Is Garlic Acidic or Alkaline? PRAL, pH and How to Use It

The short answer

Garlic is slightly acidic on the pH scale and slightly alkaline-forming after you eat it. Both statements are true because they measure different things.

The FDA's table of approximate food pH values lists garlic at about 5.8, which is mildly acidic, a little less acidic than black coffee. That number describes the raw clove itself.

The alkaline diet uses a different measure called PRAL, short for potential renal acid load. It estimates how much acid or base a food leaves for your kidneys to handle after digestion, based on its protein, phosphorus, potassium, magnesium and calcium.

Garlic's PRAL score, worked out

USDA FoodData Central lists raw garlic at about 6.4 grams of protein, 153 milligrams of phosphorus, 401 milligrams of potassium, 25 milligrams of magnesium and 181 milligrams of calcium per 100 grams.

Plugging those values into the Remer and Manz formula gives a PRAL of about -2.6 per 100 grams. The potassium and calcium outweigh the protein and phosphorus, so garlic lands just below zero, in the same range as many vegetables.

In practice, the number matters less than it looks. One clove weighs about 3 grams, so a clove contributes less than a tenth of a point to a day's total. What moves your diet's acid load is the overall balance of vegetables, fruit, grains and protein foods on your plate, not the seasoning.

Raw, roasted or powdered

Cooking garlic changes its flavor far more than its mineral content. Roasted whole heads turn sweet and spreadable, while raw garlic stays sharp and hot. Garlic powder is dried and concentrated, so a teaspoon holds the minerals of several cloves, but you use so little that its acid load is still negligible.

Garlic's strong smell comes from sulfur compounds, mainly allicin, that form when you cut or crush a clove. Letting chopped garlic sit for about 10 minutes before cooking is a common kitchen tip for getting the most of that flavor.

When garlic may not agree with you

Garlic is a common trigger for heartburn in people with acid reflux. If raw garlic bothers you, try roasted garlic, use less, or skip it and lean on herbs, lemon zest and ginger instead.

Garlic is also high in fructans, a type of carbohydrate that some people with irritable bowel syndrome do not tolerate well. Garlic-infused oil is a common workaround, because the fructans do not dissolve into the oil.

The National Center for Complementary and Integrative Health notes that garlic supplements may increase the risk of bleeding and can interact with some medications, including the HIV drug saquinavir. Cooking with garlic in normal amounts is a different matter, but if you take a blood thinner or plan surgery, tell your clinician about any garlic supplements.

Easy ways to use garlic in alkaline-friendly cooking

Whisk a grated clove into lemon tahini sauce for grain bowls.

Saute sliced garlic in olive oil, then add a big pile of kale, spinach or chard and a squeeze of lemon.

Roast a whole head alongside zucchini, carrots and chickpeas, then squeeze the soft cloves over the tray.

Blend roasted garlic into white bean dip for a mellow, creamy snack.

Sources

USDA FoodData Central, Garlic, raw: https://fdc.nal.usda.gov/

U.S. Food and Drug Administration, Approximate pH of Foods and Food Products.

Remer T, Manz F. Potential renal acid load of foods and its influence on urine pH. Journal of the American Dietetic Association, 1995.

National Center for Complementary and Integrative Health, Garlic fact sheet: https://www.nccih.nih.gov/health/garlic