Are Oysters Acidic or Alkaline?
Oysters (raw) are slightly acid-forming: Positive PRAL: acid-forming after digestion.
Classification
Raw oysters are high in protein and bring plenty of phosphorus, which gives +4.5. That is less than most fish, because oysters contain a lot of water. Cooked, the value rises only slightly to +4.9. Half a dozen without shells does not weigh much, and at 67 kcal per 100 g, an oyster night stays moderate in both acid load and calories.
In the Fish & Seafood category, oysters (raw) rank #4 of 56, sorted from alkaline to acid-forming. More alkaline options include Pollock (+4.2), Halibut (+3.9), Pollock (+3.1). More acid-forming are Sole (+5.0), Octopus (+5.4), Mussels (+5.5).
Acidic or alkaline: PRAL, not pH
On this site, acidic and alkaline refer to the PRAL (potential renal acid load). It estimates what a food leaves behind once it has been digested: a positive value is acid-forming, a negative value is alkalizing. That is different from the pH of the food itself: a lemon tastes sour, yet its PRAL is −4.0, so it is alkalizing. Your diet does not change your blood pH. It does change how much acid your kidneys have to deal with.
Oysters: raw, prepared
Same food, different state. All values per 100 g.
| State | PRAL |
|---|---|
| raw | +4.5 |
| prepared | +4.9 |
What balances oysters
A fillet (125 g) of oysters adds +5.6 to your daily balance. These three bring it back; the grams shown offset exactly this serving.
Frequently Asked Questions
Are oysters acidic?
It depends on what you mean by acidic. The pH describes the food itself, for example how sour it tastes. The PRAL describes what it leaves behind after digestion: Oysters (raw) have a PRAL of +4.5 per 100 g, so they count as slightly acid-forming in your daily acid-base balance.
How much spinach offsets a fillet (125 g) of oysters?
A fillet (125 g) of oysters adds +5.6 to your daily balance. Spinach (fresh) has −12.2 per 100 g, so about 50 g of spinach offset this serving.
Do I have to avoid oysters on an alkaline diet?
No. What counts is the balance of the whole day, not a single food. Oysters are slightly acid-forming; with enough vegetables, potatoes and fruit on the same plate, the meal stays balanced.
Oysters, raw or prepared: which is more alkaline?
Oysters (raw) is at +4.5, Oysters (prepared) at +4.9. So the "raw" version is more alkaline. Differences come from water content, cooking water or concentration during drying.
Oysters logged, balance checked.
Basentracker adds up every meal automatically and shows whether your day is in the alkaline range. The same values as on this page, all 977 foods, photo scan, recipes.
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Compare all Fish & Seafood: Fish & Seafood table. Common questions are answered in Acidic or Alkaline?, and the PRAL calculator adds up a whole meal.
Source: Basentracker food database (PRAL according to Remer & Manz, calculated from protein, phosphorus, potassium, magnesium and calcium per 100 g). This information does not replace medical advice.