Investigating physiological effects of weight loss on male fertility
Research type
Research Study
Full title
Investigating physiological effects of weight loss on male fertility
IRAS ID
236553
Contact name
Channa N. Jayasena
Contact email
Sponsor organisation
Imperial College London and Imperial College Healthcare NHS Trust
Clinicaltrials.gov Identifier
Duration of Study in the UK
4 years, 11 months, 31 days
Research summary
What do we know already? Infertility affects one in seven couples in the UK. Infertility puts enormous strain on
personal relationships, and can be socially marginalising for affected couples. Nearly half of the time, infertility is caused by the male partner having a low sperm count (‘male factor infertility’). There is currently no treatment to increase a man’s sperm count, which represents an important and unmet healthcare need. Being overweight or Obese is a major cause of male infertility. Excessive fat tissue interrupts hormonal signals within the brain and testicles which are required for sperm production. An observational study has shown that couples undergoing IVF treatment are more likely to get pregnant if the male partner loses modest amounts of weight in the year beforehand.What is the justification for doing this study?
A growing number of men with infertility are obese. No previous intervention, physiological study has investigated if short-term weight loss provides a physiological method of increasing sperm count in men.
What do we propose?
Study the effects of weight loss on sperm function in men with evidence of weight-related reproductive dysfunction. We will compare different degrees of low energy diet (LED) with standard NHS dietary advice. We will also study the physiological patterns of hormone secretion which may regulate how weight loss influences sperm function in men. We will also check to see if weight loss affects quality of life and pregnancy rates in men with weight-related reproductive dysfunction trying to conceive.What impact will the study have for the NHS?
There exists no evidence-backed therapy for improving sperm count in couples with male infertility.
This research could help the NHS develop better ways of treating couples with male infertility.
Lay summary of study results: The purpose of this study was to examine the role of weight loss on men’s reproductive capacity studying the changes that occur in parameters examined on a semen analysis (a test that assesses a man’s ability to conceive).
We conducted two studies:
- Study A: Men with obesity aged 18-60 years with normal sperm concentration as seen on the semen analysis (this study had 24 participants in total)
- Study B: Men with reduced sperm concentration (sperm concentration <15 millions/ml) (This study had 43 participants in total)
Protocol: The participants were given either 800Kcal/day (low energy diet) for 12-weeks consisting of meal replacement products (such as shakes, soups and bars) followed by a 4-week period of solid food reintroduction, or control, brief dietary intervention (NHS healthy eating), with a 16-week observation period. Semen parameters were compared at the beginning and at the end of the study.
Results: We found that low energy diet caused more weight loss compared with the healthy eating NHS advice in men taking part in both studies. Specifically, men on meal replacement lost on average 14.4 Kg versus 6.3 kg with NHS health eating in study A. Men lost on average 17.6 Kg with meal replacement versus 1.8 kg with NHS healthy eating in study B.
Of all the parameters we tested on semen analysis, we noticed a difference in motility of sperm (the ability of the sperm to move efficiently) with both dietary interventions.
Study A: Total motility increased by 25% and progressive motility increased by 29% with low energy diet. Total motility increased by 17% and progressive motility increased by 20% with NHS healthy eating.
Study B: Total motility increased by 49% and progressive motility increased by 59% with low energy diet. Total motility increased by 16% and progressive motility increased by 33% with NHS healthy eating.No differences were seen in the other sperm parameters such as sperm concentration, sperm count and morphology.
Conclusion: Low energy diet or healthy eating based on NHS advice may be sufficient to improve sperm motility in men with obesity.
NB: Total motility refers to the percentage of sperm that is moving, and progressive motility refers to the percentage of sperm with the ability to move rapidly.REC name
London - Queen Square Research Ethics Committee
REC reference
18/LO/0376
Date of REC Opinion
5 Apr 2018
REC opinion
Further Information Favourable Opinion