Health problems and vitamin C in Canadian Northern Military operations

HEALTH PROBLEMS AND VITAMIN C IN CANADIAN NORTHERN MILITARY OPERATIONS DCIEM REPORT NO. 74-R-1012 MARCH 1974 B.H. SABISTON M.W. RADOMSKI The RCT by Sabiston and Radomski (1974) is made available with the permission of the editor of DRDC Toronto, see the last page of this document. In 2009, Harri Hemilä asked Dr. Manny Radomski for certain methodological details about the trial and his answers are on the following pages. This RCT has been cited in: Hemilä H. Vitamin C and common cold incidence: a review of studies with subjects under heavy physical stress. Int J Sports Med. 1996;17(5):379-83. https://doi.org/10.1055/s-2007-972864 https://helda.helsinki.fi/handle/10250/7983 which reported a meta-analysis of 3 RCTs with physically stressed participants and found on average a 50% decrease in the risk of colds: RR = 0.50; 95% CI 0.35, 0.69. Hemilä H, Chalker E. Vitamin C for preventing and treating the common cold. Cochrane Database Syst Rev. 2013;2013(1):CD000980. https://doi.org/10.1002/14651858.cd000980.pub4 https://www.ncbi.nlm.nih.gov/pmc/articles/pmc8078152 https://helda.helsinki.fi/handle/10138/225864 which updated the above meta-analysis with physically stressed participants, including 2 further 2 RCTs (i.e. a total of 5 RCTs with participants under heavy acute physical stress) and found that the halving of the risk of colds remained but the confidence interval became slightly smaller: RR = 0.48; 95% CI 0.35, 0.64. Hemilä H. Vitamin C supplementation and respiratory infections: a systematic review. Mil Med. 2004;169(11):920-5. https://doi.org/10.7205/milmed.169.11.920 https://helda.helsinki.fi/handle/10138/225867 which reviewed vitamin C and respiratory infection trials with military personnel and with other subjects living under crowded conditions comparable to those of military recruits, and demonstrated strong evidence that vitamin C has effects in such conditions. The report is in two versions below, the first is with optical character recognition of the text, and the second with an ordinary unaltered scan of the text. Harri Hemila From: "Manny Radomski" <[email protected]> To: "Harri Hemila" <[email protected]> Sent: 12. syyskuuta 2009 22:05 Subject: Re: Vitamin C report Page 1 of 3 29.5.2012 Dear Dr. Hemila, Thank you for all of the information that you sent reference your work on Vitamin C. We have examined your questions reference our study and have the following comments to add: 1. Well, we should probably kick ourselves, but the reason we did not publish in the scientific literature is that we wanted to replicate our data in another arctic trial under exactly the same conditions and trial design parameters. Unfortunately, we never had an opportunity to participate in another military exercise to be able to replicate our trial. Time went by and we thought that our trial data was 'old news'. Unfortunately our data did not elicit much interest from the military medical branch, and it is difficult to tag onto a military trial and obtain their full cooperation. We were fortunate in that we received full cooperation from the field commanders. 2. Yes, we did assign people randomly. We had the names of people beforehand but we assigned them randomly and we provided their names on the pill vials. The Tent Group Commander was responsible for distributing the pills and recording the distribution. He did NOT know what was in the vials. 3. Yes, it was Double-Blind. While we pre-assigned Vit C and Placebo randomly, we did not break the code until after the trial. Two labelled vials were provided to the Tent Group Commanders but the Tent Group Commanders did NOT know what was in the vials. They just knew who to give the pills to. We did not label the vials Vit C and Placebo but, as I recall, we assigned a Number to the Vials which was coded to Vit C or Placebo. 6. The Vit C and Placebo were in identical capsules, so taste did not enter into the equation We obtained the empty Placebo capsules from the Vit C supplier and then we filled the Placebo capsules in the lab. Pretty sure we used Sucrose. 4. In our pre-briefing to the troops, we believe that we told the troops that they would all be getting Vitamin C but at different doses. 5. We collected the data by symptoms on T-Scan cards. We then came up with a 'scoring' system to define a cold, totally independent of examining any data. Then, three of us sat down and assigned 'scores' to each card without any knowledge, at all, with respect to Vit C or Placebo. We re-visited several cards, several times, to arrive at a consensus opinion. We did not 'break the code' until after all cards had been assessed. The environment in which we carried out the trial of Vitamin C was quite unique - first because of external conditions and the daily workload and stress imposed upon the soldiers. Secondly, they were housed in a very confining environment (10 men to a tent) in very close proximity to each other which was optimal for any transfer of infection. This made our findings even more significant as vitamin C passed under very severe conditions. Linus Pauling in his book published after our study took our data and reanalyzed it and came away with a stronger conclusion than we did as to the benefits of vitamin C in moderating and alleviating the severity of cold symptoms. In your "risk of bias table", we can say say to the four factors listed in your table. We would be pleased to provide any further clarification, our memories permitting!!! Kindest regards, Manny Radomski ----- Original Message ----- From: "Harri Hemila" <[email protected]> To: "Manny Radomski" <[email protected]> Sent: Wednesday, September 02, 2009 12:14 PM Subject: Re: Vitamin C report > Dear Prof. Radomski, > > Thank you very much for contacting me. > Please, see the attachments. > Print the "Radomski_" file and there you will see my question. > > Yours sincerely, > > Harri > > Harri Hemilä, PhD, MD > Docent (associate professor) > Department of Public Health, POB 41 > University of Helsinki > Helsinki, FIN-00014 > Finland > > > > > Manny Radomski wrote: >> Dear Harri, >> >> Your email was passed to me. I am surprised that you were able to dig >> up a reference to our Vitamin C paper. I would be pleased to answer >> any questions that you might have reference our report. >> >> Regards, >> >> Manny Radomski Page 2 of 3 29.5.2012 >> Professor Emeritus >> >> > Page 3 of 3 29.5.2012 MARCH 1974 DCIEM REPORT NO. 74-R-1012 HEALTH PROBLEMS AND VITAMIN C IN CANADIAN NORTHERN MILITARY OPERATIONS B.H. SABISTON M.W. RADOMSKI (Text of Communication presented at the Twenty-Fifth Symposium of the Defence Research Board, Department of National Defence, Canada. Presented 14 November 1973 by B.H. Sabiston) Biosciences Division DEFENCE AND CIVIL INSTITUTE OF ENVIRONMENTAL MEDICINE 1133 Sheppard Avenue West, P.O. Box 2000 DOWNSVIEW, Ontario. DEFENCE RESEARCH BOARD — DEPARTMENT OF NATIONAL DEFENCE — CANADA ABSTRACT As part of a continuing study of health problems pertinent to Canadian Northern Military operations, two aspects of Vitamin C have been examined in land element personnel participating on Northern Winter Exercises. This report describes results of an ongoing Vitamin C survey designed to examine both the Vitamin C status of troops and the effects of a daily Vitamin C supplement on the incidence and severity of colds in troops undergoing operational training. Results indicate that a daily 1000 mg supplement of Vitamin C reduced significantly the incidence of colds as assessed on the basis of symptom complexes reported on health survey cards. While the overall incidence of colds was influenced significantly by Vitamin C, both on an individual and a tent group basis, the duration of local cold symptoms was not. In those individuals who contracted a cold, nasal and throat and chest symptoms were observed to persist for similar periods of time in both placebo and Vitamin C supplemented groups. The Vitamin C group, however, did show a significant reduction in the duration of the more constitutional symptoms related to a general feeling of "well-being". The Vitamin C status of individuals was assessed on the basis of whole blood ascorbate levels determined before and after participation on Northern exercises. A significant reduction of whole blood ascorbate was observed postexercise on three separate serials of Exercise New Viking, the troops of which were supplied with RP-4 field rations. In view of the fact that only a minor reduction of whole blood ascorbate was observed on another serial, the troops of which were supplied with IRP field rations, it is not possible to determine whether the reduction in ascorbate status was a reflection of altered dietary intake or an increased requirement for Vitamin C under the activity and exposure conditions experienced on Northern operations. Further work is required to clarify this situation. (iii) HEALTH PROBLEMS AND VITAMIN C IN CANADIAN NORTHERN MILITARY OPERATIONS Since the early part of 1972, the Biosciences Division of the Defence and Civil Institute of Environmental Medicine (DCIEM) has been involved in an extensive field program designed to examine some of the health problems pertinent to Canadian Northern Military operations. Table 1 lists some of the potential health problem areas encountered in a transit military population operating under Arctic or sub-Arctic conditions. These have been divided, somewhat arbitrarily, into two groups: Environmental and Operational. TABLE 1 POTENTIAL HEALTH PROBLEM AREAS NORTHERN OPERATIONS ENVIRONMENTAL OPERATIONAL Cold Injury Frostbite Trench Foot Hypothermia Snow Blindness Sunburn Cold Sores Nutrition Rations Dehydration Constipation Tent Eye Physical Fitness Wound Heating Upper Respiratory Infection Dental (1) Environmental problems are those which arise as a consequence of direct insult upon the individual by his environment. (2) Operational problems are those which arise as a consequence of restrictions placed upon an individual by his environment. This report describes results dealing with some problems in the operational category, specifically with regard to rations and Vitamin C, the Vitamin C status of individuals, and the effect of Vitamin C supplementation on symptoms of respiratory distress. One of the approaches which has been applied throughout the field program has been the administration of a health survey to men taking part in military winter exercises. This survey was established primarily to answer the questions, "does the abrupt introduction of a man into the Northern climate produce any demonstrable change in health pattern? If so, what is the nature of this alteration? " 4 The majority of health surveys which have investigated environmental factors impinging on health have been concerned with indigenous populations or isolated communities. Data derived from such studies are not applicable directly to transit populations such as members of mobile military forces. Recognition of this fact prompted DCIEM to establish a protocol for obtaining epidemiologic data on military men making periodic excursions into the North. The survey has been restricted to members of the land element for it is these individuals who are exposed most directly to the adverse environment for periods of greater than a few hours. Table 2 lists the exercises which have been surveyed to date. With one exception (Northern Ramble, May 1972) the field program has utilized men taking part in New Viking training exercises. It is important to recognize the fact that these are training exercises and that as such, the men are living under the most "ideal" Arctic conditions in the sense that experienced instructors are with them at all times. Consequently, the men are under constant supervision to ensure that they protect themselves adequately from the environment. Hence, any health problems which arise on such exercises should be taken as a minimal estimate of problems which may arise on more operational missions. TABLE 2 NORTHERN EXERCISES UTILIZED FOR THE INVESTIGATION OF HEALTH PROBLEMS, 1972-73 The health survey card used in the collection of field data is shown in Figure 1. The health survey has been conducted on an individual tent-group basis and extensive use has been made of the tent-group commanders who have been responsible for administering the survey cards on a daily basis. The survey period has extended typically from one week before the exercise to one week after the exercise. Tabulation of the incidence of individual symptoms and symptom complexes has been carried out post-exercise and it has become apparent that, to one degree or another, the incidence of individual symptoms is affected by movement into the North. The most marked alteration in symptoms reported has been noted in symptoms related to the upper respiratory system and it is these symptoms which have been examined in greater detail in DCIEM Vitamin C studies. FIGURE 1 IN-FIELD HEALTH SURVEY CARD 3 MARCH 1974 DCIEM REPORT NO. 7A-R.IOI2 .,} HEALTH PROBLEMS AND VITAMIN C IN CANADIAN NORTHERN MILITARY OPERATIONS B.H. SABISTON M.W. RADOMSKI (Text of Communication presented at the Twenty-Fifth Symposium of the Defence Research Board. Department of lúational Defence, Canada. Presented 14 November 1973 by B.H. Sabistonl Biosciences Division DEFENCE AND CIVIL INSTITUTE OF ENVIRONMENTAL MEDICINE ll33 Sheppord Avenue West, P.O. Box 2000 DOWNSVIEW, Ontorio. DEFENCE RESEARCH BOARD - DEPARTMENT OF NATIONAL DEFENCE - CANADA ABSTRACT As part of a continuing study of health problems pertinent to Canadian Northem Military operations, two aspects of Vitamin C have been examined in land element personnel participating on Northern Winter Exercises. This report describes results of an ongoing Vitamin C survey designed to examine both the Vitamin C status of troops and the effects of a daily Vitamin C supplement on the incidence and severity of colds in troops undergoing operational training. Results indicate that a daily 1000 mg supplement of Vitamin C reduced signi-ficantly the incidence of colds as assessed on the basis of symptom complexes reported on health survey cards. While the overall incidence of colds was influenced significantly by Vitamin C, both on an individual and a tent group basis, the duration of local cold symptoms was not. In those individuals who contracted a cold, nasal and throat and chest symptoms were observed to persist for similar periods of time in both placebo and Vitamin C supplemented groups. The Vitamin C group, however, did show a significant reduciion in the duration of the more constitutional symptoms related to a general feeling of "well'being". The Vitamin C status of individuals was assessed on the basis of whole blood ascorbate levels determined before and after participation on Northern exercises. A significant reduction of whole blood ascorbate was observed post' .*rr.ñ, on three separate serials of Exercise New Viking, the troops of which were supplied with RP'4 field rations. In view of the fact that only a minor reduction of whole blood ascorbate was observed on another serial, the troops of which were supplied with IRP field rations, it is not possible to determine whether the reduction in ascorbate status was a reflection of altered dietary intake or an increased requirement for Vitamin C under the activity and exposure conditions experienced on Northern operations. Further work is required to clarify this situation. ( ¡ii) HEALTH PROBLEMS AND VITAMIN C IN CANADIAN NORTHERN MILITARY OPERATIONS Since the early part of l9't2, the Biosciences Division of the Defence and Civil Institute of Environmental Medicine (OimU) has begn involved in an extensive field program designed to examine some of the health problems pertinent to Canadian Northern Military operations. Table I lists some of the potential health problem areas encountered in a transit military population operating under Arctic or sub-Arctic conditions. These have been divided, somewhat arbitrarily, into two groups: Environmental and Operational' TABLE I POTENTIAL HEALTTI PROBLEM AREAS NORTHERN OPERATIONS ENVIRONMENTAL OPERATIONAL Cold Injury Frostbite Trench Foot Hypothermia Snow Blindness Sunbum Cold Sores Nutrition Rations Dehydration Constipation Tent Eye Physical Fitness Wound Healing Upper RespiratorY Infection Dental (l) Environmental problems are those which arise as a consequence of direct insult upon the indívidual by his environment. (2) Operational problems are those which arise as a consequence of restrictions placed upon an individual by his envíronment. This report describes results dealing with some problems in the operational category, specifically with regard to rations and Vitamin C, the Vitamin C status of individuals, and the effect of Vitamin C supplementation on symptoms of respiratory distress. One of the approaches which has been applied throughout the field program has been the administration of a health sunuey to rnen taking part in military winter exercises. This survey was established priurarily to answer the questions, "does the ab:upt introduction of a man into the Northern climate produce any clernonstrable change in health pattcrn'Ì If só, what is the nature ot'this alteration? " \ The majority of health surveys which have investigated environmental factors impinging on hc¡lth have been concerneä with indigenous populations or isolated conrmunities. Data derived from such studies are not applicable directly to transit populations such as,members of mobile military forces. Recognition of this fact prompted DCIEM to estaõlish a prôtocol for obtaining epidemiologic data on military men making periodic excursions into the North. The survey has been restricted to members of the land element for it is these individuals who are exposed nrost directly to thc adverse envirclnment for periods of greater than a few hours. Table 2 lists the exercises which have been surveyed to date. With one exception (Northern Ramble, May l97Z) the field program has utilized men taking part in New Viking training exercises. It is important to rectgnize the fact that tñese are training exercises and that as such, the men are living under the most "ideal" Arctic conditions in the sense that experienced initructors are with them at all times. Consequently, the men are under constant supervision to ensure that they protect themselves adequately from the environment. Hence, any health proble*, *hirh arise on such exercises should be taken as a minimal estimate of problems which may arise on more operational missions. TABLE 2 NORTHERN EXERCISES UTILIZED FOR THE ITIVESTIGATION OF HEALTH PROBLEMS, 1972:73 Exercise Northern Location New Viking 37 Northern Ramble New Viking 49 New Viking 52 New Viking 55 New Viking 56 New Viking 57 Coral Harbor Churchill Coral Harbor Churchill Frobisher Bay Frobisher Bay Frobisher Bay The health survey cardtrsed in the collection of field data is shown in Figure 1. The health survey has been conducted on an individual tent-group basis and extensive use has been made of the tent'group comûranders who have been r_esgonsibl-e lor adniìdisterírig tiie survey cards on a daily basrs.' The survey period has extended typically fro,n onã week before the exercise to one week after the exercise. Tabulation of the incidence of individual symptoms and symptorn cornplexes has been carried out post-exercise and it has become apparent that, to one degree or another, the incidence ol individual symptoms is afîected by movement into the Ñort¡. The rnost marked alteration in symptonrs reported has been noted in syrnptoms related to the upper respiratory system and it is these symptoms which have been examined ir greater detail in DCIEM Vitamin C studies. N Date Home CFB 70 400 100 r00 100 t20 100 March 1972 May 1972 December 1972 January 1973 February 1973 March 1973 April 1973 Petawawa Londorr London Gagetown Petawawa Calgary Petawawa 3 FIGURE 1 IN.FIELD HEALTH SURVEY CARD e¡te¡ Celete HFAbn-l o o osu rvFY "caRÞ oooo Entir&rmbntål Biology " o 40 20 30 I234567I I AO€ to 567I9 10 20 30 t234 TENT$¡O 5.5 2+.2 2"2 l. I 5c 5ö5 2.2t 2 2" 2.2 7 6 5 lcl¡ 4 3 aa 3456 da I2 2 l( symptom N N NN { N N N FE RNNY{r.¡ NNNNN NNNNYiN NN \r NN N NNN N CHEST COUGH NNNNN NN HEADACHE NN N NN NN LNN NNNN N NNN N NY.lN N ,\) f(, EÃIÍFç NNNNNNN N NNNNYNYIN s.t.N. No. NAME Idãt il svmotorn N N N NNN N NNN N SNNN N IND ¡D NTAC NS U N N NNN NN NNN NNNY N Ët?YrEt-rvr(tYElr N NNN NN N FROST NIP NNN NN NN FEET COLD N NNNN NN N NNNNN N NN NNNN N f LLI gvflL YNN N NNN N NNNN NN N 2I22Ir 2Ir 2 Ir 2I2I 434, $r 4tr 4 tr 4$r 434$r 5$r $r 6$, b $r 6$r 65b56 IRRI OF FLUID DI oooo HOW MANY oooo THERMOS C oooo lt 8 7I78 7 Ilt I ft I7, 8 to $r to oo TODAY? oo I o o o o$r to, 9to Ito Ito Ito I ffi k¡ãtTl 4 An assessment of vitamin c was undertaken for a number of reasons: (l) The whole question of Vitanrin C and its eflect on colds is a topical and debatable issue. lt was hoped that some light would be shed on this problem by utilizing a very restricted population ol cornparable age, typical cold history, common dietary regimen, activity schedule and environmental exposure. (2) It has been suggested that Vitamin C may play a role in increasing cold tolerancc -- with particular regard to maintaining peripheral circulation. (3) Finally, it was determined that the RP4 rations (1970-1 l) on which the men were living, apparently provided a maximum of 3741 mg Vitamin C per dav in a single fruildrink mix. As previous observations suggested tnat the fruit-drink mix was an unpopular item in the rations and tended to be discarded, it appeared that the individual intake of Vitarirn e could be below the recommencied daiiv allowancc. Accordingly, a protocol was established for dispensing tablets of either Vitamin C or placebo to individuals in each tent. Men in each tent group were assigned randomlv, to either the Vitamin C or placeb<r group. Extensive use was macÍe again,-of tent-group commanders who carried with them the strpply of pills lor their own tent. Two pill vials were provided for each tent, one containing Vitarnin C and one containing placebo. Each vial contained the nalnes ot rhe men who were to receive the respective pills. Pills were dispensed -twice a day, once with the morning meal and once with the evening meal. The total dose of VitaminC received êach day was 1000 mg. At the completion of the exercise the incidence and duration of colds was examined by assessing the presence oi absence of a col<l on the basis of symptom constellations. tll ordcr for a man to be-r:lassiÛed as having a cold, he had to have two nasal symptoms in coniunction with a rninimum of sore thrtlat or cltest couglr which persisted fbr two or more days. As a lurther restriction, tltc sorc tlt",t¿tt or chcst cough had to be abscnt at the lime thc nasal svr¡ptçrrrr bcg:rn. lìrequently, it was found tlrat rnorc constittttional symptorns such as headache, chills and fever, gencral nralaise, nausea or vomiting werc indicatetl at sonlc tintc <Iuring tlle synlptortr constellation. Table 3 indicates that the random allocation of lnerr,¡:o the two treatment gq<lups resulted in two well-matched populations with respect to age and typical cold history. TABLE 3 THE MEAN AGE AND COMMON COLD HISTORY OF MEMBERS OF A SINGLE INFANTRY COMPA¡IY OF I 12 MEN ALLOCATED RANDOMLY TO VITAMIN C AND PLACEBO PREPARATIONS Group Incidence of Usual Spring Cold ,,/,, Vitamin C25.3 ! 6.3* ( lìange 17 40) 6l .6 Placcb<r 25.4 ! 8.1 ( lìangc l7 41) (r0.0 *Mcan t S.l) 5 Table 4 depicts the frequency of colds assessed in a single infantry comPany on a Nortltcrtr Military exercise. The incidence of colds in two other cornpanies Participating on the exercise' but not subiecied to pill supplementation, was'21'O% ancl 29 A% respectively' The results indicate that the Vitamin C group experienced significantly fewer colds than the corresponding placebo group. This ameliorating effect ãf Vitamin C was also reflected in the frequency of colds reported by individuai tent groups (Table 5). Of the 14 tent groups involved in this study' nine groups (64.3vo) indicated the presence of at least one cold during the exercise period. of these ninegroupssix (66.6%lindicated "oror-ptærnt onry in placebo individuals, whereas the remaining three (33'3o/ù indicated àolds present in both placebo and Vitamm C groups. In no case did a tent-group indicate the presence of colds in Vitamin C individuals only' TABLE 4 INDryIDUAL INCIDENCE OF COLDS ASSESSED IN A SINGLE INFANTRY COMPAI'IY OF 112 MEN PARTICIPATING ON A NORTHERN MILITARY EXERCISE Group Percent FrequencY Vitamin C10.7 Placebo 2s.o 1z 3.87 P=0.05 TABLE 5 TENT GROTJP INCIDENCE OF COLDS IN AN INFANTRY COMPAI.IY OF 112 MEN PARTICIPATING ON A NORTHERN MILITARY EXERCISE Nu¡nber of Tent Groups Indicating Colds Present Number of Tent G¡oups Reporting One or Mo¡e Colds Amongst its Mcmbers 9114 In Both Vitamin C and Placebo Individuals 3le (33.3'/o) Ntsrequency 6 56 l4 56 In Placebo Indíviduals onlY ln Vitamin C lndividuals only 6le (66.6V") ole (64.3'/o) 6 The data presented in Table 6 inclicatc that despite a reduction in the lrequency ol colds in Vitanin C individuals, the duration of cold symptoms as related to the presence of nasal, throat or chest complaints was not signifìcantly influenced. ln otht' words, if an individual experienced a cold while on vitamin c, the continued daily intake of 1000 mg/day did not alter the course of the cold with respect to the local symptoms. Examinaiion of the more coistitutional symptoms however (Table 7) revealed that the duration of these was signi{ìcantly reduced in the vitanrin c group. This perhaps is-a-signlfìcantfinding for it is these syqptornrîni"f, are related to the general feeling of "well-being" and it is these symptotns which, in a civilian population, could predispor. i p.,,on to remain at home' In a military population where reruge cannot be sougnt easily, it is these symptoms which would tend to reduce a man's level of effectiveness' TABLE 6 THE MEAN DURATION OF UPPER RESPIRATORY SYMPTOMS ..NE.PONTBD BY MEN AFFLICTED WITH A COMMON COLD Group Vitamin C Placebo P *ysan r S.D Duration of SYInPtoms (days) Throat/Chest 4.3 13.0 6.0 I 3.0 > 0.2 > 0.3 Duration of SYmPtoms (days) 0.8 I 0.8* 2.4 x 2.1 p { 0.05 TABLE 7 THE MEAN DURATION OF CONSTITUTIONAL SYMPTOMS RELATED TO A FEELING OF WELL-BEING REPORTED BY MEN AFFLICTED WITH A COMMON COLD Group Vitarnin C Placebo on subsequent exercises an examination of the vitamin c status of men was carried out by examining the whote-bloãd aìcorbate f.t.f, ¡rià" and immediately after the exercise' Table 8 shows the incidence of altered ascorbate status on four Northern exercises' In all cases' a signÏfìcant number o[ men demonstrated a decrease in whole-blood ascorbate, however the magnitude of thrs decrease (Table 9) was signifìcant on only three of the exercises. coincident¿rlly' these three exercises were supplied with the RP4 ration while the rourth exercise (serial 56) receive, IRp fìeld rations.'r'rre IRp ration provrdes approximately 50_90 mg of Vitamin c o., Jáv,'ruout 50%.rwhich is in a single rruit-drink mix and 50% is distributed through.ut <¡ther ratton components. Nasal N 4.2 t 3.8* 5.6 x 2.8 l4 6 > 0.4 > 0.5 N 6 t4 7 TABLE 8 INCIDENCEoFALTEREDwHoLE.BLooDASCoRBATESTATUS OCCURRING ON NORTHERN Ð(ERCISES % of lndividuals below 050 nÉ/o Ascorbate Serial Post-Excrcisc NV 49 NV 5I NV 55 NV 56 8 4l t2 32 Serial TABLE 9 MEAN WHOLE.BLOOD ASCORBATE STATUS BEFORE AND AFTER PARTICIPATION ON NORTHERN EXERCISES Post-Flxcroisc Mean Change % -18 -24 -14 -4 NV 49 ¡n/ 51 NV 55 NV 56 +Mean t S.E.M one further point with reference to Table 8 is the father surprising number of men wht¡ demonstrated whole-blood ascorbate levels lower than 0.50 mg%. This value is genelally taken to indicate the threshold of a possible sub-clinical scorbutic condition. Two of the four serials examined post-exerOise demonstrated a definite shift towards this subclinical scorbutic state, one (Serial 56) remained unchanged and the other (Serial 55) demonstrated a shift in the opposite direction' ln view of the variation in diet and distribution of change in ascorbate status, it is not possible from these data to determine whether the reduction in ascorbate levels, observed post-exercise on three of the four serials, was a consequence of reduced dietary intake of vitamin c or a reflection of a possible incrcased requirement for this vitamin under the activity and exposure conditions existing on Northern operations' Clearly, a determination of ascorbate excretion is requìred before any estimate of requirement under these conditions can be made. This study is part of a continuing program to assess the nature ancl incidenoe of hcalth problenrs pertinent to Canadian militaiy Northern op.r.tionr. -With regards.t' Vitamin C an<J its influcncc ,n gcncral body health the data to date'suggest that a claily supplenrcnt of' 1000 mg Vitar¡lin c uppcarsto rcclucc tl¡c rtvcrall incidence of colds in transit military populations. lr nlust be appr0ciated howcvcr, that thr: natttrc of'tltc ;;tlì;;;;;;;re,r.,,".rf ¡epresenrs a r.arred departure trorn the "nornral" claiiy routine' Ovcr thc pcriod ttl' this stuoy, ttìe ¡ren are rransportcd by arr lnt() an urlvcrsc etìvtronnìenl and iìve in close associatittlt with that P¡r: -Lxeroise % of lndividuals Demonstrating a Dec¡ease in Ascorbate N 4 28 2l 32 '70 83 46 41 86 29 24 34 mg'/o Prellxe¡cisc Level mc% N -0.1e I 0.04 _0.21 I 0.04 _0.13 I 0.06 --0.03 I 0.06 1.05 1 0.04* 0.86 j 0.07 0.91 ! 0.10 0.76 ! 0.05 86 29 1Á LI 34 o environment. Their dietary regimen is altered dramatically with regards both to frequency of meals and nature of food eaten. In view of theæ factors the results reported here do not necessarilv characterize the civilian population in general. Further, insuffìcient data exist to enable us to determine whether the observed benefüial effect of Vitamin C observed in this study, is prophylactic or therapeutic, although the analysis of colds by tent groups suggests that the effect may be prophylaciic. In addition the study was restricted to an examination of the efficacy of a daily 1000 mg dose of vitamin c, which may repfesent neither the optimal nor minimal daily ;ü;dr"r;"; required. The whole-blood asçorbate levels of individuals receiving a Vitamin C supplement-'w'e-r-e-' increased well above normal (100-l5o7o). In view of the demonstrated decrease in whole'blood ascorbate occurring in non-supplemented men, the optimal dose of Vitamin c may be in a range which is sufficient to prevent such a decrease. Further work is required to clarify this situation'