Clam vs. Oysters — Health Impact and Nutrition Comparison

by Zvart Movsisyan | Last updated on June 02, 2023

Medically reviewed by Jack Yacoubian

Summary

Oyster is richer in mineral content, especially in zinc and copper. In contrast, the clam is the winner in terms of vitamins, particularly with B group vitamins.

Both foods are widely consumed; moreover, oysters are used in pearl production.

Choosing the right places to enjoy these foods is very important to avoid fatal results. Besides, oysters and clams can be sources of allergy and intoxication for people with a weakened immune system, especially for children and pregnant women. Enjoy them, and don’t ignore the related health hazards.

Table of contents

Introduction

Main Differences

Nutritional Content

Minerals

Vitamins

Macronutrients comparison

Health Impact

Health benefits

Nervous system benefits
Anti-oxidant, anti-fatigue, and muscle wasting
Sleep and reproductive health

Risks

Cardiovascular health
Public and environmental health

Cooking and Storing

References

Introduction

Are you a big fan of seafood? How about a bit of comparison between clams and oysters? Both clams and oysters are bivalve mollusks – shellfish with two-part shells and two muscles. Although both belong to the phylum Mollusca and their texture is slimy, and they are similar in a variety of ways, there are plenty of differences between them as well.

Main Differences

Did you know that clams usually live in freshwater, are mobile, and move around on their muscle foot by burying themselves in the sand under the water? On the other hand, oysters live in saltwater. Except for the first weeks of their initial stages when oysters still have a muscle foot, they are mainly attached to the same spot, usually a hard surface such as a rock, their entire lives. They prefer to stay near the water’s surface, and we can easily notice them in the mud when it is low tide.

Their taste is different; clam is saltier and stronger, whereas oysters are buttery in taste.

They are commonly used in soups and chowders.

Clam has a shiny and smooth shell, whereas oyster shell is more calcified and rough. Both are used as a food in many countries, but clam is preferred due to its taste and tenderness.

Besides, oysters are known for producing pearls, while clams do not. A pearl is formed when an oyster produces nacre, the mix of calcium and protein, against the foreign matter trapped in the shell. The most common type of oyster is the Pacific oysters, Eastern oysters, European flats (European flat oysters), and Olympia oysters.

Nutritional Content

In today’s competitive food market, shellfish play an important role due to their nutritional content. Although clam and oysters are both goldmines of various essential substances, we will look at the differences in their nutritional contents.

Minerals

You can easily notice from the charts below that oyster is enormously richer in copper, manganese, and zinc, considerably richer in iron, and magnesium, and lower in sodium. On the other hand, clam is richer in phosphorus, potassium, selenium, and calcium. Thus, oyster wins in this category.

Mineral Comparison

Mineral comparison score is based on the number of minerals by which one or the other food is richer. The "coverage" charts below show how much of the daily needs can be covered by 300 grams of the food.

Clam

Oysters

Contains more PotassiumPotassium	+351.8%
Contains more PhosphorusPhosphorus	+74.2%
Contains more ManganeseManganese	+69.2%
Contains more SeleniumSelenium	+62%

Contains more MagnesiumMagnesium	+94.4%
Contains more CalciumCalcium	+26.1%
Contains more IronIron	+227.8%
Contains more CopperCopper	+729.5%
Contains more ZincZinc	+2779.1%
Contains less SodiumSodium	-86.2%

Vitamins

From the viewpoint of vitamins, clam is undoubtedly the winner. It is drastically higher in vitamin B12 and vitamin C, fairly higher in vitamins B2 and B3, and somewhat higher in vitamins B5, B6, and vitamin A. However, oyster is slightly higher in folate.

The amount of vitamin B1 is equal in both foods.

Vitamin Comparison

Vitamin comparison score is based on the number of vitamins by which one or the other food is richer. The "coverage" charts below show how much of the daily needs can be covered by 300 grams of the food.

Clam

Oysters

Contains more Vitamin CVitamin C	+∞%
Contains more Vitamin AVitamin A	+557.7%
Contains more Vitamin B1Vitamin B1	+316.7%
Contains more Vitamin B2Vitamin B2	+136.7%
Contains more Vitamin B3Vitamin B3	+81.3%
Contains more Vitamin B5Vitamin B5	+52.1%
Contains more Vitamin B6Vitamin B6	+80.3%
Contains more Vitamin B12Vitamin B12	+465.1%
Contains more FolateFolate	+107.1%

~equal in Vitamin D ~0µg

Macronutrients comparison

In this section, clam is a medal-holder again with its higher concentration of protein, fewer calories, and lower saturated fat, cholesterol, and carbohydrate content.

Health Impact

Health benefits

Nervous system benefits

Clams have neuroprotective functions on the nervous system, specifically in Parkinson's disease. Clam extracts are being researched into treatment methods for different neurodegenerative diseases. This benefit was not found in oysters (1).

Anti-oxidant, anti-fatigue, and muscle wasting

Oysters contain compounds called oyster hydrosylates that have been shown to have anti-oxidative, anti-fatigue, and anti-muscle wasting effects. a
These extracts have beneficial effects on reducing oxidative stress and fatigue. In addition, as we grow older by age and adopt a more sedentary lifestyle, muscle mass starts to decrease, which in turn increases the risks of different diseases such as diabetes. It would be beneficial to add oysters to a diet (2)(3).

Sleep and reproductive health

Oysters are richer in zinc compared to clams, and this provides healthy sleep as it reduces the duration of falling to asleep. In addition, it is important to maintain normal levels of zinc for reproductive health (4)(5).

Risks

Cardiovascular health

oysters are lower in proteins and higher in total fats and specifically saturated fats. This can increase the risks of cardiovascular diseases and mortality (6).

Public and environmental health

From the very start, it is necessary to point out that clams and oysters are filter feeders, which means they use their gills to filter water and collect nutrients. So depending on where they have been harvested, there is a risk of picking up bacteria and viruses. In this connection, it should be noted that eating raw or undercooked clams and oysters can put us at risk for such serious states as paralytic, neurotoxic, diarrheic, and amnesic shellfish poisoning caused by several strains of Vibrio bacteria and Norovirus.

According to the USA Centers for Disease Control and Prevention (CDC), in the United States, Norovirus is the leading cause of gastroenteritis outbreaks; it is estimated to cause 19–21 million illnesses a year, and approximately 50% of all food-borne disease outbreaks (7).

According to the CDC report, in the United States, Vibrio parahaemolyticus is the cause of about 35000 domestically acquired food-borne infections annually, most of which are associated with the consumption of raw or undercooked shellfish (8).

According to a study published in 2013, pre-birth maternal shellfish consumption at least once a month is associated with a higher risk of food allergy (9).

Cooking and Storing

It follows logically from what has been said that proper harvesting, cooking, and storing of clams and oysters are crucial; otherwise, we run the risk of serious health threats.

It must be pointed out that both clam and oyster should be harvested alive. Clams and oysters are both eaten in a variety of ways. Although clams can be eaten raw or steamed as a half shell, they are most often eaten as a component of a more complex dish. The most popular clam dishes are New England clam chowder, linguine with clam sauce, and Spanish paella. On the other hand, eating raw oysters in the shell at many fine restaurants is a great joy for gourmets. Despite this, oysters may be used in their cooked, smoked, frozen, or canned forms.

The important point in storing clams and oysters is, once again, storing them alive. The storing conditions of clam and oyster are similar. According to the Washington State Department of Health, both should be stored in the refrigerator in an open container to ensure air circulation (10). They must be covered with a damp towel to maintain humidity. In order to avoid their death or spoiling, it is not allowed to store them in water. Shells must be closed; if they are open and don’t close after tapping, the shellfish are dead and should be discarded. In this way, clams can be stored alive for up to 7 days outside of water and oysters for up to 2-3 weeks. However, it is highly recommended to eat them as fresh as possible. The cooked shellfish can be kept for two days in the refrigerator and up to 3 months in the freezer.

You can also read about mussels vs oyster.

References

Author name: Zvart Movsisyan

Education: Medical Biochemistry MD

Last updated: June 02, 2023

Medically reviewed by Jack Yacoubian

Infographic

Infographic link

All nutrients comparison - raw data values

Nutrient			DV% diff.
Vitamin B12	98.89µg	17.5µg	3391%
Zinc	2.73mg	78.6mg	690%
Copper	0.688mg	5.707mg	558%
Iron	2.81mg	9.21mg	80%
Selenium	64µg	39.5µg	45%
Sodium	1202mg	166mg	45%
Protein	25.55g	11.42g	28%
Vitamin C	22.1mg	0mg	25%
Choline		130mg	24%
Phosphorus	338mg	194mg	21%
Vitamin B2	0.426mg	0.18mg	19%
Manganese	1mg	0.591mg	18%
Vitamin A	171µg	26µg	16%
Potassium	628mg	139mg	14%
Vitamin E		1.7mg	11%
Vitamin B1	0.15mg	0.036mg	10%
Vitamin B3	3.354mg	1.85mg	9%
Vitamin B5	0.68mg	0.447mg	5%
Magnesium	18mg	35mg	4%
Folate	29µg	14µg	4%
Cholesterol	67mg	79mg	4%
Vitamin B6	0.11mg	0.061mg	4%
Saturated fat	0.188g	0.948g	3%
Polyunsaturated fat	0.552g	1.056g	3%
Vitamin K		2µg	2%
Calories	148kcal	102kcal	2%
Fats	1.95g	3.42g	2%
Calcium	92mg	116mg	2%
Monounsaturated fat	0.172g	0.506g	1%
Carbs	5.13g	5.45g	0%
Net carbs	5.13g	5.45g	N/A
Vitamin D		2IU	0%
Sugar		1.23g	N/A
Starch		0.9g	0%
Trans fat		0.068g	N/A
Tryptophan	0.286mg	0.138mg	0%
Threonine	1.099mg	0.046mg	0%
Isoleucine	1.112mg	0.459mg	0%
Leucine	1.798mg	0.716mg	0%
Lysine	1.909mg	0.762mg	0%
Methionine	0.576mg	0.257mg	0%
Phenylalanine	0.915mg	0.413mg	0%
Valine	1.116mg	0.523mg	0%
Histidine	0.49mg	0.22mg	0%
Omega-3 - EPA	0.138g	0.353g	N/A
Omega-3 - DHA	0.146g	0.271g	N/A
Omega-3 - ALA		0.163g	N/A
Omega-3 - DPA	0.104g	0.02g	N/A
Omega-3 - Eicosatrienoic acid		0.004g	N/A
Omega-6 - Gamma-linoleic acid		0.004g	N/A
Omega-6 - Dihomo-gamma-linoleic acid		0.007g	N/A
Omega-6 - Eicosadienoic acid		0.007g	N/A
Omega-6 - Linoleic acid		0.061g	N/A