Family Practice News, November 13, 1998.

A government-sponsored trial, one of the largest ever conducted, will begin late this year to test whether commonly used antioxidants vitamin E and selenium can prevent prostate cancer, as reported by Reuters. The 12-year "SELECT" study, to involve 32,400 men at about 300 research centers in the United States and Canada, will be the biggest prevention trial ever undertaken using a drug or nutrient, said Dr. Scott Lippman, chairman of clinical cancer prevention at M.D. Anderson Cancer Center in Houston.

Dr. Lippman said a large 10-year placebo-controlled U.S. trial began in 1983 to test whether a daily dose of 200 micrograms of selenium could prevent skin cancer. Although the supplementation did not have significant effects on the incidence of skin cancers, the incidence of prostate cancer, colorectal and lung cancers was significantly reduced in subjects taking the supplement as compared to those receiving the placebo. The role of selenium in cancer prevention might be due to its incorporation into one of the body's most potent antioxidants, the enzyme glutathione peroxidase, as reported in several earlier studies.

A new study on elderly subjects shows that micronutrient levels influence the number and function of natural killer (NK) cells - immune cells that defend the body against some tumors. To explore the connection between micronutrients and NK cells, the researchers studied 62 northern Italian men and women who lived independently and who ranged in age from 90 to 106 years. All were in good health, had normal blood test values, and were not taking nutritional supplements or medications that affect the immune system, such as anti-inflammatory drugs or hormones. All were apparently well nourished.

However, the investigators found that many of these individuals had micronutrient deficiencies. The most common deficiency, found in about 50% of both men and women, was in selenium, an essential mineral and antioxidant that protects the heart. Fifty-two percent of the men and 41% of the women were deficient in zinc, which plays a role in wound healing, proper growth, and immune system functioning. Deficiencies were also noted in vitamins A, E, B6, and folate (a type of vitamin B complex), as well as in ubiquinone-10, which is associated with cell functioning.

It was found that higher serum levels of selenium in women corresponded to greater NK-cell activity. In women only, the defensive activity of the NK cells was greater when blood levels of vitamin E and ubiquinone-10 were higher. No other significant associations of micronutrients with NK cells were noted.

American Journal Clinical Nutrition 2000;71:590-598.

Researchers from the University of Miami found that selenium therapy (in the form of the yeast supplement Selenomax) has a strong potential for improving the mental state and well-being of HIV-1 seropositive drug abusers. The one-month pilot study of selenium supplementation in such subjects revealed that Selenomax administration was associated with a decreased risk in the development of depressed-dejected mood state1.

Over 95% of the selenium in selenium yeast supplements such as Selenomax is present in the form of L-(+)-Selenomethionine2.

1. Health Supplement Retailer, February 2000, page 16.
   
   
2. Proc. 6th Int. Symp. On Uses of Selenium and Tellurium. Uses of Selenium and Tellerium. (1998) Y. Palmieri, ed. Scottsdale, AZ, May 10-12, pages 77-79

L-(+)-Selenomethionine from Sabinsa Corporation is a selenium supplement with superior bioavailability. Selenium in selenium yeast occurs in the form of L-(+)-Selenomethionine.

A report from the Lutein Information Bureau advocates that people who do not consume enough lutein in food should consider a dietary supplement providing at least 6 mg per day.

American Journal of Clinical Nutrition 1999 Oct;70(4):509-24

Sabinsa Corporation supplies Lutein soft extract standardized to contain a minimum of 5% lutein esters.

This important event by the NIH group reflects the changing pattern of use of nutritional supplements, with consumers clearly taking charge of their health. This new reality necessitates a debate on efficacy, safety and bioavailability of nutritional supplements. The objective of the conference was to explore the current state of our knowledge about the important issues related to the bioavailability of nutrients and other bioactive components of dietary supplements.

The conference was divided into four plenary sessions. Session 1 covered implications of bioavailability related issues to implementation of DSHEA, e.g. content on the label vs. content of the finished product, bioavailability and structure function claims, the importance of bioavailability data to the establishment of dietary reference intakes or DRIs. Session 2 addressed general issues related to the bioavailability of the supplements, e.g. measurements of bioavailability and key factors impacting the endpoints for measuring bioavailability. Session 3 discussed impact of bioavailability on physiologic state, e.g. bioavailability of selected nutrients in children, adults and elderly. Session 4 focused on three major classes of dietary supplements, i.e. vitamins, minerals and botanicals, and the bioavailability of selected nutrients representative of these major classes were presented, i.e. folate and iron.

The speakers’ sessions were followed by five workshop sessions with the goal to discuss the following topics: what do we need to know about active ingredients?, what is the impact of formulation on bioavailability?, physiological determinants of bioavailability, methodologies, and what are the best ways to communicate the information to the consumers?

One of the key questions that that the conference tried to answer was: what is the definition of the bioavailability? The consensus among the participants of the conference was that bioavilability is crucial to the health benefits of a supplement; however, no Federal regulations require any specific level of bioavailabilty. The term bioavailability, often confused with the gastrointestinal absorption, should actually include both the efficiency of absorption as well as utilization of a nutrient. Therefore, besides the blood levels of a supplemented ingredient the functional outcome should also be measured, e.g. blood levels of calcium and its impact on bone density of postmenopausal women.

Another important discussion concerned the factors affecting the bioavailability of nutrients. Although macronutrient bioavailability (fat, protein) is not affected in human aging, the bioavailability of several micronutrients is diminished in elderly people, e.g. B12, folate, iron, calcium and fat soluble beta-carotene.

During the worksop session on Impact of Formulation on Bioavailability, Sabinsa had brought the importance of supplements like the multi-patented Bioperine® (black pepper extract standardized for alkaloid piperine) to the attention of the workshop panel and the audience. Bioperine® has bioenhancing activity proven in clinical studies with fat soluble and water soluble vitamins, as well as organic forms of minerals (e.g. complex of selenium with amino acid methionine).

Overall the conference was a good forum for the exchange of ideas and experiences regarding the bioavailability of nutrients and the development of an effective research agenda which would be a source of reliable information to health professionals’ end consumers.