本文发表在 rolia.net 枫下论坛Adequate Levels of Vitamin D
Getting enough vitamin D is a challenge especially in northern climates. Evolution has given us the ability to produce vitamin D naturally within our body. It can be synthesized just under your skin with proper exposure to sunlight. Adequate amounts of vitamin D can be made in the skin after only ten to fifteen minutes of sun exposure at least two times per week to the face, arms, hands, or back without sunscreen. However, season, geographic latitude, time of day, cloud cover, skin cover, skin colour, smog, and sunscreen affect UV ray absorption and vitamin D synthesis. For example, sunlight exposure from November through February in Canada is insufficient to produce significant vitamin D synthesis in the skin. The UV rating must be above 3 for sunlight to be effective in producing vitamin D in our skin. Vitamin D-deficient diets are associated with milk allergy, lactose intolerance, ovo-vegetarianism, and veganism. Rickets and osteomalacia are the classical vitamin D deficiency diseases. In children, vitamin D deficiency causes rickets, a disease characterized by a failure of bone tissue to properly mineralize, resulting in soft bones and skeletal deformities. In adults, vitamin D deficiency can lead to osteomalacia, resulting in weak bones. Symptoms of bone pain and muscle weakness can indicate inadequate vitamin D levels, but such symptoms can be subtle and go undetected in the initial stages. (Ref. ODS)
足量摄入维生素 D
摄入足量的维生素 D 有难度，尤其是在北方。生物进化让人类身体自发生产维生素 D。人只有暴露在阳光下，身体在皮肤下就能合成维生素 D。只要把脸，手，后背在阳光下晒10 到15 分钟，每周两次，不抹防晒霜，身体就可以产生足够的维生素 D。但是，有很多因素影响紫外线的吸收和维生素 D 的合成，比如季节，地理维度，日头，云，皮肤覆盖物，肤色，雾和防晒霜。
比如，在加拿大，从十一月到二月，日照不足够让人在皮肤里合成足够的维生素 D。人能在皮肤里合成足够的维生素 D，紫外线度要在 3 以上。奶过敏，乳糖不耐症，（食乳品和不食乳品的）素食，导致维生素 D 匮乏。軟骨病和骨軟化，佝偻病是典型的维生素匮乏症。孩子缺乏维生素 D 会引起佝偻病，表现为骨组织不能正常矿物化，导致软骨和骨骼变形。成年人缺乏维生素 D会引起软骨病，表现为骨无力。骨痛和肌肉无力症状能体现维生素缺乏度，但是在发病初期症状细微不容易检测。更多精彩文章及讨论，请光临枫下论坛 rolia.net
Getting enough vitamin D is a challenge especially in northern climates. Evolution has given us the ability to produce vitamin D naturally within our body. It can be synthesized just under your skin with proper exposure to sunlight. Adequate amounts of vitamin D can be made in the skin after only ten to fifteen minutes of sun exposure at least two times per week to the face, arms, hands, or back without sunscreen. However, season, geographic latitude, time of day, cloud cover, skin cover, skin colour, smog, and sunscreen affect UV ray absorption and vitamin D synthesis. For example, sunlight exposure from November through February in Canada is insufficient to produce significant vitamin D synthesis in the skin. The UV rating must be above 3 for sunlight to be effective in producing vitamin D in our skin. Vitamin D-deficient diets are associated with milk allergy, lactose intolerance, ovo-vegetarianism, and veganism. Rickets and osteomalacia are the classical vitamin D deficiency diseases. In children, vitamin D deficiency causes rickets, a disease characterized by a failure of bone tissue to properly mineralize, resulting in soft bones and skeletal deformities. In adults, vitamin D deficiency can lead to osteomalacia, resulting in weak bones. Symptoms of bone pain and muscle weakness can indicate inadequate vitamin D levels, but such symptoms can be subtle and go undetected in the initial stages. (Ref. ODS)
足量摄入维生素 D
摄入足量的维生素 D 有难度，尤其是在北方。生物进化让人类身体自发生产维生素 D。人只有暴露在阳光下，身体在皮肤下就能合成维生素 D。只要把脸，手，后背在阳光下晒10 到15 分钟，每周两次，不抹防晒霜，身体就可以产生足够的维生素 D。但是，有很多因素影响紫外线的吸收和维生素 D 的合成，比如季节，地理维度，日头，云，皮肤覆盖物，肤色，雾和防晒霜。
比如，在加拿大，从十一月到二月，日照不足够让人在皮肤里合成足够的维生素 D。人能在皮肤里合成足够的维生素 D，紫外线度要在 3 以上。奶过敏，乳糖不耐症，（食乳品和不食乳品的）素食，导致维生素 D 匮乏。軟骨病和骨軟化，佝偻病是典型的维生素匮乏症。孩子缺乏维生素 D 会引起佝偻病，表现为骨组织不能正常矿物化，导致软骨和骨骼变形。成年人缺乏维生素 D会引起软骨病，表现为骨无力。骨痛和肌肉无力症状能体现维生素缺乏度，但是在发病初期症状细微不容易检测。更多精彩文章及讨论，请光临枫下论坛 rolia.net