中老年人是否應該補鈣和維生素D?

One of the most contentious questions in nutrition science over the past decade has been whether older adults should be taking supplemental vitamin D and calcium.

過去十年來，在營養(yǎng)科學中，有一個問題頗具爭議：中老年人是否應該補鈣和維生素D?

As the world's population ages and broken bones and fractures become even more of a public health concern, with huge social and economic consequences, researchers have been trying to make sense of conflicting studies on the association between supplements and fracture risk.

隨著世界人口老齡化，骨折成為了公眾健康問題。許多研究試圖探索營養(yǎng)補充和骨折風險之間的聯(lián)系，但得出了矛盾的結(jié)論。

A study published in the Journal of the American Medical Association on Tuesday took a fresh look at this issue by analysing 33 randomised clinical trials involving a total of more than 50,000 adults over the age of 50.

最近，中國研究人員分析了33個隨機臨床研究，其中涉及超過5萬名50歲以上的中老年人，并將分析結(jié)果發(fā)表在《美國醫(yī)學會雜志》上。

Each of these previous research papers involved comparing calcium, vitamin D, or both, with a placebo or no treatment.

其中，每一項研究都將鈣或維生素D(或兩者兼有)和安慰劑或無治療進行對比。

The analysis, conducted by Jia-Guo Zhao of Tianjin Hospital in China, was focussed on older adults who live in the general community and did not include those in nursing homes, hospitals, and other facilities.

研究人員重點關注居住在普通小區(qū)里的中老年人，而不包括那些住進養(yǎng)老院、醫(yī)院的人。

The conclusion was clear: vitamin D and calcium supplements do not seem to be warranted to prevent bone breaks or hip fractures in those adults. Such supplements had no clear benefit regardless of dose, the gender of the patient, history of fractures, or the amount of calcium in the diet.

結(jié)果非常明確：對中老年人來說，補鈣和維生素D無法預防骨折。無論劑量大小、性別幾何、是否有過骨折史、飲食含鈣量多少，這兩種營養(yǎng)補充品都無法帶來明顯的健康益處。

The US Preventive Services Task Force, an influential federal advisory body, has raised questions about these supplements since 2013, when it issued recommendations saying evidence to support the benefit of the supplements in older adults without osteoporosis or vitamin D deficiency was "insufficient".

其實，營養(yǎng)學家早就提醒過人們，骨骼健康涉及到許多方面。若想保護骨骼，應該健康飲食、進行負重鍛煉，避免過度飲酒，避免抽煙。

Marion Nestle, a professor emerita of food sciences and nutrition at New York University, wrote in an opinion piece at that time that the UPSTF's statement should caution clinicians "to think carefully before advising calcium and vitamin D supplementation for healthy individuals".

紐約大學食品科學與營養(yǎng)學教授瑪麗恩Nestle在當時的一篇評論文章中寫道，UPSTF的聲明應該提醒臨床醫(yī)生“在為健康個體提供鈣和維生素D補充之前要慎重考慮”。

She said this week bone health involves many different aspects of eating and activity.

她說，本周骨骼健康涉及飲食和活動的許多不同方面。

"Bone preservation throughout life requires eating healthfully, engaging in weight-bearing activity, avoiding excessive alcohol, and not smoking - good advice for everyone," Nestle said.

其實，營養(yǎng)學家早就提醒過人們，骨骼健康涉及到許多方面。若想保護骨骼，應該健康飲食、進行負重鍛煉，避免過度飲酒，避免抽煙。

Vitamin D is not a vitamin but a hormone that is produced in reaction to sunlight and seems to have many different roles in the body related to bones, cancer, heart disease, diabetes, immune function, and reproductive health.

維生素D是一種類固醇激素，能夠通過曬太陽分泌。它在許多方面起到不同的作用，包括骨骼、癌癥、心臟病、糖尿病、免疫功能、生殖健康。

Daniel Fabricant, president of the Natural Products Association, which represents manufacturers and retailers of dietary supplements, said the study draws its conclusions with "too broad of a brush".He said it focusses on the healthiest segment of the population by looking at people who are able to live at home."There is a lot missing," Fabricant said. "People with prior breaks or family incidence of osteoporosis may still need vitamin D."

針對這項研究，也有營養(yǎng)學家提出質(zhì)疑，認為結(jié)論太過粗泛，只關注健康人群，忽略了很大一部分中老年人。那些有過骨折史或家人患過骨質(zhì)疏松癥的人也許依然需要補充維生素D。

Calcium and vitamin D have been known to be important to bone maintenance for a long time, and the best way to get the daily recommended doses are the natural way.

鈣和維生素D對骨質(zhì)健康很重要，這點沒錯，但最好通過天然方式進行補充。

For calcium, that means eating dairy products like milk, cheese, yogurt or calcium-rich leafy greens. For vitamin D, that means getting some sun exposure. Only a few foods contain vitamin D, and they include fatty fish like salmon.

想補鈣，就多食用乳制品，如牛奶、芝士、酸乳等。想補充維生素D，就多曬太陽。含維生素D的食物很少，其中包括鮭魚。

In 2010, the Institute of Medicine (IOM) released recommendations tripling the daily intake of vitamin D for most people to 600 IU per day and raising the calcium intake to 1,000 milligrams.

2010年，美國醫(yī)學研究所公布了每日推薦攝入量——維生素D為600IU，鈣為1,000毫克。