An in-office evaluation of four dietary supplements on natural killer cell activity

Townsend Letter for Doctors and Patients, Feb-March, 2005 by James Belanger

Abstract:

The natural killer (NK) cell activity blood test is useful in predicting the prognosis of a cancer patient. The purpose of this in-office, nonrandomized open-label trial was to determine whether four different dietary supplements commonly sold in health food stores and over the Internet, consistently and statistically affected NK cell activity in cancer patients. Thirty-four patients were assigned to one of four groups: Group A was given 1-3g/day of modified arabinoxylane with meals. Group B was given 6000mg/day of coriolus mushroom. Group C was given 4g/day of antigen-infused dialyzable bovine colostrum/whey extract and group D was given 3-6g/day of active hexose correlated compound (AHCC). NK cell activities were assessed before treatment and after an average of 16 weeks of therapy. AHCC was the only supplement that consistently and statistically increased NK cell activity. The average increase was 249%. Modified arabinoxylane statistically increased NK cell activity, but did not consistently help every patient. No side effects were encountered during the study period in any of the four groups.

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Introduction

Despite recent advances in oncology, a substantial amount of people with cancer are dying in less than five years (See table 1). (1)

To help improve these survival rates it may be important to identify and correct various adverse prognostic indicators. One negative prognostic indicator is low natural killer (NK) cell activity. Natural killer cells comprise between 5-20% of the peripheral blood lymphocytes and are capable of recognizing and killing tumor cells that completely lack expression of MHC Class I and II antigens. (2) The ability of a cancer patient's NK cells to lyse cancer cells can be determined by a 4-hr [.sup.51]chromium-release assay. Studies have shown that cancer patients with a low activity of NK cells have shorter remissions, greater tumor burdens and an increased risk for nodal metastasis. Response rates to chemotherapy may be lower and recurrence rates after surgery may be higher in patients with low baseline NK cell activities. It is also not uncommon for the activity of NK cells to decrease just prior to a recurrence in a patient's cancer. (3-22)

It may be possible to improve a cancer patient's prognosis by maintaining a high NK cell activity level. Several studies have demonstrated improved survival rates after activated killer cells are transferred into cancer patients. Transplanting activated killer cells into people, however, may create unwanted side effects, (23,24) therefore, activating the natural killer cells via an oral route may be a better choice. Various natural substances such as coriolus mushroom, active hexose correlated compound (AHCC), modified arabinoxylane and antigen-infused dialyzable bovine colostrum/whey extract have been described as oral NK cell activators in articles and advertisements. The purpose of this in-office study was to determine if these products consistently and significantly affected NK cell activity in cancer patients as advertised.

Material and Methods

Patients

This study was a nonrandomized, open-label trial in patients with a cancer diagnosis and was carried out in the author's office beginning in 2002. Thirty-six patients completed the study, but two were dropped from the statistical analysis because they were both taking high doses of fish oil and borage oil. Studies have shown that high doses of these oils severely decrease NK cell activity by decreasing levels of leukotriene-B4, a strong NK cell activator. (25,26) The 34 patients analyzed had various types of cancer in different stages. They consisted of 26 females and 8 males ranging from two to 72 years of age. None of the patients were taking a NK cell activator prior to the commencement of the study. The patients were divided into 4 groups. Group A, consisting of 15 patients, was treated with modified arabinoxylane. Group B, consisting of 8 patients, was treated with coriolus mushroom. Group C, consisting of 3 patients, was treated with antigen-infused dialyzable bovine colostrum/whey extract and group D. consisting of 8 patients, was treated with AHCC. Each group was allowed to take other nutritional supplements during the test period. Many of the same supplements were taken amongst the four groups. None of the allowed nutritional supplements, however, have been demonstrated to increase NK cell activity.

Modified arabinoxylane Group (Group A: n=15)

Modified arabinoxylane is a polysaccharide from rice bran that contains beta 1,4-xylopyranose hemicellulose that has been enzymatically treated with an extract from hyphomycetes mycelia (shiitake mushroom). Modified arabinoxylane was given in either a caplet or capsule form in a dose of 1000mg three times daily with meals and two hours away from other supplements. If the patient was taking the product longer than two months, the dose was reduced to 1000mg once daily with food. Modified arabinoxylane was chosen for this study because one human trial showed this substance increased NK cell activity by five-fold in 24 healthy individuals after eight weeks of treatment. (27)