High dietary intake of B vitamins ups endometrial cancer B族維生素的高膳食攝入量增加子宮內膜癌

Tuesday 07/13/2021 – (jkzx.com/) — A study published in Augusts 2020 in Cancer Research suggests that high dietary intake of B vitamins such as thiamine, riboflavin, vitamin B6, folate may increase risk of endometrial cancer in postmenopausal but not postmenopausal women.

For the study presented at AACR Annual Meeting 2020 in Philadelphia, PA, Ming Lei from University of Pittsburgh and colleagues sought to establish any correlation between dietary intake of some B vitamins and risk of endometrial cancer in premenopausal and postmenopausal Chinese women in Singapore.

Endometrial cancer is the sixth most common cancer worldwide. The effect of dietary factors on the risk of the cancer remains largely unknown.

The researchers analyzed data on dietary intake of some common B vitamins and risk of endometrial caner collected from 34,028 ethnically Chinese women aged 45 to 72 in Singapore among whom 166 cases of endometrial cancer were identified. They found a significant positive association between B vitamin intake and risk of endometrial cancer.

Specifically, compared to those in the lowest quartile of dietary intake of thiamine, women in the highest quartile were 74% more likely to be diagnosed with endometrial cancer. The cancer risk for women having their intake of riboflavin, vitamin B6 and folate in the highest quartile, compared to those in the lowest quartile was elevated by 58%, 71% and 56%, respectively.

The association was even stronger among postmenopausal women. The highest risk associated with highest dietary intake of riboflavin, vitamin B6 and folate increased by 74%, 91% and 89%, respectively, compared to those with lowest intake. But it is interesting that the association was not found in premenopausal women.

The study also found obesity was correlated with increased risk of endometrial cancer while having multiple children was linked to reduced risk compared to those without giving birth to any child.

This study suggests that excess dietary intake of B vitamins can be harmful to older women. Early studies have also linked high intake of B vitamins like folate to higher risk of breast cancer.

B vitamins as methyl donors are important for DNA protection through methylation.   Methylation of more genes can protect DNA integrity and maintain genomic stability.  It is believed that this methylation helps DNA survive longer or slow down the aging process which does not necessarily always mean better.   (Dr. Lu)

Reference:

Ming Lei, Shalkar Adambekov, Robert Edwards, Renwei Wang, Jianmin Yuan, Samia Lopa, Faina Linkov. Association between dietary vitamin B intake and risk of endometrial cancer in the prospective Singapore Chinese Health Study [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4646.

More information on endometrial cancer

2020 年 8 月發表在《癌症研究》上的一項研究表明，B 族維生素（如硫胺素、核黃素、維生素 B6、葉酸）的高膳食攝入量可能會增加絕經後婦女患子宮內膜癌的風險，但不會增加絕經後婦女患子宮內膜癌的風險。

對於在賓夕法尼亞州費城舉行的 AACR 年會 2020 上發表的研究，匹茲堡大學的 Ming Lei 及其同事試圖建立一些 B 族維生素的膳食攝入量與新加坡絕經前和絕經後中國女性患子宮內膜癌風險之間的任何相關性。

子宮內膜癌是全球第六大常見癌症。飲食因素對癌症風險的影響在很大程度上仍然未知。

研究人員分析了從新加坡 34,028 名 45 至 72 歲的華裔女性中收集的一些常見 B 族維生素的膳食攝入量和子宮內膜癌風險的數據，其中確定了 166 例子宮內膜癌。他們發現 B 族維生素攝入量與子宮內膜癌風險之間存在顯著的正相關。

具體來說，與飲食中硫胺素攝入量最低四分位數的女性相比，最高四分位數的女性被診斷出患有子宮內膜癌的可能性要高 74%。與最低四分位數相比，攝入核黃素、維生素 B6 和葉酸的女性的癌症風險分別升高了 58%、71% 和 56%。

這種關聯在絕經後婦女中更為明顯。與攝入量最低的人相比，與最高膳食攝入核黃素、維生素 B6 和葉酸相關的最高風險分別增加了 74%、91% 和 89%。但有趣的是，在絕經前婦女中並未發現這種關聯。

該研究還發現，肥胖與子宮內膜癌的風險增加有關，而與沒有生育任何孩子的人相比，有多個孩子與風險降低有關。

這項研究表明，從膳食中攝入過多的 B 族維生素可能對老年女性有害。早期研究還將葉酸等 B 族維生素攝入量高與患乳腺癌的風險增加聯繫起來。

B 族維生素作為甲基供體對於通過甲基化保護 DNA 很重要。更多基因的甲基化可以保護DNA的完整性並維持基因組的穩定性。據信，這種甲基化有助於 DNA 存活更長時間或減緩衰老過程，這並不一定意味著更好。 (陸博士)