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VEGETABLES AS SOURCES OF VITAMIN K IN FINLAND
VEGETABLES AS SOURCES OF VITAMIN K IN FINLAND
T. Koivu, V. Piironen and P. Mattila Department of Applied Chemistry and Microbiology University of Helsinki P.O. Box 27 00014 University of Helsinki Finland 1 INTRODUCTION Vitamin K has been historically identified for its role in blood coagulation, in which it hnctions as an essential cofactor in the posttranslational synthesis of prothrombin and other clotting proteins. It is currently known that vitamin K dependent proteins also include proteins affecting bone metabolism (1). On the other hand, dietary vitamin K has an effect on the efficiency of anticoagulant drugs. Green vegetables are generally regarded as good dietary sources of vitamin K; especially the dark-green vegetables (spinach, lettuce and broccoli) are excellent contributors of dietary phylloquinone. In the present study we estimated the average daily intake of vitamin K from vegetables, fruits and berries in Finland. 2 METHODS
The vitamin K contents of vegetables, fruits and berries used for estimation of dietary vitamin K intake were obtained from our study done during the years 1996-1997 (2). The sampling covered 38 different items available in Finland and also variation in the phylloquinone contents was investigated. Phylloquinone was quantified by the reversephase HPLC with dual-electrode electrochemical detection. Data on the average consumption of vegetables of the Finnish population was derived from the Finnish Horticultural Products (1993). 3 RESULTS
The phylloquinone contents of vegetables, fruits and berries analysed are summarized in Table 1. The best sources of phylloquinone were dark-green vegetables: parsley, dill, spinach and Brussels sprouts (mean content > 200 pg/100 8). The amounts of phylloquinone were also moderately high in other green vegetables (> 100 pg/lOO g). The phylloquinone levels were considerably lower in h i t s , berries, and red and yellow g). vegetables (generally < 20 ~g/100
Session VI Quality Assessment
301
Table 1 Phylloqiiinone in Vegetables,fruits, and berries Phylloquinone (pg/lOO g)
I
0 - 10
onion, peppers, potato, redbeets, swede, tomato, apple, plum, lingonberry, strawberry blueberry, raspberry, red currant, grapes, carrot, cucumber cauliflower, avocado, peas black currant, kiwifruit, iceberg lettuce leek, white cabbage, Chinese cabbage broccoli, lettuce in pot, leaf lettuce Brussels sprouts, dill, spinach, parsley
10-20
-
20 30 30 - 50 50 - 100 100 - 200 1200
The use of vegetables, fruits and berries has been fairly low in Finland; the average consumption figures were in 1993 169, 119 and 29 glday, respectively. The various cabbages, cucumber, tomato, and carrot were the most commonly used vegetables. On the basis of the above consumption figures, the average daily intake of vitamin K from these foods was estimated to be 37 pg, when the proportion of vegetables accounts for about 90% (Figure 1). Among the vegetables the most significant sources are various cabbages (34%), lettuces (1 5%) and root crops (15%), especially carrot. The average intake estimated here contributes approximately 50-60% of the current RDA (3). However, a fairly high variation in the consumption of vegetables among individuals is to be expected. In consequence, the daily dietary intake of phylloquinone may vary considerably.
OTHER VEGETABES 7 6 ,,g/day
I Figure 1.
58 ,,glday
Vegetables,fruits, and berries as sources osphylloquinone
302
Agri-Food Quality II: Quality Management of Fruits and Vegetables
In conclusion, green vegetables are excellent sources of phylloquinone; for example, eating 50 g of pot-grown lettuce per day will hlfil over 50% of the daily RDA. The end part of the RDA is easily satisfied by eating also one carrot (70 g) and 50 g of black currant. References 1. M. J. Shearer, Lancet, 1995, 345,229. 2. T. J. Koivu, V. I. Piironen, S. K. Henttonen and P. H. Mattila, J. Agric. Food Chem., 1997, 45,4644. 3. NRC,'Recommended Dietary Allowances', 10th ed., National Academy Press, Washington, 1989.
T. Koivu, V. Piironen and P. Mattila Department of Applied Chemistry and Microbiology University of Helsinki P.O. Box 27 00014 University of Helsinki Finland 1 INTRODUCTION Vitamin K has been historically identified for its role in blood coagulation, in which it hnctions as an essential cofactor in the posttranslational synthesis of prothrombin and other clotting proteins. It is currently known that vitamin K dependent proteins also include proteins affecting bone metabolism (1). On the other hand, dietary vitamin K has an effect on the efficiency of anticoagulant drugs. Green vegetables are generally regarded as good dietary sources of vitamin K; especially the dark-green vegetables (spinach, lettuce and broccoli) are excellent contributors of dietary phylloquinone. In the present study we estimated the average daily intake of vitamin K from vegetables, fruits and berries in Finland. 2 METHODS
The vitamin K contents of vegetables, fruits and berries used for estimation of dietary vitamin K intake were obtained from our study done during the years 1996-1997 (2). The sampling covered 38 different items available in Finland and also variation in the phylloquinone contents was investigated. Phylloquinone was quantified by the reversephase HPLC with dual-electrode electrochemical detection. Data on the average consumption of vegetables of the Finnish population was derived from the Finnish Horticultural Products (1993). 3 RESULTS
The phylloquinone contents of vegetables, fruits and berries analysed are summarized in Table 1. The best sources of phylloquinone were dark-green vegetables: parsley, dill, spinach and Brussels sprouts (mean content > 200 pg/100 8). The amounts of phylloquinone were also moderately high in other green vegetables (> 100 pg/lOO g). The phylloquinone levels were considerably lower in h i t s , berries, and red and yellow g). vegetables (generally < 20 ~g/100
Session VI Quality Assessment
301
Table 1 Phylloqiiinone in Vegetables,fruits, and berries Phylloquinone (pg/lOO g)
I
0 - 10
onion, peppers, potato, redbeets, swede, tomato, apple, plum, lingonberry, strawberry blueberry, raspberry, red currant, grapes, carrot, cucumber cauliflower, avocado, peas black currant, kiwifruit, iceberg lettuce leek, white cabbage, Chinese cabbage broccoli, lettuce in pot, leaf lettuce Brussels sprouts, dill, spinach, parsley
10-20
-
20 30 30 - 50 50 - 100 100 - 200 1200
The use of vegetables, fruits and berries has been fairly low in Finland; the average consumption figures were in 1993 169, 119 and 29 glday, respectively. The various cabbages, cucumber, tomato, and carrot were the most commonly used vegetables. On the basis of the above consumption figures, the average daily intake of vitamin K from these foods was estimated to be 37 pg, when the proportion of vegetables accounts for about 90% (Figure 1). Among the vegetables the most significant sources are various cabbages (34%), lettuces (1 5%) and root crops (15%), especially carrot. The average intake estimated here contributes approximately 50-60% of the current RDA (3). However, a fairly high variation in the consumption of vegetables among individuals is to be expected. In consequence, the daily dietary intake of phylloquinone may vary considerably.
OTHER VEGETABES 7 6 ,,g/day
I Figure 1.
58 ,,glday
Vegetables,fruits, and berries as sources osphylloquinone
302
Agri-Food Quality II: Quality Management of Fruits and Vegetables
In conclusion, green vegetables are excellent sources of phylloquinone; for example, eating 50 g of pot-grown lettuce per day will hlfil over 50% of the daily RDA. The end part of the RDA is easily satisfied by eating also one carrot (70 g) and 50 g of black currant. References 1. M. J. Shearer, Lancet, 1995, 345,229. 2. T. J. Koivu, V. I. Piironen, S. K. Henttonen and P. H. Mattila, J. Agric. Food Chem., 1997, 45,4644. 3. NRC,'Recommended Dietary Allowances', 10th ed., National Academy Press, Washington, 1989.