Age and gender specific cut-off points for body fat parameters among adults in Qatar

Background

Excessive body fat is the leading cause of many metabolic disorders. Therefore, assessing levels of body fat associated with risk of disease in specific populations is crucial. The present study aimed to identify optimal cut-off values of body fat composition including total body fat, body fat percentage, visceral fat, and trunk fat, in order to predict metabolic risk in the Qatari population.

Methods

This cross-sectional study was based on Qatar Biobank data of 2407 Qatari adults (1269 male and 1138 female) aged 21–70 years old. Individuals’ height, weight and body fat percentage were obtained. Blood test data including lipid profile, blood glucose and HbA1c data were also obtained. The area under the curve was calculated using ROC analysis to obtain the body fat percentage associated with risk of disease.

Results

The cut-off points for total fat for those aged < 40 were 34.0 kg, and for those aged ≥40 were 30.7 kg and 35.6 kg in men and women, respectively. The cut-off for body fat percent for those aged < 40 were 35.1 and 45.1%, and for those aged ≥40 were 34.8 and 46.3% in men and women, respectively. The cut-off points for trunk fat percent for those aged < 40 were 19.5 and 22.4%, and for those aged ≥40 were 21.6 and 23.4% in men and women, respectively. The cut-off points for visceral fat percent for those aged < 40 were 1.4 and 1.0%, and for those aged ≥40 were 1.9 and 1.4% in men and women, respectively.

Conclusion

This study established Qatari adult-specific cut-off values of body fat for different age and gender groups.

Cholestyramine protection against ochratoxin A toxicity: role of ochratoxin A sorption by the resin and bile acid enterohepatic circulation

We have shown that the addition of cholestyramine (CHA, a resin known to bind bile salts in the gastrointestinal tract) to ochratoxin A (OTA)-contaminated rat diets reduced plasma levels of the toxin and prevented OTA-induced nephrotoxicity. To elucidate the mechanism of action of CHA, we carried out in vitro experiments to determine whether the resin may bind the toxin. For comparative purposes, binding of bile salts to the resin was also examined. Results showed that CHA binds both OTA and bile salts (taurodeoxycholate [TDC] and taurocholate [TCA]). Also, CHA showed greater affinity for OTA and TDC than for TCA. At 1 mM concentration, 96% of OTA and 80% of TDC were bound to the resin, while for TCA binding was only 50%. However, saturation of the resin was reached at higher levels with bile acids compared to OTA (3.67 mmol/g resin for TCA and 3.71 mmol/g resin for TDC versus 2.85 mmol/g resin for OTA). To characterize the nature of the binding of the toxin to CHA, NaCl (0 to 200 mM) was added to a fixed amount of OTA or bile acids. As expected, TCA absorption was decreased by the addition of NaCl (<50 mM), indicating electrostatic binding. However, OTA and TDC sorption was decreased only at high concentrations of NaCl (>150 mM), suggesting a stronger binding to the resin than that shown with TCA. Sequential competitive studies demonstrated that CHA binds more OTA than TCA. The results of the in vivo study show the role of bile salts in OTA absorption. The toxin's plasma levels at 1 and 3 h after a single oral dose of OTA were significantly decreased in bile salt-depleted rats compared to the control. Thus, the alteration of the bile salt biliary pool and OTA enterohepatic circulation may be an additional mechanism of action of the resin against mycotoxin toxicity.

Dietary cholestyramine reduces ochratoxin A-induced nephrotoxicity in the rat by decreasing plasma levels and enhancing fecal excretion of the toxin

Ochratoxin A (OTA) is a mycotoxin that may contaminate animal feed (oat, barley, and rye) and food (wheat, rice, coffee, beer, pig meat), leading to major health problems (e.g., nephropathy) in several animal species including humans. Several methods have been tested to reduce the toxicity of OTA in animals but with limited success. In rats, the effect of cholestyramine (CHA), a bile acid-binding resin, was investigated on OTA-induced nephrotoxicity and bioavailability. Animals were fed semisynthetic diets containing two levels of OTA: 1 or 3 ppm. At each level of OTA, the diets were enriched with 0.1, 1, and 5% of CHA. The results showed that CHA decreased the concentration of OTA in plasma. At 1 and 3 ppm of OTA in the diet, CHA is effective at a level of 0.1% and 5%, respectively. The excretion of OTA and its metabolites (ochratoxin alpha and hydroxylated ochratoxin A) in bile and urine was also decreased by addition of 5% CHA in the diet. This was associated with an increase of OTA excretion in feces. Enzymuria and renal morphology revealed that dietary CHA can decrease OTA-induced nephrotoxicity, probably by reducing renal exposure to the toxin. In conclusion, CHA can reduce OTA concentrations in plasma as well as reducing nephrotoxicity, which may be attributed to a decrease of bioavailability and/or enterohepatic circulation of the toxin.