Submitted to: Phytotherapy Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/12/2006
Publication Date: 7/11/2006
Citation: Eliaz, I.,Hotchkiss, A.T., Fishman, M.L. and Rode, D . 2006. The effect of modified citrus pectin on the urinary excretion of toxic elements. Phytotherapy Research.20:859-864.
Interpretive Summary: The enormous volume of fruit and vegetable processing residues, such as orange peels and sugar beet pulp, represents an underutilized domestic resource of valuable health-promoting compounds. These residues have been used as cattle feed ingredients, but as such their value is low (under $0.05/pound) and there is more supply than demand for cattle feed. However, these residues are rich in valuable carbohydrates such as pectin. Pectin is a plant carbohydrate traditionally used in jelly and jam production. Modified citrus pectin is a dietary supplement commercial product that contains pectin fragments with demonstrated efficacy to prevent the recurrence of prostate cancer in men. We demonstrate for the first time that modified citrus pectin increases the urinary excretion of toxic metals in men and women with normal body levels of metals. While the pectin fragments in modified citrus pectin are not the same as those we previously found to enhance the growth of health-promoting gut bacteria, inhibit the binding of food pathogen toxins, and promote the cell death of colon cancer cells; all of these properties may be inter-related. Further development of these carbohydrates into commercial products will add value to citrus processing residues, and will benefit citrus growers and processors as well as public consumers.
Technical Abstract: This study was undertaken to evaluate the effect of modified citrus pectin (MCP) on the urinary excretion of toxic elements in healthy individuals. MCP is a reduced molecular weight pectin (weight-average molar mass = 15,400) that is mostly linear homogalacturonan with 3.8% degree of esterification and approximately 10% rhamnogalacturonan II based on the presence of 2-keto-3-deoxy-octonic acid. Subjects ingested 15 grams of MCP each day for five days and 20 grams on day six. Twenty-four hour urine samples were collected on day one and day six for comparison to baseline. The urine samples were analyzed for toxic and essential elements. In the first 24 hours of MCP administration the urinary excretion of arsenic increased significantly (130%, p<0.05). On day six, urinary excretion was significantly increased for cadmium (150%, p<0.05). In addition, lead showed a dramatic increase in excretion (560%, p<0.08). This pilot trial provides the first evidence that oral administration of MCP significantly increases the urinary excretion of toxic metals in subjects with a “normal” body load of metals. We suggest that systemic chelation of toxic metals by MCP may in part be attributable to the presence of rhamnogalacturonan II, which has been previously shown to chelate metals.