n-3系脂肪酸、特にDHAの吸収・消失に関する研究

抄録

Docosahexaenoic acid (DHA) is highly concentrated in the nervous system and is rapidly deposited during the brain development in the perinatal and early postnatal period. The depletion and repletion rates of brain DHA were investigated in rodents. The reversibility of the loss of DHA was studied in rodents, which were subjected to a low level of n-3 fatty acids through two generations. The n-3 deficient adult (7wks) rats were provided n-3 adequate diet containing both α-linolenic acid and DHA, and were determined the concentrations of DHA until 8 weeks after diet reversal. Full recovery of the brain DHA wasn't obtained for 8 weeks, although the levels of DHA in the serum and liver were almost repleted within 2 weeks after diet reversal. A consideration of the brain DHA repletion compared with the liver and circulation suggests that transport-related processes may limit the rate of DHA repletion in the nervous system. In the comparison of repletion and depletion rates from weanling (3 wks) and adult mice, the brain DHA recovery from weanling was faster than that of adult mice, but depletion rates in the two age groups were nearly equal. Moreover, the depletion of newborn brain DHA was measured from day 0 of life after exposure to n-3 deficient milk using an artificial rearing system. The brain DHA in n-3 deficient milk group continuously decreased, yielding about 70% decline of n-3 adequate milk group. This result suggests a first-generation model for n-3 deficiency that is similar to the case of human nutrition.