Studies Assocìated with Ascorbic Acìd

Acta aitdmìn. ewynol, (Milano), L974,28, 101 Stødåes Assocìøted, uíth Ascorbåc Acì'd' K, M. CLEGG Investigations cauied out in the Food Science Départment in connection with sscor' bic acid have followed two distinct and unrelated pathways: 1) The effect of 1 g daily closes of L-a' scorbic acid in teducing the incidence of the common cold ín 0 gtoup of volunteets was compatecl with a control group receiving o ph.ãbo, The sutvey lasted 16 veeks during ihe wint.r montlrs oÍ L97L/t972. The results (1) showecl that the 47 volunteers receiving L-ascorbÍc ncicl suffered a total of, 44 colds, whereas the 43 people taking dummy pills hacl 80 colds. That is, I g L'ascorbic acicl/day reducecl the íncidence of cold symptoms by 49V0, Pauling (2 ) has calculatecl nn approximate couelation between the dose level of L'ascorbic ncid the reduction in the incidence of colds; for one gram per day he postulated a 4570 leduction wbiclr Ís in agreement with our findings. The lezults of the survey have been rennalyzecl nccording to the sex of the volunteels anc{ flre sumrnarized in the table. Cold¡ I¡nsco¡'blc ncld (47 Pcnoru) Fcmnlcs 1zÐ Mnlcs (24) Plnccbo (41 pcr¡on¡) M¡lcs (r) Fcmnlc¡ 1u) 0 I 2 , 4 Cold/pcrson I2 0 2 0 0 1 0.58 4 I 9 I 0 L,) 4 I I , 3 1,8 2 2 2 2 5 2,0 I)cnnrrmen! of Foocl Sclencc 6¿ Nutrition rlnìvcrslty of St¡nrhclycle, Glnsgol, Íìcotlntrtl. 1.01 It is appreciated that the numbers are too small to maL. a definite claim, but there is an indication that adult males obtain more benefit than adult females in taking L'ascorbic acid to reduce the íncidence of the com' rnon cold. It is planned to rePeat the investigation in Glasiow during the winter months of \gnfi| with a double-blind design tld larger nurnbers in the groups. However, in catiying out this typJ of survey' weekly .onir.i.uith a managèable number of volun' teers in considered to yietd more reliable results than larger groups with little, or no, supervision during the period of the suwey' 2 ) L-ascorbic acid is used as an additive by ih" food industry to increasethe nutri' ri,cnal value of a product and or for its antioxidant propertie;. However, it has establi' shed thai inìcidic conditions with free amino groups pfesent, as occurs in cittus iuices, L-^t.otbi. acid oxidizes to carbonyl compounds rvhich subsequently polymerise and ieud to non-enzymic browning (3 ). Claims have been made that the chemically synthe sizecl isomer, D-isoascorbic acid (a permitted additive in some countries), oxidized preferentíally and protects any L-ascorbic acid present (4). ' Investigotions with model systems at pH 4.0 have iho*t that the rate of breakdown of both ísorners is similar when they occur in a mixture and that D'isoascorbic acid has no additional antioxidant properties for the protection of L-ascolbic acid (5). However' il,. brealçdorvn products arising frorn the oxidation of L-ascorbic acid resulted in the clevelopment of more btowning than rvith D-isoascorbic acid subjected to identical conditions. Analysis of the carbonyls in dre model systems showed that L'ascorbic acid yielded a ,maller number than D'isoascorbic acid durine the early stages of incubation' This obJervation could be explained by the in' stant polymerisation of the 2,3-diketog¡rlonic acid åriiinating from L'ascorbic acid (6) yielding increased browning and. fewer intermediatã compounds, wheteas the polymerí' sation of the 2,}-diketogulonic acid detived from D-isoascorbic acid was slower and furthet oxidation to smaller moleculat carbonyls was able to talce Ptace'- - Altho,tgh L-ascorbic acid and D"isoascorbic acid exhiËit some variance in their chemical properties, both isomers are affectecl by the pt.t.n.. of copper in a similar way resultíng in u.cel"rated Ërcakdown and telatively increased browning (7). R f ÁssuNr o Stadí sull'acido dscorbìco. In un gruppo di volonta¡i sono stati studiati gli eff.tti J.ñu ió*ministrazione di I grammo di acldo ascorbico sul raffreddote comune. Si è constatato ct e t'in.i¿enza del raffreddote è netttmente minore nei soggetti che ingerivano questa-vitamina in con' fronto-ãi quelli trattati con placebo. La ricercâ sarà riperuh nell'inverno 197J'74 con un disegno sperimentole ln doppio cieco e soPra un maggior numero dl soggetti. REFEßENCES (1) Cu¡tr.ssro¡¡ S.S. ond Ct.ncc K,M. ' Lancett ßIi, lqat. - (2') Pnurrxc L. - ( Vitamin C and the Common Cold >, Bantam Boolcs, U,S.A., 1971, p. 8Z. - (3) C¿scc f.U. ' I.S!¡ Food Agric',-L964, ii,-az¡, - t+l EsssLBN rü[.8., Povuns JJ.-uI9 Wôoo*o*o R. - /. Ind, Ens, Clten., !945, ,7-' 295' - t:l Boutos Ñ.N. - M, Sc. Thesis, Foocl Science p.p.tttn"nt, Univcsity of Strathclyde, Glnsgow, -tnt - (6) Dwr¡n -S.I. and Fn¡¡on¡"rt¡¡x T'E' - ioii¿ ntt.., ig56,2L, 519, - (7) FsnousoN s'M' - g. S.. Thåsis, Fóod'science Department, Univerqity of Sttnthclyde, Glasgow, 1973, il, 1.02 s