Evaluation of an FFQ to assess total energy and nutrient intakes in severely obese pregnant women.

OBJECTIVE: FFQ are popular instruments for assessing dietary intakes in epidemiological studies but have not been validated for use in severely obese pregnancy. The aim of the present study was to compare nutrient intakes assessed by an FFQ with those obtained from a food diary among severely obese pregnant women. DESIGN: Comparison of an FFQ containing 170 food items and a food diary for 4 d (three weekdays and one weekend day); absolute agreement was assessed using the paired t test and relative agreement by Pearson/Spearman correlation, crossclassification into tertiles and weighted kappa values. SETTING: Antenatal metabolic clinic for severely obese women. SUBJECTS: Thirty-one severely obese (BMI at booking ≥ 40.0 kg/m2) and thirty-two lean control (BMI520.0­24.9 kg/m2) pregnant women. RESULTS: The findings showed that nutrient intakes estimated by the FFQ were significantly higher than those from the food diary; average correlation was 0.32 in obese and 0.43 in lean women. A mean of 48.5% of obese and 47.3% of lean women were correctly classified, while 12.9% (obese) and 10.0% (lean) were grossly misclassified. Weighted k values ranged from 20.04 to 0.79 in obese women and from 0.16 to 0.78 in lean women. CONCLUSIONS: Overall, the relative agreement between the FFQ and food diary was lower in the obese group than in the lean group, but was comparable with earlier studies conducted in pregnant women. The validity assessments suggest that the FFQ is a useful tool for ranking severely obese pregnant women according to the levels of their dietary intake.

Health Behaviours during Pregnancy in Women with Very Severe Obesity.

The health behaviours of pregnant women with very severe obesity are not known, though these women are at high risk of pregnancy complications. We carried out a prospective case-control study including 148 very severely obese (BMI >40 kg/m²) and 93 lean (BMI <25 kg/m²) pregnant women. Diet, physical activity, smoking, alcohol and folic acid consumption were assessed by questionnaire in early and late (16 and 28 weeks gestation) pregnancy. Circulating levels of iron, vitamin B12 and folate and other essential trace elements and minerals were measured in a subset at each time point. The findings biochemically confirmed that very severely obese women consumed diets that were energy-rich but poor in essential micronutrients. A third of all women met physical activity recommendations for pregnancy. A third of very severely obese women and two thirds of lean women took folic acid supplements prior to pregnancy. Very severely obese women were more likely to smoke but less likely to drink alcohol than lean women (all p < 0.05). Women with very severe obesity have low self-reported intakes and circulating levels of essential micronutrients in pregnancy and few follow current recommendations for pregnancy nutrition and lifestyle. These high-risk women represent a group to target for education about health behaviours prior to and during pregnancy.

The postprandial rise in plasma cortisol in men is mediated by macronutrient-specific stimulation of adrenal and extra-adrenal cortisol production.

CONTEXT: Circadian variation is a fundamental characteristic of plasma glucocorticoids, with a postprandial rise in cortisol an important feature. The diurnal rhythm is presumed to reflect alterations in hypothalamic-pituitary-adrenal axis activity; however, cortisol is produced not only by the adrenal glands but also by regeneration from cortisone by the enzyme 11ß-hydroxysteroid dehydrogenase type 1, mainly in liver and adipose tissue. OBJECTIVE: We tested the contribution of peripheral cortisol regeneration to macronutrient-induced circadian variation of plasma cortisol in humans. DESIGN: This was a randomized, single-blinded, crossover study. SETTING: The study was conducted at a hospital research facility. PARTICIPANTS: Eight normal-weight healthy men participated in the study. INTERVENTIONS: Subjects were given isocaloric energy isodense flavor-matched liquid meals composed of carbohydrate, protein, fat, or low-calorie placebo during infusion of the stable isotope tracer 9,11,12,12-[2H]4-cortisol. OUTCOME MEASURES AND RESULTS: Plasma cortisol increased similarly after all macronutrient meals (by ∼90 nmol/L) compared with placebo. Carbohydrate stimulated adrenal secretion and extra-adrenal regeneration of cortisol to a similar degree. Protein and fat meals stimulated adrenal cortisol secretion to a greater degree than extra-adrenal cortisol regeneration. The increase in cortisol production by 11ß-hydroxysteroid dehydrogenase type 1 was in proportion to the increase in insulin. The postprandial cortisol rise was not accounted for by decreased cortisol clearance. CONCLUSIONS: Food-induced circadian variation in plasma cortisol is mediated by adrenal secretion and extra-adrenal regeneration of cortisol. Given that the latter has the more potent effect on tissue cortisol concentrations and that effects on adrenal and extra-adrenal cortisol production are macronutrient specific, this novel mechanism may contribute to the physiological interplay between insulin and glucocorticoids and the contrasting effects of certain diets on postprandial metabolism.