According to Gram Research analysis, a 2024 case-control study of 600 Iranian men found that high salt intake increased infertility odds by 71%, while high trans fat intake increased odds by 78%. Men eating the most salt and trans fats had significantly higher rates of infertility compared to those eating the least, suggesting that reducing these unhealthy dietary components may support male fertility.
A new study of 600 Iranian men found that eating too much salt and trans fats may be linked to male infertility. Researchers compared men who couldn’t have children with men who could, and looked at what they ate over a year. Men who ate the most salt had a 71% higher chance of infertility, while those eating the most trans fats had a 78% higher chance. Interestingly, sugar’s effect on fertility seemed to depend on a man’s weight. These findings suggest that diet quality matters for male reproductive health, though more research is needed to understand exactly why.
Key Statistics
A 2024 case-control study of 600 Iranian men found that those consuming the highest amounts of dietary sodium had 71% higher odds of infertility (OR 1.71, 95% CI: 1.05-2.80) compared to men consuming the least sodium.
In the same 2024 study of 600 men, those in the highest consumption group for trans fatty acids had 78% higher odds of infertility (OR 1.78, 95% CI: 1.03-3.05) compared to the lowest consumption group.
Among normal-weight men in the 2024 Iranian study, those consuming the most sugar had 3.47 times higher odds of infertility (OR 3.47, 95% CI: 1.38-8.72) compared to those consuming the least sugar.
A 2024 case-control study published in Scientific Reports examined 600 Iranian men and found substantial associations between dietary sodium and trans fatty acids intake and male infertility odds, independent of other dietary factors.
The Quick Take
- What they studied: Whether eating high amounts of salt, sugar, and trans fats affects a man’s ability to have children
- Who participated: 600 Iranian men aged 20-55 living in Isfahan: 300 men diagnosed with infertility and 300 men with normal fertility
- Key finding: Men eating the most salt had 71% higher odds of infertility, and men eating the most trans fats had 78% higher odds, compared to those eating the least
- What it means for you: If you’re a man concerned about fertility, reducing salt and trans fat intake may be worth discussing with your doctor. However, this is one study, and more research is needed before making major dietary changes
The Research Details
This was a case-control study, which means researchers compared two groups of men: those with infertility problems and those without. They asked 600 men in Iran detailed questions about everything they ate over the past year using a 168-item food questionnaire. This type of study is good at finding connections between diet and health problems, but it can’t prove that one thing directly causes another.
The researchers carefully measured how much salt, sugar, and trans fats each man consumed. They then looked at whether men eating the most of these substances were more likely to have infertility problems. They also adjusted their results to account for other factors that might affect fertility, like age, weight, and lifestyle habits.
This approach allowed them to see patterns in eating habits between fertile and infertile men, though they couldn’t prove that changing diet would fix infertility.
Case-control studies are useful for studying health problems that don’t happen to everyone, like infertility. By comparing men with and without the condition, researchers can spot dietary patterns that might be involved. This study is important because no one had previously looked at salt, sugar, and trans fats together in relation to male fertility.
The study was published in Scientific Reports, a respected journal. The researchers used a validated food questionnaire, meaning it’s been tested and proven reliable. They adjusted for many confounding factors (other things that could affect results). However, the study only included Iranian men, so results may not apply to all populations. Also, because it’s a case-control study, it shows association but not definite cause-and-effect.
What the Results Show
Men in the highest salt consumption group had 71% higher odds of infertility compared to men eating the least salt. This means if you imagine 100 men with low salt intake, about 71 more men in the high salt group would have infertility problems. The difference was statistically significant, meaning it’s unlikely to be due to chance.
For trans fats, the pattern was similar. Men eating the most trans fats had 78% higher odds of infertility than those eating the least. Trans fats are unhealthy fats found in processed foods, fried foods, and some baked goods.
Sugar showed a more complicated pattern. Overall, sugar intake wasn’t clearly linked to infertility across all men. However, among normal-weight men specifically, those eating the most sugar had 3.47 times higher odds of infertility. Surprisingly, among overweight or obese men, higher sugar intake was actually associated with lower infertility odds—though researchers noted this unexpected finding needs further investigation.
The study highlighted that overall diet quality matters for male fertility. The researchers noted that sodium, sugar, and trans fats often go together in processed foods, so the combined effect of poor diet quality may be more important than any single nutrient. The different sugar findings based on weight suggest that body weight and diet interact in complex ways affecting fertility.
This is the first study to examine sodium, sugar, and trans fats together in relation to male infertility. Previous research has shown that overall diet quality affects male fertility, and that antioxidant-rich foods help sperm health. This study adds to that knowledge by identifying specific unhealthy components of diet that may harm fertility.
The study only included men in Isfahan, Iran, so results may not apply to other populations with different diets and genetics. Because it’s a case-control study, researchers asked men to remember what they ate over the past year, which can be inaccurate. The study shows association, not proof of cause-and-effect—eating salt doesn’t necessarily cause infertility, but infertile men happened to eat more salt. The unexpected sugar findings in overweight men need explanation and further study.
The Bottom Line
Men concerned about fertility should consider reducing salt and trans fat intake as part of a healthy diet (moderate confidence based on this single study). Focus on eating whole foods, limiting processed foods, and reducing fried foods. Discuss specific dietary changes with a doctor or nutritionist, especially if you’re experiencing infertility (high confidence recommendation). These dietary changes also benefit overall health, so they’re worth doing regardless.
Men trying to conceive or concerned about fertility should pay attention to this research. Men with normal weight may want to be particularly mindful of sugar intake. Anyone interested in improving diet quality for overall health should note these findings. This research is less relevant for men not concerned about fertility, though the dietary recommendations benefit everyone.
Diet changes typically take 2-3 months to affect sperm quality, since sperm take about 74 days to develop. You might notice improved energy and health benefits from reducing salt and trans fats within weeks, but fertility-specific improvements would take longer to assess.
Frequently Asked Questions
Can diet really affect a man’s ability to have children?
Yes, research shows diet affects male fertility. A 2024 study found men eating high amounts of salt and trans fats had 71-78% higher infertility odds. While diet alone doesn’t determine fertility, it’s an important factor worth addressing.
What foods have trans fats that I should avoid?
Trans fats are found in fried foods, many baked goods, margarine, and processed snacks. Check nutrition labels for ‘partially hydrogenated oils.’ Choosing grilled foods, whole grains, and fresh foods instead reduces trans fat intake significantly.
How much salt is too much for male fertility?
The study didn’t specify exact amounts, but general health guidelines recommend under 2,300 mg daily. The 2024 research showed men eating the most salt had higher infertility rates, so reducing processed foods (major salt sources) is a practical step.
Does sugar affect male fertility the same way in all men?
The 2024 study found sugar’s effect depends on weight. Normal-weight men eating high sugar had 3.47 times higher infertility odds, but the pattern differed in overweight men. This suggests body weight and diet interact in complex ways.
How long does it take for diet changes to improve fertility?
Sperm take about 74 days to develop, so fertility improvements typically appear after 2-3 months of dietary changes. You’ll likely notice improved energy and health benefits from reducing salt and trans fats within weeks.
Want to Apply This Research?
- Track daily sodium intake (target: under 2,300 mg per day) and trans fat intake (target: under 2 grams per day) using the app’s food logging feature. Log weekly averages to see trends over time.
- Replace processed and fried foods with whole foods like grilled chicken, vegetables, and whole grains. When shopping, check nutrition labels for trans fats and sodium content. Swap one processed food per week for a healthier alternative.
- Review sodium and trans fat intake monthly. Set a goal to reduce both by 20% over three months. Track any health improvements and energy levels. If trying to conceive, monitor fertility markers alongside dietary changes.
This research shows an association between high salt and trans fat intake and male infertility in an Iranian population, but does not prove these foods directly cause infertility. Results may not apply to all populations. If you’re experiencing infertility, consult a fertility specialist or urologist for proper diagnosis and treatment. Dietary changes should complement, not replace, medical evaluation and treatment. Always discuss major dietary changes with your healthcare provider, especially if you have underlying health conditions or take medications.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.