コーヒーを飲んでいると自殺率が50％下がる

コーヒーを含めてカフェインの特徴です。

１．中枢神経刺激作用や痙攣誘発作用があり、喘息や無呼吸の治療目的以外では5歳未満には推奨できない。

（成人でもコーヒーを27杯飲んで痙攣を起こした症例があります。水中毒かも知れませんが。）

２．消化管からのCa吸収を妨げるため、乳幼児～思春期には”常用”は推奨できない。

３．同じ理由から骨粗鬆症の人の”常用”は推奨できない。

４．精神的ストレスのある時には、以下の理由から1日2～3杯のコーヒーやお茶の摂取が推奨される。1日8杯以上のコーヒー摂取は逆に推奨できない。

５．1日4杯以上のコーヒー摂取は脱水にさせるので、水分補給が必要である。

６．1日4杯を超える（週に28杯以上）コーヒー摂取は死亡率を上げる。55歳未満では死亡率が1.5倍になる。

７．コーヒー1日4杯以上で前立腺がんリスクが減る。

ハーバード公衆衛生大学院が、「一日に何杯かコーヒーを飲むと、男性・女性ともに自殺率を50％下げる」という研究結果を発表しました。

アメリカで行われた研究で、1日にコーヒーを2～3杯飲む成人は、「ノンカフェインや極少量のコーヒーを飲む人」、または「全く飲まない人」よりも自殺率が50％低いことが分かりました。

カフェインは中枢神経を刺激するだけでなく、セロトニン、ドーパミン、ノルアドレナリンを含む脳内の特定神経伝達物質の生産を高めることによって、軽度の抗鬱剤として作用する可能性があります。これは、過去に疫学研究が発見した「コーヒー愛飲者は鬱のリスクが低い」という説の証明になるのではないか？ と研究者は報告しています。

この最新の研究では、1988～2008年にHealth Professionals Follow-Up Studyに登録した4万3599人の男性と、1992～2008年にNurses' Health Studyに登録した7万3820人の女性、そして1993～2007年にNurses' Health Study IIに登録した9万1005人の女性を対象に調査しました。

調査員によって「カフェイン」、「コーヒー」そして「カフェインの入っていないコーヒー」のそれぞれの摂取量は、4年ごとに調査されたそうです。

そして、カフェインの消費量は、コーヒーやお茶、カフェイン入りソフトドリンク、チョコレートなど、カフェインの入っている飲料や食べ物から計算され、そしてカフェインの主要源は、NHSでは80％、NHS2では71％、またHPFSでは79％が「コーヒー」ということがわかりました。

この3つのグループの研究参加者で、277人が自殺しました。

しかし、この結果が出たからといって、成人うつ病患者のカフェイン摂取量を増やすことは勧めません。それは、最適なカフェイン摂取量には個人差があり、増やすことで好ましくないとされる副作用が出る可能性も否定出来ないからです。「全体的に、1日に2～3杯のコーヒー、もしくは400mgのカフェインの接種で、少しだけ利点があると言える」と研究者は書いています。

Harvard Gazetteより一部抜粋

コーヒーが良いとはいえ、Harvard Gazetteには、フィンランドの研究では「1日に8杯以上のコーヒーを飲む人は自殺率が高い」という結果が出ているとも書かれています。

コーヒーや紅茶の摂取によって死亡率が下がる

米国マイアミ大学のHannah Gardener氏らは、コーヒーや紅茶の摂取量と原因別の死亡率（血管関連、血管関連以外、がん、すべての原因）との関係を、多民族集団ベース研究であるNorthern Manhattan Studyでプロスペクティブに検討した。この調査では、人種によりコーヒー摂取量と血管関連死との関係が異なることが示唆された。Journal of Nutrition誌オンライン版2013年6月19日号に掲載。

　調査には、ベースライン時に脳卒中、心筋梗塞、がんの既往がなかった2,461人が参加した（平均年齢68.30±10.23歳、男性36％、白人19％、黒人23％、ヒスパニック56％）。平均追跡期間11年で、食事摂取頻度調査票により調査したコーヒーと紅茶の摂取量と863人の死亡（そのうち血管関連死は342人、がんによる死亡160人を含む非血管関連死は444人）との関連について、多変量補正Coxモデルにより検討した。

　＜結果＞

★コーヒー摂取量と全死因による死亡率の間に逆相関が認められた（1日当たりの杯数増加につき、HR＝0.93、95％CI：0.88～0.99、p=0.02）。カフェイン入りのコーヒーを4杯/日以上飲んだ人では全死因死亡における強い抑制効果が認められた。

★紅茶摂取量と全死因による死亡率の間に逆相関が認められた（1日当たりの杯数増加につき、HR=0.91、95％CI：0.84～0.99、p=0.01）。

★コーヒー4杯/日以上の摂取は非血管関連死を抑制した（1杯/月未満に対して、HR=0.57、95％CI：0.33～0.97）。

★紅茶2杯/日以上の摂取は非血管関連死（HR=0.63、95％CI：0.41～0.95）とがんによる死亡（HR=0.33、95％CI：0.14～0.80）を抑制した。

★ヒスパニックのみ、コーヒーと血管関連死の間に強い逆相関があった。

週に28杯以上のコーヒー摂取によって死亡率が上がる

一方で上記の研究と相反する結果が報告されています。

55歳未満で1日に4杯を超える（週に28杯以上の）コーヒーを飲む人では早期死亡リスクの高いことが、米ジョン・オクスナー心血管研究所（ニューオーリンズ）のCarl Lavie氏らの新たな研究で示唆された。

　Lavie氏は「週に28杯までは安全であると考えられるが、特に若い人の場合、1日の摂取量を8オンス（約240ml）カップで4杯以内に抑えるように努める理由がある」と述べている。

　コーヒーが健康によいのか、どの程度までならよいのかという問題は盛んに議論されている。既存の研究からは、コーヒーの摂取によりガン、心不全、その他の疾患リスクが低下する徴候も認められているが、確かなことはわかっていない。

コーヒーを飲む人は、ほかに健康に影響を及ぼす何らかの因子を共有している可能性もある。全米コーヒー協会（NCA）によると、米国では60%を超える成人が毎日コーヒーを飲んでおり、平均摂取量は1日3杯強という。

　今回の研究では、1971年～2002年に試験に登録した20～87歳の成人約4万4,000人を平均約16年間追跡。約4分の3が男性だった。追跡期間中、2,512人が死亡した。喫煙や体力などの因子を考慮して統計値を調整した結果、週に28杯を超えるコーヒーを飲む人は死亡リスクが21%高いことが判明。55歳未満の男女では、リスクが50%高かった。それ以下の量のコーヒーでは、影響は認められなかった。

　特定の遺伝的因子がコーヒーを多量に飲む人のリスクを高める可能性も示唆されている。

Coffee drinking tied to lower risk of suicide

Researchers link caffeine’s impact on brain chemicals as playing key role

July 24, 2013

By Marge Dwyer, Harvard School of Public Health Communications

http://news.harvard.edu/gazette/story/2013/07/drinking-coffee-may-reduce-risk-of-suicide-by-50/

Drinking several cups of coffee daily appears to reduce the risk of suicide in men and women by about 50 percent, according to a new study by researchers at the Harvard School of Public Health (HSPH). The study was published online July 2 in The World Journal of Biological Psychiatry.

“Unlike previous investigations, we were able to assess association of consumption of caffeinated and non-caffeinated beverages, and we identify caffeine as the most likely candidate of any putative protective effect of coffee,” said lead researcher Michel Lucas, research fellow in the Department of Nutrition at HSPH.

The authors reviewed data from three large U.S. studies and found that the risk of suicide for adults who drank two to four cups of caffeinated coffee per day was about half that of those who drank decaffeinated coffee or very little or no coffee.

Caffeine not only stimulates the central nervous system but may act as a mild antidepressant by boosting production of certain neurotransmitters in the brain, including serotonin, dopamine, and noradrenaline. This could explain the lower risk of depression among coffee drinkers that had been found in past epidemiological studies, the researchers reported.

In the new study, researchers examined data on 43,599 men enrolled in theHealth Professionals Follow-Up Study (HPFS) (1988–2008), 73,820 women in the Nurses’ Health Study (NHS) (1992–2008), and 91,005 women in the Nurses’ Health Study II (NHSII) (1993–2007). Caffeine, coffee, and decaffeinated coffee intake was assessed every four years by questionnaires. Caffeine consumption was calculated from coffee and other sources, including tea, caffeinated soft drinks, and chocolate. However, coffee was the major caffeine source — 80 percent for NHS, 71 percent for NHS II, and 79 percent for HPFS. Among the participants in the three studies, there were 277 deaths from suicide.

In spite of the findings, the authors do not recommend that depressed adults increase caffeine consumption, because most individuals adjust their caffeine intake to an optimal level for them and an increase could result in unpleasant side effects. “Overall, our results suggest that there is little further benefit for consumption above two to three cups/day or 400 mg of caffeine/day,” the authors wrote.

The researchers did not observe any major difference in risk between those who drank two to three cups of coffee per day and those who had four or more cups a day, most likely due to the small number of suicide cases in these categories. However, in a previous HSPH coffee-depression study published in JAMA Internal Medicine, the investigators observed a maximal effect among those who drank four or more cups per day. One large Finnish study showed a higher risk of suicide among people drinking eight or nine cups per day. Few participants in the two HSPH studies drank such large amounts of coffee, so the studies did not address the impact of six or more cups of coffee per day.

Other HSPH researchers participating in the study included senior authorAlberto Ascherio, professor of epidemiology and nutrition; Walter Willett, chair, Department of Nutrition and Fredrick John Stare Professor of Epidemiology and Nutrition; and research associates Eilis O’Reilly and An Pan. Pan now works at the National University of Singapore.

カフェインと体内の水分、運動能力の関係について1980年から研究してきたローレンス・アームストロングによると、1日の摂取量が多くなければ、カフェインの脱水作用の影響はほとんど受けないのだそうです。こういった影響を与えるのは1日500mg以上のカフェイン、コーヒーなら4杯相当です。

また、日常的にカフェインを摂取している人は、カフェインへの耐性ができ、影響を受けにくくなることが分かっています。

CAN CAFFEINE CAUSE DEHYDRATION?

JUL 26, 2011 | BY RYN GARGULINSK

Unless you're drinking more than 4 cups of coffee or the equivalent amount of caffeine each day, caffeine does not cause dehydration. Several studies led by professor and scientist Lawrence Armstrong disproved the long-standing belief that moderate amounts of caffeine cause dehydration. His studies also proved other caffeine-related facts with regard to athletic performance and the body's fluid-electrolyte balance.

DISPROVEN THEORY

The theory used to be that caffeine caused dehydration by acting as a diuretic and increasing your need to urinate. The increased loss of bodily fluids through urination would thus lead to dehydration. While that holds true for large amount of caffeine, or the more than 500 mg you'd get from drinking more than 4 cups of coffee each day, Armstrong notes it also holds true for large amounts of any beverage, including water.

EVIDENCE

In addition to his findings on dehydration, Armstrong's studies uncovered other information with regard to caffeine. There is no evidence caffeine causes an imbalance in the body's fluid and electrolytes, which would bolster another previous theory that drinking caffeine hindered athletic performance. On the contrary, caffeine consumption would have a more dramatic effect on people who were sedentary, since they do not sweat out fluids as frequently as athletes.

STUDIES

As a scientist researching the fields of human performance and thermoregulation since 1980, Armstrong conducted at least three studies that help support the fact that moderate amounts of caffeine does not lead to dehydration or impair sports performance. Two of the studies appeared in "The International Journal of Sport Nutrition and Exercise Metabolism." The study entitled "Caffeine, Body Fluid-Electrolyte Balance, and Exercise Performance" appeared in the June 2002 issue, while the study "Fluid, Electrolyte, and Renal Indices of Hydration During 11 Days of Controlled Caffeine Consumption" appeared in 2005. "Exercise and Sport Sciences Reviews" published the third study, "Caffeine, Fluid-Electrolyte Balance, Temperature Regulation, and Exercise-Heat Tolerance," in 2007. Each study involved comparing a group of people who consumed a set amount of caffeine with those who consumed a placebo.

CONSIDERATIONS

As with any drug, you can build up a tolerance to caffeine, which means its effects will not be as notable as they would be for someone who rarely consumes it or is sensitive to the substance. The more tolerance you build up, the more resistance you have to its diuretic effects, even when consuming large quantities. Although drinking caffeine does not result in dehydration, it can still lead to nervousness, sleeplessness and anxiety. Coffee is one of the most common beverages containing caffeine, but it's also in certain sodas, colas and teas.

Coffee and tea consumption are inversely associated with mortality in a multiethnic urban population.

The Journal of nutrition. 2013 Aug;143(8);1299-308. doi: 10.3945/jn.112.173807.

Hannah Gardener, Tatjana Rundek, Clinton B Wright, Mitchell S V Elkind, Ralph L Sacco

Department of Neurology, Miller School of Medicine, University of Miami, Miami, FL.

Abstract

Coffee and tea are commonly consumed beverages. Inverse associations with mortality have been suggested for coffee and tea, but the relationships with cause-specific mortality are not well understood. We examined regular and decaffeinated coffee and tea in relation to mortality due to all causes, vascular, nonvascular, and cancer in the multi-ethnic, prospective, population-based Northern Manhattan Study. The study population included 2461 participants with diet data who were free of stroke, myocardial infarction, and cancer at baseline (mean age 68.30 ± 10.23 y, 36% men, 19% white, 23% black, 56% Hispanic). During a mean follow-up of 11 y, we examined the associations between coffee and tea consumption, assessed by food frequency questionnaire, and 863 deaths (342 vascular related and 444 nonvascular including 160 cancer deaths) using multivariable-adjusted Cox models. Coffee consumption was inversely associated with all-cause mortality [for each additional cup/d, HR = 0.93 (95% CI: 0.88, 0.99); P = 0.02]. Caffeinated coffee was inversely associated with all-cause mortality, driven by a strong protection among those who drank ≥4 cups/d. An inverse dose-response relationship between tea and all-cause mortality was suggested [for each additional cup/d, HR = 0.91 (95% CI: 0.84, 0.99); P = 0.01]. Coffee consumption ≥4/d was protective against nonvascular death [vs. <1/mo, HR = 0.57 (95% CI: 0.33, 0.97)] and tea consumption ≥2/d was protective against nonvascular death [HR = 0.63 (95% CI: 0.41, 0.95)] and cancer [HR = 0.33 (95% CI: 0.14, 0.80)]. There was a strong inverse association between coffee and vascular-related mortality among Hispanics only. Further study is needed, including investigation into the mechanisms and compounds in coffee and tea responsible for the inverse associations with mortality. The differential relationship between coffee and vascular death across race/ethnicity underscores the need for research in similar multi-ethnic cohorts including Hispanics.

Association of Coffee Consumption With All-Cause and Cardiovascular Disease Mortality.

Mayo Clinic proceedings. Mayo Clinic. 2013 Aug 15; pii: S0025-6196(13)00578-8.

Junxiu Liu, Xuemei Sui, Carl J Lavie, James R Hebert, Conrad P Earnest, Jiajia Zhang, Steven N Blair

Department of Biostatistics and Epidemiology, Arnold School of Public Health, University of South Carolina, Columbia. Electronic address: LIU272@email.sc.edu.

Abstract

OBJECTIVE :

To evaluate the association between coffee consumption and mortality from all causes and from cardiovascular disease.

PATIENTS AND METHODS :

Data from the Aerobics Center Longitudinal Study representing 43,727 participants with 699,632 person-years of follow-up were included. Baseline data were collected by an in-person interview on the basis of standardized questionnaires and a medical examination, including fasting blood chemistry analysis, anthropometry, blood pressure, electrocardiography, and a maximal graded exercise test, between February 3, 1971, and December 30, 2002. Cox regression analysis was used to quantify the association between coffee consumption and all-cause and cause-specific mortality.

RESULTS :

During the 17-year median follow-up, 2512 deaths occurred (804 [32%] due to cardiovascular disease). In multivariate analyses, coffee intake was positively associated with all-cause mortality in men. Men who drank more than 28 cups of coffee per week had higher all-cause mortality (hazard ratio [HR], 1.21; 95% CI, 1.04-1.40). However, after stratification based on age, younger (<55 years old) men and women showed a significant association between high coffee consumption (>28 cups per week) and all-cause mortality after adjusting for potential confounders and fitness level (HR, 1.56; 95% CI, 1.30-1.87 for men; and HR, 2.13; 95% CI, 1.26-3.59 for women).

CONCLUSION :

In this large cohort, a positive association between coffee consumption and all-cause mortality was observed in men and in men and women younger than 55 years. On the basis of these findings, it seems appropriate to suggest that younger people avoid heavy coffee consumption (ie, averaging >4 cups per day). However, this finding should be assessed in future studies of other populations.

Coffee and tea consumption in relation to prostate cancer prognosis

Geybels MS et al. – Bioactive compounds found in coffee and tea may delay the progression of prostate cancer. Results indicate that higher pre–diagnostic coffee consumption is associated with a lower risk of prostate cancer recurrence/progression. This finding will require replication in larger studies.

Methods

• Authors investigated associations of pre–diagnostic coffee and tea consumption with risk of prostate cancer recurrence/progression.

• Study participants were men diagnosed with prostate cancer in 20022005 in King County, Washington, USA.

• They assessed the usual pattern of coffee and tea consumption two years before diagnosis date.

• Prostate cancer–specific outcome events were identified using a detailed follow–up survey.

• Multivariable Cox proportional hazards regression models were used to estimate hazard ratios (HRs) and 95 % confidence intervals (CIs).

Results

• The analysis of coffee intake in relation to prostate cancer recurrence/progression included 630 patients with a median follow–up of 6.4 years, during which 140 prostate cancer recurrence/progression events were recorded.

• Approximately 61 % of patients consumed at least one cup of coffee per day.

• Coffee consumption was associated with a reduced risk of prostate cancer recurrence/progression; the adjusted HR for ≥4 cups/day versus ≤1 cup/week was 0.41 (95 % CI: 0.20, 0.81; p for trend = 0.01).

• Approximately 14 % of patients consumed one or more cups of tea per day, and tea consumption was unrelated to prostate cancer recurrence/progression.