Reduction Effect of Calcium Alginate on Blood Triglyceride Levels Causing the Inhibition of Hepatic and Total Body Accumulation of Fat in Rats

Abstract

In this study, rats were fed a high-fat diet containing calcium alginate (Ca-Alg) for 5 weeks to examine the effects of Ca-Alg on lipid metabolism including triglyceride (TG) levels in the blood. We also investigated the mechanism of the TG-reducing effect of Alg in vitro. Rats were randomized into 5 groups: high-fat diet group (14% (w/w) lard, HF); three Ca-Alg-containing diet groups (2.5, 5 or 10% (w/w) Ca-Alg) and a resistant maltodextrin (RMD) diet group as a positive control (with 5% (w/w) RMD). The 10% Ca-Alg group showed a significant reduction of body weight increase from the 7th day. In addition, the increase of TG in blood was significantly suppressed, and the amount of TG excreted in feces was increased. Increase of body fat mass was in the order HF > RMD > Ca-Alg 2.5% > Ca-Alg 5% > Ca-Alg 10%, while the total weight of the extracted fat tissues was significantly reduced in the RMD, 5% and 10% Ca-Alg groups. Hepatic pathology showed clear circular vacuoles apparently representing TG accumulation in the HF group, while fewer vacuoles were seen in the Ca-Alg groups. The results of in vitro experiments indicated that Ca-Alg does not directly inhibit lipase activity, but may suppress absorption of TG by forming non-absorbable macromolecular micelles containing TG. These results suggest that Ca-Alg promotes excretion and suppresses absorption of TG, leading to reduced blood TG levels, and decreased hepatic and total body accumulation of fat. The findings should be helpful for designing future clinical trials.

Extraction and Characterization of Alginate from an Edible Brown Seaweed (Cystoseira barbata) Harvested in the Romanian Black Sea

“…For example, binding of glucose and α-amylase inhibition, which reduce post-prandial glucose levels [7,8]. Alginates (calcium) have the ability to absorb bile acids and lipids and therefore to lower cholesterol [9] and lipid levels [10].…”

Pharmacological Effects and Utility as a Food Additive of Calcium Alginate

“…When water was added to the emulsion, it disintegrated, precipitating lecithin and releasing TG on the liquid surface. These results suggest that Alg stabilizes bile acid micelles containing TG, possibly by absorbing them and forming large micelles that cannot be absorbed, or that are less vulnerable to lipases [24].…”

“…Area under the blood concentration-time curve of TG in rats after the 5-week feeding period with high-fat diet or high-fat diet containing Ca-Alg or high-fat diet containing RMD [24]. The data represent means ± S.D., n = 7.…”

“…Since we previously observed that the TG level in blood was decreased by Ca-Alg in rats [18], we next set out to examine the effect of Ca-Alg on elevated TG levels in the blood, hepatic and total body accumulation of fat, and body weight in rats fed a TG-loaded diet for 5 weeks. We also investigated the mechanism of the TG-reducing effect of Alg in vitro [24].…”

“…The direct binding affinity of glucose for Figure 6. A possible mechanism of TG-lowering effect of Ca-Alg [24].…”