Plastochromanol-8 and tocopherols are natural antioxidants with vitamin E activity that protect seeds and plants from oxidative damage. Whereas α-tocopherol is predominant in photosynthetic tissues, γ-tocopherol is more abundant in seeds. Ethiopian mustard (Brassica carinata A. Braun) seeds contain varying levels of both tocopherol forms. The objective of this research was to study changes in plastochromanol-8 and tocopherol contents during seed germination in Ethiopian mustard lines with contrasting seed tocopherol levels, and to evaluate their influence on seed germination and seedling growth. Cotyledons and radicles of seven lines with contrasting seed tocopherol levels and a control line were sampled periodically until 120 h after sowing (HAS) under light and dark conditions, and were analysed for plastochromanol-8 and tocopherol contents. The main factors genotype, tissue, light and HAS were significant for all the traits, excepting the light effect for total tocopherol content. Most of the lines showed a gradual decrease in γ-tocopherol that was nearly completely replaced by α-tocopherol at 120 HAS. However, line BCT-4, with high γ-tocopherol content in seeds, exhibited unusually high γ-tocopherol content in cotyledons and radicles during the whole sampling period. Light treatment and initial seed tocopherol levels had no influence on germination percentage. Despite significant differences for seedling development among genotypes, no clear association between seedling development and seed tocopherols was observed. The results revealed that the unusual presence of high γ-tocopherol levels in cotyledons and radicles of line BCT-4 did not have an effect on seedling growth.

Relationships between vitamin E status (α and γ-tocopherol and their ratio in plasma), anthropometric and biochemical indices, and food and nutrient intakes, were studied in four British National Diet and Nutrition Surveys: children aged 1·5–4·5 years, young people aged 4·0–18·0 years, adults 19·0–64·0 years and adults aged ≥65·0 years. γ-Tocopherol:α-tocopherol ratio declined with age. In older women γ-tocopherol and γ-tocopherol:α-tocopherol ratios were directly related to indices of obesity. In young men α- and γ-tocopherols were directly correlated with obesity, but γ-tocopherol:α-tocopherol ratio was not. For young people and toddlers, fewer obesity indices were available and relationships were weaker. Other fat- and water-soluble vitamin indices correlated directly with α-tocopherol and inversely with γ-tocopherol and γ-tocopherol:α-tocopherol ratio. Whereas α-tocopherol correlated directly with ‘healthy’ nutrient choices (such as intrinsic sugars, dietary fibre, vitamins and potassium) and inversely with ‘unhealthy’ choices (extrinsic sugars and monounsaturated fats, i.e. avoidance of polyunsaturated fat), γ-tocopherol and the γ-tocopherol:α-tocopherol ratio related inversely with ‘healthy’ choices. Food groups had analogous relationships; thus, α-tocopherol related directly to use of polyunsaturated fats, fresh fruits and fruit juices, and inversely to non-polyunsaturated fats and extrinsic sugar. The reverse was true for γ-tocopherol and γ-tocopherol:α-tocopherol ratio. Although the mechanisms underlying these relationships are obscure, the γ-tocopherol:α-tocopherol ratio may reveal poor dietary choices, status predictors and a propensity for obesity in later life, especially in women.

In the context of the Greek segment of the European Prospective Investigation into Cancer and Nutrition (EPIC) we have conducted a cross-sectional study to determine the effect of demographic, lifestyle and nutritional factors of plant origin on retinol, α-tocopherol and γ-tocopherol. Study subjects were a random sample of forty-five men and sixty-eight women, aged 30–82 years, from the Greek EPIC cohort of 27953 volunteers. Analyses were done using linear regression models with the vitamin blood levels as dependent variables, and BMI, the intake of selected food items, total energy intake and a set of demographic factors as independent variables. Women had significantly lower plasma retinol levels (P<0·006) than men. Both α- and γ-tocopherol levels increased by approximately 5 % for every additional 5 years of age. Among dietary factors, intake of non-fruity vegetables was associated with increase, while intake of added lipids other than olive oil with decrease, of plasma retinol levels. BMI was positively associated with plasma γ-tocopherol only, while none of the foods or food groups investigated significantly affected the plasma levels of either of the two tocopherols. These findings need to be confirmed before attempts are made to use them in the context of explanatory mechanistic processes.