Yoo Kyoung Park

Long-term vegetarians have low oxidative stress, body fat, and cholesterol levels

Excessive oxidative stress and abnormal blood lipids may cause chronic diseases. This risk can be reduced by consuming an antioxidant- and fiber-rich vegetarian diet. We compared biomarkers of oxidative stress, antioxidant capacity, and lipid profiles of sex- and age-matched long-term vegetarians and omnivores in Korea. Forty-five vegetarians (23 men and 22 women; mean age, 49.5 ± 5.3 years), who had maintained a vegetarian diet for a minimum of 15 years, and 30 omnivores (15 men and 15 women; mean age, 48.9 ± 3.6 years) participated in this study. Their 1-day, 24-h recall, and 2-day dietary records were analyzed. Oxidative stress was measured by the levels of diacron reactive oxygen metabolites (d-ROM). Antioxidant status was determined by the biological antioxidant potential (BAP) and levels of endogenous antioxidant enzymes such as superoxide dismutase, catalase, and glutathione peroxidase. We observed that vegetarians had a significantly lower body fat percentage (21.6 ± 6.4%) than that of omnivores (25.4 ± 4.6%; P < 0.004). d-ROM levels were significantly lower in vegetarians than those in omnivores (331.82 ± 77.96 and 375.80 ± 67.26 Carratelli units; P < 0.011). Additionally, total cholesterol levels in the vegetarians and omnivores were 173.73 ± 31.42 mg/dL and 193.17 ± 37.89 mg/dL, respectively (P < 0.018). Low-density lipoprotein cholesterol was 101.36 ± 23.57 mg/dL and 120.60 ± 34.62 mg/dL (P < 0.005) in the vegetarians and omnivores, respectively, indicating that vegetarians had significantly lower lipid levels. Thus, oxidative stress, body fat, and cholesterol levels were lower in long-term vegetarians than those in omnivores.

Changes in Antioxidant Status, Blood Pressure, and Lymphocyte DNA Damage from Grape Juice Supplementation

In a placebo‐controlled double‐blinded study, the effect of 8 weeks of grape juice was compared to the effect of isocaloric placebo juice. Volunteers with a systolic blood pressure > 130 mmHg and diastolic blood pressure > 90 mmHg were recruited. A total of 40 healthy subjects were randomized to receive isocaloric juices for 8 weeks. Twenty‐one subjects were instructed to consume 5.5 mL/kg daily of grape juice (GJ), and 19 subjects consumed placebo juice (PJ). Plasma antioxidant vitamin C, total radical trapping antioxidant capacity, blood pressure, and lymphocyte DNA damage were assessed pre‐ and postsupplementation. Plasma total radical‐trapping antioxidant potential showed an increase at the level of 1.31 ± 0.01 (postsupplementation) versus 1.33 ± 0.01 (presupplementation) (P < 0.1). Grape juice consumption resulted in a 26% decrease in lymphocyte DNA (both hydrogen peroxide treated or spontaneous) in the grape juice group, while no difference was found in the PJ group. Consuming moderate amounts of daily grape juice may favorably affect antioxidant defense systems and lymphocyte DNA damage in hypertensive individuals.

Growth‐Inhibitory and Proapoptotic Effects of Alpha‐Linolenic Acid on Estrogen‐Positive Breast Cancer Cells

We tested the anticarcinogenic effect of alpha‐linolenic acid (ALA) as a single compound. To test the role of ALA in breast cancer cells (MCF‐7), we analyzed the antiproliferative pathway and the proapoptotic pathway. ALA exhibited growth inhibition on MCF‐7 cells dose‐dependently of ALA in 24, 48, and 72 h, without possible cytotoxicity per se. ALA enhanced the cell growth–inhibitory activity in a dose‐dependent manner. Second, the proapoptotic pathway showed a sub‐G1 accumulation with concomitant upregulation of proapoptotic Bax expression, as well as a downregulation of antiapoptotic Bcl‐2 expression dose‐dependently, causing the Bcl‐2/Bax ratio to decrease by about 50%. Subsequent cytochrome c release and proteolytic activation of caspase‐3 followed by proteolytic cleavage of poly(ADP‐ribose) polymerase all suggest ensuing progression to apoptosis. This finding suggests that ALA alone might also be responsible for growth‐inhibitory and proapoptotic effects on estrogen‐positive breast cancer cells.

Six-week supplementation with Chlorella has favorable impact on antioxidant status in Korean male smokers.

OBJECTIVE Chlorella vulgaris is a popular food supplement in Asia and is currently marketed as a nutritional supplement. However, available scientific studies do not support its effectiveness for preventing or treating any disease in humans. Because Chlorella contains numerous nutrients, including antioxidants, it is thought to exert antioxidative functions by scavenging free radicals created by various environmental factors such as smoking. The purpose of this study was to investigate whether 6 wk of Chlorella supplementation to smokers is protective against oxidative damage in a randomized, double-blinded, placebo-controlled trial. METHODS Fifty-two smokers, aged 20-65 y, were given 6.3g of Chlorella or placebo every day for 6 wk. Blood samples were drawn at the beginning and after the supplementation. Plasma antioxidant vitamin levels and lipid peroxidation levels were measured. As a marker of oxidative stress, lymphocyte DNA damage was measured. RESULTS Chlorella supplementation increased plasma vitamin C (44.4%), alpha-tocopherol (15.7%), and erythrocyte catalase and superoxide dismutase activities. Although 6 wk of Chlorella supplementation resulted in a significant decrease in lymphocyte DNA damage, as measured by comet assay, placebo supplementation also decreased the measured amount of lymphocyte DNA damage. CONCLUSION Chlorella supplementation resulted in the conservation of plasma antioxidant nutrient status and improvement in erythrocyte antioxidant enzyme activities in subjects. Therefore, our results are supportive of an antioxidant role for Chlorella and indicate that Chlorella is an important whole-food supplement that should be included as a key component of a healthy diet.

Urine and Serum Metabolite Profiling of Rats Fed a High-Fat Diet and the Anti-Obesity Effects of Caffeine Consumption

In this study, we investigated the clinical changes induced by a high fat diet (HFD) and caffeine consumption in a rat model. The mean body weight of the HFD with caffeine (HFDC)-fed rat was decreased compared to that of the HFD-fed rat without caffeine. The levels of cholesterol, triglycerides (TGs), and free fatty acid, as well as the size of adipose tissue altered by HFD, were improved by caffeine consumption. To investigate the metabolites that affected the change of the clinical factors, the urine and serum of rats fed a normal diet (ND), HFD, and HFDC were analyzed using ultra performance liquid chromatography quadruple time-of-flight mass spectrometry (UPLC-Q-TOF-MS), gas chromatography (GC-TOF-MS), and linear trap quadruple mass spectrometry (LTQ-XL-MS) combined with multivariate analysis. A total of 68 and 52 metabolites were found to be different in urine and serum, respectively. After being fed caffeine, some glucuronide-conjugated compounds, lysoPCs, CEs, DGs, TGs, taurine, and hippuric acid were altered compared to the HFD group. In this study, caffeine might potentially inhibit HFD-induced obesity and we suggest possible biomarker candidates using MS-based metabolite profiling.

The anti-obesity effect of Lethariella cladonioides in 3T3-L1 cells and obese mice.

The aim of this study was to investigate whether a water extract of L. cladonioides (LC) has an anti-obesity effect in 3T3-L1 cells and obese mice. Treatment of differentiated 3T3-L1 adipocytes with LC caused a significant increase in glycerol release and reduced the protein expression of the adipogenic transcription factors, PPARγ and C/EBPα. In an animal model, obese mice were artificially induced by a high fat diet for 10 weeks. Experimental groups were treated with LC (100 mg/kg/day) by gavage for the next 10 weeks. At the end of experiment, the body weight of the LC group mice was reduced by 14.2% compared to the high fat diet (HFD) group. The treatment also decreased liver (31.0%), epididymal (18.0%) and retroperitoneal (19.3%) adipose tissue, and kidney (6.7%) weights, respectively, compared with those of the HFD group. LC prevented diet-induced increases in the serum level of TC (22.6%), TG (11.6%), and glucose (35.0%), respectively, compared with the HFD group. However, the HDL-C level was higher in the LC group (26.1%) than the HFD group. The results of this study thus suggest that LC suppressed lipid accumulation and expression of adipogenic transcription factors, and increased the amount of glycerol release. LC also indicated an anti-obese and anti-hyperlipidemic effect.

Metabolite Profiling Reveals the Effect of Dietary Rubus coreanus Vinegar on Ovariectomy-Induced Osteoporosis in a Rat Model

The study was aimed at exploring the curative effects of Rubus coreanus (RC) vinegar against postmenopausal osteoporosis by using ovariectomized rats as a model. The investigations were performed in five groups: sham, ovariectomized (OVX) rats without treatment, low-dose RC vinegar (LRV)-treated OVX rats, high-dose RC vinegar (HRV)-treated OVX rats and alendronate (ALEN)-treated OVX rats. The efficacy of RC vinegar was evaluated using physical, biochemical, histological and metabolomic parameters. Compared to the OVX rats, the LRV and HRV groups showed positive effects on the aforementioned parameters, indicating estrogen regulation. Plasma metabolome analysis of the groups using gas chromatography-time of flight mass spectrometry (GC-TOF-MS) and ultra-performance liquid chromatography quadrupole-TOF-MS (UPLC-Q-TOF-MS) with multivariate analysis revealed 19 and 16 metabolites, respectively. Notably, the levels of butyric acid, phenylalanine, glucose, tryptophan and some lysophosphatidylcholines were marginally increased in RC vinegar-treated groups compared to OVX. However, the pattern of metabolite levels in RC vinegar-treated groups was found similar to ALEN, but differed significantly from that in sham group. The results highlight the prophylactic and curative potential of dietary vinegar against postmenopausal osteoporosis. RC vinegar could be an effective natural alternative for the prevention of postmenopausal osteoporosis.

Effect of a continuous diabetes lifestyle intervention program on male workers in Korea.

AIMS This study was conducted to compare the effects of two years of lifestyle intervention to no intervention or one year of intervention on diabetes risk factors in male workers with impaired fasting glucose (IFG) or diabetes. METHODS We conducted a randomized lifestyle intervention trial designed to alter personal lifestyles among 123 industrial male workers (CG; control group, n=75; OIG; one-year intervention group, n=23; TIG; two-year intervention group, n=25). The intervention consisted of two parts, the main program (face-to-face counseling five times/12 weeks) and a follow-up program (e-mail counseling ten times/30 weeks). Assessments included biochemical characteristics, anthropometry and nutrient intake at baseline and after two years. RESULTS After two years, systolic blood pressure, HOMA-IR, HDL cholesterol and total energy intake (p<0.05) were reduced in the OIG group, while weight, body mass index, waist circumference, blood pressure, fasting plasma glucose (FPG), HbA1c and nutrient intake (total energy, carbohydrate, protein and sodium) were significantly decreased (p<0.05, respectively) in the TIG group. When compared to the CG, subjects in OIG and TIG showed significant improvements in the level of FPG and HbA1c (p<0.05). CONCLUSIONS Continuous lifestyle intervention for two years is more effective at improving diabetes risk factors than OIG.

The effect of carrot juice, β-carotene supplementation on lymphocyte DNA damage, erythrocyte antioxidant enzymes and plasma lipid profiles in Korean smoker

High consumption of fruits and vegetables has been suggested to provide some protection to smokers who are exposed to an increased risk of numerous cancers and other degenerative diseases. Carrot is the most important source of dietary β-carotene. Therefore, the objective of this study was to investigate whether carrot juice supplementation to smokers can protect against lymphocyte DNA damage and to compare the effect of supplementation of capsules containing purified β-carotene or a placebo (simple lactose). The study was conducted in a randomized and placebo-controlled design. After a depletion period of 14 days, 48 smokers were supplemented with either carrot juice (n = 18), purified β-carotene (n = 16) or placebo (n = 14). Each group was supplemented for 8 weeks with approximately 20.49 mg of β-carotene/day and 1.2 mg of vitamin C/day, as carrot juice (300 ml/day) or purified β-carotene (20.49 mg of β-carotene, 1 capsule/day). Lymphocyte DNA damage was determined using the COMET assay under alkaline conditions and damage was quantified by measuring tail moment (TM), tail length (TL), and% DNA in the tail. Lymphocyte DNA damage was significantly decreased in the carrot juice group in all three measurements. The group that received purified β-carotene also showed a significant decrease in lymphocyte DNA damage in all three measurements. However, no significant changes in DNA damage was observed for the placebo group except TM (P = 0.016). Erythrocyte antioxidant enzyme was not significantly changed after supplementation. Similarly plasma lipid profiles were not different after carrot juice, β-carotene and placebo supplementation. These results suggest that while the placebo group failed to show any protective effect, carrot juice containing beta-carotene or purified β-carotene itself had great antioxidative potential in preventing damage to lymphocyte DNA in smokers.

Long-term Treatment with Oriental Medicinal Herb Artemisia princeps Alters Neuroplasticity in a Rat Model of Ovarian Hormone Deficiency.

Artemisia princeps (AP) is a flowering perennial used as a traditional medicine and dietary supplement across East Asia. No study has yet assessed its effects on synaptic plasticity in hippocampus and much less in a model of ovarian hormone deficiency. We examined the influence of chronic oral AP ethanol extract treatment in ovariectomized rats on the induction of long-term depression in a representative synapse (CA3-CA1) of the hippocampus. Ovariectomized rats demonstrated lower trabecular mean bone mineral densities than sham, validating the establishment of pathology. Against this background of pathology, AP-treated ovariectomized rats exhibited attenuated long-term depression (LTD) in CA1 relative to water-treated controls as measured by increased field excitatory post-synaptic potentials (fEPSP) activation averages over the post-stimulation period. While pathological significance of long-term depression (LTD) in ovariectomized rats is conflicting, that AP treatment significantly affected its induction offers justification for further study of its influences on plasticity and its related disorders.