Victorine Imrhan

Lifestyle and Advanced Glycation End Products (AGEs) Burden: Its Relevance to Healthy Aging

Uncontrolled continued exposure to oxidative stress is a precursor to many chronic diseases including cancer, diabetes, degenerative disorders and cardiovascular diseases. Of the many known mediators of oxidative stress, reactive oxygen species (ROS) and advanced glycation end products (AGEs) are the most studied. In the present review, we have summarized current data on the origin of circulating AGEs, discussed issues associated with reliable assessment of its steady state level, and changes in its level with age and select metabolic diseases. Lastly, we have made recommendations about life style changes that may decrease AGEs burden to promote healthy aging.

Serum and liver lipids in rats fed diets containing corn oil, cottonseed oil, or a mixture of corn and cottonseed oils

Previous research has demonstrated that the total replacement of corn oil (CO) with cottonseed oil (CSO) in the diets of growing male rats results in a lowering of the total cholesterol (TC) concentration in the serum. It is not, however, known if a partial replacement of dietary CO with CSO would be sufficient to lower TC levels, nor is the effect of replacing dietary CO with CSO on other indices of cholesterol status (e.g., the levels of high-density lipoprotein cholesterol [HDL-C], non-HDL-C [i.e., very-low and low-density lipoprotein-cholesterol], or the TC/HDL-C ratio). Growing male rats were fed diets having CO, CSO, or a CO/CSO (1:1, w/w) oil mixture (OM) as the source of dietary oil (diet groups CO, CSO, and OM, respectively). There were no differences between CO and OM groups for TC, HDL-C, non-HDL-C, or the TC/HDL-C ratio. However, TC was significantly lower (p≤ 0.05)for the CSO group than the CO group (2.85 vs. 3.23 mmol/l, or 110 vs. 125 mg/dl, respectively) as was HDL-C (1.83 vs. 2.13 mmol/l, or 71 vs. 82 mg/dl, respectively), but there were no differences between these groups for non-HDL-C or the TC/HDL-C ratio. Diet had no effect on serum triglycerides (TGs) or on total liver content of either cholesterol or TGs. Thus, partial (50%) replacement of CO with CSO was without effect on any of these serum indices of cholesterol status, but total replacement resulted in lower TC and HDL-C, without affecting non-HDL-C or the TC/HDL-C ratio. Because, relative to CO, CSO has higher levels of saturated fatty acids but lower levels of monounsaturated and polyunsaturated fatty acids, the cholesterol-lowering effect of CSO appears to be unrelated to its fatty acid composition, and may be caused by a component of its nonsaponifiable fraction.

Can self-estimates of body weight and height be used in place of measurements for college students?

A study was conducted to determine how accurately college students can estimate their height and body weight. Four hundred and sixty-nine students (136 females and 333 males) completed a short questionnaire eliciting self-estimates of height and weight, frequency and recency of measuring them, age, and gender. Immediately afterwards, their height and weight were measured. Three hundred and forty-nine subjects were told that they would be measured later; the others were not told that they would be measured. Analysis of the data revealed relatively small absolute errors of estimation (1.00—3.54%); both males and females overestimated height and underestimated weight; females estimated weight less accurately and height more accurately than males; and knowing that ones estimation would be checked by measurement produced slightly more accurate estimations. Simple self-estimates of height and weight are accurate enough to be used in place of measurements.

Effect of Blueberry Polyphenols on 3T3-F442A Preadipocyte Differentiation

Today obesity is an epidemic, and its prevalence has increased significantly over the last few decades. To avoid excessive accumulation of fat, optimum energy intake along with regular exercise is mandatory. Polyphenols present in green tea, grape seeds, orange, and grapefruit combat adipogenesis at the molecular level and also induce lipolysis. However, very little is known regarding the role of blueberry polyphenols on adipocyte differentiation. Hence we tested the dose-dependent effects of blueberry polyphenols on mouse 3T3-F442A preadipocyte differentiation and lipolysis. 3T3-F442A preadipocytes were incubated with three doses of blueberry polyphenols (150, 200, and 250 μg/mL [BB-150, BB-200, and BB-250, respectively]), and intracellular lipid content, cell proliferation, and lipolysis were assayed. Blueberry polyphenols suppressed adipocyte differentiation determined by Oil Red-O staining and AdipoRed assay. Intracellular lipid content in control (11,385.51±1,169.6 relative fluorescence units) was significantly higher (P<.05) than with the three doses of blueberry polyphenols (8336.86±503.57, 4235.67±323.17, and 3027.97±346.61, respectively). This corresponds to a reduction of 27%, 63%, and 74%, respectively. Cell proliferation was observed to be significantly higher in the control (0.744±0.035 optical density units) than with BB-150 (0.517±0.031), BB-200 (0.491±0.023), and BB-250 (0.455±0.012). However, when tested for lipolysis, there was no significant difference observed among the groups. We conclude that blueberry polyphenols may play an effective role in inhibiting adipogenesis and cell proliferation.

Serum soluble receptor for advanced glycation end products correlates inversely with measures of adiposity in young adults.

Advanced glycation end products (AGEs) may promote inflammation by interacting with the receptor for advanced glycation end products. Serum soluble receptor for advanced glycation end products (sRAGE), a form of receptor for advanced glycation end products thought to mediate AGEs inflammatory properties, is decreased in diabetes mellitus and coronary artery disease. Evidence in older adults suggests that sRAGE is depressed in individuals without current disease who are obese; however, 2 studies have failed to find this correlation. We hypothesized that sRAGE would be inversely correlated with adiposity and positively correlated with inflammation, even in apparently healthy, young adults. By considering adults of body mass index (BMI) varying from normal weight to overweight and obese, we aimed to define how closely AGEs and sRAGE correlate with adiposity and other indicators of metabolic stress. Anthropometric measurements and fasting blood samples were obtained from participants (n = 69). Sera were analyzed for sRAGE, n-epsilon carboxy-methyl-lysine, a measure of AGEs, and high sensitivity C-reactive protein. High molecular weight adiponectin, glucose, insulin, total cholesterol, high-density lipoprotein, and triacylglycerol were also assessed (n = 32). Spearman rank correlations were used to evaluate the relationship among indicators of adiposity and biochemical indicators of metabolic health and inflammation. Factors inversely correlated with sRAGE include weight (Rs = -0.397; P = .001), waist circumference (-0.291; P = .015), and BMI (-0.3338; P = .004). High molecular weight adiponectin was positively correlated with sRAGE, and predictors of sRAGE included BMI and total cholesterol. This is the first time these associations have been found in a diverse population of young adults.

Measurement and validation of the nature of salivary adiponectin

Adiponectin (Ad) is an adipocyte-derived hormone that plays an essential role in regulating insulin sensitivity, inflammation, and atherogenesis. Levels of some hormones in saliva change in a fashion similar to that in plasma in response to a disease or physiological condition. Since saliva is an easy to obtain biological fluid, measurements of salivary hormonal changes are preferred in diagnoses and treatments. Therefore, it was of interest to examine the nature of salivary Ad. While there have been two publications in the literature reporting presence of Ad in human saliva, the nature of salivary Ad has not been characterized. To this end, we investigated the effect of sample dilution on the measurement of Ad in saliva. To our surprise, we observed an increase in measurable level of Ad in saliva on sample dilution. One explanation for this paradoxical observation may be the presence of inhibitor(s) of Ad/anti-Ad binding in saliva that following dilution relieves the inhibitory effect. Working with this hypothesis, we were able to demonstrate the presence of an inhibitor in saliva that co-eluted with the dimeric form of Ad and was capable of inhibiting Ad assay. The presence of such inhibitor(s) may lead to underestimation of Ad in saliva.

Sensory characteristics of high‐amylose maize‐resistant starch in three food products

Type 2 resistant starch from high-amylose maize (HAM-RS2) is considered a functional ingredient due to its positive organoleptic and physiochemical modifications associated with food and physiological benefits related to human health. The sensory characteristics of three types of food products (muffins, focaccia bread, and chicken curry) with and without HAM-RS2 were evaluated using a 9-point hedonic scale. The HAM-RS2-enriched muffins, focaccia bread, and chicken curry contained 5.50 g/100 g, 13.10 g/100 g, and 8.94 g/100 g RS, respectively, based on lyophilized dry weight. The HAM-RS2-enriched muffin had higher moisture content and was perceived as being significantly moister than the control according to the sensory evaluation. The addition of HAM-RS2 to muffins significantly enhanced all sensory characteristics and resulted in a higher mean overall likeability score. The HAM-RS2-enriched focaccia bread appeared significantly darker in color, was more dense, and had the perception of a well-done crust versus the control. A grainer texture was observed with the chicken curry containing HAM-RS2 which did not significantly affect overall likeability. We concluded that the addition of HAM-RS2 may not significantly alter consumers acceptability in most food products.

Advanced Glycation End Products, Inflammation, and Chronic Metabolic Diseases: Links in a Chain?

Advanced glycation end products (AGEs) are a diverse group of compounds produced when reducing sugars react with proteins or other compounds to form glycosylated molecules. AGEs may form endogenously, and glycation of molecules may negatively affect their function. AGEs may also be consumed in food form with dietary AGEs reported to be particularly high in foods treated with high heat: baked, broiled, grilled, and fried foods. Whether dietary AGEs are absorbed in significant quantities and whether they are harmful if absorbed is a question under current debate. The American Diabetes Association makes no recommendation regarding avoidance of these foods, but many researchers are concerned that they may be pro-inflammatory and way worsen cardiac function, kidney function, diabetes and its complications and may even contribute to obesity.

Prescribing Personalized Nutrition for Cardiovascular Health: Are We Ready?

Of all chronic metabolic diseases, cardiovascular disease (CVD) is the leading cause of death worldwide. Most research over the past 100 years show a link between CVD and lifestyle, including diet; thus, public health messages have focused on modifications of the diet to better manage this disease. Despite this effort, the CVD mortality rate continues to rise. Therefore, is it possible that this failure may be due to individual variability in response to dietary recommendations? The elucidation of the structure of the human genome combined with the knowledge that nutrients are capable of modifying gene expression and genetic variability regulates how individuals respond to a diet have led to the possibility of personalized nutrition for disease prevention. While this possibility is real for the future, our current understanding of nutrient-gene interactions for CVD is limited, making personalized nutrition therapy difficult at this time. With advances in nutritional genomics, in the near future, dietitians and nutritionists will be able to give personalized nutritional advice based on a combination of lifestyle factors and genetics.

Contribution of dietary advanced glycation end products (AGE) to circulating AGE: role of dietary fat

The purpose of this pilot study was to determine whether macronutrient content (low-fat v. high-fat diet) influences an indicator of advanced glycation end products (AGE), N(ε) carboxymethyl-lysine (CML), in the context of a 1-d, high-AGE diet. The effect of the diets on inflammatory markers was also assessed. A total of nineteen overweight and obese adults (nine men and ten women) without known disease were recruited to participate in a crossover challenge of a high-fat, high-AGE (HFHA) and low-fat, high-AGE (LFHA) diet. In each phase patients had fasting blood drawn, followed by consumption of a high-fat or low-fat breakfast test meal, then three postprandial blood draws at 1, 2 and 3 h after consuming the test meal. After consuming high-AGE meals for the remainder of the day, participants returned the next day for a follow-up analysis. A different pattern in the 3-h post-meal CML and soluble receptor for AGE response to the two diets was observed (P=0·01 and 0·05, respectively). No change in serum CML was observed following consumption of a LFHA breakfast (535 (25th-75th percentile 451-790) to 495 (25th-75th percentile 391-682) ng/ml; P=0·36), whereas a rise in CML occurred after the HFHA breakfast (463 (25th-75th percentile 428-664) to 578 (25th-75th percentile 474-865) ng/ml; P=0·05). High sensitivity C-reactive protein and high molecular weight adiponectin were not affected by either diet. These findings suggest that dietary CML may not be as important in influencing serum CML as other dietary factors. In addition, acute exposure to dietary CML may not influence inflammation in adults without diabetes or kidney disease. This is contrary to previous findings.