Lifestyle and Dietary Effects on Male Fertility

There is a large amount of information on the internet regarding things that you can do to improve semen analysis parameters and the chances of conception. In reality, the strength of the medical evidence to support their use is not particularly strong. Fortunately, most of these interventions are harmless. 

General recommendations

1. Avoidance of excessive heat. We know that excessive heat impairs sperm production. Avoid using hot tubs, saunas and jacuzzi tubs as even short term use may impair sperm production and have a negative effect on the mature sperm which have already been produced. Hot showers are perfectly fine.

2. Avoid toxins such as cigarette smoke and marijuana. These can impair sperm production and motility.

3. Moderate alcohol intake is fine.

4. Under no circumstances should testosterone (including anabolic steroids) or supplements for bodybuilding be taken. Ingestion of the substances can impair production of sperm, sometimes irreversibly

5. A healthy balanced diet with a mix of fruits, vegetables, protein and starches. It is unlikely that moderate intake of any one particular food impair his sperm production. However, soy products (e.g. tofu) contain substances which can have effects similar to estrogen and excessive consumption should be avoided.

Supplements, Natriceuticals, Vitamins and Other Treatments

The short answer is that there are no dietary supplements or vitamins that seem to improve the fertility potential in men. Read on if you want to know why.

Some of the most common questions from patients (men and their partners) revolve around the use of various types of supplements to enhance fertility. Historically, physicians (and others) have made recommendations that supplements such as folate, various antioxidants, vitamin C, zinc, L-carnitine, co-enzyme Q10 amongst others might be beneficial - you can include me (Dr. Poon) in that group. While the data was voluminous, it was generally of poor quality. However, there seemed to be little harm and patients generally feel better about doing something rather than nothing. In order to overcome some of the methodological issues, various authors (notably the people from The Cochrane Collaboration) have attempted to pool data from multiple studies in order to provide recommendations. The conclusion from the Antioxidants for male subfertility (Review) published in 2014 (DOI: 10.1002/14651858.CD007411.pub3.) was the following :

“There is low quality evidence from only four small randomized controlled trials suggesting that antioxidant supplementation in subfertile males may improve live birth rates for couples attending fertility clinics. Low quality evidence suggests that clinical pregnancy rates may increase. There is no evidence of increased risk of miscarriage but this is uncertain as the evidence is fo very low quality. Data were lacking on other adverse effects. Further large well-designed randomized placebo-controlled trials are needed to clarify these results.”

This was faint praise for the use of supplements and vitamins and was in stark contrast to the assertions of the nutraceutical industry that promised instant, almost miraculous results. Despite the Cochrane results, for years I have tepidly suggested that patients take the supplements I’ve mentioned above but cautioned that patients should not to ‘break the bank’ when purchasing or feel badly if they didn’t take the supplements.

Fortunately, two separate groups in 2020 published much better data from randomized controlled trials that has largely answered the question of benefit. The answer is that you can save your money and forego use of vitamins and supplements since the evidence shows no benefit. These 2 studies have methodological weakness, as does every randomized controlled trial, though those weaknesses are small and do not detract from the above advice. The primary difference between the recommendations from these studies and the assertions of the supplement industry, naturopathy and homeopaths is that everything in these studies is out in the open for all to scrutinize and the conclusions are supported by the data. The fact that they were published in 2 of the most prestigious medical journals speaks to the quality of the studies.

Frequently Asked Questions

Question: Will accupuncture improve my semen analysis or the chances of a pregnancy?

Answer: Probably not. To date, there have not been any good large scale trials. Studies, all with some serious methological flaws, have shown both benefit and harm with accupuncture. My take is that any fluctuations noted in the semen analysis profiles, for better or worse, are due to normal biological variation rather than any treatment effect. There had been evidence from methodologically flawed studies suggesting that accupuncture might increase the succes of embryo transfer in women. A recent well designed randomized controlled trial published in 2010 (Andersen in Reprod Biomed Online) has demonstrated no benefit. Accupuncture is unlikely to help or harm your chances of pregnancy. As always, do what your wife tells you.

Question: Are boxer shorts better than briefs?

Answer: There appears to be no difference in either semen analysis parameters nor the chances of conception depending on your underwear. This has been studied a fair amount. There does NOT seem to be any significant effect on the chances of pregnancy.

General Comments on Non-Medical Treatments

Whether non-medical interventions such as acupuncture, homeopathic, chiropractic or naturopathic treatments have beneficial effects on fertility is a common question. The answer is really quite simple - we really don’t know whether they are beneficial or conversely if they are harmful.

The primary issue is that naturopathy and homeopathy are not based on the scientific method. These groups have chosen to forego scientific scrutiny of their treatments and offer recommendations without evidence to support their use. The recommendation for treatments is entirely based on belief and opinion rather than scientific evidence. One must recognize that it is not enough to have a rationale for why a treatment might or should work. Such assertions should generate questions and hopefully spur investigations to find the truth of the matter. The scientific method is a process to answer such questions and has replaced belief and intuition. Use of the scientific method has provided the answers to questions that have resulted in the things you use every day - from your phone to the materials in the clothes and shoes that you wear to the advances in medicine that have allowed physicians and other members of the health care team to prolong and advance life. The key to understanding the scientific method is to appreciate that it is a process to get true answers to questions. It separates coincidence from causation and chance from effect.

Assertions of effectiveness of a treatment should be backed by evidence of effectiveness and this requires using the scientific method to compare a proposed treatment against doing nothing (or using a placebo). Blinded, randomized controlled trials continue to be the gold standard to evaluate treatments. Some types of questions are not readily answered or are impossible to answer with randomized controlled trials. In these cases, other types of investigation such as observational studies are necessary. In every case, however, the strengths and weakness as well as the validity and accuracy of the answers can be scrutinized and judged in the context of the methodology of the study. As with any human endeavour, they are subject to flaws but their strength is that they provide the best method to answer a question and are far more effective than human intuition and unfounded beliefs. Most anything else is simply guessing. Naturopathy and homeopathy assert an answer to a question without showing the work which makes it impossible to assess benefit or harm.

If you have questions about the effectiveness of an intervention, you have a right to ask your health care provider to the rationale and strength of the evidence for any intervention. In an ideal world, we would have double-blinded randomized controlled studies for everything we do. Not everything in traditional medicine meets this standard, but it is important to at least acknowledge where there is a lack of evidence. Caveat emptor ('buyer beware') applies if you cannot get a credible answer to your questions on effectiveness. The supplement and natriceutical industry is identical to the pharmaceutical industry in all respects - with two very important exceptions.

1. At present, the supplement industry is not required to demonstrate efficacy (effectiveness) of a treatment. Therefore the possibility of both benefit and harm exists. The current govermental regulations on supplements are a compromise which were designed to limit an excessive burden of regulation on substances which are mainly harmless or associated with minimal harm. The current absence of any regulatory requirement to prove the efficacy and safety of supplements imposes a specific legal requirement that supplement manufacturers are not permitted to make any claims regarding the efficacy of these substances on any specific medical condition. Even though doing so is a violation of US law, it is rarely enforced which often results in misleading and false claims in advertising. The FDA has a limited ability to enforce the the supplement industry, in large part because of underfunding.

2. There is no requirement to confirm the purity or content of any substance that is sold as a supplement. Some manufacturers are better than others. In 2010, the FDA began imposing Good Manufacturing Practice (GMP) regulations on the supplement industry to ensure that consumers were at least getting the substance that they were paying for, if not the desired effect. Compliance with GMP means that you are getting the substance you paid for, not a guarantee of effectiveness or absence of harm.