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Free and Total Folate Activity in Strained Baby Foods
Free and Total Folate Activity in Strained Baby Foods K. Hoppner Nutrition Division, Food and Drug Directorate, Department of National Health and Welfare, Ottawa, Ontario
Abstract
baby foods.
Samples of 40 strained baby foods were obtained on the Canadian market and assayed microbiologically for "free" and "total" folate activity using L. easei. The "free" and "total" folate activity, respectively, ranged from 0.1-1.0 /Lg/100 g and 0.4-2.9 /Lg/100 g for strained fruits, 0.3-3.4 /Lg/lOO g and 1.6-11.6 /Lg/lOO g for strained vegetables, and 0.2-8.0 /Lg/lOO g and 1.3-12.6 p:g/lOO g for strained meats and meat combinations. On general comparison with published values of fresh foods, the strained fruits and vegetables show much lower folate activity. The values for the strained meats were only slightly lower than published values. The contribution of folate activity from strained baby foods as part of the total daily intake is estimated and discussed.
Materials and Methods
Resume
Des echantillons de 40 aliments filtres pour heMs ont ete recueillis sur Ie marche canadien et examines microbiologiquement pour leur activite en acide folique Iibre et total it I'aide du L. easei. L'activite acide folique Iibre et total a varie respectivement de 0.1-1.0 /Lg/lOO g et 0.4-2.9 /Lg/100 g pour les fruits filtres, 0.3-3.4 /Lg/lOO g et 1.6-11.6 /Lg/lOO g pour les legumes filtres, et 0.2-8.0 /Lg/lOO g et 1.3-12.6 /Lg/100 g pour les viandes et les melanges de viande filtres. Par rapport aux donnees pubIiees pour les aliments frais, I'activite acide folique des fruits et legumes filtres est beaucoup inferieure tandis que celIe des viandes filtn§es n'est que legerement inferieure. La contribution de I'activite acide folique des aliments filtres pour bebes it I'ingestion quotidienne totale a ete estimee et fait I'objet d'une discussion.
Introduction A number of surveys have reported the occurrence of folate deficiency in pregnant women, infants and the elderly (Herbert, 1968); Girdwood, 1969; Willoughby and Jewell, 1968). In a preliminary report of mass surveys currently being conducted in the United States, Sauberlich (1969) reports a high incidence of low folate values in serum and red blood cells in various population groups. There is some evidence for the occurrence of deficiency in Canada (Lowenstein et at., 1966; 1966a). Recent revisions of the Recommended Dietary Allowances (R.D.A.) of the National Academy of Sciences-~ational Research Council, United States (1968) have iucluded daily folate allowances for the I'Hriow,; age groups. The Canadian Dietary Standard is prese:ltly under review with expected publication of a revision by 1972 (Sabry, 1970). Information on the folate content of foods (Toepfer et at., 1951; Chung et at., 1961; Butterworth et at., 1963; 1968) is useful in establishing adequate and recommended levels of intake. However, data on folate activity in processed foods such as strained baby foods has been lacking. Strained baby foods are commonly introduced into infant diets during the third month. Since data on folate content of these foods are scarce, a study was conducted to determine the folate content of strained J. lnst. Can. Techno!. Ailment. Vo!. 4, No 2, 1971
Over a period of 4-5 months, samples of 40 strained baby foods from two brands were obtained on the Canadian market and analyzed for "free" and "total" folate activity. Folate activity was assayed microbiologically with L. casci by an adaptation of the methods recommended by Herbert and Bertino (1967) and Baker and Frank (1967). Each jar of strained baby food was thoroughly mixed before the preparation of duplicate extracts. The test extracts were prepared as follows: to approximately 2 g strained food sample in a 15 ml. grad. centrifuge tube was added 5 ml of phosphate buffer, pH 6.1, containing ascorbate (2 mg/ml). The extracts were mixed using a vortex mixer. The tubes prepared in this way were autoclaved in a steam-bath for 10 minutes and cooled in cold water. For the determination of "total folate activity" 1 ml supernatant of "Difco" desiccated chicken pancreas extracted in water (6 mg/ml) was added to each tube and after incubation at 37°C for 16 hI'S the contents were adjusted to 10 ml with phosphateascorbate buffer, pH 6.1. After further mixing, centrifugation and appropriate dilution, the extracts were assayed as described above. For the determination of "free" folate activity the conjugase treatment was omitted and the contents of the tubes were directly adjusted to 10 ml, remixed, centrifuged and after appropriate dilution, assayed.
Results and Discussion The results obtained for "free" (F.F.A.) and "total folate (T.F.A.) activity" on a variety of strained baby foods are shown in Tables 1, 2, and 3. The values of folate activity have been expressed as /Lg/100 g (or 3% oz) of product. Samples from both brands were pooled and in a few instances (as noted in tables) results are from one brand only. 'rable 1 summarizes F.F.A. and T.F.A. present in strained fruits with an overall mean value of 0.4 /Lg/ 100 g F.F.A. and 1.0 /Lg/100 g T.F.A. Table 2 summarizes the folate activity present in strained vegetables, showing overall mean values of 0.9 /Lg/100 g for F.F.A. and 5.0 /Lg/100 g T.F.A. Spinach, peas, beans and squash showed the highest T.F.A. values. For the strained meats and meat combinations (Table 3), the overall mean value was 1.4 /Lg/100 g F.F.A. and 4.6 /Lg/I00 g T.F.A. with the "meat with broth" product having generally the highest folate activities. Among the baby foods analyzed, egg yolk was the best source of folate activity, having 7.5 /Lg/100 g F.F.A. and 19.5 /Lg/100 g 'f.F.A. A comparison with T.:F.A. values of fresh foods is not possible since the processed products include other ingredients as indicated per label. However, on 51
Table 1.
Free and total folate activity in commercial strained Baby foods-fruits.
Food Sample
general comparison with T.F.A. values of fresh foods in the literature (Toepfer et al., 1951), it appears that the strained fruits and vegetables show much lower T.F.A., probably due to loss during processing. In the meats, the extent of such loss appears to be less. Similar observations have been reported in earlier work (Schweigert et al., 1946; Cheldelin et al., 1943; Hurdle et al., 1968). Matoth et al. (1965) estimated the daily folate requirement of infants to be about 20 fLg/day. Ford and Scott (1968) suggest that this should be regarded as the minimum requirement and that 40 fLg, as provided by breast milk (800 ml at 52 p,g/l) , be taken as the optimum. The R.D.A. (1968) of folate are 50 p,g for infants 0 to 6 months of age and 100 p,g for infants G to 12 months of age; these requirements are based on dietary sources as determined by L. casei assay. The folate activity of the strained vegetables, strained meat and meat combinations (Tables 2 and 3) are approximately comparable to the range of folate activity found in an equal weight of milk. Estimates of the average daily intake of folate in the case of 3- and 6-month old babies receiving cow's milk and solid baby foods is shown in Table 4. The average body weights and food intake data were chosen with reference to R.D.A. (1968), Dietary Standard for Canada (1964), Ho and Brown (1970), Farnan et al.
3
4 3 2 3 4 2 2 3
4 4
Range
Mean
0.1-0.1 0.1-0.3 0.1-0.3 0.3-0.4 0.4-1.0 0.4-0.7 0.3-0.5 0.2-0.4 0.2-0.3 0.1-1.0 0.3-0.5
0.1 0.2 0.2 0.4 0.6 0.6 0.4 0.3 0.2 0.5 0.4
No. of Samples
4 4 4 3 3 5 3 2 4 5
4
Range
Mean
0.6-0.7 0.8-1.3 0.9-1.1 0.7-1.4 1.1-1.3 1.2-2.9 0.6-1.2 0.7-0.9 0.6-1.0 0.4-1.0 0.7-1.5
0.6 1.0 1.0 1.1 1.3 2.1 0.9 0.8 0.8 0.9 1.0
(1970), and Filer and Martinez (1964). 'The range of milk folate activity was estimated from data by Ghitis (1966), Matoth et al. (1965), Ford and Scott (1968), and the values for cereals and custard as reported by Toepfer et al. (1951) and Hurdle et al. (1968), respectively. These estimates show that the contribution from solid baby foods is approximately 20-25% of the total daily intake, the remainder being supplied by mille Studies on the folate binding properties of milk, the binding protein responsible (Ghitis, 1967; Ghitis et al., 1969; Metz et al., 1968; Ford et al., 1969), and on the availability of milk folate (Ghitis and Tripathy, 1970), suggest that binding facilitates more efficient uptake and nutritional availability of milk folate in infants. Whether or not the nutritional availability of natural forms of folate from other foods is equally efficient is not known. Studies by Butterworth et al. (1969) in human volunteers indicated that 50-75% of administered synthetic heptaglutamyl folate appeared to be absorbable. These factors deserve consideration in the estimation of daily folate intake in infants, especially as some milks are low in folate and as the intake of solid foods such as strained baby foods is increasing. There is little information on comparative intestinal conjugase activities in adults and infants on the absorption of natural forms of food folate
Free and total folate activity in commercial strained Baby foods-vegetables.
Food Sample Golden Wax Beans Sweet Potatoes Peas & Carrots Squash Carrots Mixed Vegetables Peas Green Beans Creamed Corn" Creamed Spinach" Beets" "Samples of one Brand only.
52
Total folate activity fLg/100 g ofproduct
No. of Samples
Apricots Pears Peaches Blueberry Dessert" Apple Raspberry" Bananas Raspberry Dessert" Apple Sauce F1uJlls Mixed Fruit Prunes "Samples of one Brand only.
Table 2.
Free Folate activity fLg/lOO g of product
Free Folate activity
Total folate activity
p,g/lOO g of product
fLg/100 g of product
No. of Samples
Range
Mean
No. of Samples
Range
Mean
3 2 3 4 4 4 3 4 2 3 3
0.5-0.8 0.3-0.9 0.4-0.5 0.4-0.7 0.4-0.7 1.2-1.3 0.6-1.2 0.4-0.6 0.4-1.5 0.8-3.4 1.3-3.0
0.7 0.6 0.5 0.5 0.6 1.3 0.9 0.5 0.9 1.7 1.9
5 5 5 3 4 4 4 4 3 3 3
3.9-8.0 2.1-3.8 3.5-8.9 4.3-7.1 1.8-3.6 3.2-5.9 6.3-8.7 5.0-6.6 1.6-4.6 2.6-4.1 6.7-11.6
6.0 2.6 5.7 5.9 2.5 4.5 7.3 5.8 2.7 3.5 9.9
Can. lnst. Food Techno!. J, Vo!. 4. No.2, 1971
Table 3.
Free and total folate activity in commercial strained Baby foods-meats, meats with vegetables, eggs. Free Folate activity j.tg/lOO g of product
Food Sample
No. of Samples
Range
Mean
No. of SalIl[lles
Range
Mean
4 4 4 4 3 3 4 4 4 4 4 4 4 4 5 3 3 4
0.8-1.4 0.5-2.0 0.8-1.2 0.9-1.4 0.6-Ll 0.5-0.8 1.0-1.7 1.4-2.4 0.3-0.7 0.2-0.4 0.6-1.0 0.7-2.1 0.9-1.7 2.0-3.6 Ll-8.0 1.0-1.6 1.0-1.3 6.4-8.3
Ll 1.2 1.0 Ll 0.9 0.6 1.3 1.6 0.5 0.3 0.8 1.3 1.4 2.4 4.0 1.2 1.2 7.5
4 3 4 4 3 3 4 4 3 6 3 5 3 4 6 2 3 4
3.0- 5.7 2.5- 5.0 5.2- 7.5 2.1- 4.3 5.7-10.2 1.3- 2.8 4.1- 6.7 2.6-12.6 2.6- 5.4 3.4- 7.6 1.7- 2.8 1.6- 4.0 2.2- 4.8 3.7- 5.3 3.7- 7.6 4.4- 4.5 3.4- 5.5 14.1-24.0
4.8 3.4 6.1 2.8 8.3 2.0 5.2 7.4 4.0 6.2 2.3 2.5 3.8 4.3 5.7 4.5 4.5 19.5
Beef with Vegetables Vegetables & Beef Beef with Broth Beef with Farina Lamb with Vegetables Vegetables & Lamb" Veal with Vegetables Veal with Broth Ham with Vegetables Ham with Broth Chicken with Vegetables Chicken with Broth Turkey with Vegetables Turkey with Broth Vegetables & Liver with Bacon Egg & Bacon with Vegetables" Egg & Bacon Breakfast" Egg Yolks "Samples of one Brand only.
during the neonatal period. The data on folate activity of some commercial strained baby foods as provided in this study should be a useful guide in defining practical intake levels that are encountered in infant diets which, in addition to milk formulae, include strained baby foods.
Acknowledgements The author wishes to thank Dr. T. K. Murray for helpful suggestions, and the technical assistance of B. J. Lampi and D. E. Perrin is gratefully acknowledged.
References Baker, H. and Frank, O. 1967. A microbiological assay for folate activity. In The Vitamins, chemistry, physiology, pathology, methods; Vo!. VII, 2nd ed., edited by P. Gyorgy and W. N. Pearson, Academic Press, New York and London, p. 243. Butterworth, C. E., Jr., Baugh, C. M. and Krumdieck, C. 1969. Availability to man of folate ingested In polyglutamate form Amer. J. Clin. Nutr. 22, 670. Butterworth, C. E., Jr. 1968. The availability of food folate. Brit. J. Haematol. 14, 339. Butterworth, C. E. Jr., Santini, R., Jr. and Frommeyer, W. B. Jr. 1963. The pteroylglutamate components of American diets as determined by chromatographic fractionation. J. Clin. Invest. 42, 1929. Cheldelin, V. M., Woods, A. M. and Williams, R. J. 1943. Losses of B-vitamlns due to cooking of foods. J. Nutr 26, 477 Chung, A.S.M., Pearson, W. M., Darby, W. J., Miller, O. N. and Goldsmith, G. A. 1961. Folic acid, vitamin B G, pantothenic
Table 4.
Total folate activity j.tg/l00 g of product
acid and vitamin B 12 in human dietaries. Am. J. Clin. Nutr. 9, 573. Dietary Standard for Canada. 1964. Can. Bull. Nutr. 6. NO.1 Filer, L. J., Jr. and Martinez, G. A. 1964. Intake of selected nutrients by Infants in the United States. Clin. Pedlat. 3. 633. Fomon, S. J., Thoman, L. M. and Filer, L. J. 1970. Acceptance of unsalted strained foods by normal Infants J. Pedlat. 76, 242. Ford, J. E., Salter, D. N. and Scott, K. J. 1969. The folate-binding protein In milk. J. Dairy Res. 36, 435. Ford, J. E. and Scott, K. J. 1968. The folic acid activity of some milk foods for babies. J. Dairy Res. 35, 85. Ghltls, J. and Tripathy, K. 1970. Availability of milk folate studies with cow's milk In experimental folic acid deficiency. Amer. J. Clin. Nutr. 23, 141. Ghitis, J., Mandelbaum-Shavit, F. and Grossowicz, N. 1969. Binding of folic acid and derivatives by milk. Amer. J. Clin. Nutr. 22, 156. Ghitis, J. 1967. The folate binding in milk. Am. J. Clin. Nutr. 20, 1. Ghltls, J. 1966. The labile folate of milk. Amer. J. Clin. Nutr. 18, 452. Girdwood, R. H. 1969. Folate depletion in old age. Amer. J. Clin. Nutr. 22, 234. Herbert. V. 1968. Nutritional requirements for vitamin B and folic acid Amer. J. Clin. Nutr. 21 (7), 743. Herbert, V. and Bertino, J. R. 1967. In The Vitamins; chemistry, physiology, pathology, methods. Vo!. VII, 2nd ed., edited by P. Gyorgy and W. N. Pearson, Academic Press, New York and London, p. 243. Ho, C. H. and B-own, M. L. 1970. Food intake of infants attending well-baby clinics In Honolulu. J. Amer. dletet. Assoc. 57, 17. Hurdle, A. D. F., Berton, D. and Searles. I. H. 1968. A method for measuring folate in food and Its application to a hospital diet. Amer. J. Clin. Nutr. 21, 1202. Lowenstein, L., Brunton, L. and Hsieh, Yang-ShU. 1966. Nutritional anemia and megaloblastic In pregnancy. Can. Med. Assoc. J. 94, 636. Lowenstein, L., Cantlie, G., Ramon, O. and Brunton, L. 1966. The Incidence and prevention of folate deficiency in a pregnant clinic population. Can. Med. Assoc. J. 95, 797.
Estimated daily intake of folate by 3-and 6-month old infants receiving cow's milk and strained baby foods.
~ge
3 _mon-!~~;~Wc.:. . ::e-"ig",h=-:t"--,-=5-=-.7:....-=k"'g'-Food intake, ml, g Folate intake, j.tg Min. Max. Mean
Age, 6 months; Weight 7.6 kg Food intake, ml, g Folate intake, j.tg Min. Max. Mean J. Inst. Can. Techno!. Aliment. Vol. 4, No 2, 1971
Milk
Cereals 15
30
Vegetables 60
Fruits 60
Custard
_
60 Total
700 19.6 49.0 35.0
3
900
20
25.0 63.0 45.0
Meats
0.4 3.8 1.4 40
1.0 7.0 3.0 80
0.2 1.7 0.6 80
1.8
44.8
80 Total
4
0.5 5.0 1.8
1.3 9.3 4.0
0.3 2.3 0.8
2.4
58.0
53
Matoth, Y., Pinkas, A. and Sroka, C. 1965. Studies on folic acid In Infancy. III. Folates In breast-fed Infants and their mothers. Amer. J. Clln. Nutr. 16, 356. Metz, J., Zalusky, R. and Herbert V. 1968. Folic acid binding by serum and milk. Amer. J. Clln. Nutr. 21, 289. Recommended Dietary Allowances, 1968. Food and Nutrition Board, National Academy of Sciences-National Research Council. Seventh revised edition, Washington, D.C. Sabry, Z. I. 1970. The Canadian Dietary Standard. J. Am. Dletet. Assoc. 56, 195. Sauberllch, H. E. 1969. Anemia problems. Presented at meetings of
54
Fed. Amer. Soc. Exp. Bioi., April 13-18. Quoted In Dairy CounCil Digest 40, 19. Schweigert, B. S., Pollard, A. E. and Elvehjem, C. A. 1946. The folic acid content of meats and the retention of this vitamin during cooking. Arch. Blochem. Blophys. 10, 107. Toepfer, E. W. Zook, E. G., Orr, M. L. and Richardson, L. R. 1951. Folic acid content of foods. U.S. Dept. Agr. Handbook, No. 29. Willoughby, M. L. N. and Jewell, F. G. 1968. Folate status through_ out pregnancy and In postpartum period. Brit. Med. J. 4, 356. Received Jan. 11, 1971.
Can. Inst. Food Techno!. J. Vol. 4, No.2, 1971
Abstract
baby foods.
Samples of 40 strained baby foods were obtained on the Canadian market and assayed microbiologically for "free" and "total" folate activity using L. easei. The "free" and "total" folate activity, respectively, ranged from 0.1-1.0 /Lg/100 g and 0.4-2.9 /Lg/100 g for strained fruits, 0.3-3.4 /Lg/lOO g and 1.6-11.6 /Lg/lOO g for strained vegetables, and 0.2-8.0 /Lg/lOO g and 1.3-12.6 p:g/lOO g for strained meats and meat combinations. On general comparison with published values of fresh foods, the strained fruits and vegetables show much lower folate activity. The values for the strained meats were only slightly lower than published values. The contribution of folate activity from strained baby foods as part of the total daily intake is estimated and discussed.
Materials and Methods
Resume
Des echantillons de 40 aliments filtres pour heMs ont ete recueillis sur Ie marche canadien et examines microbiologiquement pour leur activite en acide folique Iibre et total it I'aide du L. easei. L'activite acide folique Iibre et total a varie respectivement de 0.1-1.0 /Lg/lOO g et 0.4-2.9 /Lg/100 g pour les fruits filtres, 0.3-3.4 /Lg/lOO g et 1.6-11.6 /Lg/lOO g pour les legumes filtres, et 0.2-8.0 /Lg/lOO g et 1.3-12.6 /Lg/100 g pour les viandes et les melanges de viande filtres. Par rapport aux donnees pubIiees pour les aliments frais, I'activite acide folique des fruits et legumes filtres est beaucoup inferieure tandis que celIe des viandes filtn§es n'est que legerement inferieure. La contribution de I'activite acide folique des aliments filtres pour bebes it I'ingestion quotidienne totale a ete estimee et fait I'objet d'une discussion.
Introduction A number of surveys have reported the occurrence of folate deficiency in pregnant women, infants and the elderly (Herbert, 1968); Girdwood, 1969; Willoughby and Jewell, 1968). In a preliminary report of mass surveys currently being conducted in the United States, Sauberlich (1969) reports a high incidence of low folate values in serum and red blood cells in various population groups. There is some evidence for the occurrence of deficiency in Canada (Lowenstein et at., 1966; 1966a). Recent revisions of the Recommended Dietary Allowances (R.D.A.) of the National Academy of Sciences-~ational Research Council, United States (1968) have iucluded daily folate allowances for the I'Hriow,; age groups. The Canadian Dietary Standard is prese:ltly under review with expected publication of a revision by 1972 (Sabry, 1970). Information on the folate content of foods (Toepfer et at., 1951; Chung et at., 1961; Butterworth et at., 1963; 1968) is useful in establishing adequate and recommended levels of intake. However, data on folate activity in processed foods such as strained baby foods has been lacking. Strained baby foods are commonly introduced into infant diets during the third month. Since data on folate content of these foods are scarce, a study was conducted to determine the folate content of strained J. lnst. Can. Techno!. Ailment. Vo!. 4, No 2, 1971
Over a period of 4-5 months, samples of 40 strained baby foods from two brands were obtained on the Canadian market and analyzed for "free" and "total" folate activity. Folate activity was assayed microbiologically with L. casci by an adaptation of the methods recommended by Herbert and Bertino (1967) and Baker and Frank (1967). Each jar of strained baby food was thoroughly mixed before the preparation of duplicate extracts. The test extracts were prepared as follows: to approximately 2 g strained food sample in a 15 ml. grad. centrifuge tube was added 5 ml of phosphate buffer, pH 6.1, containing ascorbate (2 mg/ml). The extracts were mixed using a vortex mixer. The tubes prepared in this way were autoclaved in a steam-bath for 10 minutes and cooled in cold water. For the determination of "total folate activity" 1 ml supernatant of "Difco" desiccated chicken pancreas extracted in water (6 mg/ml) was added to each tube and after incubation at 37°C for 16 hI'S the contents were adjusted to 10 ml with phosphateascorbate buffer, pH 6.1. After further mixing, centrifugation and appropriate dilution, the extracts were assayed as described above. For the determination of "free" folate activity the conjugase treatment was omitted and the contents of the tubes were directly adjusted to 10 ml, remixed, centrifuged and after appropriate dilution, assayed.
Results and Discussion The results obtained for "free" (F.F.A.) and "total folate (T.F.A.) activity" on a variety of strained baby foods are shown in Tables 1, 2, and 3. The values of folate activity have been expressed as /Lg/100 g (or 3% oz) of product. Samples from both brands were pooled and in a few instances (as noted in tables) results are from one brand only. 'rable 1 summarizes F.F.A. and T.F.A. present in strained fruits with an overall mean value of 0.4 /Lg/ 100 g F.F.A. and 1.0 /Lg/100 g T.F.A. Table 2 summarizes the folate activity present in strained vegetables, showing overall mean values of 0.9 /Lg/100 g for F.F.A. and 5.0 /Lg/100 g T.F.A. Spinach, peas, beans and squash showed the highest T.F.A. values. For the strained meats and meat combinations (Table 3), the overall mean value was 1.4 /Lg/100 g F.F.A. and 4.6 /Lg/I00 g T.F.A. with the "meat with broth" product having generally the highest folate activities. Among the baby foods analyzed, egg yolk was the best source of folate activity, having 7.5 /Lg/100 g F.F.A. and 19.5 /Lg/100 g 'f.F.A. A comparison with T.:F.A. values of fresh foods is not possible since the processed products include other ingredients as indicated per label. However, on 51
Table 1.
Free and total folate activity in commercial strained Baby foods-fruits.
Food Sample
general comparison with T.F.A. values of fresh foods in the literature (Toepfer et al., 1951), it appears that the strained fruits and vegetables show much lower T.F.A., probably due to loss during processing. In the meats, the extent of such loss appears to be less. Similar observations have been reported in earlier work (Schweigert et al., 1946; Cheldelin et al., 1943; Hurdle et al., 1968). Matoth et al. (1965) estimated the daily folate requirement of infants to be about 20 fLg/day. Ford and Scott (1968) suggest that this should be regarded as the minimum requirement and that 40 fLg, as provided by breast milk (800 ml at 52 p,g/l) , be taken as the optimum. The R.D.A. (1968) of folate are 50 p,g for infants 0 to 6 months of age and 100 p,g for infants G to 12 months of age; these requirements are based on dietary sources as determined by L. casei assay. The folate activity of the strained vegetables, strained meat and meat combinations (Tables 2 and 3) are approximately comparable to the range of folate activity found in an equal weight of milk. Estimates of the average daily intake of folate in the case of 3- and 6-month old babies receiving cow's milk and solid baby foods is shown in Table 4. The average body weights and food intake data were chosen with reference to R.D.A. (1968), Dietary Standard for Canada (1964), Ho and Brown (1970), Farnan et al.
3
4 3 2 3 4 2 2 3
4 4
Range
Mean
0.1-0.1 0.1-0.3 0.1-0.3 0.3-0.4 0.4-1.0 0.4-0.7 0.3-0.5 0.2-0.4 0.2-0.3 0.1-1.0 0.3-0.5
0.1 0.2 0.2 0.4 0.6 0.6 0.4 0.3 0.2 0.5 0.4
No. of Samples
4 4 4 3 3 5 3 2 4 5
4
Range
Mean
0.6-0.7 0.8-1.3 0.9-1.1 0.7-1.4 1.1-1.3 1.2-2.9 0.6-1.2 0.7-0.9 0.6-1.0 0.4-1.0 0.7-1.5
0.6 1.0 1.0 1.1 1.3 2.1 0.9 0.8 0.8 0.9 1.0
(1970), and Filer and Martinez (1964). 'The range of milk folate activity was estimated from data by Ghitis (1966), Matoth et al. (1965), Ford and Scott (1968), and the values for cereals and custard as reported by Toepfer et al. (1951) and Hurdle et al. (1968), respectively. These estimates show that the contribution from solid baby foods is approximately 20-25% of the total daily intake, the remainder being supplied by mille Studies on the folate binding properties of milk, the binding protein responsible (Ghitis, 1967; Ghitis et al., 1969; Metz et al., 1968; Ford et al., 1969), and on the availability of milk folate (Ghitis and Tripathy, 1970), suggest that binding facilitates more efficient uptake and nutritional availability of milk folate in infants. Whether or not the nutritional availability of natural forms of folate from other foods is equally efficient is not known. Studies by Butterworth et al. (1969) in human volunteers indicated that 50-75% of administered synthetic heptaglutamyl folate appeared to be absorbable. These factors deserve consideration in the estimation of daily folate intake in infants, especially as some milks are low in folate and as the intake of solid foods such as strained baby foods is increasing. There is little information on comparative intestinal conjugase activities in adults and infants on the absorption of natural forms of food folate
Free and total folate activity in commercial strained Baby foods-vegetables.
Food Sample Golden Wax Beans Sweet Potatoes Peas & Carrots Squash Carrots Mixed Vegetables Peas Green Beans Creamed Corn" Creamed Spinach" Beets" "Samples of one Brand only.
52
Total folate activity fLg/100 g ofproduct
No. of Samples
Apricots Pears Peaches Blueberry Dessert" Apple Raspberry" Bananas Raspberry Dessert" Apple Sauce F1uJlls Mixed Fruit Prunes "Samples of one Brand only.
Table 2.
Free Folate activity fLg/lOO g of product
Free Folate activity
Total folate activity
p,g/lOO g of product
fLg/100 g of product
No. of Samples
Range
Mean
No. of Samples
Range
Mean
3 2 3 4 4 4 3 4 2 3 3
0.5-0.8 0.3-0.9 0.4-0.5 0.4-0.7 0.4-0.7 1.2-1.3 0.6-1.2 0.4-0.6 0.4-1.5 0.8-3.4 1.3-3.0
0.7 0.6 0.5 0.5 0.6 1.3 0.9 0.5 0.9 1.7 1.9
5 5 5 3 4 4 4 4 3 3 3
3.9-8.0 2.1-3.8 3.5-8.9 4.3-7.1 1.8-3.6 3.2-5.9 6.3-8.7 5.0-6.6 1.6-4.6 2.6-4.1 6.7-11.6
6.0 2.6 5.7 5.9 2.5 4.5 7.3 5.8 2.7 3.5 9.9
Can. lnst. Food Techno!. J, Vo!. 4. No.2, 1971
Table 3.
Free and total folate activity in commercial strained Baby foods-meats, meats with vegetables, eggs. Free Folate activity j.tg/lOO g of product
Food Sample
No. of Samples
Range
Mean
No. of SalIl[lles
Range
Mean
4 4 4 4 3 3 4 4 4 4 4 4 4 4 5 3 3 4
0.8-1.4 0.5-2.0 0.8-1.2 0.9-1.4 0.6-Ll 0.5-0.8 1.0-1.7 1.4-2.4 0.3-0.7 0.2-0.4 0.6-1.0 0.7-2.1 0.9-1.7 2.0-3.6 Ll-8.0 1.0-1.6 1.0-1.3 6.4-8.3
Ll 1.2 1.0 Ll 0.9 0.6 1.3 1.6 0.5 0.3 0.8 1.3 1.4 2.4 4.0 1.2 1.2 7.5
4 3 4 4 3 3 4 4 3 6 3 5 3 4 6 2 3 4
3.0- 5.7 2.5- 5.0 5.2- 7.5 2.1- 4.3 5.7-10.2 1.3- 2.8 4.1- 6.7 2.6-12.6 2.6- 5.4 3.4- 7.6 1.7- 2.8 1.6- 4.0 2.2- 4.8 3.7- 5.3 3.7- 7.6 4.4- 4.5 3.4- 5.5 14.1-24.0
4.8 3.4 6.1 2.8 8.3 2.0 5.2 7.4 4.0 6.2 2.3 2.5 3.8 4.3 5.7 4.5 4.5 19.5
Beef with Vegetables Vegetables & Beef Beef with Broth Beef with Farina Lamb with Vegetables Vegetables & Lamb" Veal with Vegetables Veal with Broth Ham with Vegetables Ham with Broth Chicken with Vegetables Chicken with Broth Turkey with Vegetables Turkey with Broth Vegetables & Liver with Bacon Egg & Bacon with Vegetables" Egg & Bacon Breakfast" Egg Yolks "Samples of one Brand only.
during the neonatal period. The data on folate activity of some commercial strained baby foods as provided in this study should be a useful guide in defining practical intake levels that are encountered in infant diets which, in addition to milk formulae, include strained baby foods.
Acknowledgements The author wishes to thank Dr. T. K. Murray for helpful suggestions, and the technical assistance of B. J. Lampi and D. E. Perrin is gratefully acknowledged.
References Baker, H. and Frank, O. 1967. A microbiological assay for folate activity. In The Vitamins, chemistry, physiology, pathology, methods; Vo!. VII, 2nd ed., edited by P. Gyorgy and W. N. Pearson, Academic Press, New York and London, p. 243. Butterworth, C. E., Jr., Baugh, C. M. and Krumdieck, C. 1969. Availability to man of folate ingested In polyglutamate form Amer. J. Clin. Nutr. 22, 670. Butterworth, C. E., Jr. 1968. The availability of food folate. Brit. J. Haematol. 14, 339. Butterworth, C. E. Jr., Santini, R., Jr. and Frommeyer, W. B. Jr. 1963. The pteroylglutamate components of American diets as determined by chromatographic fractionation. J. Clin. Invest. 42, 1929. Cheldelin, V. M., Woods, A. M. and Williams, R. J. 1943. Losses of B-vitamlns due to cooking of foods. J. Nutr 26, 477 Chung, A.S.M., Pearson, W. M., Darby, W. J., Miller, O. N. and Goldsmith, G. A. 1961. Folic acid, vitamin B G, pantothenic
Table 4.
Total folate activity j.tg/l00 g of product
acid and vitamin B 12 in human dietaries. Am. J. Clin. Nutr. 9, 573. Dietary Standard for Canada. 1964. Can. Bull. Nutr. 6. NO.1 Filer, L. J., Jr. and Martinez, G. A. 1964. Intake of selected nutrients by Infants in the United States. Clin. Pedlat. 3. 633. Fomon, S. J., Thoman, L. M. and Filer, L. J. 1970. Acceptance of unsalted strained foods by normal Infants J. Pedlat. 76, 242. Ford, J. E., Salter, D. N. and Scott, K. J. 1969. The folate-binding protein In milk. J. Dairy Res. 36, 435. Ford, J. E. and Scott, K. J. 1968. The folic acid activity of some milk foods for babies. J. Dairy Res. 35, 85. Ghltls, J. and Tripathy, K. 1970. Availability of milk folate studies with cow's milk In experimental folic acid deficiency. Amer. J. Clin. Nutr. 23, 141. Ghitis, J., Mandelbaum-Shavit, F. and Grossowicz, N. 1969. Binding of folic acid and derivatives by milk. Amer. J. Clin. Nutr. 22, 156. Ghitis, J. 1967. The folate binding in milk. Am. J. Clin. Nutr. 20, 1. Ghltls, J. 1966. The labile folate of milk. Amer. J. Clin. Nutr. 18, 452. Girdwood, R. H. 1969. Folate depletion in old age. Amer. J. Clin. Nutr. 22, 234. Herbert. V. 1968. Nutritional requirements for vitamin B and folic acid Amer. J. Clin. Nutr. 21 (7), 743. Herbert, V. and Bertino, J. R. 1967. In The Vitamins; chemistry, physiology, pathology, methods. Vo!. VII, 2nd ed., edited by P. Gyorgy and W. N. Pearson, Academic Press, New York and London, p. 243. Ho, C. H. and B-own, M. L. 1970. Food intake of infants attending well-baby clinics In Honolulu. J. Amer. dletet. Assoc. 57, 17. Hurdle, A. D. F., Berton, D. and Searles. I. H. 1968. A method for measuring folate in food and Its application to a hospital diet. Amer. J. Clin. Nutr. 21, 1202. Lowenstein, L., Brunton, L. and Hsieh, Yang-ShU. 1966. Nutritional anemia and megaloblastic In pregnancy. Can. Med. Assoc. J. 94, 636. Lowenstein, L., Cantlie, G., Ramon, O. and Brunton, L. 1966. The Incidence and prevention of folate deficiency in a pregnant clinic population. Can. Med. Assoc. J. 95, 797.
Estimated daily intake of folate by 3-and 6-month old infants receiving cow's milk and strained baby foods.
~ge
3 _mon-!~~;~Wc.:. . ::e-"ig",h=-:t"--,-=5-=-.7:....-=k"'g'-Food intake, ml, g Folate intake, j.tg Min. Max. Mean
Age, 6 months; Weight 7.6 kg Food intake, ml, g Folate intake, j.tg Min. Max. Mean J. Inst. Can. Techno!. Aliment. Vol. 4, No 2, 1971
Milk
Cereals 15
30
Vegetables 60
Fruits 60
Custard
_
60 Total
700 19.6 49.0 35.0
3
900
20
25.0 63.0 45.0
Meats
0.4 3.8 1.4 40
1.0 7.0 3.0 80
0.2 1.7 0.6 80
1.8
44.8
80 Total
4
0.5 5.0 1.8
1.3 9.3 4.0
0.3 2.3 0.8
2.4
58.0
53
Matoth, Y., Pinkas, A. and Sroka, C. 1965. Studies on folic acid In Infancy. III. Folates In breast-fed Infants and their mothers. Amer. J. Clln. Nutr. 16, 356. Metz, J., Zalusky, R. and Herbert V. 1968. Folic acid binding by serum and milk. Amer. J. Clln. Nutr. 21, 289. Recommended Dietary Allowances, 1968. Food and Nutrition Board, National Academy of Sciences-National Research Council. Seventh revised edition, Washington, D.C. Sabry, Z. I. 1970. The Canadian Dietary Standard. J. Am. Dletet. Assoc. 56, 195. Sauberllch, H. E. 1969. Anemia problems. Presented at meetings of
54
Fed. Amer. Soc. Exp. Bioi., April 13-18. Quoted In Dairy CounCil Digest 40, 19. Schweigert, B. S., Pollard, A. E. and Elvehjem, C. A. 1946. The folic acid content of meats and the retention of this vitamin during cooking. Arch. Blochem. Blophys. 10, 107. Toepfer, E. W. Zook, E. G., Orr, M. L. and Richardson, L. R. 1951. Folic acid content of foods. U.S. Dept. Agr. Handbook, No. 29. Willoughby, M. L. N. and Jewell, F. G. 1968. Folate status through_ out pregnancy and In postpartum period. Brit. Med. J. 4, 356. Received Jan. 11, 1971.
Can. Inst. Food Techno!. J. Vol. 4, No.2, 1971