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    3 Comments for this article
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    The make up of the 3-fatty
    Meh Miller, MLIS | Librarian
    What was the make up of the ω-3 fatty acid supplement? I am interested to know if all the participants took the exact same dosage of ω-3 fatty acid supplements.
    CONFLICT OF INTEREST: None Reported
    Fish oil supplements threaten fisheries and human livelihoods
    Rosalie Schultz, MB BS, MPH, PhD | Ngaanyatjarra Health
    Further research into possible health benefits of fish oils should demonstrate where fish oils will be obtained. Fisheries around the world are already over-exploited. Aquaculture merely moves the consumption of wild caught fish from the consumer to the fish farm.

    Until we are able to sustain global fish stocks, encouraging uptake of fish oils in any form contributes to the diminution of fisheries, affecting fishing -dependent communities worldwide. I urge researchers and research review boards to consider fish supplies when research is conducted into possible benefits to humans of fish consumption.


    Greene J, Ashburn SM, Razzouk L,
    Smith DA. Fish oils, coronary heart disease, and the environment. Am J Public Health. 2013;103(9):1568–1576. doi:10.2105/AJPH.2012.300959
    CONFLICT OF INTEREST: None Reported
    READ MORE
    No clarity on the impact of the many possible confounding factors
    Victor Cortes, MD PhD | Pontificia Universidad Católica de Chile
    I found the study is interesting and provocative but it lacks systematic analysis of possible confounding elements, with a high risk of reverse causality in their conclusions. A likely explanation for the better testicular performance in the omega 3 group is that they are globally healthier than the other individuals. Also, what might the impact of this study in very young men on older individuals that are pursuing reproductive goals?
    CONFLICT OF INTEREST: None Reported
    Original Investigation
    Public Health
    January 17, 2020

    Associations of Fish Oil Supplement Use With Testicular Function in Young Men

    Author Affiliations
    • 1Department of Environmental Medicine, University of Southern Denmark, Odense, Denmark
    • 2Department of Growth and Reproduction, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
    • 3International Center for Research and Research Training in Endocrine Disruption of Male Reproduction and Child Health, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
    • 4Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
    • 5Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
    • 6Section of Biostatistics, Department of Public Health, University of Copenhagen, Copenhagen, Denmark
    • 7Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
    • 8Channing Division of Network Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts
    JAMA Netw Open. 2020;3(1):e1919462. doi:10.1001/jamanetworkopen.2019.19462
    Key Points español 中文 (chinese)

    Question  Is intake of fish oil supplements associated with testicular function as measured by semen quality and reproductive hormone levels among young healthy men?

    Findings  In this cross-sectional study including 1679 young men in Denmark, fish oil supplements were associated in a dose-response manner with higher semen volume and total sperm count, larger testicular size, a higher calculated free testosterone to luteinizing hormone ratio, and lower follicle-stimulating hormone and luteinizing hormone levels after adjusting for confounders.

    Meaning  These findings suggest that healthy men may benefit from intake of fish oil supplements, but a well-designed randomized clinical trial among unselected men is warranted.

    Abstract

    Importance  Many young men have poor semen quality, and the causes are often unknown. Supplement intake of ω-3 polyunsaturated fatty acid has been found to improve semen quality among men with infertility, but the association with semen quality among healthy men is unknown.

    Objective  To determine if intake of ω-3 fatty acid supplements is associated with testicular function as measured by semen quality and reproductive hormone levels among healthy men.

    Design, Setting, and Participants  This cross-sectional study included young Danish men from the general population recruited between January 1, 2012, and December 31, 2017, at compulsory examinations to determine their fitness for military service. Young unselected men were approached after the examination and invited to participate in a study of reproductive function, regardless of their fitness for military service. Data analysis was conducted from September 1, 2018, to June 30, 2019.

    Exposures  Intake of supplements, including fish oil, during the past 3 months.

    Main Outcomes and Measures  Semen quality, measured as volume, concentration, total sperm count, percentage of morphologically normal spermatozoa, and motility, and serum reproductive hormone levels, measured as follicle-stimulating hormone, luteinizing hormone, testosterone, free testosterone, and inhibin B levels.

    Results  Among 1679 young Danish men (median [interquartile range] age, 18.9 [18.7-19.4] years) recruited to participate, 98 men (5.8%) reported use of fish oil supplements during the past 3 months, of whom 53 (54.1%) reported intake on 60 or more days. After adjustment and compared with men with no supplement intake, men with fish oil supplement intake on fewer than 60 days had semen volume that was 0.38 (95% CI, −0.03 to 0.80) mL higher, and men with fish oil supplement intake on 60 or more days had semen volume that was 0.64 (95% CI, 0.15 to 1.12) mL higher (P for trend < .001). Similarly, testicular size in men with supplement intake on fewer than 60 days was 0.8 (95% CI, −0.2 to 1.9) mL larger and in men with fish oil supplement intake on 60 or more days was 1.5 (95% CI, 0.2 to 2.8) mL larger compared with men with no supplement intake (P for trend = .007). After adjustment, men with fish oil supplement intake had a 20% (95% CI, 9%-31%) lower follicle-stimulating hormone level and 16% (95% CI, 8%-24%) lower luteinizing hormone level compared with men with no supplement intake. There were no associations of intake of other supplements with measures of testicular function.

    Conclusions and Relevance  These findings suggest that intake of fish oil supplements was associated with better testicular function, which is less likely to be due to confounding by indication, as no associations of intake of other supplements with testicular function were found. This cross-sectional study did not examine the actual content of ω-3 fatty acids in the supplements; therefore, these findings need confirmation in well-designed randomized clinical trials among unselected men.

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