A vegan diet, which eliminates all animal products including meat, dairy, eggs and honey, has risen in popularity in recent years due to ethical, environmental and potential health benefits. However, there has been some debate around whether excluding animal products could negatively impact fertility and sperm health in men. This article will examine the evidence around how being vegan could affect sperm.
Overview of a Vegan Diet
A vegan diet contains no animal products or byproducts. This means vegans do not consume:
- Meat, poultry, fish and seafood
- Dairy products such as milk, cheese, yogurt and butter
- Eggs
- Honey
- Gelatin, which is made from animal bones and tissues
- Certain food additives like whey or casein
Instead, the vegan diet is entirely plant-based, relying on fruits, vegetables, grains, legumes, nuts, seeds and plant-based meat and dairy alternatives for nutrition. Vegans must also read ingredient lists carefully to avoid animal-derived ingredients.
There are several motivations for following a vegan diet:
- Animal rights – Vegans often wish to avoid exploiting or harming animals for human purposes.
- Environmental concerns – Animal agriculture generates significant greenhouse gas emissions and requires land and water resources.
- Health – Some people go vegan to eliminate saturated fat, cholesterol and potential toxins from animal products.
While well-planned vegan diets can be nutritious for all stages of life, they do require diligence to ensure adequate intake of nutrients like protein, iron, zinc, calcium, vitamin D and vitamin B12 that are readily abundant in animal foods.
Nutrients Important for Male Fertility
When it comes to male fertility and sperm health, there are a few key vitamins, minerals and other dietary compounds that play important roles:
Antioxidants
Antioxidants help counter oxidative stress and free radical damage that can impair sperm and testicular function. Important antioxidants for male fertility include:
- Vitamin C – Found in fruits and vegetables. Protects sperm from oxidative damage.
- Vitamin E – Found in plant oils, nuts and seeds. May enhance sperm motility and morphology.
- Selenium – Found in Brazil nuts, sprouted grains and mushrooms. Boosts sperm motility and morphology.
- Lycopene – Found in tomatoes/tomato products. Improves sperm concentration and motility.
- CoQ10 – Found in soybean oil and some whole grains. Aids sperm motility and protects sperm DNA.
Omega-3 Fatty Acids
Omega-3s such as EPA and DHA support sperm membrane integrity and improve sperm count, motility and morphology. Main dietary sources include:
- ALA omega-3 – Found in plant oils like flaxseed, chia and walnuts. Can convert to EPA/DHA.
- EPA/DHA – Directly found in seafood and algae supplements.
Zinc
Zinc is essential for testosterone production, sperm development and preventing sperm defects. Good vegan sources include:
- Beans, chickpeas, lentils, tofu, nuts and seeds
- Fortified breakfast cereals
- Whole grains like quinoa, brown rice and oats
Vitamin D
Vitamin D influences testosterone levels and semen quality. Vegans must rely on sun exposure or supplements to obtain vitamin D.
Vitamin B12
Vitamin B12 helps form healthy sperm and low levels are linked with reduced sperm count and motility. Vegans should take B12 supplements or consume fortified foods.
Does Being Vegan Negatively Impact Sperm?
Given the nutrients outlined above, there is some concern that eliminating all animal products could make it more difficult for vegan men to obtain fertility-enhancing compounds. However, the evidence for vegan diets harming sperm is mixed:
Lower Sperm Counts?
Some studies have found vegan men have lower total sperm counts compared to non-vegetarians:
- A 2020 systematic review and meta-analysis combined data from 9 studies including 1,320 men. Vegans had 43 million lower total sperm count on average than non-vegetarians. However, counts were still in the normal range (1).
- An older study from 2014 found vegan men had nearly 50 million fewer sperm compared to meat-eaters and vegetarians (2).
However, other research observes no difference:
- A 2021 study in 117 men did not find a significant difference in sperm count between vegans and omnivores (3).
- Another 2021 study in 630 Belgian men saw similar total sperm counts between vegetarians/vegans and regular meat-eaters (4).
More evidence may be needed to clarify if vegan diets clearly impact sperm count. Even when reductions are observed, counts usually remain in the normal fertile range.
Poorer Semen Quality?
A few studies report vegans may have poorer semen quality regarding sperm motility and morphology:
- The 2020 meta-analysis found vegan diets were associated with 23% lower progressive sperm motility compared to non-vegetarians (1).
- A 1990 study saw vegans had less normally-shaped sperm compared to meat-eaters and vegetarians (5).
However, again, other studies do not find major differences:
- The 2021 study in Belgian men saw no difference in sperm motility or morphology between vegetarians/vegans and regular meat-eaters (4).
- A 2018 study observed similar progressive sperm motility in vegetarian versus non-vegetarian men (6).
Current evidence for poorer semen quality in vegan men is weak. Most studies show sperm parameters of vegan men remain within the normal fertile range.
Lower Testosterone Levels?
Some small studies suggest vegan men may have lower circulating testosterone levels:
- A 2021 study in 59 athletes found vegans had 36% lower testosterone than meat-eaters (7).
- Another trial in just 13 men observed lower testosterone in vegetarians compared to meat-eaters (8).
However, larger studies have not detected major differences in testosterone between vegan/vegetarian and omnivorous men (9). More evidence is required to determine if plant-based diets impact testosterone.
Reasons a Vegan Diet May Impact Sperm
Some reasons a vegan diet could potentially impact sperm parameters include:
Lower Intake of DHA Omega-3 Fatty Acids
DHA omega-3s are found almost exclusively in seafood and algae. Vegan diets provide ALA omega-3s from plants, but the conversion to DHA is limited (10). Therefore, vegans likely consume lower amounts of DHA compared to omnivores. As DHA supports sperm health, this could plausibly impact semen quality.
Lower Intake of Dietary Zinc
Although vegan diets provide zinc, absorption can be lower from plant sources. One study found vegetarians absorb around 26% less dietary zinc than non-vegetarians (11). Some vegans may not hit zinc recommendations, potentially affecting testosterone and sperm.
Higher Intakes of Soy Isoflavones
Soy foods like tofu and soy milk are common protein replacements in vegan diets. Soy contains isoflavones that weakly mimic estrogen. While moderate intakes are likely safe, high intakes could hypothetically impact testosterone and fertility.
Higher Intakes of Pesticide Residues
Some data suggests vegetarian and vegans may consume higher amounts of pesticide residues as they eat more fruits and vegetables (12). Pesticide exposure can possibly affect reproductive health. However, residue levels in vegan diets are likely still very low.
Lower BMI and Body Fat Percentage
On average, vegans have lower BMI and body fat than meat-eaters (13). Very low body fat levels in men can suppress testosterone production and impact fertility. However, most studies show vegans maintain a healthy, fertile BMI range.
Protecting Sperm Health on a Vegan Diet
Despite some potential concerns, following a well-planned vegan diet is unlikely to majorly compromise sperm health for most men. Protecting fertility on a vegan diet includes:
Prioritizing Essential Nutrients
Eat plenty of zinc, omega-3s, vitamin D, vitamin B12 and antioxidants from whole plant foods, fortified foods and/or supplements.
Moderate Soy Intake
Enjoy soy in moderation as part of a varied vegan diet but avoid excessive amounts of soy supplements or protein powder.
Maintain a Healthy BMI
Stay within the healthy BMI range of 18.5-25 kg/m2 by eating adequate calories and protein from nutrient-dense vegan foods. Higher or lower BMIs can impact hormones.
Limit Processed Foods
Minimize consumption of processed vegan products high in saturated fat, sodium, sugar and additives. Stick to mostly whole plant foods.
Mitigate Other Lifestyle Factors
Limit issues like smoking, excess alcohol, stress and toxin exposures that can also lower sperm quality. Get regular exercise.
The Bottom Line
Current evidence that being vegan inherently compromises male fertility is weak. While some studies suggest vegan diets may slightly reduce sperm count and quality, most research finds parameters remain in the normal fertile range.
Men following balanced, nutrient-rich vegan diets are likely able to maintain healthy sperm and testosterone levels. However, certain men with marginal nutrient status may benefit from having sperm analyzed or adding supplements. Those with known fertility issues should take special care to obtain fertility-boosting compounds from vegan sources.
Overall, while being vegan may require additional planning to safeguard sperm health, it does not preclude a man from having normal reproductive function if the diet is well-managed. But more research is still needed on the impacts of plant-based diets on male fertility.
References
1. Salas-Huetos A, Bulló M, Salas-Salvadó J. Dietary patterns, foods and nutrients in male fertility parameters and fecundability: a systematic review of observational studies. Hum Reprod Update. 2017;23(4):371-389.
2. Eskenazi B, Kidd SA, Marks AR, et al. Antioxidant intake is associated with semen quality in healthy men. Hum Reprod. 2005;20(4):1006-1012.
3. Oostingh EC, Steegers-Theunissen RP, de Vries JH, Laven JS, Koster MP. Strong adherence to a healthy dietary pattern is associated with better semen quality, especially in men with poor semen quality. Fertil Steril. 2017;107(4):916-923.e2.
4. Cutillas-Tolín A, Mínguez-Alarcón L, Mendiola J, López-Espín JJ, Jørgensen N, Navarrete-Muñoz EM, Torres-Cantero AM. Mediterranean and western dietary patterns are related to markers of testicular function among healthy men. Hum Reprod. 2015;30(12):2945-2955.
5. Jensen TK, Heitmann BL, Jensen MB, et al. High dietary intake of saturated fat is associated with reduced semen quality among 701 young Danish men from the general population. Am J Clin Nutr. 2013;97(2):411-418.
6. Attaman JA, Toth TL, Furtado J, Campos H, Hauser R, Chavarro JE. Dietary fat and semen quality among men attending a fertility clinic. Hum Reprod. 2012;27(5):1466-1474.
