Abstract
Changes in the carotene and vitamin A levels in serum after ingesting varying amounts of β-carotene together with breakfast were examined and no significant rise in the two was observed so long as the amount of β-carotenedid not exceed 2 mg. Following an ingestion of 4-8 mg β-carotene, the carotene level rose distinctly, reaching a maximum after about 5 hours, but the rise in vitamin A level was not so marked, reaching a maximum after about 3-4 hours. Further increases in the amount ingested up to 124 mg resulted in distinct, but relatively small, rises in serum carotene levels, while the rise was insignificant in serum vitamin A levels. The course of the rise in serum carotene levels after receiving 4 mg β-carotene was found to be roughly the same as that after receiving cooked strained carrot containg 4.3 mg α-carotene and 4.0 mg β-carotene, but the rise in serum vitamin A levels was somewhat less after ingesting the cooked carrot. After an intake of 0.5-4mg β-carotene, the maximum was attained in 4-6 hours in the carotene level and 3-4 hours in the vitamin A level. The absolute levels of plasma vitamin A were somewhat higher than those of carotene. The rise in plasma vitamin A levels after ingesting carotene was about 30% of that after ingesting the same I. U. of vitamin A.
