Vitamin E Inadequacy in Humans: Causes and Consequences

Abstract

It is estimated that >90% of Americans do not consume sufficient dietary vitamin E, as α-tocopherol, to meet estimated average requirements. What are the adverse consequences of inadequate dietary α-tocopherol intakes? This review discusses health aspects where inadequate vitamin E status is detrimental and additional vitamin E has reversed the symptoms. In general, plasma α-tocopherol concentrations <12 μmol/L are associated with increased infection, anemia, stunting of growth, and poor outcomes during pregnancy for both the infant and the mother. When low dietary amounts of α-tocopherol are consumed, tissue α-tocopherol needs exceed amounts available, leading to increased damage to target tissues. Seemingly, adequacy of human vitamin E status cannot be assessed from circulating α-tocopherol concentrations, but inadequacy can be determined from “low” values. Circulating α-tocopherol concentrations are very difficult to interpret because, as a person ages, plasma lipid concentrations also increase and these elevations in lipids increase the plasma carriers for α-tocopherol, leading to higher circulating α-tocopherol concentrations. However, abnormal lipoprotein metabolism does not necessarily increase α-tocopherol delivery to tissues. Additional biomarkers of inadequate vitamin E status are needed. Urinary excretion of the vitamin E metabolite α-carboxy-ethyl-hydroxychromanol may fulfill this biomarker role, but it has not been widely studied with regard to vitamin E status in humans or with regard to health benefits. This review evaluated the information available on the adverse consequences of inadequate α-tocopherol status and provides suggestions for avenues for research.

Complexity of vitamin E metabolism

“…Although the recommended amount of vitamin E is higher for men than for women, Dutch women consume less vitamin E more often compared to Dutch men [17] . Data by Traber [18] published last year suggest that more than 90% of United States Americans consume insufficient amounts of vitamin E.…”

“…Next to dietary habits, hereditary disorders are known to cause primary and secondary vitamin E deficiencies or inadequate vitamin E bioavailability [19] . Because the official intake recommedations of vitamen E are so seldom met, along with the rare occurance of deficiency symptoms (apart from being caused by disease, addressed later), Traber [18] recently questioned whether the recommended α-TOH intake is set too high and whether a diet low in dietary α-TOH intake has any biological significance. However as of now, circulating α-TOH concentrations below 9 mmol/L for men or below 12 mmol/L for women are considered as deficient and only marginal for healthy adults, respectively [18] .…”

“…Because the official intake recommedations of vitamen E are so seldom met, along with the rare occurance of deficiency symptoms (apart from being caused by disease, addressed later), Traber [18] recently questioned whether the recommended α-TOH intake is set too high and whether a diet low in dietary α-TOH intake has any biological significance. However as of now, circulating α-TOH concentrations below 9 mmol/L for men or below 12 mmol/L for women are considered as deficient and only marginal for healthy adults, respectively [18] . When supplements are used to maintain vitamin E balance, either self-medicated or by medical prescription, questions of toxicity and other safety concerns must be considered.…”

The socioeconomic variables influence in the alpha-tocopherol concentration of the maternal serum

“…24,26,27 In this study influence of socioeconomic characteristics with alpha-tocopherol serum levels and maternal vitamin E deficiency were not found (Table 2), a result similar to a cohort on pregnant women in the Peru. 3 Gurgel et al, 8 observed that women who were attended for childbirth in the private health network were more likely to have satisfactory vitamin concentrations (OR= 0.3; CI95%: 0.1-0.8).…”

“…21,24 Studies show that in low income situations there is a change in food choices, characterized by the acquisition of cheaper items and with high energy density. 7,22,23 The first items that are out of the diet are usually the healthier food, which the population cannot reach the recommended quantities, such as grains of high quality protein, vegetables and greenery, extra virgin olive oil and fresh fruit, 6,22,25 some important sources of vitamin E.…”