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SELENIUM  and CARDIOVASCULAR DISEASE                       

Abstract:  Selenium appears to act as an antioxidant that reduces risk of cardiovascular diseases as well as risk of cancer. An estimate from 7 of 8 studies found suggests risk of heart disease and stroke may be reduced by about 40% by an added 100 mg per day of dietary selenium.  A usual amount in diet is about 90 mg. per day, but benefits may accrue from amounts of selenium up to 200 mg per day.  Selenium is included in Life Ahead as one of four antioxidants that acts in combination with each other but that in total has a limiting value.  But because of its potential benefit to heart disease, stroke, and cancer health-interested persons should consider taking a 100 mg daily supplement of selenium.

See other papers of antioxidants and CV disease for Vitamin E;  Vitamin A;  Vitamin C;, papers of antioxidants and cancer for Vitamin E;  Vitamin A;  Vitamin C; and Selenium, and Antioxidants, Death from All Causes and Antioxidants, a Global Analysis..

Selenium has been extensively studied as an agent that might reduce risk of cancer.  Dozens of biochemical studies have indicated that this mineral acts as an active antioxidant.  Thus as expected it also reduces risk of cardiovascular diseases.  Results from eight studies found relating the risk of cardiovascular diseases to selenium intake are shown in Table S following.  Selenium was measured as amounts in blood.  Risk ratios are for higher vs. lower amount use, and thus as usual in Life Ahead risk ratios below 1.00 identify benefit for the mineral.  Selenium in blood probably reflects fairly recent dietary use, but we have no data from the research on how long selenium was used, and dietary intake of selenium usually was not available in this research. Estimates of a possible difference in dietary selenium are given in Table S from very limited information relating Selenium in blood to that in diet

Some of the individual studies have unusually high margins of error.  For example study #1 has an error margin of 1.58 that is well above the usual level of 1.00 considered as a maximum error margin recognized as useful for inclusion of a result in Life Ahead.  But all other studies and especially those having lower error margins show significant lowering of cardiovascular diseases for highest amounts of included Selenium.  Because of these error margins the conclusions cited in abstracts of individual studies have been statistically confusing and inconsistent.  Note that this research was based on amounts of selenium in the blood, a basis that can be accurate than estimating results from diets.

A log-basis average of all results produces a risk ratio of about 0.60 with 5% to 95% limits of about 0.41- 0.88.  The data on stroke identify a very high 2/3rds benefit, but error margins on these studies are too high to accept this level of benefit.  This average result from all studies identifies selenium as providing a 99% chance of benefit, a 90% chance of at least a 20% reduction in risk, and a most probable 40% reduction of risk of cardiovascular disease from the daily addition use of about 100 mg of selenium.  No specific information was found relating benefits of combinations of selenium with other antioxidants.  But further supporting importance of its probable health value are results of many biochemical studies showing that Selenium is an antioxidant that should slow the atherosclerosis that produces these diseases.  Also, populations with low selenium in local soils have been found to experience higher death rates, and no really significant health negatives have been established for its use at the levels considered in Life Ahead.

Life Ahead includes Selenium as one of four antioxidants taken in sum as a group that benefit all cardiovascular diseases.  See the Antioxidant Model.  In accord with the BioChemical mechanism of atherosclerosis the benefits of antioxidants are taken as a duration of exposure related risk, with a recognized limit of both maximum benefit and duration of exposure.  A usual US diet includes about 80-90 mg of Selenium per day.  Life Ahead credits a benefit for up to 100 mg of supplemental use beyond that usual in diet. But this benefit accrues via the antioxidant model only gradually over a 20 year period, and is usually reduced further by presence of accompanying amounts of other antioxidants.  If substantial amounts of Vitamin E and other antioxidants are present in diet and supplements, the addition of selenium may produce no added computed benefit for cardiovascular diseases.  The antioxidant model for heart disease includes the benefits of selenium at a % per year of duration of use.  Thus the total above benefit would not be achieved via Life Ahead until selenium had been used for 20 years.

But Selenium also appears to have a substantial benefit by reducing risk of cancer.  Thus the taking a of a Selenium supplement of  100 mg per day would appear to be a prudent action for any health-interested person.

                                                                                            TABLE S

                                 RESEARCH on CARDIOVASCULAR DISEASE and SELENIUM