Recommended dietary allowance for vitamin E

Comparative analysis of selected bioactive components (fatty acids, tocopherols, xanthophyll, lycopene, phenols) and basic nutrients in raw and thermally processed camelina, sunflower, and flax seeds (Camelina sativa L. Crantz, Helianthus L., and Linum L.)

The aim of study was to determine the content of basic nutrients, the level of fatty acids, tocopherols, xanthophyll, and lycopene, and the total phenolic content in camelina (Camelina sativa L. Crantz) (Cs), sunflower (Helianthus L.) (Ha), and flax (Linum L.) (Lu) seeds. The seeds were either raw or subjected to processing, i.e. boiling, micronization, or microwave roasting. The basic chemical composition was established and the fatty acid composition as well as the content of tocopherol (α, β, γ, δ, total), β-carotenoids, xanthophyll, lycopene, and total phenolics were determined in the analyzed oil seeds. The analyzed oil seeds are a rich source of protein and PUFAs as well as α-tocopherols (Ha) and γ-tocopherols (Cs, Lu), xanthophyll, and phenolics One portion of seeds covered from 746/513 (Cs) to as much as 1209/813% (Lu) (female/male) of the ALA daily intake. The AI value in the processed seeds increased (P < 0.05) and the values of H/H and HC declined (P < 0.05). The oil seed processing resulted in loss of most nutrients and bioactive constituents and appearance of some amounts of trans isomers, especially in the microwave roasted seeds (0.99-1.79 g/100 g crude lipid). The phenolic content decreased in the boiled seeds (Ha: 1301; Cs: 578.3, and Lu: 62.75 mg/100 g).

Vitamin E function and requirements in relation to PUFA

Vitamin E (α-tocopherol) is recognised as a key essential lipophilic antioxidant in humans protecting lipoproteins, PUFA, cellular and intra-cellular membranes from damage. The aim of this review was to evaluate the relevant published data about vitamin E requirements in relation to dietary PUFA intake. Evidence in animals and humans indicates a minimal basal requirement of 4–5 mg/d of RRR-α-tocopherol when the diet is very low in PUFA. The vitamin E requirement will increase with an increase in PUFA consumption and with the degree of unsaturation of the PUFA in the diet. The vitamin E requirement related to dietary linoleic acid, which is globally the major dietary PUFA in humans, was calculated to be 0·4–0·6 mg of RRR-α-tocopherol/g of linoleic acid. Animal studies show that for fatty acids with a higher degree of unsaturation, the vitamin E requirement increases almost linearly with the degree of unsaturation of the PUFA in the relative ratios of 0·3, 2, 3, 4, 5 and 6 for mono-, di-, tri-, tetra-, penta- and hexaenoic fatty acids, respectively. Assuming a typical intake of dietary PUFA, a vitamin E requirement ranging from 12 to 20 mg of RRR-α-tocopherol/d can be calculated. A number of guidelines recommend to increase PUFA intake as they have well-established health benefits. It will be prudent to assure an adequate vitamin E intake to match the increased PUFA intake, especially as vitamin E intake is already below recommendations in many populations worldwide.

Low-dose eicosapentaenoic or docosahexaenoic acid administration modifies fatty acid composition and does not affect susceptibility to oxidative stress in rat erythrocytes and tissues

In view of the promising future for use of n-3 polyunsaturated fatty acids (PUFA) in the prevention of cancer and cardiovascular diseases, it is necessary to ensure that their consumption does not result in detrimental oxidative effects. The aim of the present work was to test a hypothesis that low doses of eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) do not induce harmful modifications of oxidative cell metabolism, as modifications of membrane fatty acid composition occur. Wistar rats received by gavage oleic acid, EPA, or DHA (360 mg/kg body weight/day) for a period of 1 or 4 wk. Fatty acid composition and alpha-tocopherol content were determined for plasma, red blood cell (RBC) membranes, and liver, kidney, lung, and heart microsomal membranes. Susceptibility to oxidative stress induced by tert-butylhydroperoxide was measured in RBC. EPA treatment increased EPA and docosapentaenoic acid (DPA) content in plasma and in all the membranes studied. DHA treatment mainly increased DHA content. Both treatments decreased arachidonic acid content and n-6/n-3 PUFA ratio in the membranes, without modifying the Unsaturation Index. No changes in tissue alpha-tocopherol content and in RBC susceptibility to oxidative stress were induced by either EPA or DHA treatment. The data suggest that EPA and DHA treatments can substantially modify membrane fatty acids, without increasing susceptibility to oxidative stress, when administered at low doses. This opens the possibility for use of low doses of n-3 PUFA for chemoprevention without risk of detrimental secondary effects.

[Fatty acids in 80 brands of edible vegetable oil and in 14 brands of mayonnaise (author's transl)]

The fatty acid patterns have been defined in 80 commonly used table oils chosen at random and of 14 brands of mayonnaise commercially available in West Germany. In addition, sterols of the various mayonnaises were analysed. The oils could be grouped into 8 different categories: 12 oliver oils, 8 maize oils, 14 soya oils, 5 linseed oils, 22 sunflower oils, 3 safflower oils, 5 groundnut oils, and 8 rapeseed oils. As a result of the analyses, it is in almost every case a question of a pure variety of non-animal oils. The range of the values obtained for the composition of the fatty acids for each variety, which can be considerable, represents a modern complement to previous analyses. The fatty acid pattern of 3 additional commerical table oils suggest an amalgamation with fats of other types, among which are 2 cases of mixture with rapeseed oils. For mayonnaise, soya oil is used almost exclusively as a fat component. The presence of sunflower oil was only confirmed in one brand of mayonnaise. The concentrations of cholesterol which were determined lie between 17.0 and 72.3 mg (average 53 mg) per 100 g mayonnaise, so that even in the case of persons which present an elevated risk of atherosclerosis there can be no objection to the consumption of mayonnaise. The nutritive-physiological significance of these various oils for human nutrition is thoroughly discussed. A possible health hazard is the sale of vegetable oils rich in erucic acid permitted in the West German Republic (proportion of erucic acid in the 8 samples examined: 223-53%). These vegetable oils, as is shown by the additionally indicated trade names with the corresponding supplementary specifications are overwhelmingly labelled as vegetable oil (Pflanzenöl) or table oil (Speiseöl). The purchase prices indicated and paid by us for the oils examined are subject to considerable fluctuations even for oils of the same quality.

Comparison of dried milk preparations for babies on sale in 7 European countries. II. Folic acid, vitamin B6, thiamin, riboflavin, and vitamin E

Four vitamins of the B-complex—thiamin, riboflavin, vitamin B₆, and folate—were measured in 30 dried milk preparations for babies, representing products of manufacturers in 7 European countries. 7 of the preparations were also assayed for vitamin E. The milks varied widely in their B-vitamin composition. The content of riboflavin ranged from 2·8 to 11·2 μg/g, thiamin from 2·8 to 13·0, vitamin B₆ from 1·5 to 12·7, and folate from 0·03 to 1·12. Compared on a basis of equal solids content, all the preparations were considerably richer than mature human milk in thiamin and vitamin B₆, and most were similar to human milk in their content of riboflavin, though a few were markedly higher. With folate the findings were less reassuring. In 3 of the products the content was close to that in goat's milk, which may cause folate-deficiency anaemia in infants. In a further 8 the content was less than 60% of that in human milk. The 7 products tested showed marked differences in vitamin E content. In 4, which contained cow's milk fat only, the vitamin E content was 0·70-0·83 mg α-tocopherol equivalents/100 g as against 2·33 mg/100 g solids in human milk. The remaining 3 products contained vegetable oils and were considerably richer, with 4·77-10·21 mg/100 g.