Tetsuro Nagasawa

The effect of docosahexaenoic acid on aggression in elderly Thai subjects--a placebo-controlled double-blind study

Docosahexaenoic acid (DHA) administration controls extraggression (aggression against others) in young subjects under psychological stress. However, it is not known whether its administration affects extraggression of elderly subjects. Forty Thai subjects of 50–60 years of age (22 males and 18 females) were recruited from Silpakorn University and nearby villages. They were allocated to the control and DHA groups in a double-blind fashion, and took 10 mixed plant oil capsules and 10 DHA capsules (1.5 g DHA/day) for 2 months, respectively. Extraggression was measured with a psychological test (PF Study) at the beginning and end of the study. Just prior to the PF Study at the end of the study, subjects were asked to watch a stressful videotape as a stressor component. The average DHA intake from food was 150–160 mg/day. In the group of university employees, extraggression did not change over time with placebo, whereas extraggression significantly decreased (31 ± 13 to 24 ± 13%, P = 0.04 by the paired-t test, P = 0.04 by ANOVA). In the group of villagers, there was no significant difference between the control and DHA groups in extraggression. The DHA administration favorably controlled extraggression in at least elderly white-collar workers. The daily intake of 150160 mg/day of DHA was not enough to control extraggression.

Administration of Docosahexaenoic Acid Influences Behavior and Plasma Catecholamine Levels at Times of Psychological Stress

The purpose of the present research was to clarify the effect of docosahexaenoic acid (DHA) intake on behavior and plasma catecholamines (CA). In Study 1, 42 students took either DHA-rich oil capsules containing 1.5–1.8 g DHA/d or control oil capsules containing 97% soybean oil plus 3% of another fish oil for 3 mon in a double-blind fashion. They took a psychological test (PF Study) at the start and end of the study. This study started at the end of summer vacation and ended just before the final exams. In the control group, external aggression (aggression against others) in PF Study was significantly increased at the end of the study as compared with that measured at the start (+8.9%), whereas it was not significantly changed in the DHA group (−1.0%). In a similar double-blind study (Study 2), we measured external aggression under nonstressful conditions. External aggression slightly decreased in the control group, whereas there were no significant changes in the DHA group. In Study 3 with 14 students, plasma CA were measured at the start and end of capsule administration period of 2 mon. Subjects were under continuous stress of the final exams that lasted throughout the whole study period. The ratio of plasma epinephrine to norepinephrine concentrations was significantly increased in the DHA group (78%), whereas it stayed at the same level in the control group. In Study 4, mice were fed either DHA-deficient diet or -sufficient diet for 4 wk, and their rearing frequency (an anxiety index) was measured. In the DHA-sufficient group, the rearing frequency was significantly less than in the other group. These effects of DHA intake may be applied to people in an attempt to ameliorate stress-related diseases.

Inhibitory effect of 5,8,11-eicosatrienoic acid on angiogenesis.

INTRODUCTION Cartilage contains high levels of n-9 eicosatrienoic acid (20:3n-9) but no blood vessels. 20:3n-9 might inhibit angiogenesis. MATERIALS AND METHODS Angiogenesis was measured in human umbilical vein endothelial cells and diploid fibroblasts. Co-culture was performed with vascular endothelial growth factor-A (VEGF-A, 10 ng/mL) and fatty acids (0.1-10 μmol/L). After 10 days of incubation and immunostaining for endothelial cells, vessel areas were calculated with image analyser software. RESULTS Addition of 20:3n-9 and n-3 eicosatrienoic acid (20:3n-3) dose dependently inhibited VEGF-A-stimulated angiogenesis (more than the positive control suramin). Arachidonic, eicosapentaenoic, dihomo-γ-linolenic (20:3n-6) and oleic acids did not affect VEGF-A-stimulated angiogenesis even at 10 μmol/L. Arachidonic and dihomo-γ-linolenic acids enhanced angiogenesis without VEGF-A. DISCUSSION AND CONCLUSIONS We suggest that the presence of 20:3n-9 in cartilage may be related to its vessel-free status and that 20:3n-9 may be useful for the treatment of disorders with excessive vasculature. ACKNOWLEDGEMENTS This work was partly supported by Polyene Project, Inc.

Helicobacter pylori alters n‐6 fatty acid metabolism and prostaglandin E2 synthesis in rat gastric mucosal cells

Little is known about whether Helicobacter pylori infection alters fatty acid metabolism in gastric mucosal cells. By using cultured rat gastric mucosal cells (RGM‐1), we investigated the effect of H. pylori broth culture filtrates on this point. Furthermore, our study aimed to find out whether n‐6 long chain polyunsaturated fatty acids from linoleic acid are formed in RGM‐1 cells.

Is vaccenic acid (18:1t n-7) associated with an increased incidence of hip fracture? An explanation for the calcium paradox.

High calcium intake may increase hip fracture (HF) incidence. This phenomenon, known as the calcium paradox, might be explained by vaccenic acid (18:1t n-7, VA), the highly specific trans fatty acid (TFA) present in dairy products. First, we ecologically investigated the relationship between 18:1 TFA intake and HF incidence using data from 12 to 13 European countries collected before 2000; then we measured the effects of VA and elaidic acid (18:1t n-9, EA) on osteoblasts from goldfish scales (tissues very similar to mammalian bone), with alkaline phosphatase as a marker; and finally we measured the effect of VA on mRNA expression in the scales for the major bone proteins type I collagen and osteocalcin. HF incidence was significantly correlated with 18:1 TFA intake in men (r=0.57) and women (r=0.65). Incubation with 1μmol/L VA and EA for 48h significantly decreased alkaline phosphatase activity by 25% and 21%, respectively. Incubation of scales with 10μmol/L VA for 48h significantly decreased mRNA expression for type I collagen and osteocalcin (by about 50%). In conclusion, VA may be causatively related to HF and could explain the calcium paradox. It may be prudent to reduce 18:1 TFA intake, irrespective of trans positions, to prevent HF.

Influence of Dietary Protein on Serum Total Protein and Albumin

血清総たん白, アルブミンレベルに対する摂取たん白質の影響を検討した結果, つぎの点が明らかにされた。(1) 各種たん白質で飼育したラットの血清総たん白, アルブミンレベルはカゼイン群で最も高く, ついでツェイン群, カゼイン水解物群, ゼラチン群の順番となり, たん白質の種類によって明らかな差異がみられた。(2) 食餌中のたん白 (カゼイン) 含量を変えた場合には, 総たん白, アルブミンレベルともに無たん白食, 低たん白食では低いレベルを維持していたが, カゼイン含量の増加とともに上昇し, 25%含有食までほぼ直線的に上昇した。高たん白食でもその値は上昇していたが, 増加率においてやや劣る傾向を示した。(3) 低たん白 (2%カゼイン) 食で飼育したラットの飼育日数による変化を調べたところ, 総たん白値では2%カゼイン食摂取7日目で最も著明な減少を示したが, さらに飼育日数を延長していった場合には逆に上昇していた。これに対してアルブミン値は14日目まで低下し, 21日目で上昇していた。