High Fish Consumption Could Possibly Influence Melanoma Risk

Key Takeaways:

• A study of over 490,000 mature Americans indicates a potential correlation between high fish consumption and an increased risk of developing melanoma over a 15-year span.
• The associated risk might not originate from the fish itself, but from pollutants such as mercury and PCBs found in some fish. However, these are only speculations and more research is needed to confirm this hypothesis.
• The study’s participants with the highest fish intake had a 22% greater risk of malignant melanoma, and a 28% increased risk of melanoma in situ, compared to those who consumed the least fish.
• Despite the potential risks, experts continue to recommend consuming fish due to its health benefits, which include improved heart and brain health. However, cooking methods such as baking or steaming are favoured over deep-frying, which can reduce the fish’s beneficial fats.
• While the relationship between fish consumption and melanoma risk is a topic of interest, the primary preventative measures remain limiting exposure to ultraviolet rays and regularly checking the skin for any changes.

Research involving over 490,000 mature Americans suggests that the highest 20% fish consumers may face approximately a 25% increase in the likelihood of developing disease over a 15-year duration, contrasted with the lowest 20% of fish eaters.

However, it’s crucial to note that these findings indicate only a correlation, not discerning seafood as the definite culprit.

The Broader Scope

An independent oncology dietitian underlines the need to look at the “bigger picture”.

Typically, fish is recognized as a healthy protein, often abundant in anti-inflammatory omega-3 fatty acids, as stated by Amy Bragagnini, of Mercy Health Lacks Cancer Center, in Grand Rapids, Mich.

In light of its proven advantages — encompassing improved heart and brain health — professionals frequently advise aiming for two 4-ounce servings of fish weekly, Bragagnini, who is also a spokesperson for the Academy of Nutrition and Dietetics noted.

She shared that fish is a “great alternative” for those desiring to reduce red and processed meats — which are linked to elevated risks of particular cancers, including colon and rectal cancers.

Fish and Melanoma?

Given these benefits, one may wonder why fish would be associated with melanoma, a disease primarily connected to sunburns and family history?

The root cause is ambiguous, shared lead researcher Eunyoung Cho. One possibility is that it’s not the fish, but pollutants — like mercury and PCBs — present relatively abundantly in some fish.

Previous studies have associated mercury exposure to increased melanoma and other skin cancers risks, Cho, a faculty member at Brown University’s Warren Alpert Medical School, in Providence, R.I mentioned.

However, she cautions, this contaminant hypothesis is just a speculation. “As the inaugural study to reveal this correlation,” Cho said, “more research is required to corroborate these findings before we advocate any dietary recommendations.”

Study’s Parameters

The study, based on 491,000 Americans aged between 50 and 71, spanned over 15 years. At the beginning, they filled out questionnaires regarding their diet, exercise, and smoking and drinking habits.

During the course of the study, just over 5,000 participants were diagnosed with malignant melanoma, with almost 3,300 developing melanoma in situ or superficial spreading malignant melanoma where cells are confined to the top surface of the skin.

Cho’s team discovered that individuals in the highest percentile for fish intake had a 22% greater risk of malignant melanoma, and a 28% increased risk of melanoma in situ, versus the least fish-consuming participants.

Lifestyle Factors Considered

This elevated risk persisted when the researchers accounted for other aspects like lifestyle habits, race, educational level, and region of residence.

It’s worth mentioning that the study missed particulars on individual’s personal sun habits, remarked Dr. William Dahut, Chief Scientific Officer for the American Cancer Society. It’s undetermined whether fish lovers were more likely to have outdoor hobbies, he added.

Dahut, who did not participate in the study, described it as “interesting,” and deserving of a detailed exploration.

However, he expressed, “I wouldn’t discourage people from eating fish due to fear of melanoma risk.”

Further Findings

Dahut also alluded to an unforeseen finding: Individuals who reported eating more non-grilled fish or canned tuna faced an increased risk of malignant melanoma. Conversely, those who consumed a high quantity of grilled fish actually exhibited a decreased risk.

Both Cho and Bragagnini concurred that this finding is challenging to decipher. It’s plausible, Cho speculated, that the type of fish consumed could make a difference, and future studies might investigate whether specific kinds of fish are linked to higher melanoma risk.

Recommendations

For now, Bragagnini advised focusing on a balanced diet, comprising generous amounts of plant foods such as vegetables, fruits, beans, nuts, and fiber-rich grains. As for fish, she recommended baking or steaming as opposed to deep-frying, which can deplete its beneficial fats.

When dealing with malignant melanoma, Dahut emphasized that the primary preventative measures remain the same: limiting exposure to ultraviolet rays — both from the sun or tanning beds- and checking the skin for new growths or changes to existing moles.

For more information:

The American Cancer Society offers advice on diet and lifestyle.