protect against coronary heart disease, as well as helping to develop strong bones and teeth. Shellfish are particularly rich in zinc, which is essential for healthy skin and muscles as well as fertility. Casanova reputedly ate 50 oysters a day. Texture and taste Over 33,000 species of fish and many more marine invertebrate species have been described. Bromophenols, which are produced by marine algae, gives marine animals an odor and taste that is absent from freshwater fish and invertebrates. Also, a chemical substance called dimethylsulfoniopropionate (DMSP) that is found in red and green algae is transferred into animals in the marine food chain. When broken down, dimethyl sulfide (DMS) is produced, and is often released during food preparation when fresh fish and shellfish are heated. In small quantities it creates a specific smell one associates with the ocean, but which in larger quantities gives the impression of rotten seaweed and old fish. Another molecule known as TMAO occurs in fishes and give them a distinct smell. It also exists in freshwater species, but becomes more numerous in the cells of an animal the deeper it lives, so that fish from the deeper parts of the ocean has a stronger taste than species who lives in shallow water. Eggs from seaweed contains sex pheromones called dictyopterenes, which are meant to attract the sperm. These pheromones are also found in edible seaweeds, which contributes to their aroma. However, only a small number of species are commonly eaten by humans. Health benefits There is broad scientific consensus that docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) found in seafood are beneficial to neurodevelopment and cognition, especially at young ages. The United Nations Food and Agriculture Organization has described fish as "nature's super food." Seafood consumption is associated with improved neurologic development during pregnancy and early childhood and more tenuously linked to reduced mortality from coronary heart disease. Fish consumption has been associated with a decreased risk of dementia, lung cancer and stroke. A 2020 umbrella review concluded that fish consumption reduces all-cause mortality, cancer, cardiovascular disease, stroke and other outcomes. The review suggested that two to four servings per week is generally safe. However, two other recent umbrella reviews have found no statistically significant associations between fish consumption and cancer risks and have cautioned researchers when it comes to interpreting reported associations between fish consumption and cancer risks because the quality of evidence is