The Canadian Cancer Society says the daily upper safety limit is 2,000 units, and that their recommendation of 1,000 IU takes into account itamin D from diet and other sources.

• 加拿大癌症协会说每日维生素D服用量的安全上限为2000IU，他们之所以推荐每日服用1000IU维生素D是考虑到饮食和其它一些维生素D的来源。