Local Fish Liver - Vitamin A-rich and Safe

by Dr. Lois Englberger

Recent analyses on the liver of Pohnpei tuna and parrotfish show that they are high in the essential nutrient retinol (vitamin A). Also, the fish liver samples were found to be within safe limits of the natural contaminant mercury.

Fish liver and all types of liver are reported to be rich sources of vitamin A, as liver is the organ where vitamin A is stored. However, food composition tables had no data for the vitamin A content of fish liver and no data were available on fish liver from Pohnpei or other islands of the Federated States of Micronesia (FSM).

Health experts warn that mercury is a natural contaminant that may concentrate in organ meats. Studies are needed to confirm that local foods do not contain high mercury levels, as mercury damages the nervous system, especially the brain. If pregnant and breastfeeding women eat too much mercury, it can adversely affect the child's intelligence, coordination, and memory.

There are distinct differences in the appearance and taste of different fish liver. Yellowfin tuna liver (eh en karangahp) and two kinds of parrot fish liver (lidoi and mwahmw mei) are local delicacies and are often eaten as sashimi. Skipjack tuna liver (eh en kasuo) has a strong taste on its own, but is well-liked by many people when it is cooked and prepared as part of a dish. All these types of fish liver were analyzed. It was not possible to get samples of shark liver, which is eaten by many people in the Mortlocks and other parts of FSM.

The samples were prepared as composite samples, made up of cooked fish liver from a number of small fish (from 6 to 12 fish) weighing around 500 grams (about a pound) in weight. The fish liver themselves weighed from 1 to 60 grams. Two sets of samples were analyzed for retinol and mercury by the Institute of Applied Sciences of the University of the South Pacific in Suva, Fiji, in February and November 2002.

The retinol content ranged from 3200 µg/100g in the lidoi parrot fish to 204,012 µg/100g in the yellowfin tuna liver. A 60-gram portion (about 3 tablespoons) which was the average weight for the yellowfin tuna liver for the sample) would provide over 200 times the daily estimated requirements of a non-pregnant, non-breastfeeding woman. Pregnant women are advised to avoid liver because of the high levels and danger of toxicity, which could cause harm to the unborn child.

However, the general public is encouraged to eat small amounts, mixed with other food, in order to contribute to vitamin A status and good health. The amount of mercury was less than 1 mg/kg, which is the cut-off level for safety.

The Food and Drug Administration in Lenexa, Kansas, also analyzed the samples for mercury, and got very similar results as the Fiji laboratory, 0.029 mg/kg mercury in lidoi and 0.024 mg/kg in mwahmw mei.

Informants in FSM said that yellowfin tuna liver especially is well-liked. It is eaten, but often it may be used for bait or is discarded during cleaning before it is sold at the market. Some fishermen and government officers indicated that if the public health department could run a campaign on the value of fish liver and create a demand for fish liver, it would be possible to develop this new salable commodity item. Fishermen could collect the livers, bag them in a small plastic bag, and sell them. This could make a well-liked nutritious food available to the people at a low price. However, this would be a new product requiring a marketing campaign.

In summary, there are good sources of vitamin A from local FSM seafood, in particular fish liver, and it is safe to eat. One type of tasty liver (yellowfin tuna) is a nutritious food source that is presently underutilized.

NOTE: Much discussion has also been held in Kosrae on fish liver. They are called there by these names: esa in owlwohl (yellowfin tuna), esa in katsuo (skipjack tuna), and esa in mweshik (parrotfish).