356 Part III: Muscle Foods
Other Components
Seafood, like other animal products, contains cho-
lesterol. The cholesterol content in fish and mollusks
ranges from 40 to 100 mg/100 g portion and is low-
er than in other meat such as beef, pork, and chick-
en. The shellfish, shrimp, and prawns, however, are
quite high in cholesterol—195 mg /100 g portion of
shrimp. The cholesterol content of shrimp is of in-
terest to individuals with cardiovascular disease who
are advised to limit dietary cholesterol to 300–400
mg/day. However, diets high in total fat and saturat-
ed fat also increase the risk for cardiovascular dis-
ease, and both shrimp and prawns contain negligible
amounts of fat.
HEALTHATTRIBUTES
In the history of mankind, fish has been considered
to have special health attributes, especially in vari-
ous ethnic populations. Recently, scientific research
has confirmed certain claims and raised controversy
in relation to others. Seafood is a rich source of
omega-3 fatty acids and may be good for the heart.
Fish is being recommended for people of all ages to
prevent a variety of disorders. Fish is also being pro-
moted for women during pregnancy, for children at
risk for asthma, and in the elderly to reduce the risk
of Alzheimer’s disease. However, pregnant women
and children have been advised to limit fish to pre-
vent the risk of mercury toxicity. Natural habitats
are becoming polluted with mercury that is taken up
and stored in some varieties of fish. Fish farming is a
rapidly growing enterprise and has the benefit of
controlling the food and water supply to avoid possi-
ble contamination of fish with toxic materials.
Fish and shellfish are an important part of a
healthy diet. Fish and shellfish contain high quality
protein and other essential nutrients, are low in satu-
rated fat, and contain two omega-3 fatty acids, eicosa-
pentoic acid (EPA) and docosahexanoic acid (DHA).
The American Heart Association recommends that
healthy adults eat at least two servings of fish a
week (12 ounces) especially varieties that are high
in omega-3 fatty acids, such as mackerel, lake trout,
herring, sardines, albacore tuna, and salmon.
Fish oil can help reduce deaths from heart dis-
ease, according to evidence in reports from the Agen-
cy for Healthcare Research and Quality (AHRQ,
http://www.ahrq.gov/clinic/epcindex.htm#dietsup)..) A sys-
tematic review of the available literature found evi-
dence that long-chain omega-3 fatty acids, the bene-
ficial component ingested by eating fish or taking a
fish oil supplement, reduce not only the risk for a
heart attack and other problems related to heart and
blood vessel disease in persons who already have
these conditions, but also their overall risk of death.
Although omega-3 fatty acids do not alter total cho-
lesterol, HDL cholesterol, or LDL cholesterol, evi-
dence suggests that they can reduce levels of triglyc-
erides—a fat in the blood that may contribute to
heart disease.
The AHRQ review reported evidence that fish oil
can help lower high blood pressure slightly, may
reduce the risk of coronary artery reblockage after
angioplasty, may increase exercise capability among
patients with clogged arteries, and may possibly
reduce the risk of irregular heart beats—particularly
in individuals with a recent heart attack. Alpha-
linolenic acid (ALA), a type of omega-3 fatty acid
from plants such as flaxseed, soybeans, and walnuts,
may help reduce deaths from heart disease, but to a
much lesser extent than fish oil.
Based on the evidence to date, it is not possible to
conclude whether omega-3 fatty acids help improve
respiratory outcomes in children and adults who have
asthma. Omega-3 fatty acids appear to have mixed
effects on people with inflammatory bowel disease,
kidney disease, and osteoporosis, and no discernible
effect on rheumatoid arthritis.
Depending on the stage of life, consumers need
to be aware of both the benefits and risks of eating
fish. Fish may contain mercury, which can harm an
unborn baby or young child’s developing nervous
system. For most people, the risk from mercury by
eating fish and shellfish is not a health concern.
However, the Food and Drug Administration (FDA)
and the Environmental Protection Agency (EPA)
are advising women who may become pregnant,
pregnant women, nursing mothers, and young chil-
dren to avoid some types of fish known to be high in
mercury content.
The risks from mercury in fish and shellfish
depend on the amount of fish and shellfish eaten and
the levels of mercury in the fish and shellfish. Nearly
all fish and shellfish contain traces of mercury, but
two varieties of fish high in omega-3 fatty acids
(mackerel and albacore tuna) may contain high
amounts of mercury. Larger fish that have lived
longer have the highest levels of mercury because