Ergocalciferol (D2) vs. Cholecalciferol (D3) Food Fortification: Comparative Efficiency in Raising 25OHD Status & Mechanisms of Action (D2-D3 Study)

维生素D是用于描述两种分子的术语，麦角钙化醇（维生素D2）和胆钙化醇（维生素D3）。第一种是通过紫外线照射广泛分布在植物和其他真菌中的麦角固醇而产生的，而胆钙化醇是通过紫外线照射皮肤而形成的。维生素D缺乏在英国是一个非常普遍的问题。这对健康有重要影响（如肌肉/骨骼功能，增加糖尿病风险）。我们迫切需要找到提高维生素D摄入量的方法，作为一种公共卫生战略。我们萨里大学的研究小组刚刚完成的研究（食品标准局资助;项目编号NO5064; 50万英镑）表明：（1）维生素D的饮食摄入量太低，对维生素D状况没有任何影响，因为提供有价值的天然来源的食物太少;（2）南亚妇女严重缺乏维生素D;（3）白种人普遍存在维生素D不足。文献中有证据表明，亚洲印度人与高加索人中对维生素D代谢至关重要的重要基因的关键多态性存在差异，以及关键维生素D代谢酶的差异。这需要进行更全面的调查，因为维生素D2和维生素D3的可获得性存在差异，因此关于增加维生素D摄入量的公共卫生建议（特别是关于富含维生素D的食品的开发）需要确认任何一种形式的维生素D都是有效的。此外，南亚社区是纯素/严格素食者（约26%），因此维生素D3的来源是这个群体的一个问题，因为它们来自动物（维生素D3补充剂来自羊毛脂，羊毛脂是从羊毛中提取的）。目前关于维生素D2与D3在提高人类25HOD水平方面的有效性存在争议。在20世纪30年代的研究中，人们认为D2和D3对人类同样有效，但一些研究表明D3在提高25 OHD水平方面优于D2，而最近发表的数据表明D2和D3同样有效。这需要紧急关注。拟议的研究将能够更好地了解两种形式的维生素D（麦角钙化醇[D2] vs.胆钙化醇[D3]）在提高高加索人和亚洲人维生素D状态方面的可比性，并研究两种维生素D形式之间或种族群体之间观察到的任何差异的作用机制。作用机制将集中在遗传差异以及维生素D代谢酶的差异上。我们的主要目标是：（i）比较10 mcg/d [400 IU/d]麦角钙化醇的效率（维生素D2）与胆钙化醇（维生素D3）强化食品以提高亚洲/高加索妇女的25 OHD水平;（二）确定哪些车辆需要加固（即固体与液体食物）（维生素D2）与胆钙化醇（维生素D3）在提高25OHD水平方面更有效，与种族无关;（iii）调查10 mcg/d [400 IU/d]是否能有效地将冬季25 OHD水平提高到"缺乏/不足"阈值以上（分别为25 nmol/l和40 nmol/l）在高加索和亚洲女性中，麦角钙化醇与胆钙化醇强化是否存在任何差异，与种族无关; iv）研究（i）、（ii）和（iii）中观察到的差异的机制（遗传/酶）。

Vitamin D is the term used to describe two molecules, ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3). The first of these is derived by ultra-violet irradiation of the ergosterol that is widely distributed in plants and other fungi whereas cholecalciferol is formed from the action of ultra-violet irradiation on the skin. Poor vitamin D status is a very common problem in the UK. This has important health consequences (such as muscle/bone function, increasing the risk of diabetes). We urgently need to find ways of improving vitamin D intake that are acceptable as a public health strategy. Research that has just been completed by our group at the University of Surrey (Food Standards Agency funding; Project No. NO5064; £0.5M) has shown that (1) dietary intake of vitamin D is too low to have any effect on vitamin D status as there are too few foods providing a valuable natural source; (2) South Asian women are extremely vitamin D deficient; (3) Caucasians have extensive vitamin D insufficiency. There is evidence in the literature of differences in key polymorphisms of important genes that are critical to vitamin D metabolism in Asian Indian vs. Caucasians aswell as differences in key vitamin D metabolism enzymes. This requires a fuller investigation since there are differences in the availability of vitamin D2 and vitamin D3 and hence public health advice on increasing vitamin D intake (particularly with respect to the development of vitamin D rich food products) needs to confirm that either form of vitamin D is effective. Furthermore, the South Asian community are vegan/strict vegetarians (~26%) and hence the source of vitamin D3 is a problem in this group due to being derived from animals (vitamin D3 supplements come from Lanolin, which is extracted from sheep's wool.) There is currently controversy as to the effectiveness of vitamin D2 vs. D3 in raising 25HOD levels in humans. It has been assumed, largely on the strength of evidence from studies in the 1930s, that D2 and D3 were equally effective in humans but some studies show that D3 is superior to D2 in raising 25OHD levels whereas the most recently published data suggests that D2 and D3 are equally effective. This requires urgent attention. The proposed study will enable a better understanding of how comparable the two forms of vitamin D (ergocalciferol [D2] vs. cholecalciferol [D3]) are at raising vitamin D status in Caucasians and Asians and investigate the mechanisms of action with respect to any differences observed between the two vitamin D forms or between ethic groups. Mechanisms of action will focus on genetic differences aswell as differences in vitamin D metabolizing enzymes. Using a team of scientists with different expertise, our principal objectives are to: (i) compare the efficiency of 10mcg/d [400IU/d] of ergocalciferol (Vitamin D2) vs. cholecalciferol (Vitamin D3) fortification of food products in raising 25OHD levels in Asian/Caucasian women; (ii) determine which vehicle for fortification (i.e. a SOLID vs. FLUID food) with ergocalciferol (Vitamin D2) vs. cholecalciferol (Vitamin D3) is more effective in raising 25OHD levels, independent of ethnicity; (iii) investigate if 10mcg/d [400IU/d] is effective in raising wintertime 25OHD levels above 'deficiency/insufficiency' thresholds (25nmol/l and 40nmol/l respectively) in Caucasian and Asian women and whether there are any differences in ergocalciferol v. cholecalciferol fortification, independent of ethnicity; iv) investigate the mechanisms (genetic/enzymatic) for the differences observed in (i), (ii) & (iii).