytic activity.’, Br Med J, 3 (5614), 351-52. PubMed: 5662989
Sharquie, KE and HK Al-Obaidi (2002), ‘Onion juice (Allium cepa L.), a new topical treatment for alopecia areata.’, J Dermatol, 29 (6), 343-46. PubMed: 12126069
Zhou, Y, et al. (2011), ‘Consumption of large amounts of Allium vegetables reduces risk for gastric cancer in a meta-analysis.’, Gastroenterology, 141 (1), 80-89. PubMed: 21473867