Whole flaxseeds but not sunflower seeds in rye bread reduce apparent digestibility of fat in healthy volunteers.

OBJECTIVE: The aim of this study was to measure the apparent digestibility of fat and the transit time upon addition of whole sunflower seeds (SU) or flaxseeds (FL) to rye breads consumed as part of a whole diet. METHOD: In a randomized crossover study, gross intake and faecal excretion of fat and energy were measured in 11 young healthy men aged 24.6+/-2.7 years. During each 7 days intervention periods, the subjects received a basal diet plus 300 g of one of four rye breads: (1) rye bread; (2) rye bread with SU; (3) rye bread with FL; (4) low extraction rate rye bread with SU and FL. Fat binding properties of rye breads (1) and (3) were determined by in vitro digestion. RESULTS: Addition of whole SU or FL to breads increased daily gross intake of fat and energy (P<0.001). The amounts of apparently digested fat (g/day) and energy were lowered when subjects consumed the SU or FL rye bread (P<0.001). The effect on energy digestibility of FL was more pronounced than that of SU. The in vitro fat digestibility of rye breads and whole diets show fat-binding properties of FL when compared to the rye bread diet (P<0.05). CONCLUSIONS: Enrichment of bread with whole FL does not appear to result in increased fat and energy intake when added to breads, but the results rather indicate an impairment of nutrient utilization.

Non-haem iron availability from pork meat: Impact of heat treatments and meat protein dose.

Pork meat heated at 60, 80, 100, and 120°C (1h), raw pork meat, BSA, casein and haemoglobin were examined for their effects on in vitro iron availability measured as Fe(2+)-dialysability, and on iron-reducing capacity following in vitro protein digestion (IVPD-dialysis). The pepsin-digested samples of meat heated at 80, 100, and 120°C resulted in increased in vitro iron availability. Generally, the capacity to reduce Fe(3+) to Fe(2+) was higher in the pepsin digests, whereas Fe(2+) decreased significantly after pepsin+pancreatin digestion and only part of the Fe(2+) was dialysable. Regardless of protein concentration, casein had no effect on in vitro iron availability, while pork meat protein treated at 120°C showed dose dependency reaching a plateau at 50mg protein/ml. In conclusion, the major effects on iron availability in vitro was shown in pepsin digests under conditions mimicking those in the duodenal lumen and heat-treatment of meat at 120°C showed the most pronounced effects.

A simplified method for determination of radioactive iron in whole-blood samples.

For studies on iron absorption in man radioisotopes represent an easy and simple tool However, measurement of the orbital electron emitting radioiron, 55Fe, in blood is difficult and insufficiently described in the literature. The present study describes a relatively simple method for simultaneous determination of 55Fe and 59Fe in blood, using a dry-ashing procedure and recrystallization of the remaining iron. The detection limit of the method permits measurements of 0.1 Bq/ml blood thus allowing detection of less than 1% absorption from a 40 kBq dose, which is ethically acceptable in humans. The overall recovery of radioiron from blood is more than 90%, and the coefficient of variation, as judged by the variation in the ratio 55Fe/59Fe is in the order of 4%. Combined with whole-body counting of 59Fe and direct gamma-counting of 59Fe on blood samples, this method represents a sensitive method for studying the intestinal absorption of 55Fe and 59Fe in man and at the same time allows estimation of the amount of radioiron located in the vascular compartment.