We don't usually think about seafood as a source of antioxidants, but shrimp features at least three unique antioxidants in its nutrient composition: the xanthophyll carotenoid called astaxanthin, and the minerals selenium and copper.
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 is possible for a 4-ounce serving of shrimp to contain 1-4 milligrams of astaxanthin. In animal studies, astaxanthin has been shown to provide antioxidant support to both the nervous system and musculoskeletal system. In addition, some animal studies have shown decreased risk of colon cancer to be associated with astaxanthin intake, as well as decreased risk of certain diabetes-related problems. Under natural conditions, shrimp get astaxanthin through their diet, by consuming smaller organisms that contain this carotenoid, including algae and zooplankton. When farmed, the astaxanthin content of shrimp depends on the composition of their feed. Both synthetic forms of astaxanthin and naturally occurring forms of astaxanthin have been used in shrimp farming, and the use of synthetic astaxanthin remains a topic of ongoing controversy. In general, when purchasing farmed shrimp, we believe that it makes sense to select shrimp that have consumed natural and plentiful amounts of astaxanthin from natural dietary sources including marine algae and zooplankton. You will find more recommendations regarding shrimp selection in our How to Select and Store and Individual Concerns sections below.
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 56 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.
Copper is also classified as an antioxidant mineral, and one of its key roles in our health is related to the function of an enzyme called copper-zinc superoxide dismutase (SOD). SOD is found in the major fluid compartment of our cells (called the cytosol) and it is known to play a major role in regulation of oxygen metabolism and prevention of oxidative stress. Shrimp is our only fish at WHFoods to qualify as a "very good" source of copper in our rating system and it stands out in this respect as a source of antioxidant minerals. Not be overlooked, of course, is the fact that we also rank shrimp as a good source of zinc—the second mineral required for effective SOD function.
At nearly 26 grams per 4-ounce serving, shrimp ranks as a very good source of protein at WHFoods, and provides over half of the Daily Value (DV) in each serving. In fact, among all WHFoods, shrimp ranks as our 8th best source of 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 (or any other food) is broken down during digestion, smaller protein fragments called peptides are formed. (Peptides are chains of amino acids. Proteins are too, but they are longer chains and more complicated in their structure.) Some relatively short peptides—consisting of only 10-25 amino acids—have been found to be present in partially digested shrimp proteins and appear able 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.
At only 7 calories per shrimp, we can eat a relatively large amount of this shellfish 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 or 50% of the Daily Value (DV).They also provide nearly 2 micrograms of vitamin B12—over 80% of the Dietary Reference Intake (DRI) level for adults. When this nutrient richness list for shrimp is continued across the list of other vitamins and minerals provided by this fish, it becomes striking how much nourishment can be provided by shrimp for less than 10% of a total day's calories.
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 ) and this outer skeleton (technically called an exoskeleton) 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 most other countries. Shrimp account for about 30% of all seafood consumed in the U.S. Out of 14-15 pounds of total seafood per year consumed by the average U.S. adult each year, about 4-5 pounds come from shrimp. (Salmon and tuna have typically engaged in a tug-of-war for second place, and are typically consumed in average amounts of approximately 2-3 pounds per year. Shrimp are produced, sold, and consumed in a variety of different forms, including fresh, frozen, breaded, cooked, dried, and in paste form. In addition, you will find shrimp that are peeled, unpeeled, veined, deveined, and with head on or head off.
It would be difficult to find a WHFood with greater diversity than shrimp. While we are accustomed to thinking about foods like potatoes as involving a wide variety of colors and shapes (for example, large brown russets, medium sized golds, or small fingerlength reds), there are hundreds of commercially important shrimp species and literally thousands of total species worldwide. Yet, there is no relationship between the species of a shrimp and its color. You can find pink, red, white, brown, blue, and green shrimp, but within each of these color categories can be found a wide variety of shrimp species. No less diverse are the habitats of shrimp. These remarkable crustaceans can live in freshwater, saltwater, brackish water, or a combination of habitats. (Brackish water—also sometimes called briny water—is simply water that falls in between freshwater and saltwater. It is more salty than freshwater and less salty than saltwater.) In terms of saltwater habitats, the Pacific, Atlantic, and Indian Oceans serve as the top three saltwater habitats for shrimp. Added to this unusual diversity of habitats is the tendency of some researchers to group shrimp together based on the average water temperature of their environment. Warm-water shrimp come from tropical waters in southern parts of the world, and cold-water shrimp come from colder northern waters.
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.
We have created the chart below to give you a better idea about the amazing diversity of shrimp. As you will see in the chart, there are numerous shrimp families, and within any given family, you will find examples of shrimp that are being referred to by a particular color, or by the name "prawn" versus "shrimp." However, these common names do not necessarily provide you with helpful information about the nutrient content of the shrimp, since that nutrient content typically depends more on the species of shrimp and its lifelong habitat (including of course, its diet).
|aztecus (brown shrimp)|
|brasiliensis (pinkspotted shrimp)|
|brevirostris (crystal shrimp, pink shrimp)|
|californiensis (yellowleg shrimp)|
|duorarum (pink shrimp)|
|paulensis (pink shrimp)|
|subtilis (southern brown shrimp)|
|chinensis (fleshy prawn)|
|indicus (Indian white shrimp)|
|merquiensis (banana prawn)|
|penicillatus (redtail prawn)|
|schmitti (white shrimp)|
|setiferus (white shrimp)|
|stylirostris (blue shrimp)|
|vannamei (Pacific white shrimp)|
|esculentus (brown tiger prawn)|
|monodon (black tiger shrimp)|
|semisulcatus (green tiger prawn)|
|Sicyoniidae (rock shrimps)|
|burkenroadi (spiny rock shrimp)|
|brevirostris (coral shrimp)|
|dorsalis (lesser rock shrimp)|
|ingentis (ridgeback rock shrimp)|
|lancifer (knight rock shrimp)|
|Solenoceridae (solenocerid shrimps)|
|mulleri (Argentine red shrimp)|
|robustus (royal red shrimp)|
|Solenocera (humpback shrimps)|
|agassizzi (kolibri shrimp)|
|crassicornis (coastal mud shrimp)|
|koelbeli (Chinese mud shrimp)|
|vioscai (humpback shrimp)|
|alaskensis (Alaskan bay shrimp)|
|crangon (brown shrimp)|
|franciscorum (California bay shrimp)|
|septemspinosa (sand shrimp)|
|norvegicus (Norwegian shrimp)|
|Palaemonidae (palaemonid shrimps)|
|malcomsonii (monsoon river prawn)|
|nipponense (oriental river prawn)|
|rosenbergii (giant freshwater prawn)|
|varians (Atlantic ditch shrimp)|
|Pandalideae (pandalid shrimps)*|
|bonnieri (whip shrimp)|
|leptocerus (bristled longbeak)|
|borealis (northern shrimp)|
|eous (northern pink shrimp)|
|hypsinotus (coonstripe shrimp)|
|abricii (Arctic eualid)|
|polaris (polar shrimp)|
|groenlandicus (spiny lebbeid)|
|lamellicornis (Dana's blade shrimp)|
|liljeborgii (friendly blade shrimp)|
|spinus (parrot shrimp)|
* The name "caridean shrimp" is also sometimes used to refer to panadalid shrimp from the Pandalideae family (and from three other shrimp families as well). It is based on a scientific classification rank called an "infraorder."
Unfortunately, there is no way to take this amazing diversity of shrimp species and narrow it down to some simple set of shrimp recommendations that is based primarily on species or habitat. Some natural habitats remain fairly healthy and well suited for shrimp harvesting, and other do not. Similarly, it is important to remember that about 55% of shrimp consumed in the U.S. and worldwide are presently farmed, and the quality of shrimp farming conditions can also vary widely. Some farmed shrimp are raised in fully recirculating, fully open, or other types of systems that are carefully monitored and that come closer to approximately natural conditions than other types of shrimp farms. In addition, the diet fed to farmed shrimp can vary widely, and in some cases incorporates natural feedstocks involving both algae and zooplankton.
As a result of these many different factors, some shrimp raised under farmed conditions may provide a favorable option to non-farmed shrimp that have lived in contaminated and/or overfished habitats. While we recognize the ongoing nature of environmental debates over farmed fish (aquaculture) versus caught fish (catch fishery), we believe that in today's marketplace—and based on research studies about the nutrient content of shrimp—your best bet when selecting shrimp is to follow the recommendations of an organization that continually monitors shrimp quality in the U.S. marketplace and makes recommendations based on a combination of actual marketplace and environmental factors rather than any single, pre-established criterion (for example, farmed versus caught, freshwater versus saltwater, Atlantic Ocean versus Pacific Ocean, large versus small, etc.). In our Individual Concerns section, we provide you with website links to some of seafood monitoring organizations that rank at the top of our recommendation list for making shrimp choices.
It's virtually impossible to find a continent or major world location in which shrimp has not been traditionally enjoyed as a part of local cuisine. Whether you look to North America, Central America, South America, Europe, the Mediterranean, Africa, the Middle East, Asia, Australia, or the Arctic, you will find traditions in which shrimp have been enjoyed as a regular part of the meal plan. That's why you will find 2014 imports of shrimp into the U.S. from about two dozen different countries, including India, Bangladesh, Thailand, Indonesia, Vietnam, Malaysia, China, Ecuador, Peru, Venezuela, Argentina, Honduras, Panama, Nicaragua, Canada, Mexico, and the Philippines. Similarly, you will find capture fisheries and aquaculture being practiced in most of these countries, as well as others.
About 55% of global commercial shrimp is currently farmed. Litopenaeus vannemei (Pacific white shrimp) is the most widely farmed single species. Other widely farmed species include Macrobrachium rosenbergii (giant freshwater prawn) and Penaeus monodon (black tiger shrimp). Crangon crangon (brown shrimp) are among the most widely caught shrimp species. Many observers expect shrimp farming to increase over the next decade, with a heightened focus on aquafeed management, broodstock, larviculture, and growout. It remains to be seen whether overall shrimp farming practices will be able to develop in ways that can further recognize and accommodate some of the barriers inherent with aquaculture, and whether the overall quality of farmed shrimp will compare favorably or unfavorably to overall quality of wild shrimp. As stated in the previous section, however, we believe that it does not make sense to purchase your shrimp based on any single criterion, regardless of whether that criterion is farmed versus caught, freshwater versus saltwater, etc. Instead, we believe that your best bet is to follow the recommendations of an organization that continually monitors shrimp quality and makes its recommendations based on a combination of many different factors. In our Individual Concerns section below, we provide practical recommendations in this regard.
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.
Contamination of ocean waters, overfishing of fish and shellfish species, quality of fish farming practices, potential detrimental effects of certain fishing methods on wildlife, and risk of exposure to fish contaminants (especially mercury) have become individual concerns for many consumers. (These concerns are not limited to shrimp, but extend to all seafood.) Luckily, two organizations in the U.S. have worked to evaluate all the issues listed above, and offer practical recommendations for making fish choices in light of these concerns. We encourage you to make use of the resources provided by both of these organizations. The first organization is the Monterey Bay Seafood Watch (www.seafoodwatch.org)
You can find practical recommendation for 65 different types of fish thanks to the work of Monterey Bay, as well as Best Choices, Good Alternatives, and Choices to Avoid. You can also download seafood guides specific to your region of the United States and a mobile app providing you with this information. The Monterey Bay Seafood Watch program is associated with the Monterey Bay Aquarium in Monterey Bay, California and run by the not-for-profit Monterey Bay Aquarium Foundation.
The second organization is the National Ocean and Atmospheric Administration Fish Watch (http://www.fishwatch.gov/). The National Ocean and Atmospheric Administration (NOAA) is a federal agency in Washington, D.C. that has used its FishWatch website to create educational, user-friendly profiles of over 100 fish and shellfish, with up-to-date information about fishing rate, habitat impacts, population, bycatch, species science, nutrient content, and marketplace availability. In comparison with the Monterey Bay Seafood Watch, the FishWatch site is more educational in nature, and is focuses on the providing of information that can be used to make informed seafood choices.
Crustacean shellfish, such as shrimp, are among the eight food types considered to be major food allergens in the U.S., requiring identification on food labels. For helpful information about this topic, please see our article, An Overview of Adverse Food Reactions.
Shrimp, large, steamed
GI: very low
|vitamin B12||1.88 mcg||78||10.4||excellent|
|protein||25.83 g||52||6.9||very good|
|phosphorus||347.00 mg||50||6.6||very good|
|choline||153.54 mg||36||4.8||very good|
|copper||0.29 mg||32||4.3||very good|
|iodine||46.00 mcg||31||4.1||very good|
|vitamin B3||3.04 mg||19||2.5||good|
|vitamin E||2.49 mg (ATE)||17||2.2||good|
|vitamin B6||0.27 mg||16||2.1||good|
|omega-3 fats||0.34 g||14||1.9||good|
|pantothenic acid||0.59 mg||12||1.6||good|
|vitamin A||102.06 mcg RAE||11||1.5||good|
Density>=7.6 AND DRI/DV>=10%
Density>=3.4 AND DRI/DV>=5%
Density>=1.5 AND DRI/DV>=2.5%