Why You Should Avoid Eating the Heads of Shrimp and Prawns

Health authorities, including the Spanish Agency for Food Safety and Nutrition (AESAN), advise consumers to limit the intake of the dark meat found in the heads of crustaceans like shrimp and prawns to reduce exposure to cadmium. While these shellfish are nutrient-dense, the head accumulates heavy metals that can pose long-term health risks if consumed habitually.

Why is cadmium a health concern?

Cadmium is a heavy metal found naturally in the environment and as a byproduct of industrial activity. According to AESAN, the human body has no biological need for cadmium, yet it accumulates slowly in the liver and kidneys, where it can remain between 10 and 30 years. Chronic exposure to high levels of cadmium is linked to renal dysfunction and the demineralization of bones.

Where does cadmium accumulate in shellfish?

In crustaceans such as shrimp and prawns, cadmium concentrates primarily in the hepatopáncreas, an organ located within the head. Data reviewed by European food safety authorities indicate that consuming the head of these crustaceans can increase cadmium intake by up to four times compared to eating only the white muscle of the abdomen. While European regulations set maximum limits for cadmium in the edible abdomen and appendages, the cultural practice of consuming the head content significantly increases the total dietary intake of the metal.

Is it safe to eat shrimp occasionally?

Occasional consumption of the head of shrimp or prawns does not represent a significant health risk for the general population. The primary concern is the cumulative effect of long-term, frequent intake. Health experts, including Andrea Calderón, a professor of nutrition at the European University, emphasize that risk is tied to the habit of regular consumption. Vulnerable groups, including children, pregnant women, and individuals with existing renal conditions, should exercise particular caution regarding their total cumulative exposure to heavy metals.

How to reduce exposure during preparation

Cooking methods can influence the concentration of contaminants in seafood. According to nutritional guidance, boiling shrimp or prawns may allow a portion of the cadmium to leach into the cooking water, potentially reducing the final concentration in the animal. Conversely, cooking methods such as grilling tend to concentrate fats and liposoluble substances, which may retain higher levels of contaminants.

Nutritional Profile vs. Safety

Despite the risks associated with the head, shrimp and prawns remain valuable components of a balanced diet. They provide:

• High-quality proteins.
• Essential minerals, including selenium, zinc, and iodine.
• Vitamin B12 and omega-3 fatty acids, which support cardiovascular health.

To balance these benefits with safety, nutritionists recommend prioritizing the meat of the abdomen and limiting the consumption of the head to minimize the intake of heavy metals.