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zoom RSS コーヒーを飲む女性はうつ病になりにくい

<<   作成日時 : 2011/09/28 20:14   >>

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 1日2杯以上コーヒーを飲む女性はうつになりにくいという。
 カフェイン抜きのコーヒーは同じ効果が見られないので、コーヒーのカフェインが脳内化学物質を変える可能性があるという。
 米国で50,000人以上の女性看護師についての研究でわかった。ハーバードの研究チームが1996〜2006年の10年間に健康調査とコーヒー消費記録からつきとめた。この間に2,600人がうつ病を発症したがコーヒーを飲まない人が多かった。1日2−3杯コーヒーを飲む人は週に1杯以下の人より15%リスクが低かった。1日4杯以上飲む人は20%リスクが低かった。
 コーヒーを飲む人は自殺率が低いという研究もある。
 コーヒーは、ドーパミン産生を増加させるのと同様な効果を、アデノシンのような化学受容を阻害することで脳機能に影響を及ぼしている。
 ただし、抑鬱気分の人はコーヒーを飲まないということが影響している可能性はある。また、うつの不眠をカフェインは悪化させる可能性もある。

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26 September 2011 Last updated at 23:59 GMT

Coffee may prevent depression, scientists say
By Michelle Roberts Health reporter, BBC News
http://www.bbc.co.uk/news/health-15059266

画像Women who drink two or more cups of coffee a day are less likely to get depressed, research suggests.

It is not clear why it might have this effect, but the authors believe caffeine in coffee may alter the brain's chemistry. Decaffeinated coffee did not have the same effect.

The findings, published in Archives of Internal Medicine, come from a study of more than 50,000 US female nurses.

The experts are now recommending more work to better understand the link.

And they say it is certainly too soon to start recommending that women should drink more coffee to boost mood.
Caffeine lift

The Harvard Medical School team tracked the health of the women over a decade from 1996 to 2006 and relied on questionnaires to record their coffee consumption.
Continue reading the main story
“Start Quote

This fits nicely with a lot of the previous work and what we know about caffeine and the brain”

Prof Bertil Fredholm Karolinska Institute

Just over 2,600 of the women developed depression over this time period.

More of these women tended to be non- or low-coffee drinkers rather than frequent coffee consumers.

Compared with women who drank one cup of caffeinated coffee or less per week, those who consumed two to three cups per day had a 15% decreased risk of developing depression.

Those who drank four or more cups a day cut their risk by 20%.

Regular coffee drinkers were more likely to smoke and drink alcohol and were less likely to be involved in church, volunteer or community groups. They were also less likely to be overweight and have high blood pressure or diabetes.

Even after controlling for all of these variables, the trend of increasing coffee consumption and lower depression remained.
Mounting evidence

The researchers say their findings add weight to the work of others which found lower suicide rates among coffee drinkers.

They suspect caffeine is the key player - it is known to enhance feelings of wellbeing and energy.
Continue reading the main story
How much caffeine?

There is no recommended level a person should consume
But pregnant women are advised to consume less than 200mg a day
One mug of instant coffee: 100mg
One mug of filter coffee: 140mg
One mug of tea: 75mg
One can of cola: 40mg
One 50g bar of milk chocolate: about 25mg

Source: NHS Choices

And it has a physical effect on brain function and transmission by blocking certain chemical receptors, like adenosine. But more research is needed to show if this might mean it is useful for warding off depression.

Alternatively, it might be that people with low moods chose not to drink coffee because it contained caffeine, point out the researchers. One of the common symptoms of depression is disturbed sleep, and caffeine can exacerbate this because it is a stimulant.

Too much caffeine can also increase feelings of anxiety.

Prof Bertil Fredholm, an expert in pharmacology and physiology at Sweden's Karolinska Institute, said the findings were reassuring for coffee-lovers.

"This fits nicely with a lot of the previous work and what we know about caffeine and the brain. It blocks adenosine, which produces a similar effect to increasing dopamine production. And it's becoming increasingly clear that the dopamine-rich areas of the brain are much more important in depression that previously thought.

"Despite valiant efforts to show how dangerous coffee is for us, it is not proving so.

"This removes yet another anxiety regarding caffeine use. Drunk in moderation, the evidence is strong that it is not one of the things we do that is going to damage your health."

----------------------------------------------------
Coffee, Caffeine, and Risk of Depression Among Women

Michel Lucas, PhD, RD; Fariba Mirzaei, MD, MPH, ScD; An Pan, PhD; Olivia I. Okereke, MD, SM; Walter C. Willett, MD, DrPH; E'ilis J. O’Reilly, ScD; Karestan Koenen, PhD; Alberto Ascherio, MD, DrPH

Arch Intern Med. 2011;171(17):1571-1578. doi:10.1001/archinternmed.2011.393

Background Caffeine is the world's most widely used central nervous system stimulant, with approximately 80% consumed in the form of coffee. However, studies that analyze prospectively the relationship between coffee or caffeine consumption and depression risk are scarce.

Methods A total of 50 739 US women (mean age, 63 years) free of depressive symptoms at baseline (in 1996) were prospectively followed up through June 1, 2006. Consumption of caffeine was measured from validated questionnaires completed from May 1, 1980, through April 1, 2004, and computed as cumulative mean consumption with a 2-year latency period applied. Clinical depression was defined as self-reported physician-diagnosed depression and antidepressant use. Relative risks of clinical depression were estimated using Cox proportional hazards regression models.

Results During 10 years of follow-up (1996-2006), 2607 incident cases of depression were identified. Compared with women consuming 1 or less cup of caffeinated coffee per week, the multivariate relative risk of depression was 0.85 (95% confidence interval, 0.75-0.95) for those consuming 2 to 3 cups per day and 0.80 (0.64-0.99; P for trend <.001) for those consuming 4 cups per day or more. Multivariate relative risk of depression was 0.80 (95% confidence interval, 0.68-0.95; P for trend = .02) for women in the highest (?550 mg/d) vs lowest (<100 mg/d) of the 5 caffeine consumption categories. Decaffeinated coffee was not associated with depression risk.

Conclusions In this large longitudinal study, we found that depression risk decreases with increasing caffeinated coffee consumption. Further investigations are needed to confirm this finding and to determine whether usual caffeinated coffee consumption can contribute to depression prevention.


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