To identify dietary phenolic compounds capable of improving vitamin E status, male Sprague-Dawley rats were fed for 4 weeks either a basal diet (control) with 2 g/kg cholesterol and an adequate content of vitamin E or the basal diet fortified with quercetin (Q), (2)-epicatechin (EC), or (1)-catechin (C) at concentrations of 2 g/kg. All three catechol derivatives substantially increased concentrations of a-tocopherol (a-T) in blood plasma and liver. To study potential mechanisms underlying the observed increase of a-T, the capacities of the flavonoids to i ) protect a-T from oxidation in LDL exposed to peroxyl radicals, ii ) reduce a-tocopheroxyl radicals (a-T˙) in SDS micelles, and iii ) inhibit the metabolism of tocopherols in HepG2 cells were determined. All flavonoids protected a-T from oxidation in human LDL ex vivo and dose-dependently reduced the concentrations of a-T˙. None of the test compounds affected vitamin E metabolism in the hepatocyte cultures. In conclusion, fortification of the diet of Sprague-Dawley rats with Q, EC, or C considerably improved their vitamin E status. The underlying mechanism does not appear to involve vitamin E metabolism but may involve direct quenching of free radicals or reduction of the a-T˙by the

Our results suggest that some components of milk protein may promote bone mineralization. Further studies are needed to elucidate this phenomenon.

We previously reported that high intake of milk, but not meat, equal in protein content, increased serum insulin-like growth factor-I (sIGF-I) in prepubertal boys. sIGF-I plays a key role in bone metabolism. Therefore, the aim of this cross-sectional study was to investigate associations of total, dairy, and meat protein intake with markers for bone turnover and sIGF-I in prepubertal, healthy boys (n = 81). We measured bone turnover (enzyme-linked immunoassay) in serum osteocalcin (sOC), bone-specific alkaline phosphatase (sBAP), and C-terminal telopeptide of collagen type-I (sCTX); dietary intake was estimated from a 3-d weighed food record. sIGF-I and its binding protein-3 were assessed (immunoassay) in a subgroup of 56 boys. All statistical models included effects of age, BMI, and energy intake. Dairy protein was negatively associated with sOC (P = 0.05) but not significantly associated with sBAP and sCTX. Further analyses showed that dairy protein decreased (P = 0.05) sOC at a high meat protein intake (>0.8 g/kg), whereas meat protein increased (P = 0.03) sOC at a low dairy protein intake (<0.4 g/kg). Total and meat protein intake was positively associated with sBAP (P < or = 0.04) but not significantly associated with sOC and sCTX. Free sIGF-I was positively associated with total (P < 0.01) and dairy (P = 0.06) protein but not with meat protein. Our results indicate that dairy and meat protein may exhibit a distinct regulatory effect on different markers for bone turnover. Future studies should focus on differential effects of dairy and meat protein on bone health during growth.

Secoisolariciresinol diglucoside (SDG) is an important dietary lignan that is found at very high levels in flaxseed (1-4 %, w/w). Flaxseed lignans have received much research interest in recent years because of reported phyto-oestrogenic, anticarcinogenic, and anti-atherogenic effects. Previously, flaxseed feeding has been shown to decrease vitamin E concentrations in rats despite the antioxidant potential of SDG in vitro. Sesamin, a sesame lignan, on the other hand has been shown to increase vitamin E concentrations in rats. The aim of the present study was to investigate the effect of dietary SDG and its oligomers on vitamin E and cholesterol concentrations in rats. SDG was extracted from defatted flaxseed flour with a dioxane -ethanol mixture and purified by silica column chromatography. The major oligomers with 3-hydroxy-3-methyl glutaric acid, containing a high ratio of SDG to p-coumaric and ferulic acid glucosides, were purified from the extracts by reversed-phase liquid chromatography. When fed to rats at 0·1 % in the diet for 27 d, both SDG and its oligomers had no effect on animal performance but caused an increase in liver cholesterol and a 2-fold reduction in the levels of a-and g-tocopherols in rat plasma and liver. It is notable that a phenolic antioxidant, such as SDG, causes a vitamin E-lowering effect in rats. This cannot be explained at present, but warrants further investigations with respect to the magnitude, mechanism, and significance of the observed effect for human nutrition.

Objective: To compare the short-term effect of a high milk and a high meat intake, identical in protein amount, on bone turnover during prepuberty. Setting: A University Department. Design and Subjects: From 28, randomly recruited, 8-year-old boys, first 14 were assigned to the milk group and next 14 to the meat group. In each group, 12 boys finished the dietary intervention. Intervention: Milk (1.5 l/day) and meat (250 g/d), both containing B53 g of protein, were given together with the habitual diet for 7 days. At baseline and dayÀ7, serum osteocalcin (s-OC), bone-specific alkaline phosphatase (s-BAP) and C-terminal telopeptides of type I collagen (s-CTX) were measured (immunoassay) and dietary intake was estimated (a 3-day weighted food record). Results: Baseline s-OC, s-BAP and s-CTX were not significantly different between the groups. After 7 days, the average protein intake increased in both groups by 47.5 g; the milk group had higher (Po0.0001) calcium intake; s-OC and s-CTX decreased (Pp0.04) in the milk group (À30.9%; À18.7%, respectively) compared with the meat group ( þ 6.4%; À1.0%, respectively) and s-BAP decreased (P ¼ 0.06) both in the milk (À3.9%) and the meat group (À7.5%). Conclusions: At the equal protein intake, milk, but not meat, decreased bone turnover in prepubertal boys after 7 days. This effect was probably due to some milk-derived compounds, rather than to the total protein intake. Future studies should elucidate the mechanism(s) of milk-related decline of bone turnover and its relevance for peak bone mass during growth. Sponsorship: University PhD scholarships.