South Africans as most of the rest of the world are increasingly
conscious of the importance of sensible eating habits. A well balanced, nutritious diet and
regular exercise are vital factors in a healthy lifestyle.
Nutritionists have known for years that seafood is a source of
top-quality protein. Seafood can make a significant contribution to the nutrient needs of all
consumers, especially growing children and the elderly.
Nutrition is the net effect of the process by which an organism
ingests and uses foods for growth and maintenance of the body. Foods are composed of specific
nutrients; protein, fats, carbohydrates, vitamins, and minerals. These nutrients serve as the
raw material and energy needed for the body to carry out all of its functions.
Seafood is high in Protein
Proteins are large molecules composed primarily of amino acids. Our body's digestive enzymes break down the protein we consume to release amino acids which are in turn used to make new proteins the body uses for growth and maintenance. There are nine amino acids which the body cannot manufacture; we must get them from food. They are called essential amino acids. Seafood contains all nine essential amino acids; therefore, it is an excellent choice for meeting our daily protein needs. An added advantage of seafood is that its protein is highly digestible. The protein in seafood is more readily broken down and absorbed than the protein in red meats and poultry. This advantage makes seafood an excellent food choice for people of all ages. Fish contain 17 to 25% protein with an average content of 19 g/100 g.
Seafood is low in Fat and Calories
What is a calorie? Many people count calories or "weight-watch," but do they really understand what they are counting? The food calorie or kilogram calorie is a measure of energy, defined as the amount of heat required to raise the temperature of one kilogram (approximately 2.2 pound) of water one degree Celsius. The calories in food supply the energy the body needs to carry out all its many functions. The nutrients in food that supply energy are fat (nine calories per gram) and carbohydrates and proteins (four calories per gram each). Most varieties of finfish and shellfish are low in fat, less than 5%, and, in many cases, less than 1% fat. Therefore, most varieties of seafood provide 100 to 200 calories per 3-1/2 ounces.
The Dietary Guidelines published by the USDA and the Department of Health and Human Services advice us to eat less total fat. More specifically reduce overall fat consumption from approximately 40 to 30% of energy intake." This means that of all the calories we derive from the food we eat, only 30% of them should come from fat. The Dietary Guidelines go on to suggest the type of fat. "Reduce saturated fat consumption to account for about 10% of total energy intake, and balance that with polyunsaturated and monounsaturated fats, which should account for about 10% of energy intake each."
Seafood goes a long way to helping consumers achieve these dietary goals. The total amount of fat in seafood is very low in most varieties and the fat is rich in polyunsaturated fatty acids. It is typically the way seafood is prepared that can add fat, such as sauces and deep-fat frying, not from the fish itself. Cooking techniques such as broiling, barbecuing, poaching, microwaving, or steaming on a rack will help reduce the amount of fat in the total fish recipe. On a unit calorie basis, seafood can provide a broad range of nutrients. Increasing the intake of fish is compatible with a reduction of calorie intake and saturated fatty acid intake.
Seafood is high in vitamins and minerals
There are two types of vitamins, fat soluble (A, D, E, and K) and water soluble (C and the B complex). Vitamins A and D are found in fish liver oils and in small amounts in the fatty tissues of fish. Seafood is generally low in fat and we usually don't consume fish liver oils; therefore, seafood is not considered a significant source of the fat-soluble vitamins. There is little Vitamin C found in seafood, but it is considered an excellent source of the B complex vitamins, particularly niacin, B12 and B6. Thiamine is also found in Seafood’s in fair amounts.
Seafood is an excellent source of Minerals
Fish are one of the most important sources of
calcium. The soft bones of small fish such as sardines and smelts and canned
varieties such as salmon are especially valuable sources of calcium. Other
minerals in seafood include zinc (oysters and crustaceans), iron (oysters,
bluefish, and shrimp), copper (oysters, crabs, and lobster), potassium
(mussels, scallops, and clams), and iodine, phosphorus, and selenium (all
seafood in general. Fresh seafood is low in sodium. For those who have to
restrict the intake of sodium, fresh seafood is an excellent choice,
although you should limit your intake of processed seafood’s such as smoked,
cured, and most canned seafood’s. Salt is added in the processing of these
seafood products as it is in imitation seafood products.
Seafood is low in Cholesterol
Cholesterol levels are not significant in most
seafood products. Finfish are generally quite low in cholesterol, with
shellfish having low to moderate amounts. In the past, shellfish have been
excluded from low cholesterol diets because they were believed to be high in
cholesterol. New sophisticated measuring techniques have indicated that
cholesterol levels of many molluscan shellfish are much lower than was
previously thought. In fact, molluscs, such as clams, oysters, scallops, and
mussels were found to have a large percentage of non cholesterol sterols
present that appear to have a positive effect. These sterols inhibit the
absorption of cholesterol eaten at the same meal.
levels in such crustaceans as crab and lobster are similar to that found in
the dark meat of chicken. While the cholesterol in prawn varies considerably
by specie, it generally is 1-1/2 to 2 times higher than in the dark meat of
chicken, but far less than in eggs. Because shellfish contain very little
saturated fat, they are no longer excluded from typical low cholesterol
diets Again, seafood fits right in when trying to meet the U.S. dietary goal
--reduce cholesterol consumption to about 300 mg a day. Fish averages about
50-90 mg cholesterol per 3-1/2 ounces. Shellfish tend to contain slightly
higher amounts of cholesterol; thus crustaceans (crab, lobsters, and shrimp)
contains 60- 100 mg/3-1/2 ounces and molluscs (clams, oysters, scallops),
40-110 mg/3-1/2 ounces. Squid and octopus may contain relatively high
levels, 250 and 122 mg/3-1/2 ounces, respectively.
The above indicates that seafood consumption
is a good idea that is compatible with optimum dietary practices
recommendations and those substitutions of fish for other foods can help
maintain a balanced nutrient intake compatible with a low-fat diet. The
consumption of fish oils may provide added significant health benefits. Fish
oils may provide a protective effect in minimizing the development of
several chronic degenerative diseases and may have a therapeutic effect in
certain cases, for example, arthritis, atherosclerosis, and
Fish oils are composed of fatty acids which consist of a chain of carbon
atoms with a carboxyl group at one end and a methyl group (CH3) at the
other. Polyunsaturated fatty acids (PUFA) contain several double bonds
between carbon atoms in the chain; the more double bonds, the higher the
degree of unsaturation. Fish oils are unique in that they contain a large
portion of highly unsaturated fatty acids and some fatty acids with an odd
number of carbons in the chain.Many fish oils are composed primarily of the
omega-3 fatty acids.
They differ from most plant oils which contains mainly the omega-6 fatty
acids. The most important omega-3 fatty acids found in seafood are
eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Fish and
shellfish ingest and accumulate omega-3 fatty acids through the food chain
from algae and phytoplankton, the primary producers of omega-3 fatty acids.
Man can only produce saturated and omega-9 fatty acids, which means we have
to get the omega-3 fatty acids we need through our daily foods.
How do omega-3 fatty acids prevent or improve human diseases?
After several medical studies, it now
appears that the omega-3 fatty acids help keep our bodies from over-producing
eicosanoids, a group of hormone-like substances that can, in large amounts,
contribute to arthritis, asthma, heart disease, stroke, and related disorders.
The eicosanoids are normally derived from the omega-6 PUFA arachidonate, found
predominantly in plant oil. Omega-3 fatty acids act as an antagonist to
eicosanoid synthesis, thereby lowering their production. It also forms modified
eicosanoids less active than the normal compounds. A diet that balances plant
foods with fish foods and their omega-3 fatty acids remains an effective and
enjoyable way to combat health problem
Omega-3s can help prevent the
spread of some cancers:
Tests have shown that eating more oily fish
and/or taking fish oil capsules may help prevent the spread of some cancers, in
particular, breast cancer. This is partly explained by the fact that fish oil
boosts the immune system. This, in turn, helps destroy cancer cells that may not
have been removed by surgery. Omega-3s also help curb metastasis.
Omega-3s help relieve inflammatory diseases
Studies of patients suffering from rheumatoid
arthritis have shown that eating a daily portion of 200g of salmon can
dramatically reduce symptoms of inflammation, tenderness and swollen joints.
Omega-3s can improve the skin condition of psoriasis sufferers
Psoriasis, an inflammatory skin disease which
causes redness and itching of the skin, can be significantly reduced in
patients taking as little as 1.8g of fish oil per day.
Most nutrition researchers now say that eating
seafood once or twice a week may be beneficial in preventing coronary heart
The high content of PUFA in seafood lowers
serum cholesterol levels. Omega-3 fatty acids change the critical balance of
certain blood components called lipoproteins, thus reducing the low-density
lipoproteins (LDL) and very low density lipoproteins (VLDL) that deposit
cholesterol along the artery walls. The omega-3 fatty acids also lower the
levels of triglycerides, another type of fat involved in heart disease.
Also, the omega-3 fatty acids form a different pattern of prostaglandin,
diminishing the clotting of blood cells, reducing the number and stickiness
of blood platelets, and making red blood cells more flexible so that they
flow more smoothly.
Other health problems that may be controlled
or alleviated by the consumption of omega-3 fatty acids from fish are
asthma, arthritis, diabetes, multiple sclerosis, hypertension, migraine
headaches, cancer, and some kidney diseases.
How much seafood should we eat?
"Do your Health a Favour eat Seafood at least
three times a week"
Fresh seafood is an excellent source of
proteins, a good source of minerals, and some vitamins, and it is low in
fats, cholesterol, and sodium. In general, seafood is one of the most
nutritionally balanced foods. A seafood diet helps control weight and goes a
long way toward preventing heart disease. Besides, a seafood diet is a
delicious way to accomplish heart-healthy eating habits