XI. REQUIREMENTS 389 



Research Council (1948) recommended 30 uv^. daily. In fact, careful experi- 

 mental work indicates that 10 mg. daily is sufficient to prevent scurvy and 

 maintain good healing properties of tissues for a period of a year, even if 

 plasma ascorbic^ acid le\'els are zero and white cell levels almost zero.^- 

 There is difference of opinion as to whether subtle tissue deterioration occurs 

 at these subsaturation le\"els. Changes in the gums have been reported by 



TABLE XI 

 Daily Allowances of the National Research Council 



Ascorbic acid, mg. 



Man (154 lb., 70 kg.) 



Sedentary 75 



Physically active 75 



With heavj'' work 75 



Woman (123 lb., 56 kg.) 



Sedentary 70 



Moderately active 70 



Very active 70 



Pregnancy (latter half) 100 



Lactation 150 



Children up to 12 jears 



Under 1 year 30 



1-3 years (27 lb., 12 kg.) 35 



4-6 years (42 lb., 19 kg.) 50 



7-9 years (58 lb., 26 kg.) 60 



10-12 years (78 lb., 35 kg.) 75 



Children over 12 years 

 Girls 



13-15 years (108 lb., 49 kg.) SO 



16-20 years (122 lb., 55 kg.) 80 



Boys 



13-15 years (108 lb., 49 kg.) 90 



16-20 years (141 lb., 64 kg.) 100 



some investigators at these subsaturation le\'els. Most authors feel that 

 the tissues are not damaged morphologically, but it is impossible to say 

 whether chemical damage or interference with enzyme systems occur. "\Mien 

 possible, it is best to adhere to the National I research Council recommenda- 

 tions, (Table XI) but under difficult circumstances such as existed in Great 

 Britain during World War II, it is probal)le that 18 to 2.5 mg. per day will 



■2 H. A. Krebs, R. A. Peters, K. H. Coward, L. W. Mapson, L. G. Parsons, B. S. 

 Piatt, J. C. Spence, and J. R. P. O'Brien, Lancet I, 853 (1948). 



