Clam vs. Oysters — Health Impact and Nutrition Comparison

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. 

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

4

Oysters

6

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

9

Oysters

3

Contains more Vitamin CVitamin C	+∞%
Contains more Vitamin AVitamin A	+547.7%
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 benefits

Risks

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

1. https://pubmed.ncbi.nlm.nih.gov/35160004/ 
2. https://pubmed.ncbi.nlm.nih.gov/30488053/
3. https://pubmed.ncbi.nlm.nih.gov/34959937/
4. https://pubmed.ncbi.nlm.nih.gov/15041778/
5. https://pubmed.ncbi.nlm.nih.gov/28019085/ 
6. https://pubmed.ncbi.nlm.nih.gov/19631050/ 
7. Travel-Related Infectious Diseases
8. https://www.cdc.gov/mmwr/preview/mmwrhtml/mm6315ahtm
9. https://www.ncbi.nlm.nih.gov/pubmed/24295221
10. Shellfish Handling, Storing, and Cooking