Pharmaceutical and Medical Uses

*Alginates - Recent Uses of This Natural Polymer*

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2016;**139**:106-114

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**Chapter 2**

**Abstract**

tive for long-term use.

**1. Introduction**

fat, blood glucose level, particle size, noodles

Na-Alg, it might prove to be of greater benefit.

Pharmacological Effects and

Utility as a Food Additive of

Here we review the physiological effects of the calcium salt of alginate (Ca-Alg),

focusing on our own work. First, we found that Ca-Alg promotes the excretion and decreases the absorption of various metals, and does so more effectively than sodium alginate (Na-Alg). Ca-Alg also reduced plasma cholesterol (Cho) in rats fed a high-Cho diet for 2 weeks. This was considered to be due to reduced intestinal reabsorption of bile acid, resulting from the binding of Ca-Alg and bile acid; this induces an increase of bile acid synthesis from Cho in the liver, leading to a decrease in Cho in plasma. The increase of blood triglyceride (TG) levels in rats fed a highfat diet for 5 weeks was significantly suppressed by Ca-Alg, leading to decreased fat accumulation in the liver and whole body. Ca-Alg in food was also effective in suppressing the postprandial increase of blood glucose level in rats and humans. An in vitro study suggested that Ca-Alg inhibits the interaction between α-glucosidase and its substrate maltose. In conclusion, Ca-Alg has a number of beneficial effects as a functional food ingredient, and is expected to be a safe and effective food addi-

**Keywords:** calcium alginate, toxic metal, cholesterol, bile acid, triglyceride, micelle,

Alginic acid (Alg) is a polysaccharide derived from algae. Sodium alginate (Na-Alg) is commonly used in foodstuffs as a thickening agent and stabilizer, and is also used as a health food to suppress weight gain and lower blood cholesterol (Cho) [1–4]. In addition, Na-Alg has a protective action on the gastric mucosa [5, 6]. Moreover, when Na-Alg is ingested prior to exposure to strontium (Sr), Sr accumulation in the human body is decreased [7]. However, the sodium salt of Alg can potentially cause hypertension, a major risk factor for dyslipidemia and arteriosclerosis [8]. Therefore, if the calcium salt (Ca-Alg) is as effective as, or superior to,

In this chapter, focusing on our own work on Ca-Alg, we will firstly describe how Alg enhances excretion and reduces absorption of Sr and cesium (Cs) in rats. Secondly, we discuss the relationship between the physical parameters of various metal ions and their binding affinity to Alg. Thirdly, we describe the

*Fumiyoshi Kasahara, Yoko Idota, Yuuki Fukai,* 

*Chihaya Kakinuma and Takuo Ogihara*

Calcium Alginate
