Shrimp

An Important Message About ShrimpWe have placed shrimp on our "10 Most Controversial WHFoods List." This list was created to let you know that even though some foods (like shrimp) can make an outstanding contribution to your meal plan, they are definitely not for everyone. Shrimp can be difficult to find in high-quality form; can be more commonly associated with adverse reactions than other foods; and can present more challenges to our food supply in terms of sustainability. More details about our 10 Most Controversial WHFoods can be found here.

What's New and Beneficial About Shrimp

Shrimp are an unusually concentrated source of the antioxidant and anti-inflammatory nutrient called astaxanthin. It's not unusual for a single 4-ounce serving of shrimp to contain 4 milligrams of astaxanthin. Astaxanthin is a carotenoid that is receiving special attention in the latest health research, primarily for its anti-inflammatory and antioxidant properties. Release of inflammatory messaging molecules (like tumor necrosis factor alpha and interleukin 1B) is suppressed by astaxanthin, and so is unwanted oxidation of fats in immune cells. In animal studies, risk of colon cancer is lowered by intake of astaxanthin, and immune-related problems of diabetes are also reduced. It's the antioxidant and anti-inflammatory properties of astaxanthin that seems to explain these disease-related benefits. Since few commonly consumed fish (with the exception of salmon) can provide us such concentrated amounts of astaxanthin, shrimp may be making a unique health contribution in this way.

At 56 micrograms in every 4 ounces, shrimp is an excellent source of the antioxidant mineral selenium. Recent research studies show that the selenium contained in shrimp can be well-absorbed into the human body. In one study, we've seen an estimate of about 80-85% for total selenium absorption from this shellfish. Since selenium deficiency has been shown to be a risk factor for heart failure and other forms of cardiovascular disease, as well as for other problems including type 2 diabetes, compromised cognitive function, and depression, shrimp may have a unique role to play in your meal plan if your health history places you at special risk in any of these areas.

Shrimp is often included on the "avoid" list for persons wanting to minimize their dietary intake of cholesterol. The 220 milligrams of cholesterol contained in a 4-ounce serving of shrimp makes this approach a legitimate concern. However, despite its high cholesterol content, several recent research studies have noted some desirable aspects of the fat profile in shrimp. One of these desirable aspects is shrimp's omega-3 fat content. Four ounces of shrimp provides about 350-375 milligrams of omega-3 fatty acids, including about 50% EPA (eicosapentaenoic acid) and 50% DHA (docosahexaenoic acid). EPA and DHA are especially important omega-3s for cardiovascular and nervous system health. In addition to this great mixture of omega-3s, shrimp also provides an outstanding ratio of omega-3:omega-6 fats. There are approximately three times as many omega-3s as omega-6s in shrimp. Since higher ratios of omega-3:omega-6 are associated with decreased risk of many chronic diseases—including obesity, high blood pressure, and type 2 diabetes—this aspect of shrimp's fat content is a huge plus. Finally, it is interesting to note that according to recent studies, cholesterol is not the only sterol in shrimp. This type of fat is found in smaller amounts in the form of beta-sitosterol, campesterol, and brassicasterol. While chemically similar to cholesterol, these other sterols function as anti-inflammatory molecules and they are associated with decreased levels of LDL-cholesterol, which would be considered a health benefit by many researchers. When looked at from this broader perspective, risks related to the high cholesterol content of shrimp might be overshadowed by its omega-3 and sterol composition—but we will need future studies to help us understand more about the big picture involving shrimp and fat. As always, if you have concerns that have you need to be cautious about cholesterol intake, discuss the inclusion of shrimp in your diet with your healthcare practitioner.

If you are planning to eat wild-caught, cold-water shrimp, the Monterey Bay Aquarium Seafood Watch has determined that your best overall choices in this category of shrimp are British Columbia spot prawns, California coonstripe shrimp (caught using submerged pots), and Oregon pink shrimp. (You probably won't be able to tell from a label whether your shrimp have been pot-caught, so you will need to talk to your fishmonger or the fishery itself in order to determine this information.)

If you are concerned about environmental consequences when consuming farmed shrimp, the Monterey Bay Aquarium Seafood Watch recommends that you restrict your intake to shrimp that have been raised in a fully re-circulating system. These systems make direct use of filtered seawater or try to recreate the mineral composition of seawater in freshwater. (You will often need to contact the supplier in order to determine whether this type of farming system was used.) Pacific white shrimp (Litopenaeus vannamei) can make an excellent choice when farmed in this way.

While U.S. farmed, freshwater shrimp are not widely available in the marketplace, they are also recommended by the Monterey Bay Aquarium Seafood Watch as a Best Choice when choosing shrimp.

Shrimp, large, steamed
4.00 oz
(113.40 grams)

Calories: 135
GI: very low

NutrientDRI/DV

 selenium102%

 vitamin B1278.3%

 protein51.6%

 phosphorus49.5%

 choline36.1%

 copper32.2%

 vitamin B319%

 zinc16.8%

 vitamin E16.6%

 vitamin B615.8%

 omega-3 fats14.1%

 pantothenic acid11.8%

 vitamin A11.3%

This chart graphically details the %DV that a serving of Shrimp provides for each of the nutrients of which it is a good, very good, or excellent source according to our Food Rating System. Additional information about the amount of these nutrients provided by Shrimp can be found in the Food Rating System Chart. A link that takes you to the In-Depth Nutritional Profile for Shrimp, featuring information over 80 nutrients, can be found under the Food Rating System Chart.

Health Benefits

Description

History

How to Select and Store

Tips for Preparing and Cooking

How to Enjoy

Individual Concerns

Nutritional Profile

References

Health Benefits

Anti-Inflammatory and Antioxidant Support

We don't usually think about seafood as a source of antioxidants, but shrimp features at least two unique antioxidants in its nutrient composition: the xanthophyll carotenoid called astaxanthin, and the mineral selenium.

Astaxanthin

Astaxanthin is the primary color pigment in many shrimp, and it helps provide their tissue with its red and orange shades. While many reddish-orange foods get their color from other carotenoids (or from flavonoids), shrimp are especially concentrated in this one particular type of carotenoid. (Astaxanthin often accounts for at least two-thirds of all carotenoids in shrimp.) It's not unusual for a 4-ounce serving of shrimp to contain 4 milligrams of astaxanthin.

Astaxanthin is a carotenoid that is receiving special attention in the latest health research, primarily for its anti-inflammatory and antioxidant properties. Release of inflammatory messaging molecules (like tumor necrosis factor alpha and interleukin 1B) is suppressed by astaxanthin as is the unwanted oxidation of fats in immune cells. In animal studies, risk of colon cancer is lowered by intake of astaxanthin, and immune-related problems of diabetes are reduced. Since few fish (with the exception of salmon) can provide us with more concentrated amounts of astaxanthin, shrimp is likely to provide us with some unique health benefits in this context.

Selenium

In the world of antioxidants, few enzymes are more important in our body than glutathione peroxidase (GPO). GPO helps protect most of our body systems from unwanted damage by oxygen-containing molecules. It is critical in body systems like the lungs, where exposure to these molecules is especially high. GPO is an enzyme that cannot function without the mineral selenium.

At 45 micrograms in every 4 ounces, shrimp is an excellent source of this antioxidant mineral. Shrimp is not only rich in selenium; research studies show that the selenium found in shrimp can be well-absorbed into the human body. In one study, we've seen an estimate of about 80-85% for total selenium absorption from this shellfish. In addition to risk of problems involving lung function, selenium deficiency has been shown to increase our risk of heart failure and other forms of cardiovascular disease, as well as for other problems including type 2 diabetes, compromised cognitive function, and depression. If your health history places you at special risk in any of these areas, shrimp may be an especially valuable food in your meal plan due to its selenium content.

Protein and Peptide Support

At 6 grams per ounce, shrimp is very good source of protein. In fact, among all WHFoods, shrimp ranks as our 8th best source of high-quality protein! The protein richness of shrimp is one of the reasons this shellfish is relied on in so many different culinary traditions.

When the protein in fish is broken down during digestion, smaller protein fragments called peptides are formed. Recent research studies have shown that many of these peptides have unique properties, including the ability to stimulate release of the hormone cholecystokinin (CCK) from cells that line our intestinal tract. Release of CCK is important for many reasons, including the role of CCK in regulating appetite. Our feeling of satiety (lack of appetite) is partly related to the levels of CCK in our digestive tract. By helping trigger release of CCK, shrimp peptides may play a role in helping us feel full. In the long run, this feeling of satiety may also be an advantage in helping to decrease our risk of obesity. Research on shrimp peptides and satiety is in its early stage, and largely limited to animal studies at this point. But we expect to see increasing interest in this area of shrimp and health.

Other Health Benefits

At a mere 7 calories per shrimp, we can eat a relatively large amount of shrimp without using up too many of our daily calories. For example, a person eating 1,800 calories per day could consume 20 shrimp and only be "spending" about 8% of his or her daily calories. This very low calorie cost would not be so remarkable if it were not for the fact that shrimp provides us with significant amounts of so many nutrients. We usually have to eat foods with a far greater calorie content to get the nutrient richness provided by shrimp. For example, those same 20 shrimp that provide us with about 140 calories also provide us with 25 grams of protein, almost 2 mcg of vitamin B12, as well as contributing minerals such as copper, magnesium, phosphorus, and zinc. In addition to vitamin B12, shrimp also provides us with most other B vitamins—such as niacin, choline, vitamin B6, and pantothenic acid—in significant amounts. The overall nutrient richness of shrimp gives it the ability to help balance out our nutrient intake in a wide variety of areas.

Description

Shrimp are crustaceans (just like lobsters and crabs) and they belong to a category of living things called arthropods. Like all arthropods, shrimp have their skeleton on the outside instead of the inside (it's called an exoskeleton) and this outer skeleton is one of the features that gives shrimp their unusual look - almost like having a head shield that blocks out all of their features except their eyes, mouth opening, and antennae. In the U.S., consumers don't typically eat the outer skeleton, heads, or tails of shrimp, even though these parts are often rich in nutrients and commonly consumed in other countries. Shrimp accounts for about 25% of all seafood sold in the United States.

The terms "shrimp" and "prawns" can be confusing. Even scientists often use these words inconsistently. In the popular press and in many restaurants, larger shrimp—often from freshwater habitats—are referred to as "prawns," while smaller shrimp—often from saltwater habitats—are called "shrimp." In terms of size, "large" typically means that you get about 40 or less per cooked pound (in comparison to about 50 for "medium" and 60 for "small"). But from a science perspective, both shrimp and prawns can come from saltwater or freshwater, and there is no absolute standard for measuring small, medium, or large. In this article and throughout our website, we'll be using the word "shrimp" as a general term that includes all species—even those which might be referred to as "prawns" in some research studies or in some restaurants.

Many people ask about the way shrimp sizes (small, medium, large, jumbo) are determined. While there is no precise method typically used for shrimp sizing, count per pound is the most common method used. (Count per pound refers to the number of shrimp that you get when you purchase or consume one pound.) With small cooked shrimp, that number is usually around 60. With medium cooked shrimp, it falls to about 50 (since the shrimp are bigger, and each one weighs more). For large shrimp, the count per pound is about 40. For jumbo shrimp the count per pound is about 30.

Traditionally, shrimp have grouped together into categories based on their natural habitats. Warm-water shrimp come from tropical waters in southern parts of the world, and cold-water shrimp come from northern climates. Many warm-water shrimp belong to one specific family called Penaeidae. Tiger prawns, tiger shrimp, and Indian prawns are members of this family. Many cold-water shrimp belong to a second family called Pandalidae. Spot shrimp, striped shrimp, dock shrimp, humpback shrimp, Northern shrimp, and Northern prawns are members of this second family. You'll find white shrimp, pink shrimp, and brown shrimp that come from both water-warm and cold-water regions.

Both warm-water and cold-water shrimp belonging to these two families are saltwater shrimp. They are found in many of the world's oceans and seas, where they are typically caught by trawling.

Freshwater shrimp is a third category based on habitat. Just like the name implies, freshwater shrimp are not native to oceans and seas but to non-salt waters including lakes, rivers, and streams. Freshwater shrimp belong to a scientific category of living things (infraorder) called Caridea.

Unfortunately, the traditional ways of classifying shrimp listed above are no longer adequate for understanding shrimp in the marketplace due to the quick rise of shrimp farming and globalization of the food supply. It's become common for shrimp to be removed from their native habitat and raised in farm settings that don't always resemble their native conditions. Today, the vast majority of shrimp available in U.S. groceries are farmed shrimp, and the quick rise in shrimp farming has raised concerns among many consumers about the health safety and environmental safety of shrimp. For more information about these concerns, please see our Individual Concerns section.

As described above, it's possible to find white shrimp, pink shrimp, and brown shrimp that are native to warmer southern waters as well as older northern ones. However, the flesh of virtually all shrimp—when cooked—turns a vibrant shade of pink.

History

Shrimp and other shellfish were enjoyed in the world's Mediterranean region during the early centuries AD. Classical Greek and Roman texts include shrimp recipes and descriptions of fishing practices. During most of shrimp's culinary history, farming was not used as a method of shrimp production. Shrimp were caught in pots or traps—not only by hand, but also in relatively small amounts. During certain periods of history, the labor-intensive nature of shrimp fishing turned shrimp into a delicacy that was both rare and costly.

Beginning in the 1400-1500's, trawling became a more widespread method for catching shrimp. Trawling refers to the attachment of a large net behind a fishing boat (trawler) that gets dragged through the water as a means of trapping the fish. Shrimp trawlers became a way of catching more shrimp more quickly, and with less manpower. However, large nets ended up trapping other sea creatures, not just shrimp. This problem—which became known as "by-catch"—continues to this day. For example, in 1989, the U.S. Congress passed a law banning the import of wild-caught shrimp from Thailand because Thai shrimp trawlers had failed to install turtle excluder devices (TEDs) that could help prevent sea turtles from getting caught up in the fishing nets.

Beginning in the 1970's, a new trend began to emerge in the shrimp industry. This new trend was shrimp farming. Many factors led to the development of shrimp farming, including depletion of wild shrimp stock, technological developments in aquaculture (the raising of fish in containment facilities), globalization of the food supply, and economic opportunities associated with large-scale shrimp production. In what has been called the "Blue Revolution," world production of shrimp went from 25,000 metric tons in the 1970's to more than 750,000 metric tons in less than two decades. Today there are more than 25,000 shrimp farms in Thailand alone, and shrimp farms line the coastal areas of many Asian countries, including Vietnam, Indonesia, and China. India, Myanmar (Burma), Bangladesh, Australia, and the Philippines are also important shrimp farming countries, as are the Central American countries of Ecuador, Guatemala, and Honduras as well as the South American countries of Colombia, Venezuela, and Peru. In North America, Canada, Mexico, and the United States also produce important amounts of farmed shrimp. Many individuals have concerns about the consequences of shrimp farming for the environment as well as for human health. For more information about these concerns, please see our Individual Concerns section.

How to Select and Store

Just as with any seafood, it is best to purchase shrimp from a store that has a good reputation for having a fresh supply. Get to know a fishmonger (person who sells the seafood) at the store so that you can have a trusted resource from whom you can purchase your seafood.

When you will be preparing the shrimp should influence your decision as to whether you should buy fresh or frozen shrimp. Frozen shrimp offer the longest shelf life, as they are able to be kept for several weeks, whereas fresh shrimp will only keep for a day or two. We think about fresh shrimp as a very perishable food, ideally eaten on the same day as they are purchased.

Fresh shrimp should have firm bodies that are still attached to their shells. They should be free of black spots on their shell since this indicates that the flesh has begun to break down. In addition, the shells should not appear yellow or gritty as this may be indicative that sodium bisulfate or another chemical has been used to bleach the shells.

Smell is a good indicator of freshness; good quality shrimp have a slightly saltwater smell. Since a slightly "off" smell cannot be detected through plastic, if you have the option, purchase displayed shrimp as opposed to those that are prepackaged. Once the fishmonger wraps and hands you the shrimp that you have selected, smell them through the paper wrapping and return them if they do not smell right. When fresh shrimp have been left out for too long, some people describe them as having an "ammonia" smell.

Color can also be an indicator of poor fresh shrimp quality. Unless you are purchasing spotted or striped shrimp, you should not see dark spots or rings of any kind. These markings are usually a sign of deterioration.

When storing any type of seafood, including shrimp, it is important to keep it cold since seafood is very sensitive to temperature. Therefore, after purchasing shrimp or other seafood, make sure to return it to a refrigerator as soon as possible. If the shrimp is going to accompany you during a day full of errands, keep a cooler in the car where you can place the shrimp to make sure it stays cold and does not spoil.

The temperature of most refrigerators is slightly warmer than ideal for storing seafood. Therefore, to ensure maximum freshness and quality, it is important to use special storage methods so as to create the optimal temperature for holding the shrimp.

One of the easiest ways to do this is to place the shrimp in a zip-lock bag in a baking dish layered with ice or icepacks. Place ice or icepacks over the shrimp as well. The baking dish and shrimp should then be placed on the bottom shelf of the refrigerator, which is its coolest area. Replenish ice one or two times per day. Shrimp can be refrigerated for up to two days although it should be purchased as close to being served as possible.

You can extend the shelf life of shrimp by freezing it. To do so, wrap it well in plastic and place it in the coldest part of the freezer where it will keep for about one month.

To defrost shrimp place it in a bowl of cold water or in the refrigerator. Do not thaw the shrimp at room temperature or in a microwave since this can lead to a loss of moisture and nutrients, and can increase risk of contamination.