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许多人需要补充维生素D 但你可能不必

更新时间:2018-11-9 10:04:10 来源:纽约时报中文网 作者:佚名

Should everyone be taking vitamin D?
许多人需要补充维生素D 但你可能不必

As the days get shorter in the Northern hemisphere, concerns tend to arise about the lack of sunlight – and possible vitamin D deficiency. For many, a go-to fix is to take supplements.

随着北半球日照时间逐渐缩短,阳光不足往往受到更多关注,因为这可能导致人体缺乏维生素D。对于很多人来说,关键在于服用补充剂。

The supplement, after all, has been touted as a near-miracle. Both vitamin D2 and D3 supplements are available over-the-counter without a prescription and have been linked to improving immunity, tiredness and muscle weakness, bone pain, and depression. They’ve also been said to help stave off cancer and the consequences of ageing.

毕竟,营养补充剂现在已经被吹嘘得神乎其神。维生素D2和D3药丸是可以去商店买的非处方药,药效据称包括增强免疫力、消除疲劳和肌肉无力、缓解骨痛、抗抑郁,甚至还有助于对抗癌症和衰老的症状。

It may be little wonder that, according to research by market analysis company Mintel, a third of adults in the UK who take vitamin supplements count vitamin D among them.

根据市场研究咨询公司英敏特(Mintel)的调查,英国三分之一的成年人服用维生素补充剂量;他们认为维生素D具有此类疗效。

But the debate over whether all adults need to take vitamin D supplements is contentious.

但是否所有成年人都需要补充维生素D ?这个問題至今仍有争议。

Few doubt the role that vitamin D plays in our bone health to regulate calcium and phosphate in the body, which is why those who have a vitamin D deficiency are particularly encouraged to address it. And that may be more people than you think: one study estimates that around 20% of the population in the UK has a profound vitamin D deficiency, for example.

几乎无人怀疑维生素D可以调节体内钙和磷酸盐的水平,对于人体骨骼是有益处,这也是为什么医生会特别建议缺乏维生素D的群体采取措施补充。而且,这个群体可能比你想象的庞大。例如,根据一项研究预测,英国约有20%的人口严重缺乏维生素D。

But some experts say that people with healthy levels have no need of vitamin D supplements – which would be most people. In other words, they argue that in healthy people, vitamin D is not, as some have hoped, a way to prevent disease.

但是有些专家称,健康的人无需补充维生素D——这里指的是大部分人。也就是说,并不像有些人所以为的人人都需要服用,其实健康的人用不着补充维生素D来预防疾病。

So what’s the reality?

那么真相是什么?

The basics

常识

Despite its name, vitamin D is not a vitamin. Instead, it is a hormone that promotes the absorption of calcium in the body. The challenge is that, aside from a few foods like oily fish, vitamin D is hard to find in the average diet. But in the presence of ‘ultraviolet B’ rays, our skin can produce its own from a common cholesterol.

尽管称为维生素,维生素D实际不是维生素的一种,而是促进体内钙吸收的一种激素。问题是除了少数几种食物来源,比如富含脂肪的鱼类,维生素D很难由日常饮食中摄入。但是有"紫外线B"的日光浴会促使皮肤从常见的胆固醇中生成维生素D。

There are two main types of D. The first is vitamin D3, which is found in animals including fish and is the kind the skin makes when exposed to sunlight. The second is vitamin D2, which comes from plant-based foods including mushrooms. Studies have found that D3 is more effective, and the conclusions of a 2012 meta-analysis argue that D3 is the preferred choice for supplementation.

维D家族中有两个重要成员。一是维生素D3(胆钙化醇),在包括鱼类的动物体内存在,人体皮下受紫外线照射后也产生维生素D3。二是维生素D2(麦角钙化醇),来自于蔬果类食物,包括蘑菇在内。研究表明,维生素D3的效果更明显。根据2012年一项综合分析的结论,维生素D3是更常用的补充剂。

Today, the UK’s Public Health England (PHE) recommends every adult takes a 10-microgram supplement in autumn and winter, when the angle of the sunlight hitting the earth prevents as many UVB rays from penetrating the atmosphere. The government body also recommends that those at risk of lower vitamin D levels, including people with darker skin, take a supplement year-round.

英国公共卫生署(PHE,Public Health England)目前建议成年人在秋冬两季服用10微克的补充剂,因为这两个季节的太阳高度角阻碍了大量紫外线B光束穿过大气层。政府部门也建议那些维生素D水平较低的潜在人群,包括肤色较深者,全年服用维生素补充剂。

Other countries follow similar guidelines. In Canada, adults are advised to get 15 micrograms of vitamin D and have two servings of vitamin-D fortified milk or soy alternatives every day, while cow's milk and margarine must be fortified with vitamin D by law. In the US, adults also are advised to get 15 micrograms, while much of the country’s milk, breakfast cereals, margarine, yogurts and orange juice is fortified, too.

别的国家也遵循相似的准则。在加拿大,建议成年人服用15微克维生素D,一日两次摄入维生素D强化奶或豆乳,生牛乳和人造黄油必须依法添加维生素D以强化功效。在美国,成年人也被建议服用15微克,很多牛乳、早餐麦片、人造黄油、酸奶和橙汁也有强化功效。

Those guidelines and fortification efforts came about largely in an attempt to fight rickets in the mid-20th Century. We know that low vitamin D levels reduce the body’s levels of calcium, which leads to a decrease in bone density and can cause rickets, particularly in babies and children.

这些准则和强化措施的确立,很大程度上是为了抗击20世纪中期的软骨病。我们知道维生素D水平偏低会降低机体的钙含量,从而导致骨质密度下降,导致软骨病,尤其是在婴儿和儿童中间。

We also know that low vitamin D may cause muscle weakness and fatigue. One study found that low vitamin D was high among people with fatigue and that their symptoms improved after five weeks of vitamin D supplements, while a small study from Newcastle University found that low vitamin D could cause fatigue as low levels cause mitochondria, the ‘power stations’ in every cell of the body, to be less efficient. Studies of cancer patients have found similar effects. Vitamin D may also help bolster and regulate the immune system by clearing bacteria.

我们也知道缺乏维生素D会导致肌肉乏力疲劳。一项研究发现,维生素D水平偏低在易疲劳人群中比较常见,服用维生素D补充剂五周后,他们的症状会有所改善。根据纽卡斯尔大学一项小范围的研究,缺乏维生素D会引起疲劳,因为维生素D水平偏低使得线粒体的工作效率下降,而线粒体是人体细胞进行有氧呼吸的主要场所。对于癌症患者的研究也发现类似的效果。维生素D通过杀菌的作用,也有助于免疫系统的增强和调节。

Broken bones

骨折

But vitamin D’s importance doesn’t necessarily mean people with healthy levels of vitamin D require supplements. Consider one of the most common reasons for supplementation: bone growth and maintenance.

但是维生素D很重要,未必等于维生素D水平达标的人也需要维生素D补充剂。服用维生素D健康品的一个最常见的原因是:促进骨骼的生长与保养。

The current guidelines on how much vitamin D to take were informed by research involving the elderly population living in care homes, who don’t get as much exposure to the sun and are more prone to fractures and osteoporosis than the general population. But Tim Spector, professor of genetic epidemiology at King's College London, has argued that such studies are “probably flawed”.

目前,围绕养老中心的老龄人口所作的研究,提出维生素D摄入剂量的指导意见,因为老人晒太阳的机会不多,比普通人更容易出现骨裂和骨质疏松症。伦敦国王学院遗传流行病学教授斯佩克特(Tim Spector)认为,此类研究“可能有缺陷”。

It’s true that the evidence isn’t clear-cut. One meta-analysis published in August 2018 concluded that increasing the levels of vitamin D in the general population is unlikely to decrease the risk of bone fractures in healthy people. And a meta-analysis of 81 studies found that vitamin D supplementation doesn’t prevent fractures or falls, or improve bone mineral density. The researchers concluded that guidelines should be updated to reflect this.

诚然,实证分析并不明确。2018年8月发表的一项综合分析总结道,普通人群提高维生素D的水平,不会降低出现健康者骨裂的可能。一项包含81份研究的综合分析发现,补充维生素D不能预防骨裂或摔跤,或者促进骨骼矿物质密度。研究人员的总结是,补充维生素D的指导意见应该对此做出更新。

But Sarah Leyland, osteoporosis nurse consultant at the National Osteoporosis Society, says vitamin D supplements may be useful for at-risk groups who don’t get any sunlight exposure. According to the NHS, people only need to be outside for a short period of time, with hands and forearms uncovered and without sunscreen, to get enough vitamin D between March and October.

然而英国慈善组织“国家骨质疏松症协会”(NOS,National Osteoporosis Society)骨质疏松症护理顾问莱兰(Sarah Leyland)表示,维生素D补充剂可能对不晒太阳的易发人群有所帮助。根据英国国家医疗服务体系(NHS,National Health Service),3月至10月间,人们只需要到外面稍微呆一会,露出手和前臂,不要涂防晒霜,就可获得足够的维生素D。

“We know that healthy people living in the community won’t reduce their fracture risk by taking calcium and vitamin D supplements,” Leyland says. “However, people who may not be getting enough – such as those who are housebound or live in sheltered accommodation – can benefit from these supplements.”

莱兰说,"我们知道一般社区居民服用钙片或维生素D补充剂,不会因此减少骨裂的出现。然而,日照条件不充分的人群——比如因疾病出不了门或住在养护中心的人——摄入补充剂会有所好转。"

Still, researchers haven’t found clear evidence of that, either. One meta-analysis examining the prevention of fractures in community, nursing home and hospital inpatient populations concluded that vitamin D alone is unlikely to prevent fractures in the doses and formulations tested so far in older people. And some evidence suggests that high doses can actually result in an increased number of fractures and falls. One randomised study found that high-dose monthly vitamin D supplements increased the risk of falls among the elderly population by 20-30% compared to those on a lower dose.

不过,对此,研究人员也没有发现确凿的根据。一项综合分析考察了居民社区、养老中心和住院病人的骨裂防治情况,研究总结道,按照目前测得老龄人口摄入的剂量和配方,仅靠维生素D不能预防骨裂。一些研究显示,大剂量事实上会导致骨裂和摔跤次数的增加。一项随机研究发现,相比维生素D摄入剂量较低的老龄人口,每月服用高剂量会增加摔跤的可能达20-30%。

D for disease

维生素D治病?

There is also conflicting research on the relationship between vitamin D and other diseases, even ageing.

对于维生素D和其它疾病乃至衰老的关系,学术界的争论也很激烈。

One main claim is that vitamin D supplements will boost the immune system. Adrian Martineau, professor of respiratory infection and immunity at The London School of Medicine and Dentistry, Queen Mary University of London, who leads a research group on the effects of vitamin D on health, has found that vitamin D plays a role in improving respiratory infections.

一派主要观点是,补充维生素D会提高免疫能力。英国伦敦玛丽王后大学伦敦医学及牙科学院呼吸感染和免疫专业教授马蒂诺(Adrian Martineau)带领研究团队专攻维生素D对健康的作用,发现维生素D能起到改善呼吸感染的作用。

When his team analysed raw data from 25 clinical trials involving 11,000 patients from 14 countries, they found a small benefit to taking daily or weekly vitamin D supplements to reduce the risk of respiratory infections, asthma attacks and bronchitis. Although the paper soon attracted robust criticism, Martineau points out that the reduction of risk, while slight, is still significant and comparable to the effects of other health measures: to prevent a single respiratory infection, you’d have to give 33 people vitamin D supplements – compared to, for example, giving a flu vaccination to 40 people to prevent a single case of flu.

他的团队分析的原始数据来自14个国家的25项临床试验,涉及患者多达11000人。他们发现每日或每周补充维生素D具有些微疗效,可以减少呼吸系统感染、哮喘和支气管炎的发病风险。虽然研究成果立刻招致激烈批评,马蒂诺辩称,降低发病风险效果虽然轻微,却有重大意义;这与其它预防措施类似:例如为了防止出现一例呼吸系统感染,需要给33人开维生素D补充剂,而为了防止出现一例流感,则要给40人注射流感疫苗。

Or take ageing. One paper looking at the link between vitamin D and life expectancy found that vitamin D3 can help with protein homeostasis – the process by which proteins are regulated within cells to maintain their health. “Our observation that D3 improves protein homeostasis and slows ageing highlights the importance of maintaining appropriate vitamin D serum levels,” the researchers write.

再来说说衰老。有一项研究分析了维生素D与寿命之间的关系,发现维生素D有助于体内蛋白质平衡,即细胞内调控蛋白质的过程,从而维持新陈代谢。研究人员撰写报告称,“我们的观察结果是维生素D3能促进体内蛋白质平衡,减缓衰老。这凸现了维持适当的维生素D血清水平的重要性。”

But other studies have been less conclusive. One meta-analysis concluded that more research is needed to clarify the effect of vitamin D on mortality. The link between cardiovascular disease and vitamin D also has yet been properly established: the link could mean that heart disease is causing low vitamin D levels, not the other way around.

但是,其它研究却没有得出如此确凿的结论。一项综合分析指出,要揭示维生素D与死亡率之间的关联,还需要做更多研究。另外,心血管疾病和维生素D之间的关系需要更精准的表述:两者的关系有可能是指心脏病会导致维生素D水平偏低,而不是缺乏维生素D会引发心脏病。

Correlation or causation?

相互关联还是因果关系?

This is an issue with nearly all of the studies that link low D to diseases.

关于维生素D缺乏与疾病的关系,几乎所有的研究都碰到这个问题:两者究竟是相互关联还是存在因果关系?

Ian Reid, professor in medicine at the University of Auckland, believes that diseases cause low vitamin D levels, as being unwell often leads to spending less time outdoors exposed to sunlight, rather than vice versa. “If you take any group of patients with almost any disease, their vitamin D levels will be lower than in a healthy individual. This has led some to hypothesise it’s low vitamin D developing the disease, but there’s no evidence to prove it,” he says.

奥克兰大学医学专业教授里德(Ian Reid)相信疾病导致身体维生素D水平偏低,因为生病往往会缩短到户外沐浴阳光的时间,而不是反向使然。他说:“以任何疾病的任意一组患者为例,他们的维生素D都会低于健康水平。有些人因而假设,发病的原因是缺乏维生素D,但目前尚没有事实依据可以证明这个假设。”

Researchers have found that higher vitamin D levels are associated with a lower risk of colorectal cancer – it plays a role in stemming the formation of new blood vessels and stimulating better communication between cells. Vitamin D also has been found to help maintain normal levels of calcium in the colon, which slows growth of non-cancerous but high-risk cells.

研究人员发现,维生素D水平越高,结肠直肠癌的发病率越低;体内维生素D含量高,对于抑制新血管的形成和刺激细胞之间互动起到一定作用。研究人员还发现,维生素D有助于维持结肠内正常的钙含量,从而抑制非肿瘤但属于高风险的细胞的增生。

Other studies, including of the link between vitamin D and liver cancer, breast cancer and prostate cancer, suggest there is good reason to think that low vitamin D plays a part in the spread of cancer cells. But taking supplements would then, surely, help stave off cancer – and a recent meta-analysis failed to find that supplementation reduced cancer risk.

其它研究,包括维生素D与肝癌、乳腺癌和前列腺癌关系的研究显示,有理由认为缺乏维生素D会刺激癌细胞扩散。那么,服用补充剂因此就肯定有助于抗癌吗?最近一项综合分析没有得出补充剂会降低癌症发病率的结论。

“This is likely to be a two-way street, with cancer causing vitamin D deficiency by affecting vitamin D metabolism, dietary intake and sun exposure, and vice versa via anti-proliferative effects of vitamin D. The two hypotheses are not mutually exclusive,” says Martineau.

马蒂诺说:“这可能是双向车道,癌症会通过影响维生素D代谢、经饮食摄入和照晒阳光生成维生素D而导致维生素D含量偏低,与之相对,维生素D对癌细胞也有抑制作用。两种假设并不互相排斥。"

D for depression

维生素D抗抑郁

Another oft-discussed condition is seasonal affective disorder (SAD), a mood disorder caused by the seasonal drop in exposure to sunlight. The link between light exposure and SAD is long-established. But again, a direct link to vitamin D has been difficult to prove.

另一种经常讨论的症状是季节性情绪紊乱(SAD),这是因季节因素致使接觸日光缩短而引起的情绪问题。光照程度与季节性情绪紊乱的关系确定已久。可是同样地,与维生素D的直接关系则难以证实。

Evidence suggests there may be a relationship since vitamin D is associated with levels of both serotonin, important for mood regulation, and melatonin, which regulates our sleep. Low levels of either hormone could contribute to SAD symptoms. Researchers have yet to carry out a definitive randomised control trial, however, and the exact mechanism by which vitamin D bolsters the hormones is unknown. One theory is that vitamin D receptors – which are found in many parts of the brain and concentrated in the hypothalamus, a region involved in our circadian timing – play a part in controlling the body’s hormone levels.

实证依据表明,可能存在联系,因为维生素D与血清素和褪黑激素都有关联,血清素令人愉悦放松,褪黑激素可改善睡眠质量。缺乏血清素和褪黑激素这两种荷尔蒙会产生季节性情绪紊乱的症状。然而,研究人员还没有就此展开具体的随机对照实验,因此维生素D赖以提高这两种激素作用的机制还不得而知。有一项理论是,维生素D受体(VDR)具有调控体内激素水平的作用 — 已发现大脑中多个部位含有维生素D受体,而以控制人体内的生物时钟功能的下丘脑最为集中。

Research has found that vitamin D plays a wider role in our mental health, from depression to schizophrenia, as well as in brain development, but how it plays a role also remains unclear. A meta-analysis published earlier this year found that while there is a correlation between lower vitamin D levels and depression, that didn’t necessarily mean D caused depression.

研究发现,从抑郁症到精神分裂症,还有大脑发育,维生素D对我们的精神健康大有益处,但其作用方式和机制同样尚不清楚。今年早些时候刊发的一项综合分析显示,维生素D水平较低和抑郁症存在联系,但那不一定意味是维生素D缺乏诱发抑郁症。

Again, perhaps depressed people just went out less and got less sunlight.

同样,也许抑郁症患者只是户外活动不够,日晒不足。

Sunshine serum

阳光与血清

If studies are inconclusive, though, perhaps that doesn’t reflect on the importance of vitamin D. Perhaps it’s the fact that most of them are based on supplements, not sunshine.

如果研究目前尚无定论,也许是对维生素D的重要性认识不足。也许是研究大多以补充剂为基础,而不是阳光。

Some scientists argue that getting vitamin D from supplements isn’t as effective as getting it straight from the sun, as the process that happens before the body makes vitamin D from sun exposure is more beneficial. More conclusive research around this is currently underway.

一些科学家认为,通过补充剂摄入的维生素D的效果比不上直接从日照中获取,因为人体从阳光曝晒中生成维生素D之前的过程更有益处。有关此问题,目前正在开展有望得到更明确结论的研究。

Even so, most experts generally agree that even vitamin D supplements can benefit those who have very low levels. Martineau says his research found that those with low levels of vitamin D tend to see the most benefits of supplementation preventing respiratory infections, whereas the effects are a lot more modest when levels are moderately low.

尽管如此,大多数专家一般都同意,服用补充剂能帮助维生素D水平很低的人群。马蒂诺称他通过研究发现,补充剂往往对维生素D水平偏低的人群最有疗效,能够预防呼吸感染,而对于水平中低的人群,效果就逊色得多。

Reid says his studies have also shown benefits in those with low levels. But as most people have vitamin D levels above that threshold, they wouldn’t see benefits from supplementing.

里德说他也通过研究发现,补充剂对维生素D水平偏低者有好处。但由于大多数人的维生素D含量高于这个水平,因此服用补充剂未见得有帮助。

The trouble is that it can be difficult to predict who is at a highest risk of suffering from low vitamin D. As medical historian Roberta Bivins of the University of Warwick points out, the amount of vitamin D a person stores, and therefore requires over winter, isn’t just dependent on skin tone and the amount of time a person spend outdoors.

棘手的是难以预测哪些人最容易出现维生素D不足情况。如华威大学医学历史学家比文(Roberta Bivins)指出,人体内储存的以及过冬时所需的维生素D含量,不仅取决于肤色的深浅和户外时间的长短。

“It’s very individual how much sun exposure a person needs during summer, depending on the pigment in the skin to the amount of fat in the body and how quickly your body makes new bone. It’s incredibly complicated,” she says.

她说:“夏季人们所需的日晒程度完全因人而异,取决于皮肤色素沉着、体脂含量以及体内成骨速率等多种因素。情况非常复杂。”

That’s why the best way to determine if you have low vitamin D is not by symptoms alone, but with a blood test arranged through your medic.

这就是为什么维生素D水平是否偏低的最佳办法不是单看症状,医生还会要求验血。

Supplement levels

多多益善?

Then there is the question of exactly what level of supplementation people need. Reid says there’s “no danger” in taking over-the-counter vitamin D of less than 25 nanomols per day.

接下来的问题是,到底需要补充多大的量。里德说,每天服用低于25微克的非处方维生素D,“没有大碍”。

But with supplements offering doses as high as 62.5 micrograms available over the counter, there are concerns around the risk of excessive vitamin D levels, which can, in rare cases, cause side effects, including nausea and vomiting. In the long term, some studies suggest too much vitamin D can increase risk of cardiovascular disease, although the research isn’t conclusive.

但是商店柜台可以买到的补充剂量高达62.5毫克,人们担心会出现维生素D水平过量,在罕见的情况下这可能产生副作用,如恶心和呕吐。一些研究表示,长远来看,高剂量的维生素D会增加心血管疾病的发病率,虽然尚未有确凿的研究。

But others argue that even more vitamin D is needed.

可是其他人认为,人体所需要的维生素D含量应该还要高一些。

In 2012, chief medical officer Sally Davies wrote a letter to GPs urging them to recommend vitamin D supplements to all at-risk groups, writing that a “significant proportion” of people in the UK probably have inadequate levels of vitamin D. In June 2018, researchers from the University of Birmingham's Institute of Metabolism and Systems Research wrote that the death of a baby from complications of heart failure caused by severe vitamin D deficiency, and the serious health complications of two others, was just the “tip of the iceberg” in vitamin D deficiencies among those at risk.

2012年,英国政府首席卫生官戴维斯(Sally Davies)写信给家庭医生,敦促他们向所有可能会维生素D摄取量不足者建议补充维生素D。信中提到,在英国“相当大比例”的人口可能维生素D水平不足。2018年6月,伯明翰大学代谢与系统研究学院的研究人员撰写报告称,维生素D严重不足引起心脏衰竭的并发症,导致一名婴儿死亡,另有两人也伴随严重的并发症,维生素D匮乏为高风险人群造成的后患,这些只是“冰山一角”。

Suma Uday, co-author of the paper and PhD doctoral researcher at the university, says these deficiencies occur because infant vitamin D supplementation programs are poorly implemented in the UK and not monitored. “In the infants we describe, deficiency occurred because infant vitamin D supplementation was not recommended or monitored. Any infant devoid of vitamin D for prolonged durations can develop low calcium levels, which can result in life threatening complications such as seizures and heart failure,” she says.

伯明翰大学博士学位研究员乌黛(Suma Uday)是论文的联合作者之一。她说,之所以出现维生素D缺乏,是因为英国婴幼儿维生素D补充剂方案落实不到位,没有受到监管。她说:“我们提到的这些婴幼儿,他们缺乏维生素D是因为没有建议服用幼儿维生素D补充剂,或没有相应的监管。婴幼儿只要长时间维生素D摄取不足,就会引起钙含量偏低,出现危及生命的症状,如癫痫发作和心脏病之类。”

With such conflicting results, it’s unsurprising that medical experts themselves are deeply divided over the benefits of widespread supplementation. Some even argue that vested interests are propping up the billion-dollar vitamin industry, with Spector calling vitamin D supplements a “pseudo-vitamin for a pseudo-disease”.

上述科学研究结果大相径庭,鲜明对立。对于广泛使用的维生素D补充剂的益处,医学专家们意见分歧严重也就不足为奇了。一些专家甚至认为,是既得利益者支撑着10亿美元规模的维生素产业;斯佩克特称维生素D补充剂是“治伪病的伪维生素”。

While the debate continues, many experts are looking to Brigham and Women’s Hospital, an affiliate of Harvard Medical School in Boston, whose researchers are carrying out a long-awaited randomised trial, VITAL, to investigate whether supplementation of vitamin D and omega 3 has any effect on cancer, stroke and heart disease in 25,000 adults.

争论仍方兴未艾,很多专家指望着位于波士顿的哈佛医学院教学附属医院布列根和妇女医院的研究结果。那里的研究人员正在进行一项医学界等候已久的随机实验VITAL。这项研究涉及25000名成人研究对象,目的是搞清楚维生素D和欧米伽3的补充剂是否对癌症、中风和心脏病有疗效作用。实验结果预计将于2018年底前发表。

It’s hoped that these results, expected to publish later this year, will bring the debate closer to being resolved. In the meantime, it’s widely agreed that vitamin D supplements, especially over winter, will be a waste of money at worst.

人们希望这可以让维生素D补充剂之争早日见分晓。同时,大家普遍认为,服用维生素D补充剂的最坏结果无非是烧钱,尤其是冬季。

It’s likely you won’t get enough from your diet between now and next spring, but the impact this could have on your health is still up for debate.

从现在到明年春天,你通过饮食摄入的维生素D也许确实不够,但这对你的身体会产生什么影响则是仍有争议的题目。

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