Scientists discovered that pumpkin peel powder can help protect fish from harmful chemicals in water. When fish were exposed to mercury and zinc—common water pollutants—those fed pumpkin peel showed much better health outcomes. The pumpkin peel reduced stress hormones, protected cells from damage, and prevented tissue injury in the fish’s brain and gills. This research suggests that adding pumpkin peel to fish feed could be a natural way to help aquatic animals survive in polluted environments, and it might eventually have applications for protecting other animals or even humans from similar chemical exposures.

The Quick Take

  • What they studied: Whether pumpkin peel powder could protect fish from the harmful effects of mercury and zinc in their water
  • Who participated: 160 young tilapia fish (a common food fish) weighing about one ounce each, divided into four groups and observed for two months
  • Key finding: Fish exposed to mercury and zinc without pumpkin peel had a 27.5% death rate and severe damage to their brains and gills. Fish that ate pumpkin peel-supplemented food showed significantly better survival rates and much less tissue damage, suggesting the pumpkin peel protected them from the toxic effects
  • What it means for you: While this study was done in fish, it suggests that natural plant-based foods like pumpkin may have protective properties against environmental toxins. However, this is early research in animals, and much more study is needed before any recommendations can be made for human health

The Research Details

Researchers divided 160 young tilapia fish into four equal groups. One group served as a control (normal conditions), one received only pumpkin peel powder in their food, one was exposed to contaminated water with mercury and zinc, and one received both the pumpkin peel supplement and was exposed to the contaminated water. All groups were monitored for two months while researchers measured various health markers in the fish’s blood, brain tissue, and gill tissue.

The contaminated water contained mercury at 0.05 mg/L and zinc at 7.00 mg/L—levels that can occur in polluted aquatic environments. The pumpkin peel was added to the fish food at a concentration of 12 grams per kilogram of feed. This design allowed researchers to see both the harmful effects of the pollutants and whether the pumpkin peel could reduce that harm.

Scientists measured multiple indicators of health including stress hormones (cortisol and norepinephrine), blood sugar levels, protective enzymes in the gills, and damage markers in cells. They also examined tissue samples under a microscope to see if there was physical damage to the brain and gill structures.

This research approach is important because it mimics real-world conditions where fish and other aquatic animals are exposed to multiple pollutants at once. Rather than studying just one chemical, the researchers used a mixture of mercury and zinc, which is more realistic. By comparing four different groups, they could clearly see what damage the pollutants caused and whether the pumpkin peel actually prevented that damage. This type of controlled experiment is the best way to determine if a natural substance has protective effects.

This study has several strengths: it used a reasonable sample size (160 fish), included proper control groups for comparison, measured multiple health markers rather than just one outcome, and examined both blood chemistry and actual tissue damage. The study lasted two months, which is long enough to see meaningful changes. However, the study was conducted only in fish, so results may not directly apply to other animals or humans. The research appears to be well-designed and published in a peer-reviewed journal, which means other scientists reviewed it before publication.

What the Results Show

Fish exposed to mercury and zinc without pumpkin peel supplementation showed severe negative effects. Their survival rate dropped to 72.5%, meaning about 1 in 4 fish died. These fish showed dramatically elevated stress hormones—cortisol and norepinephrine levels were much higher than normal, indicating their bodies were in a state of distress. Their blood sugar also increased significantly, another sign of stress.

In contrast, fish that received pumpkin peel powder in their food showed much better outcomes. Their survival rates improved substantially, and their stress hormone levels returned closer to normal. The pumpkin peel appeared to protect the fish’s cells from oxidative damage—a type of cellular injury caused by harmful chemical reactions. Markers of this damage (measured by malondialdehyde levels) were significantly reduced in fish that ate the pumpkin peel.

When researchers examined the fish’s brain and gill tissues under a microscope, they found extensive damage in fish exposed to the pollutants without pumpkin peel. The tissue showed signs of deterioration and cell death. However, fish that received pumpkin peel supplementation had much better-preserved tissue structure, with significantly less visible damage. This suggests the pumpkin peel actively protected the delicate tissues from the toxic effects of mercury and zinc.

The research revealed that mercury and zinc exposure triggered a cellular self-destruct program called apoptosis (programmed cell death). Multiple genes involved in this death pathway were activated at high levels in exposed fish. Pumpkin peel supplementation reduced the activation of these death-promoting genes. Additionally, the pollutants triggered something called endoplasmic reticulum stress—essentially, a malfunction in the cell’s protein-making machinery. Pumpkin peel appeared to reduce this stress response as well. The fish’s natural protective enzymes (like glutathione peroxidase) were depleted by the pollutants, but pumpkin peel helped maintain these protective systems.

This research builds on previous studies showing that pumpkin and related plants have antioxidant properties (meaning they protect against cellular damage). Earlier research has suggested that pumpkin contains beneficial compounds that can reduce inflammation and protect cells. This study is novel because it’s one of the first to test pumpkin peel specifically against a mixture of real-world pollutants in a living organism. The findings align with the known protective properties of pumpkin while providing new evidence that these benefits extend to protecting against heavy metal toxicity.

This study was conducted only in fish, so we cannot directly conclude that the same effects would occur in humans or other animals. The dose of pumpkin peel used (12 grams per kilogram of feed) was specific to fish and would need to be adjusted for other species. The study lasted only two months, so we don’t know if the protective effects would continue long-term or if fish would develop tolerance. The research doesn’t identify which specific compounds in pumpkin peel are responsible for the protective effects, so we can’t yet optimize the treatment. Additionally, the pollutant levels used were chosen for the study and may not represent all real-world pollution scenarios.

The Bottom Line

Based on this research, pumpkin peel supplementation appears promising for protecting aquatic animals from heavy metal pollution in fish farming operations. However, these findings are preliminary and limited to fish. For humans, this research is too early to make any dietary recommendations. If you’re interested in the potential benefits of pumpkin for your own health, continue eating it as part of a balanced diet, but don’t expect it to protect you from environmental toxin exposure. More research in mammals and eventually humans would be needed before any health claims could be made.

Fish farmers and aquaculture operations in areas with water pollution should find this research interesting, as it suggests a practical, natural way to improve fish health and survival rates. Environmental scientists studying pollution effects on aquatic life may find this useful. The general public should be aware that this research highlights the problem of heavy metal pollution in water systems. However, this research should not be used to make health decisions for humans at this time. People with specific health concerns should consult their healthcare provider rather than relying on this fish study.

In the fish studied, protective effects from pumpkin peel became apparent within the two-month study period. However, the timeline for any potential human applications would be much longer. If this research eventually leads to human studies, it would likely take 5-10 years of additional research before any recommendations could be made. For fish farming applications, benefits could potentially be seen within weeks to months of dietary supplementation.

Want to Apply This Research?

  • If using an app to track environmental health concerns, users could monitor their exposure to potential water contaminants by tracking their water source (tap, filtered, bottled) and any local water quality alerts. They could also track consumption of antioxidant-rich foods like pumpkin and note any health changes.
  • Users could increase their intake of pumpkin and pumpkin-based foods as part of a general antioxidant-rich diet. This might include adding pumpkin puree to smoothies, soups, or baked goods. While this won’t protect against environmental toxins, it supports overall cellular health through natural compounds.
  • Track consumption of antioxidant-rich foods weekly and monitor general wellness markers like energy levels, digestion, and overall health. Users could also monitor local water quality reports if available in their area and track any changes in water quality or health symptoms that might correlate with water conditions.

This research was conducted in fish and does not directly apply to human health or medical treatment. The findings are preliminary and should not be used to make health decisions for yourself or others. If you have concerns about exposure to environmental toxins or heavy metals, consult a qualified healthcare provider. Pumpkin is a food, not a medicine, and should not be used as a substitute for medical treatment. Always speak with a doctor before making significant dietary changes, especially if you have existing health conditions or take medications.