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In research studies calcium has been shown
对钙质的研究表明
to play a preventative role in colon cancer
钙质对结肠癌和乳腺癌起到防治作用
and breast cancer, especially breast cancer
尤其是对绝经女性的
in pre-menopausal women. The exact mechanism
乳腺癌防治
by which calcium prevents cancer is unclear.
钙质防治癌症的具体原理还不清楚
At the biochemical level it is clear that calcium
在生物化学层面，我们清楚的是
binds to both bile and fatty acids in the
钙与胃肠道中的胆汁和脂肪酸结合
gastrointestinal tract to form insoluble complexes.
形成了无法溶解的复合物
Because the calcium is bound to the acids it reduces
因为钙与酸的结合
the ability of the acids to damage cells located
降低了酸的能力
in the lining of the colon. Calcium also acts directly
破坏结肠粘膜的癌细胞
in reducing cell proliferation in the lining of
钙还能直接抑制癌细胞在结肠粘膜的扩散
the colon. Both mechanisms are thought to contribute
这两种原理都支持了钙质
to calcium's prevention of cancer.
能够防治癌症的理论
A strong relationship between calcium intake 2002年
国家癌症研究院发表的
and colorectal cancer risk was found
护士健康研究和保健专业医生
in the participants of the Nurses' Health Study
随访研究
and Health Professionals' Follow-up Study
从研究对象身上发现了钙摄入量
published by the Journal of the National Cancer
和直肠癌风险之间的密切关系
Institute in 2002. In this study researchers
在这个研究中
analyzed 135 thousand men and women and
研究人员分析了男性和女性共13万5千人
found that people who consumed 700 milligrams
发现每天摄入700毫克钙的人群
of calcium per day reduced their risk of colorectal
与每天摄入500毫克钙的人群相比
cancer by 35 to 45% when compared to people
结肠直肠癌的风险降低了
with intakes of 500 mg of calcium per day or less.
35%到45%
This effect was only recognized in the
研究发现，这一效果只会发生在结肠的末梢
distal area of the colon and intake showed
在近端结肠
no effect on the proximal colon.
没有防治效果
Another study done by the National Institutes
另一个相关研究
of Health-American Association of Retired Persons Diet
由美国国家卫生研究院下属的
and Health Study which was published in 2009
美国退休人员饮食和健康研究协会完成
by Archives of Internal Medicine showed
并于2009年由《国家内科医学档案》发表
that high intakes of total calcium, dietary calcium
研究显示总钙，膳食钙和钙补充剂的高摄取量
and calcium supplements were associated with
能够使男性的结肠直肠癌风险降低20%
20% lower risk of colorectal cancer among men
使女性的这一风险
and 30% lower risk among women.
降低30%
A study published in 1998 by Cancer
《肿瘤流行病学生物标志物和预防》
Epidemiology Biomarkers and Prevention
于1998年发表的研究调查了
examined women living in Iowa.
居住在爱荷华州的女性
This study compared 34000 women divided into
研究将34000名女性分成两组来作比较
two groups. One group consumed
每组成员每天摄取大约1280毫克的钙质
approximately 1,280 mg of calcium or more a day
或者更多，另一组成员每天摄取800毫克钙
and was compared to a second group of women
或者更少
with calcium intakes of 800 mg per day or less.
两组成员摄取的钙质
Total intakes in the two groups were from both
来源于膳食或者钙补充剂
diet and supplements. The group of women
摄取更多钙质的女性
who consumed the higher intake of calcium
结肠癌风险
were associated with a 41% reduction
减少了41%
in colon cancer risk while the group of women
相比之下，摄取800毫克或更少钙质的
which consumed calcium intakes of 800 mg or less
另一组女性的结肠癌风险
per day showed no reduction in colon cancer risk.
没有降低
The Nurses' Health Study published in 2002
2002年，护士健康研究
by the Journal of National Cancer Institute
发表在美国国家癌症研究院期刊上
included 3000 women and concluded
研究对象包括3000名女性
higher calcium intakes of more than 800 mg
研究结果表明
per day reduced the risk of breast cancer
未绝经的女性每天摄取大于800毫克的钙质
in pre-menopausal women. This study compared
能够降低患乳腺癌的风险
two groups of women where one group consumed
该研究比较了两组女性
a higher amount of calcium of 800 mg per day or more
一组女性每天摄取800毫克或更多的钙质
and the second group of women consumed
另一组女性每天仅摄取
a lower amount of calcium of 200 mg a day or less.
200毫克或更少的钙
The group of women with the higher calcium intakes
摄取更多钙质的那组女性
consumed calcium specifically from dairy products
特别要从乳制品中获取钙
and in particular low fat or non-fat milk,
尤其是低脂或脱脂牛奶
yogurt and cheese. The researchers concluded
酸奶和奶酪，研究人员获得结果
that increased calcium intake of 800 mg per day
每天800毫克的钙摄入量
from dairy sources reduced the risk of breast cancer
能够减少未绝经女性患乳腺癌的风险
in pre-menopausal women but
但是对已经绝经的女性
not in post-menopausal women.
没有效果
