Micronutrients intake is associated with improved sperm DNA quality in older men

Capsule:
Older men with higher dietary and supplement intake of certain micronutrients, including vitamin C, vitamin E, folate, and zinc, but not b-carotene, may produce sperm with less DNA damage.

Authors:
Thomas E. Schmid, Ph.D., Brenda Eskenazi, Ph.D., Francesco Marchetti, Ph.D., Suzanne Young, M.P.H., Rosana H. Weldon, Ph.D., Adolf Baumgartner, Ph.D., Diana Anderson, Ph.D., Andrew J. Wyrobek, Ph.D.

Volume 98, Issue 5, Pages 1130-1137.e1, November 2012

Abstract:

Objective:
To investigate whether lifestyle factors such as increased dietary intake of micronutrients reduce the risks of sperm DNA damage, and whether older men benefit more than younger men.

Design:
Cross-sectional study design with equalized assignments into age groups.

Setting:
National laboratory and university.

Patient(s):
Nonclinical group of 22–80-year-old nonsmoking men (n = 80) who reported no fertility problems.

Main Outcome Measures:
Sperm DNA damage measured by alkaline and neutral DNA electrophoresis (i.e., sperm Comet assay).

Results:
Sociodemographics, occupational exposures, medical and reproductive histories, and lifestyle habits were determined by questionnaire. The average daily dietary and supplement intake of micronutrients (vitamin C, vitamin E, b-carotene, zinc, and folate) was determined using the 100-item Modified Block Food Frequency Questionnaire (FFQ). Men with the highest intake of vitamin C had approximately 16% less sperm DNA damage (alkaline sperm Comet) than men with the lowest intake, with similar findings for vitamin E, folate, and zinc (but not β-carotene). Older men (>44 years) with the highest vitamin C intake had approximately 20% less sperm DNA damage compared with older men with the lowest intake, with similar findings for vitamin E and zinc. The older men with the highest intake of these micronutrients showed levels of sperm damage that were similar to those of the younger men. However, younger men (<44 years) did not benefit from higher intakes of the micronutrients surveyed. Conclusions:
Men with higher dietary and supplement intake of certain micronutrients may produce sperm with less DNA damage, especially among older men. This raises the broader question of how lifestyle factors including higher intakes of antioxidants and micronutrients might protect somatic as well as germ cells against age-associated genomic damage.

  • Pravin Rao

    This is very interesting, but as mentioned it’s difficult to determine its clinical relevance. This article should serve as more impetus to perform better clinical trials, rather than to directly change clinical practice. It is hard to know how the DFI’s of normal/fertile can be useful for infertile men. Also, it’s hard to believe that a survey could effectively account for the seemingly endless possibilities of confounding factors (including physical exam findings). I wonder whether the survey questions could be posted as an appendix to the online article…?

  • eykko

    Interesting article on the potential correlation of dietary intake of antioxidants and oxidative DNA damage. Although men with higher intake of studied antioxidants had lower % of oxidative DNA damage, we have to remember that all of these men had NO fertility problems. So I am not sure of the clinical significance of this data.

    It would be more important to prospectively analyze how intake of certain antioxidants, at specific doses, and at fixed intervals would impact semen parameters in infertile men with significant oxidative DNA derangements. So a call for future randomized, placebo-controlled studies is definitely appropriate.

    Another important aspect is lifestyle, since it is often closely tied to quality of diet. Those that are healthier overall tend to be more active and practice better eating habits. Does an older fit male that has excellent lifestyle habits with low levels of antioxidant intake have a higher likelihood of having worse semen parameters vs. a sedentary obese male that eats poorly but pops multiple supplements and vitamins daily? I would like to presume that a person eating heart healthy well-balanced meals and takes care of his body with exercise and diet would have “normal” semen parameters and low levels of DNA oxidative damage.

    Several issues are not addressed by this interesting article:

    1. Other risk factors for infertility: chemical/work related exposures, varicocele status.

    2. Other antioxidants/vitamins that could have influenced the overall oxidative DNA damage parameters – i.e. L-carnitine, Co-Enzyme Q10, lycopene, etc.

    Despite all of the potentially positive effects that antioxidants have on our overall health, this article should not be used to promote a dramatic increase in antioxidant intake just for the purpose of improving semen parameters, because the overall data on poorly designed, small cohort, lack of dietary controlled, lack of dose control studies previously published have not conclusively demonstrated significant consistent improvements in semen analyses or overall fertility potential.

  • Cristina G. Ravina

    Congratulations for your interesting work, which is focused on a specific population, individual >45 yo, that nowadays represent a great percentage of patients demanding ART. After reading your article, and your previous reference related to seminal parameters, I wonder if you have analyzed them in the patients of the present study, specially the motility.
    Finally, regarding to your results perhaps it would be interesting to test FISH analysis in order to know if higher dietary and micronutrients intake may reduce aneuploidies in older patients.

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