Metabolic responses to albumin deficiency differ distinctly between partial and full ablation of albumin expression in mice.

It had been observed that homozygous albumin knockout mice (Alb-/-) exhibit low plasma free fatty acid (FFA) concentration and improved blood glucose regulation. However, it was not yet known to what extent heterozygous albumin knockout (Alb+/-) mice would display a similar phenotype. Alb-/-, Alb+/-, and wild-type (WT) female mice were studied on a low-fat diet (LFD) or high-fat diet (HFD). On both diets, decreased plasma FFA concentration, and improved glucose tolerance test were observed in Alb-/-, but not in Alb+/-, compared to WT. Plasma adiponectin concentration showed greater elevation in Alb-/- than Alb+/-. Consistent with that, adiponectin gene expression was significantly higher in Alb-/- mice than in Alb+/- and WT mice. A dose-dependent response was observed for hepatic Acadl gene expression showing higher Acadl gene expression in Alb-/- mice than in Alb+/- and WT mice. In conclusion, although female Alb+/- mice exhibited some slight differences from WT mice (e.g., increased plasma adiponectin and hepatic Acadl gene expression), Alb+/- mice did not exhibit improved glucoregulation in comparison to WT mice, indicating that a minor suppression of albumin expression is not sufficient to improve glucoregulation. Furthermore, it is now clear that although the response of female mice to HFD might be unique from how males generally respond, still the complete albumin deficiency in Alb-/- mice and the associated FFA reduction is capable of improving glucoregulation in females on this diet. The present results have implications for the role of albumin and FFA in the regulation of metabolism.

Performance evaluation of different albumin assays for the detection of analbuminemia.

Analbuminemia is characterized by the near absence of albumin in the plasma. Different methods are available for measuring albumin levels, but they do not necessarily agree with one another. It is a concern that analbuminemic samples could be falsely characterized due to the incorrect estimation of albumin. The objective of the work was to evaluate the performance of different assays in detecting analbuminemia. Albumin knockout (Alb-/-) mouse plasma was used to test the suitability of different albumin assays for their ability to properly characterize extreme albumin deficiency. Bromocresol green (BCG), bromocresol purple (BCP), enzyme-linked immunosorbent assay (ELISA), liquid chromatography-tandem mass spectrometry (LC-MS/MS), and gel electrophoresis were tested. The LC-MS/MS assay exhibited broad coverage of the amino acid sequence of albumin and indicated 8,400-fold lower (P<0.0001) albumin expression in Alb-/- than wildtype (WT), demonstrating its suitability for identifying extreme albumin deficiency. ELISA estimated albumin at 1.5±0.1 g/dL in WT and was below the detection limit in all Alb-/- samples. Gel electrophoresis yielded consistent results with LC-MS/MS and ELISA. The BCG assay overestimated albumin with apparently appreciable albumin concentrations in Alb-/- mice, yet the assay still indicated a significant difference between genotypes (Alb-/-, 1.2±0.05 g/dL, WT, 3.7±0.1 g/dL, P<0.0001). BCP drastically overestimated albumin and could not successfully identify the known analbuminemic phenotype of Alb-/- mice. By using Alb-/- plasma as a reference material and LC-MS/MS as a reference method, ELISA and gel electrophoresis appear appropriate for identifying analbuminemia, while BCG and BCP are not suitable. It is concluded that dye-binding assays should be avoided when extreme hypoalbuminemia or analbuminemia is suspected.

Albumin Deficiency Reduces Hepatic Steatosis and Improves Glucose Metabolism in a Mouse Model of Diet-Induced Obesity.

Serum albumin facilitates the transport of free fatty acids (FFAs) from adipose tissue to other organs. It was not known if impeding this process could protect from hepatic steatosis and metabolic dysfunction in obesity. We tested whether albumin knockout (Alb-/-) mice would exhibit a reduction in plasma FFA concentration, reduced hepatic lipid accumulation, and improved glucoregulation as compared to wild-type (WT) mice. Male homozygous albumin knockout mice (Alb-/-) and WT controls were fed a low-fat diet (LFD) or high-fat diet (HFD). Alb-/- mice exhibited a similar body weight gain and body composition as WT on both diets. Despite HFD-induced obesity, Alb-/- mice were protected from various comorbidities. Compared to WT mice on the HFD, Alb-/- exhibited lower plasma FFA levels, lower blood glucose levels during glucose tolerance and insulin tolerance tests, and lower hepatic steatosis and inflammation. Alb-/- mice on HFD also exhibited elevated expression of multiple genes in the liver and adipose tissues, such as peroxisome proliferator-activated receptor α in both tissues, as well as glucose transporter-4 and adiponectin in adipose tissues. The results indicate that albumin's FFA transport function may be involved in the development of hepatic lipid accumulation and dysregulated glucose metabolism in obesity.

Ultraprocessed Foods and Obesity Risk: A Critical Review of Reported Mechanisms.

Epidemiologic evidence supports a positive association between ultraprocessed food (UPF) consumption and body mass index. This has led to recommendations to avoid UPFs despite very limited evidence establishing causality. Many mechanisms have been proposed, and this review critically aimed to evaluate selected possibilities for specificity, clarity, and consistency related to food choice (i.e., low cost, shelf-life, food packaging, hyperpalatability, and stimulation of hunger/suppression of fullness); food composition (i.e., macronutrients, food texture, added sugar, fat and salt, energy density, low-calorie sweeteners, and additives); and digestive processes (i.e., oral processing/eating rate, gastric emptying time, gastrointestinal transit time, and microbiome). For some purported mechanisms (e.g., fiber content, texture, gastric emptying, and intestinal transit time), data directly contrasting the effects of UPF and non-UPF intake on the indices of appetite, food intake, and adiposity are available and do not support a unique contribution of UPFs. In other instances, data are not available (e.g., microbiome and food additives) or are insufficient (e.g., packaging, food cost, shelf-life, macronutrient intake, and appetite stimulation) to judge the benefits versus the risks of UPF avoidance. There are yet other evoked mechanisms in which the preponderance of evidence indicates ingredients in UPFs actually moderate body weight (e.g., low-calorie sweetener use for weight management; beverage consumption as it dilutes energy density; and higher fat content because it reduces glycemic responses). Because avoidance of UPFs holds potential adverse effects (e.g., reduced diet quality, increased risk of food poisoning, and food wastage), it is imprudent to make recommendations regarding their role in diets before causality and plausible mechanisms have been verified.

Alterations in the Plasma Protein Expression Pattern in Congenital Analbuminemia-A Systematic Review.

Albumin is a highly abundant plasma protein with multiple functions, including the balance of fluid between body compartments and fatty acid trafficking. Humans with congenital analbuminemia (CAA) do not express albumin due to homozygosity for albumin gene mutation. Lessons about physiological control could be learned from CAA. Remarkably, these patients exhibit an apparently normal lifespan, without substantial impairments in physical functionality. There was speculation that tolerance to albumin deficiency would be characterized by significant upregulation of other plasma proteins to compensate for analbuminemia. It is unknown but possible that changes in plasma protein expression observed in CAA are required for the well-documented survival and general wellness. A systematic review of published case reports was performed to assess plasma protein pattern remodeling in CAA patients who were free of other illnesses that would confound interpretation. From a literature search in Pubmed, Scopus, and Purdue Libraries (updated October 2022), concentration of individual plasma proteins and protein classes were assessed. Total plasma protein concentration was below the reference range in the vast majority of CAA patients in the analysis, as upregulation of other proteins was not sufficient to prevent the decline of total plasma protein when albumin was absent. Nonetheless, an impressive level of evidence in the literature indicated upregulated plasma levels of multiple globulin classes and various specific proteins which may have metabolic functions in common with albumin. The potential role of this altered plasma protein expression pattern in CAA is discussed, and the findings may have implications for other populations with hypoalbuminemia.

Albumin knockout mice exhibit reduced plasma free fatty acid concentration and enhanced insulin sensitivity.

Circulating albumin is expected to play a significant role in the trafficking of plasma free fatty acids (FFA) between tissues, such as FFA transfer from adipose tissue to the liver. However, it was not yet known how disrupting FFA binding to albumin in circulation would alter lipid metabolism and any resulting impacts upon control of glycemia. To improve understanding of metabolic control, we aimed to determine whether lack of serum albumin would decrease plasma FFA, hepatic lipid storage, whole body substrate oxidation, and glucose metabolism. Male and female homozygous albumin knockout mice and C57BL/6J wild type controls, each on a standard diet containing a moderate fat content, were studied at 6-8 weeks of age. Indirect calorimetry, glucose tolerance testing, insulin tolerance testing, exercise performance, plasma proteome, and tissue analyses were performed. In both sexes of albumin knockout mice compared to the wild type mice, significant reductions (p < 0.05) were observed for plasma FFA concentration, hepatic triacylglycerol and diacylglycerol content, blood glucose during the glucose tolerance test, and blood glucose during the insulin tolerance test. Albumin deficiency did not reduce whole body fat oxidation over a 24-h period and did not alter exercise performance in an incremental treadmill test. The system-level phenotypic changes in lipid and glucose metabolism were accompanied by reduced hepatic perilipin-2 expression (p < 0.05), as well as increased expression of adiponectin (p < 0.05) and glucose transporter-4 (p < 0.05) in adipose tissue. The results indicate an important role of albumin and plasma FFA concentration in lipid metabolism and glucoregulation.

The association between deficiency of nutrient intake and resting metabolic rate in overweight and obese women: a cross-sectional study.

OBJECTIVE: The double burden of malnutrition is an emerging public health concern nowadays which a correlation with obesity. This study aimed to examine the relationship between resting metabolic rate (RMR) and dietary intake of zinc, vitamin C, and riboflavin in overweight and obese women. RESULTS: The RMR/FFM showed a significant association with riboflavin (ß = 1.59; 95% CI 1.04-23.26, P = 0.04) and zinc (ß = 0.78; 95% CI 1.04-4.61, P = 0.03) in the crude model. Moreover, differences in vitamin C and RMR/FFM was marginal significant (ß = 0.75; 95% CI 0.95-4.77, P = 0.06). After adjusting for confounders the riboflavin association change to marginal significance (ß = 1.52; 95% CI 0.91-23.04, P = 0.06). After controlling for potential confounders, the associations change between zinc and RMR/FFM (ß = 0.66; 95% CI 0.78-4.86, P = 0.15) and between RMR/FFM and vitamin C (ß = 0.48; 95% CI 0.66-3.96, P = 0.28). Our study showed a significant association between dietary intake of zinc, riboflavin, and vitamin C and change in RMR/FFM in overweight and obese women.

Artificial sweeteners are related to non-alcoholic fatty liver disease: Microbiota dysbiosis as a novel potential mechanism.

Non-alcoholic fatty liver disease (NAFLD) is a systemic and wide-spread disease characterized by accumulation of excess fat in the liver of people who drink little or no alcohol. Artificial sweeteners (ASs) or sugar substitutes are food additives that provide a sweet taste, and are also known as low-calorie or non-calorie sweeteners. Recently people consume increasingly more ASs to reduce their calorie intake. Gut microbiome is a complex ecosystem where 1014 microorganisms play several roles in host nutrition, bone mineralization, immune system regulation, xenobiotics metabolism, proliferation of intestinal cells, and protection against pathogens. A disruption in composition of the normal microbiota is known as 'gut dysbiosis' which may adversely affect body metabolism. It has recently been suggested that dysbiosis may contribute to the occurrence of NAFLD. The aim of the present study was to investigate the effects of ASs on the risk of NAFLD. The focus of this review is on microbiota changes and dysbiosis. Increasing evidence shows that ASs have a potential role in microbiota alteration and dysbiosis. We speculate that increased consumption of ASs can further raise the prevalence of NAFLD. However, further human studies are needed to determine this relationship definitively.

The association between total antioxidant capacity and resting metabolic rate (RMR) / respiratory quotient (RQ) in overweight and obese woman.

OBJECTIVE: The effect of total antioxidant capacity on resting metabolic rate (RMR) and respiratory quotient (RQ) of overweight and obese woman has been debated globally. Total Antioxidant Capacity may have an independent effect on resting metabolic rate and respiratory quotient. METHODS AND MATERIALS: A study population of 263 aged 18-50 years participated in this cross-sectional study from the communities of Tehran based on cluster sampling. Dietary intake assessed by using a semi quantitative food frequency questionnaire (FFQ) Demographic questions. Anthropometrics measurements for each participant were done. Dietary total antioxidant capacity (DTAC) was calculated by the 147-item food frequency questionnaire (FFQ) and FRAP assay. Resting metabolic rate and respiratory quotient was measured by Indirect calorimetry. RESULTS: The mean DTAC of the study participants was 1251.8 (SD 893.60). There was a statistically significant relationship between dietary total antioxidant capacity (DTAC) and respiratory quotient (P > 0.013). People with high dietary total antioxidant capacity have tended to show a lower RQ than those with a lower one. There was a significant correlation between DTAC and RQ for both the adjusted model for age, total energy intake, BMI, physical activity, higher DTAC diet and the crude model which were (ß = 0.011; SE = 0.005; CI = -0.021_0) and (ß = -3.143E-6; SE = 0; CI = 0), respectively. However, we found no correlation between the DTAC and RMR/FFM-RES (P < 0.49). Also, a significantly higher relationship was demonstrated between dietary total antioxidant capacity and intake vegetables (P ≤ 0.006), fruits (P ≤ 0.009), white meet (P ≤ 0.03) and dairy products (P ≤ 0.005). CONCLUSION: RQ is correlated with total antioxidant capacity. Increased intake of high DTAC foods may result in weight loss maintenance. This result may suggest a beneficial role of higher-DTAC diets in the prevention of obesity.

Relationship between major dietary patterns and sarcopenia among menopausal women.

BACKGROUND AND AIM: Dietary habits have been associated with the prevalence of the sarcopenia and limited data are available in this field for menopausal women. This study focused on the relationship between dietary patterns and prevalence of the sarcopenia in menopausal women. METHODS: This cross-sectional study was done in 250 menopausal women 45 years old or older. Dietary data were collected using a food-frequency questionnaire and physical activity was assessed by International Physical Activity Questionnaire (IPAQ). Height, weight, skeletal muscle mass, hand grip, and gait speed were measured and sarcopenia was defined based on European Working Group on Sarcopenia in Older People (EWGSOP) guidelines. RESULTS: Using factor analysis, two major dietary patterns were found: a Western pattern (high in commercial beverage, sugar and dessert, snacks, solid fat, potato, high fat dairy, legume, organ meat, fast food, and sweets) and a Mediterranean pattern (high in olive, low-fat dairy, vegetable, fish, nut, and vegetable oil). After adjusting for confounding variables, for the highest vs the lowest tertiles, the Odds Ratio (OR) for sarcopenia was 1.06 [95% confidence interval (CI), 0.47-2.37] in the Western pattern and 0.40 [95% confidence interval (CI), 0.17-0.89] in the Mediterranean pattern. CONCLUSIONS: Our findings suggest that Mediterranean dietary pattern has a favorable role in the prevention of sarcopenia.

Iranian Television Advertisement and Children's Food Preferences.

BACKGROUND: In this study, the nature of food commercials in children's television (TV) was monitored and analyzed; simultaneously, the relationship between recalling TV food commercials and children's interest in them and in the consumption of the same food products was evaluated. METHODS: A total of 108 h children's programs broadcast on two channels (Two and Amouzesh) of Islamic Republic of Iran Broadcasting (IRIB) media organization were monitored (May 6-12, 2015). Simultaneously, a cross-sectional study using 403 primary schoolchildren (201 boys) in four schools of Shirvan, Northeast of Iran, was executed. The children were prompted to recall all TV commercials broadcast on IRIB. Meanwhile, they were directed to define in the list of recalled TV food commercials those were interested in and the commercials (food products) they actually were willing to consume. RESULTS: Regarding the frequency and duration of broadcasting, food commercials ranked fifth and sixth, respectively. Fruit leather and plum paste were the most frequently broadcast food commercials. "High quality" (19%), "good taste" (15%), "novelty", and "message on nutritional composition" (13%) were the most frequent messages used in promoting the sale of food products, respectively. In addition, focus on "high quality/precision in the preparation of the food products" was the most frequently used appeals in TV commercials. There was a significant relationship between recalling TV food commercials and the interest in five out of eight of the commercials (62.5%) (P < 0.05). The relationship between recalling TV food commercials and the interest in the consumption of the same food product ("Tomato paste B") was statistically significant for 12.5% of the commercials (P < 0.05). CONCLUSIONS: TV food commercials do not encourage healthy eating. The current study provides convincing evidence for policy-makers and researchers to pay more attention to this area.