The effect of dietary vitamin, protein, and intake levels on the life span of mice of different ages

Abstract

Groups of 057BL/6J male mice, aged 1, 12, 17, and 20 months, were divided into four dietary groups which were fed ad libitum diets containing either an amount of vitamins recommended by the National Academy of Sciences National Research Council, one half this amount, four times this amount or an amount of vitamins recommended by the American Institute on Nutrition. Each of the sixteen dietary groups contained approximately 50 animals. Feeding one half the amount of vitamins recommended by the National Research Council statistically significantly reduced the life span of animals, starting at 17 months of age or younger. Increasing the vitamin level four fold did not increase the life span of adult animals. A comparison of the life spans of adult animals fed the daily allowance recommended by the National Research Council and that of the American Institute of Nutrition indicated no statistical difference. However there was a small but statistically significant lower life span (12%) in young growing animals fed the former as compared to the latter vitamin mixture. Four hundred and ninety-five 25 month old C57BL/6J male mice were divided among nine dietary groups. Seven of the groups were offered one of the following dietary protein levels ad libitum: 24, 18, 12, 10, 8, 6, or 4 percent. The two remaining groups, intermittent-heavy (i.e., marked food restriction) and intermittent-light, were fed the 24 percent protein diet for 24 hrs. on Monday and Thursday and for 8 hrs. on Friday, and for 24 hrs. on Monday, Tuesday, and Thursday and for 8 hrs. on Friday, respectively. The mean life span of the animals fed the 24% protein diet ad libitum was 29.2±0.4 mos. Dietary restriction did not significantly increase the life span of any of the animals.