Free Radical Effects -

Seminal Fluid Antioxidants

Few people seem to realize that the adverse effects of smoking extend every beyond the smoker and others forced to breathe the smoker’s exhalations. Epidemiologists at the University of North Carolina carried out a study of 15,000 children born between 1959 and 1966. this showed that the children of men who, prior to the birth, had smoked more than 20 cigarettes a day were twice as likely to suffer from certain genetic defects such as cleft lip and palate and congenital heart disorders. Another associated study by scientists at the National Institute of Environmental Health of North Carolina found that leukaemia and lymph node cancer were twice as common in the children of male smokers as in the children of non-smokers. Brain tumours were also significantly more common.

Interestingly, the effect seems to be on sperm DNA but not on egg ( ovum) DNA. No genetic links have been found that can be attributed to smoking by the mother. This is probably because cells forming sperms are far more often in a state of division ( mitosis ) than are eggs. Mutations occur mostly during mitosis because repair activity is temporarily halted during this phase.

You may be wondering what all this has to do with antioxidant vitamins. Reporting these findings at an international conference on environmental causes of cancer in February 1993, the American biochemist Bruce Ames, of the University of California at Berkeley, pointed out that much of the damage resulting from smoking comes from strongly oxidizing compounds in cigarette smoke, such as free radicals. When this damage affects the DNA in the cells that produce sperms, then some of the sperms will carry mutant DNA. If a child happens to be produced by fertilization by such a damaged sperm, congenital defects will result and the resulting mutations can, as Ames put it, cause ‘an effect that will reverberate down the generations.’

Ames points out that there is about eight times as much vitamin C in seminal fluid as there is in blood. This cannot be a mere coincidence. This antioxidant vitamin must play an important role in protecting sperms from genetic damage so as to minimize the number of inheritable disorders caused by mutations. Since, like all cells in the body, sperms are attacked by about 10,000 oxidizing reactions every day, they clearly need such protection. The amount of vitamin C in the seminal fluid sensitively reflects the amount present in the diet. Even more significant, a low dietary intake of vitamin C immediately produces a substantial increase in the amount of a substance called 8-hydroxydeoxyguanosine. This is a breakdown product of DNA that is produced in increased quantity when DNA is being damaged. The current official recommended daily allowance of about 60 mg is too low to produce enough vitamin C in semen to reduce this DNA damage to safe levels. Research suggests that a minimum daily intake of 250 mg should suffice. Smoking uses up much of the vitamin C levels in the body to cope with the large amounts of oxidizing compounds in absorbed smoke, so smokers are clearly at greater risk.