The objective of this experiment was to determine the branched-chain amino acid (BCAA) content in five different sport nutrition supplements compared to the amount claimed on the label.
To measure ...the BCAA content of five nutritional supplements, a leucine dehydrogenase enzyme assay was used. This enzyme catalyzes the reaction of turning the given BCAA (L-leucine, L-valine, and L-isoleucine), water, and NAD+ into their respective metabolite, NH3, NADH, and H+. Ultraviolet-visible light spectrophotometry (UV/Vis) was used at 340 nm to create a standard curve. This curve uses the Beer-Lambert Law to measure NADH concentration from absorbance. NADH is in a 1:1 ratio with each BCAA molecule thus relaying the content of the given sample. The assay is specific to the three BCAAs in their free form. Other amino acids, as well as BCAAs in oligopeptides, do not interfere with this experiment. Products including oligo- and polypeptides were not included for testing. The assay was performed for each product and ran against a known standard (≥98% L-leucine) for validation. Due to different supplements having different BCAA amounts per serving, % content of the claimed amount was measured.
Compared to the amount provided by the labels of each supplement, BCAA content was on average only 61% of the manufacturer claims when compared to ≥98% L-leucine. This shows that these BCAA supplements do not meet label claims for BCAA content (P < 0.01).
The five tested nutritional supplements contain significantly less branched-chain amino acid content than claimed on the label. This experiment can be expanded on in the future to test content of other BCAA containing supplements to determine how common underdosing is in the industry as a whole.
The author claims no funding sources.
Dietary fiber is a group of polysaccharides consisting of long chains of various carbohydrate monomers than cannot be digested by the human body (1). High fiber diets are associated with decreases in ...body mass index, cholesterol, blood sugar, and blood pressure (BP) (2). With an increasing percentage of the population suffering from obesity, diabetes, and heart disease, diets high in fiber containing foods such as fruits and vegetables may be one way to alleviate these conditions (3). Fiber from one food in particular, peas (pulses), has been shown to improve heath from multiple mechanisms. Pulses are a subgroup of legumes and crop plant members of the Leguminosae family that are grown for human and animal consumption and includes green peas, chickpeas, beans, and lentils. When consuming high amounts of pea fiber (≥16 g/day) individuals have reported decreased appetite which could lead to decreased energy intake resulting in weight loss (4). Mechanisms for the effect could include gut bacteria in the large intestinemetabolizing the fiber and releasing short chain fatty acids (SCFA), the three main SCFA being acetate, butyrate, and propionate. These SCFA can be absorbed by enterocytes to be transported by the blood (5,6,7). These SCFA are then taken up by the brain, signaling that there is sufficient fuel. This releases satiety signals to the body which can decrease appetite resulting in a reduced desire for high energy-density foods.
Dietary components high in fiber have been shown to uniquely influence the gut microbiome through growth of beneficial bacteria. To determine if fiber from a pulse source (pea fiber) improves ...microbiome profiles, we tested the hypothesis that a high-fiber (HiFi) diet will result in improvements in microbial composition and diversity compared to a low-fiber (LowFi) diet.
In a parallel arm, repeated-measures design, overweight or obese adult males and females with at least one characteristic of the metabolic syndrome, were randomly assigned to consume a standard diet consisting of 25g/d (HiFi) or 5g/d (LowFi) of added pea fiber for 4 weeks (HiFi: n = 5, mean ± SD, BMI 30.1 ± 2.4 kg/m2, 30.6 ± 9.9 y; LowFi: n = 5, BMI 28.6 ± 3.4 kg/m2, 32.2 ± 11.7 y). The intervention meals were matched for palatability, energy, and macronutrient composition. Fecal sampling was performed on days 0, 7, 14, 21, and 28 of the intervention for a total of 50 samples. Gut microbiome composition was assessed by 16S rRNA amplicon sequencing.
Alpha diversity as assessed by the Shannon index remained unchanged in both the HiFi and LowFi groups after 4 weeks. Beta diversity analysis (by Principal Coordinates) demonstrated that there was a statistically significant difference in microbial composition between the HiFi and LowFi group (p = 0.0001, F = 4.04) but no significant effect of time (p = 1, F = 0.28). There were differences seen in the microbial taxa in both groups at day 0 in comparison to the days after. For example, members of the genus Blautia, and Subdoligranulum (belonging to the phylum Firmicutes, known producers of short chain fatty acids (SCFA)) were low at day 0 in the HiFi group but increased from day 7 through day 28. These genera were unchanged in the LowFi group.
These preliminary results provide evidence of differential effects of HiFi compared to LowFi diets on the gut microbiome, particularly an increase in SCFA producers with HiFi.
University of Missouri and NIH-K01- NHLBI.
Conventional radiation therapy of brain tumors often produces cognitive deficits, particularly in children. We investigated the potential efficacy of merging Orthovoltage X-ray Minibeams (OXM). It ...segments the beam into an array of parallel, thin (~0.3 mm), planar beams, called minibeams, which are known from synchrotron x-ray experiments to spare tissues. Furthermore, the slight divergence of the OXM array make the individual minibeams gradually broaden, thus merging with their neighbors at a given tissue depth to produce a solid beam. In this way the proximal tissues, including the cerebral cortex, can be spared. Here we present experimental results with radiochromic films to characterize the method's dosimetry. Furthermore, we present our Monte Carlo simulation results for physical absorbed dose, and a first-order biologic model to predict tissue tolerance. In particular, a 220-kVp orthovoltage beam provides a 5-fold sharper lateral penumbra than a 6-MV x-ray beam. The method can be implemented in arc-scan, which may include volumetric-modulated arc therapy (VMAT). Finally, OXM's low beam energy makes it ideal for tumor-dose enhancement with contrast agents such as iodine or gold nanoparticles, and its low cost, portability, and small room-shielding requirements make it ideal for use in the low-and-middle-income countries.
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