著者

Harumi Okuyama Yoichi Fujii Atsushi Ikemoto

出版者

The Pharmaceutical Society of Japan

雑誌

Journal of Health Science (ISSN:13449702)

巻号頁・発行日

vol.46, no.3, pp.157-177, 2000-06-01 (Released:2008-04-14)

参考文献数

183

被引用文献数

16 27

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Classic lipid nutrition for the prevention of chronic, elderly-onset diseases was apparently established before 1960, assuming that hypercholesterolemia is the major risk factor and that raising the polyunsaturated/saturated (P/S) ratio of dietary fatty acids is hypocholesterolemic. However, the hypocholesterolemic effect of linoleic acid (LA) was found to be transient. Furthermore, hypercholesterolemia itself is unlikely to be a serious risk factor for diseases in the elderly because serum cholesterol level is positively correlated with longevity. Instead, a high n-6/n-3 ratio of dietary fatty acids was found to increase thrombotic tendency, decrease peripheral blood flow and lead to persistent inflammation, which was proposed to be the major risk factor for atherosclerosis and related diseases. Based on animal experiments and epidemiological studies, we recommend a reduction in the intake of LA from a current value of >6 en% to half, and a reduced n-6/n-3 ratio from the current value of >4 to 2. Simply decreasing LA intake would produce the recommended n-6 and n-3 fatty acid balance in Japan due to the typical Japanese diet, but both decreasing the intake of LA and increasing that of n-3 fatty acids, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), is necessary in Western industrialized countries for the effective prevention of atherosclerosis and related diseases, as well as of apoplexy, allergic hyper-reactivity and cancers typical in Western populations.

著者

Harumi Okuyama Naoki Ohara Kenjiro Tatematsu Shinya Fuma Tomoyuki Nonogaki Kazuyo Yamada Yuko Ichikawa Daisuke Miyazawa Yuko Yasui Seijiro Honma

出版者

The Japanese Society of Toxicology

雑誌

The Journal of Toxicological Sciences (ISSN:03881350)

巻号頁・発行日

vol.35, no.5, pp.743-747, 2010-10-01 (Released:2010-10-01)

参考文献数

25

被引用文献数

7 13 5

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Canola and some other types of oil unusually shorten the survival of stroke-prone spontaneously hypertensive rats (SHRSP), compared with soybean oil, perilla oil and animal fats. Since differential effects of canola and soybean oil on steroid hormone metabolism were suggested by a preliminary DNA microarray analysis as a reason for this, the steroid hormone levels in the serum and tissues of SHRSP fed different oils were investigated. The testosterone levels in the serum and the testes were found to be significantly lower in the canola oil group than in the soybean oil group, while no significant differences were detected in the corticosterone and estradiol levels in tissues. In a second experiment, it was found that hydrogenated soybean oil, with a survival-shortening activity comparable to that of canola oil, also decreased the testosterone level in testes to a similar degree. The testosterone-lowering activity of canola and hydrogenated soybean oil observed in SHRSP was considered in relation to other factors possibly affecting the physiology of SHRSP.

著者

Tomohito Hamazaki Harumi Okuyama Akira Tanaka Yasuo Kagawa Yoichi Ogushi Rokuro Hama

出版者

Japan Society for Lipid Nutrition

雑誌

脂質栄養学 (ISSN:13434594)

巻号頁・発行日

vol.21, no.1, pp.67-75, 2012 (Released:2012-04-29)

被引用文献数

1

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Almost all Japanese epidemiological studies showed that all-cause mortality was lower in subjects with high serum total or LDL-cholesterol levels. Studies showing the disadvantage of high cholesterol levels included or were likely to include more participants with FH than in the general Japanese population. This also explains why epidemiological studies with elderly people are not able to detect any disadvantage of high cholesterol levels; groups of elderly subjects contain a smaller proportion of vulnerable FH patients who die earlier than those without FH. Meta-analyses of the effects of statins were used to indicate the favorable effects of these drugs, which might be considered as proof that cholesterol has unfavorable effects. However, the absolute effect size of statins on all-cause mortality is rather small, if any. Moreover, studies included in meta-analyses of statins were performed before the new clinical research regulation came into effect in 2005-2006 in the EU, which required clinical trial results to be published even if the data were not favorable for the tested drugs (BJOG 2007; 114: 917, http://www.bjog.org/view/0/index.html). Considering the fact that placebo-controlled clinical trials performed after the new regulation were mostly negative (J Lipid Nutr 2010; 19: 65, http://www.jstage.jst.go.jp/article/jln/19/1/65/_pdf/-char/ja/), the results published before the regulation were questionable and should not be used as the basis for recommendations for treatment with cholesterol-lowering medications. Because the relative risks of high cholesterol for CHD vary from 5, administering cholesterol-lowering medications to all Japanese individuals equally is not rational; at least women and elderly men need to be carefully re-examined because no or little positive associations between plasma cholesterol and CHD mortality rates have been reported in these groups.

著者

Mai Nishikawa Naoki Ohara Yukiko Naito Chihiro Amma Yoshiaki Saito Kenjiro Tatematsu Jinhua Baoyindugurong Daisuke Miyazawa Yoko Hashimoto Harumi Okuyama

出版者

The Japanese Society of Toxicology

雑誌

Fundamental Toxicological Sciences (ISSN:2189115X)

巻号頁・発行日

vol.9, no.1, pp.7-16, 2022 (Released:2022-01-15)

参考文献数

30

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The present study was conducted to survey the influence of canola oil (CAN) ingestion on the steroid hormone production in stroke-prone spontaneously hypertensive rats (SHRSP). Male SHRSP were fed a diet containing 10 wt/wt% soybean oil (SOY, the control) or CAN as the sole dietary fat for 8 weeks. Plasma concentration of luteinizing hormone (LH) was similar in the 2 dietary groups. However, the plasma testosterone level in the CAN group, 1.36 ± 0.271 ng/mL, was lower than in the SOY group, 2.79 ± 0.514 ng/mL (p < 0.05, unpaired t-test; n = 10), and plasma concentration of aldosterone in the CAN group, 345 ± 79.6 pg/mL, was higher than in the SOY group, 159 ± 33.7 pg/mL (p < 0.05, unpaired t-test; n = 10). In the testis, the expressions of mRNA for StAR, CYP11A1, CYP17, 3βHSD and 17βHSD and the amounts of the corresponding proteins were significantly decreased. However, in the adrenal gland, the expressions of mRNA for StAR, CYP11A1, 3βHSD and CYP11B1 in the CAN group were not different from those in the SOY group, but the expression of mRNA and the amount of the corresponding protein for CYP11B2 were increased significantly in the CAN group. These findings are indicative of a peripheral, testicular toxicity of CAN. The decreased testosterone and the concomitantly increased aldosterone may play a role in the aggravation by CAN of the genetic diseases (i.e., metabolic syndrome-like complications) in male SHRSP.