Are Flaxseeds Acidic or Alkaline?
Flaxseeds (raw) are slightly acid-forming: Positive PRAL: acid-forming after digestion.
Classification
At +4.2, flaxseeds are in the acid-forming range, because the seeds' protein and phosphorus outweigh the magnesium and potassium they contain. For a seed, that's a middling value. Pumpkin seeds are well above it. A tablespoon of ground flaxseed, about 10 g, in your muesli comes to about +0.4, which is negligible.
In the Nuts & Seeds category, flaxseeds (raw) rank #14 of 29, sorted from alkaline to acid-forming. More alkaline options include Sesame seeds (+3.9), Almond butter (+3.7), Pistachios (+2.7). More acid-forming are Walnuts (+5.6), Chia seeds (+6.3), Cashew butter (+6.8).
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.
What balances flaxseeds
A handful (30 g) of flaxseeds adds +1.3 to your daily balance. These three bring it back; the grams shown offset exactly this serving.
Frequently Asked Questions
Are flaxseeds 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: Flaxseeds (raw) have a PRAL of +4.2 per 100 g, so they count as slightly acid-forming in your daily acid-base balance.
How much spinach offsets a handful (30 g) of flaxseeds?
A handful (30 g) of flaxseeds adds +1.3 to your daily balance. Spinach (fresh) has −12.2 per 100 g, so about 10 g of spinach offset this serving.
Do I have to avoid flaxseeds on an alkaline diet?
No. What counts is the balance of the whole day, not a single food. Flaxseeds are slightly acid-forming; with enough vegetables, potatoes and fruit on the same plate, the meal stays balanced.
Flaxseeds 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 Nuts & Seeds: Nuts & Seeds 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.