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Lycopene Continues To Show Promise As An Antioxidant Linked To The Prevention Of Prostate Cancer

 

On March 6, 2002 the Journal of the National Cancer Institute featured an update from the Health Professionals Follow-Up Study (HPFS), showing that frequent tomato or lycopene intake was associated with a reduced risk of prostate cancer. The initial findings from the HPFS, which followed 47,363 male health practitioners (non-MD) from 1986 to January 31, 1992, had previously shown a correlation between lycopene intake and a reduced risk of prostate cancer. This most recent study of the same cohort demonstrated that this correlation persists with continued follow-up on these men for an additional six years, through to January 31, 1998. In short, the most recent data suggests that men who consume two or more servings per week of tomato sauce (the primary source of bioavailable lycopene) versus less than one serving per month, show a 23% reduction in risk of developing prostate cancer. Simply ingesting more lycopene from tomatoes, other tomato products or lycopene itself, was shown to reduce risk of prostate cancer by 16%, after controlling for other confounding variables such as total fruit and vegetable consumption and for olive oil use (a marker for Mediterranean diet). These values agree with those of the Physicians’ Health Study (which measured blood levels of lycopene and other nutrients) and the original data compiled by E. Giovannucci in the first observations of the HPFS.

Lycopene is a powerful fat-soluble antioxidant (hence its high bioavailability from tomato sauce, which usually contains olive oil) and is known to concentrate in the prostate gland in humans, where it has been shown to participate in free radical scavenging and in the process of cellular differentiation. Both of these activities are involved in the prevention of the multi-step process of cancer development and are likely to be the way in which lycopene may act as a chemopreventive agent in the prostate gland. The initial data showed that men consuming 6.5 mg per day or more of lycopene, from any source, were deriving benefits in regards to the prevention of prostate cancer. Therefore, consuming the equivalent one to one and a half whole tomatoes per day, on average (make sure it is consumed with a little bit of fat to facilitate lycopene absorption) and/or the intake of lycopene from supplements, continues to be a prudent strategy for men to consider as part of a prostate cancer prevention campaign.

Reference: Giovannucci E et al, A Prospective Study of Tomato Products, Lycopene, and Prostate Cancer Risk. 2002. J Natl.Cancer Instit; 94, 5 : 391-398

Green Tea May Help Ward Off Osteoarthritis and Rheumatoid Arthritis

Green tea is a rich source of a special class of antioxidants known as catechins. These polyphenolic compounds have been shown to reduce inflammation in a murine model of inflammatory arthritis. Recently, in the Journal of Nutrition, C. Adocks et al, investigated the effects of green tea catechins on cartilage extracellular matrix components using an in vitro model system. Bovine nasal and metacarpophalangeal cartilage as well as human nondiseased, osteoarthritic and rheumatoid cartilage were cultured with and without reagents known to accelerate cartilage matrix breakdown. Individual catechins derived from green tea were added to the cultures and the amount of released proteoglycan and type II collagen was measured by metachromatic assay and inhibition ELISA, respectively. The results showed that certain catechins, particularly gallate ester, were effective at micromolar concentrations at inhibiting proteoglycan and type II collagen breakdown. No toxic effects of the catechins were evident.

The researchers conclude that some green tea catechins are chondoprotective and that consumption of green tea or green tea extract may be prophylactic for arthritis and may benefit the arthritis patient by reducing inflammation and slowing cartilage breakdown. This data agrees with other published reports showing that supplementation with 400 IU of vitamin E or 100-200 mcg of selenium can help to improve arthritic symptoms in human trials. Like green tea catechins, vitamin E and selenium, at these supraphysiological levels, provide enhanced antioxidant protection and appear to promote the production of anti-inflammatory prostaglandins by modulating the activities of the cyclooxygenase enzyme system. Further studies using green tea catechins are required before definitive statements can be made about its use as a preventive or therapeutic aid for arthritis. However, higher levels of green tea intake is associated with a lower risk of stomach and esophageal cancer and possibly acts to help reduce risk at other tissue sites as well. Thus, it appears that green tea intake may be a healthier alternative to coffee and other hot beverages for a variety of reasons, which may now include helping to prevent or reduce the breakdown of joint cartilage and controlling inflammation.

Reference: Adcocks C et al, Catechins from Green Tea Inhibit Bovine and Human Cartilage Proteoglycan and Type II Collagen Degradation In Vitro. 2002. J. Nutr.; 132: 341-346

 

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