Researchers studied over 700 American adults to see if a type of healthy fat called hexadecenoic acid could help prevent glaucoma, a serious eye disease that can cause blindness. They found that people who ate more of this fat had fewer cases of glaucoma. For every extra gram of this fat people ate daily, their glaucoma risk dropped by about 39%. While these results are promising, scientists say we need more research to confirm that eating this fat actually prevents the disease, not just that people who eat it happen to have healthier eyes.

The Quick Take

  • What they studied: Whether eating more of a specific type of healthy fat (hexadecenoic acid) is connected to having less glaucoma, a disease that damages the eye and can cause blindness.
  • Who participated: 705 American adults who were 40 years old or older. Researchers looked at what they ate using food diaries and checked their eyes for signs of glaucoma using special imaging.
  • Key finding: People who ate more hexadecenoic acid had significantly lower rates of glaucoma. Eating just 1 extra gram per day of this fat was linked to a 39% lower chance of having glaucoma.
  • What it means for you: This suggests that eating foods with this healthy fat might help protect your eyes, but it’s too early to say for certain. More research is needed before doctors can recommend it as a glaucoma prevention strategy. If you’re concerned about glaucoma, talk to your eye doctor about all the ways to protect your vision.

The Research Details

This was a cross-sectional study, which means researchers took a snapshot in time of a large group of Americans and looked at their eating habits and eye health all at once. They used data from a national health survey called NHANES that tracked what people ate over two days using detailed food diaries. At the same time, eye doctors examined photos of participants’ eyes to check for signs of glaucoma. The researchers then used statistical tools to see if people who ate more hexadecenoic acid (a type of monounsaturated fat) were less likely to have glaucoma.

This type of study is useful for spotting patterns and connections between diet and disease in real-world populations. Because hexadecenoic acid has natural anti-inflammatory properties, it makes sense to study whether it might protect the eyes. However, this study design can only show that two things are connected—it can’t prove that one causes the other, which is why the researchers are calling for future studies to confirm their findings.

The study used a nationally representative sample, meaning the participants were chosen to reflect the overall American population, which strengthens the findings. The researchers carefully adjusted their analysis to account for other factors that might affect glaucoma risk, like age, education, and diabetes. However, because this is a cross-sectional study, we can’t be completely sure the fat prevents glaucoma—people who eat this fat might have other healthy habits that protect their eyes. The study also relied on people remembering what they ate, which can sometimes be inaccurate.

What the Results Show

The main finding was clear: people who ate more hexadecenoic acid had less glaucoma. When researchers looked at the group eating the most of this fat compared to those eating the least, the high-intake group had significantly fewer cases of glaucoma. The relationship appeared to be linear, meaning the more of this fat people ate, the lower their glaucoma risk seemed to be—there wasn’t a point where eating more stopped helping. The statistical analysis showed this wasn’t likely due to chance, with a p-value of 0.018, meaning there’s only about a 1.8% chance these results happened randomly.

The protective effect was stronger in certain groups. Men showed a more pronounced benefit from eating more hexadecenoic acid than women. People with less formal education and those without diabetes also showed stronger protective associations. These differences suggest that hexadecenoic acid’s effects might vary depending on a person’s sex, education level, and overall health status.

This is one of the first studies to specifically examine hexadecenoic acid and glaucoma risk. Previous research has shown that various dietary fats and nutrients affect eye health, and that inflammation plays a role in glaucoma development. Since hexadecenoic acid has anti-inflammatory properties, this study builds on the general understanding that what we eat can influence eye disease risk. However, most previous eye health research has focused on other nutrients like omega-3 fatty acids and antioxidants.

The biggest limitation is that this study only shows association, not causation—we can’t prove that eating this fat prevents glaucoma. The study was also a snapshot in time, so we don’t know if the same people who ate this fat years ago still have healthy eyes. People’s memories about what they ate might not be perfectly accurate. The study also couldn’t account for all possible factors that might affect glaucoma risk, and the sample size, while reasonable, was relatively modest for detecting effects in subgroups.

The Bottom Line

Based on this research, there’s moderate evidence suggesting that including foods with hexadecenoic acid in your diet may be beneficial for eye health. However, this single study isn’t strong enough for doctors to make official recommendations yet. If you want to eat more of this fat, focus on including it as part of a generally healthy diet rich in fruits, vegetables, and other healthy fats. This is a low-risk approach since hexadecenoic acid is a natural component of foods. Confidence level: Moderate—this is promising but preliminary evidence.

Anyone over 40 should care about glaucoma prevention since the disease becomes more common with age. This research is especially relevant for men, people with lower education levels, and those without diabetes, since the study showed stronger effects in these groups. If you have a family history of glaucoma or other risk factors, this information might be particularly interesting to discuss with your eye doctor. However, this research shouldn’t replace regular eye exams, which are the best way to catch glaucoma early.

If hexadecenoic acid does protect against glaucoma, the benefit likely develops over months to years of consistent eating habits, not days or weeks. Glaucoma develops slowly, so any protective effect would also be gradual. You wouldn’t expect to notice changes in your vision or eye health immediately from dietary changes.

Want to Apply This Research?

  • Track your daily intake of hexadecenoic acid-rich foods (such as certain oils and animal products) in grams per day, aiming to monitor whether you’re consistently including these foods in your diet. Set a goal of 1-2 grams daily and log foods that contain this fat.
  • Add one hexadecenoic acid-rich food to your daily routine—this could be including certain oils in cooking, eating specific nuts or seeds, or incorporating other food sources. Start with one meal per day and gradually build the habit.
  • Track weekly averages of hexadecenoic acid intake rather than daily fluctuations. Every 3 months, review your eating patterns to ensure consistency. Schedule annual eye exams to monitor overall eye health, and discuss your dietary changes with your eye care provider.

This research suggests a possible connection between hexadecenoic acid intake and lower glaucoma risk, but it cannot prove that eating this fat prevents glaucoma. This study was conducted at one point in time and cannot establish cause and effect. Always consult with your eye doctor or healthcare provider before making significant dietary changes, especially if you have glaucoma, a family history of glaucoma, or other eye conditions. Regular eye exams remain the most important way to detect and manage glaucoma early. This information is for educational purposes and should not replace professional medical advice.