This study evaluated the effects of 2 levels of intake of high-amylose maize type 2 resistant starch (HAM-RS2) on insulin sensitivity (SI) in participants with waist circumference ≥89 (women) or ≥102 cm (men). Participants received 0 (control starch), 15, or 30 g/d (double-blind) of HAM-RS2 in random order for 4-wk periods separated by 3-wk washouts. Minimal model SI was assessed at the end of each period using the insulin-modified i.v. glucose tolerance test. The efficacy evaluable sample included 11 men and 22 women (mean ± SEM) age 49.5 ± 1.6 y, with a BMI of 30.6 ± 0.5 kg/m2 and waist circumference 105.3 ± 1.3 cm. A treatment main effect (P = 0.018) and a treatment × sex interaction (P = 0.033) were present. In men, least squares geometric mean analysis for SI did not differ after intake of 15 g/d HAM-RS2 (6.90 × 10−5 pmol−1 · L−1 × min−1) and 30 g/d HAM-RS2 (7.13 × 10−5 pmol−1 · L−1 × min−1), but both were higher than after the control treatment (4.66 × 10−5 pmol−1 · L−1 × min−1) (P < 0.05). In women, there was no difference among the treatments (overall least squares ln-transformed mean ± pooled SEM = 1.80 ± 0.08; geometric mean = 6.05 × 10−5 pmol−1 · L−1 × min−1). These results suggest that consumption of 15–30 g/d of HAM-RS2 improves SI in men. Additional research is needed to understand the mechanisms that might account for the treatment × sex interaction observed.

The in vitro estimates of starch digestibility by the Englyst method predicted the effects of starch composition on blood glucose concentrations and FI in young men 30 and 120 min after consumption. This trial was registered at clinicaltrials.gov as NCT00980941 for experiment 1 and NCT00988689 for experiment 2.

The toxicological significance of oxidized cholesterol has been well documented in numerous studies. This review focuses on the analysis of dietary sterol oxides in the foodstuffs examined to date with particular emphasis on isolation and characterization techniques. Eight common oxidation products of cholesterol have been identified in certain cholesterol-rich foods subjected to oxidative stress during food processing and/or storage. These products include 25-hydroxycholesterol, α or β 5,6-epoxycholesterol, α or β 7-hydroxycholesterol, 7-ketocholesterol, cholesta-3,5-dien-7-one and cholestane-3β, 5α, 6β-triol. A limited number of studies on the biological effects of dietary phytosterol oxides indicate these products may also be of nutritional concern. Four common autoxidation products of β-sitosterol have been identified in edible oils; these include α or β 7-hydroxysitosterol, 7-ketositosterol and setosta-3,5-dien-7-one. Few quantitative data are available on the sterol oxide content of foods. Moreover, studies without apparent precautions against the artifactual formation of sterol oxides may be flawed. Additional research is necessary to adequately identify and quantify the sterol oxides which most likely exist in certain foods.

Butteroil samples bleached with benzoyl peroxide (BP) and 17 commercial cheeses were screened for oxidized sterols by thin layer chromatography (TLC). Ungrated cheeses made from bleached milk and freshly bleached butteroil contained no detectable oxidized sterols. Oxidized sterols were detected in stored, bleached butteroils and in grated cheeses. Four major oxidation products were the isomeric 5,6‐epoxycholesterols and the epimeric 7‐hydroxycholesterols identified by TLC, high performance liquid chromatography (HPLC) and mass spectrometry (MS). Additional sterol oxides (tentatively identified and not quantified) present in these samples included low levels of 7‐ketocholesterol and cholesta‐3,5‐dien‐7‐one. The epimeric 7‐hydroxycholesterols were detected in bleached butteroils stored in air (BP‐A) and nitrogen (BP‐N) for 22 days at 15 C. Butteroil, after 90 days of storage at 15 C, had 30 (BP‐N) and 60 (BP‐A) µg total oxides/g of bleached oil and, after 1‐year at −20 C, had 70 (BP‐N) and 180 (BP‐A) µg/g butteroil. A grated, unbleached cheese packaged in clear glass contained the most oxidized sterols (44 µg/g). Sterol oxides were not detected in bleached cream using a simulated industrial process.