PRAL: Understanding Potential Renal Acid Load for Kidney Disease

PRAL or the potential renal acid load refers to the amount of acid produced when foods are digested. The higher the PRAL, the more acid produced. This also means more work for your kidneys. Those with poor kidney function should consider their PRAL food intake. Learn how different foods can help or hurt your kidneys depending on their PRAL value.

What is PRAL

PRAL stands for the potential renal acid load. In other words, this is the amount of acid that is produced by the body after digesting certain foods. 

PRAL, Kidneys, and Acid Balance

Too much acid in the body can lead to metabolic disorders including insulin resistance, diabetes, heart disease, blood pressure, and other health conditions.

Excess body acid needs to be filtered and placed in the kidney’s renal solute load. However, this is the name for all of the substances that are removed by the kidneys. Acid pushed out in a urinary excretion often referred to as the renal net acid excretion. It includes acid from both metabolic and dietary sources. 

High PRAL Foods Can Affect Kidney Function

Animal proteins are a big source of acid. To clarify, these include meat, cheese, and eggs. Processed and sugary foods and beverages can also produce high amounts of acid.

Large consumption of these high PRAL foods produces a lot of acid. To prevent acidosis the kidneys will need to work harder to lower the body’s pH and get rid of the excess acid. However, this can put a strain on the kidneys. Similarly, it may also lead to chronic kidney disease (CKD) and worsen existing kidney conditions.

The Potential of Hydrogen (pH) Food Scale Determines PRAL

In case you’re not familiar with pH here is a brief overview. Every substance has a potential of hydrogen or pH. In other words, this is a measure of how many hydrogen atoms are found in a specific substance.  

So the ph food scale works the same way. It runs from 0 to 14. Seven is neutral and everything above seven is considered to be a base or alkaline. On the other hand, anything below seven is acid or acidic. 

Compounds that contain a lot of hydrogens are acidic and have a pH of less than 7. Anything low in hydrogen atoms will be a base and have a ph greater than 7.

To give you an example, water is neutral at 7 a pH of seven while stomach acid is very acidic and has a pH of 2. Apples have a pH of 8 and celery has a pH of 9. 

In other words, the higher the pH the more acidic the food. 

But how do they assign value to these foods? With the PRAL value or Pral Score of a food.

What is PRAL Value or the PRAL Score of a Food

To find how acidic a food or diet was, the pH needs to be determined. This number became the PRAL value. 

The PRAL values are based on a formula devised by Thomas Remer and other researchers at the Department of Nutrition and Health: The Research Institute of Child Nutrition, in Dortmund, Germany.

They found diets and certain food components had an impact on the body’s acid-base balance. More importantly, they found the following parameters were necessary for estimating the PRAL value for food or diet:

  • Protein, chloride, phosphorus, sodium, potassium, calcium, and magnesium content of a food
  • How fast a nutrient is absorbed by the intestine
  • The presence of the mineral sulfate made from certain amino acids
  • How fast phosphorus from foods will be absorbed by the body at a pH of 7.4
  • How quickly calcium can affect bond with magnesium

The total net acid excretion or PRAL score was determined by looking at all the substances that are produced when these foods are digested. However, it also takes into account the normal urine production versus the additional components that are produced from high acid foods.

How Do You Calculate PRAL Score

After looking at the effects of protein, phosphorus, potassium, and magnesium on the body, Remer and his colleagues came up with the following equation to assign a PRAL score to various foods and diets. 

PRAL of a food =  

0.49 x protein (gram/day)  

+  0.037 x phosphorus (mg/d) 

— 0.021 x potassium (mg/day) 

— 0.026 magnesium (mg/day) 

— 0.013 x calcium (mg/day) 

The results of this formula will give you a positive or negative PRAL value or score for any food. 

  • A POSITIVE score is an ACID-producing food
  • A NEGATIVE score is a BASE or alkaline-producing food 

How The PRAL Score Comes Out to Be a Negative or Positive Number

You may be wondering how a PRAL score becomes either a positive or negative number. That is to say, it has to do with the amount of the above nutrients found in each food. 

If a food has a higher protein and phosphorus content it tends to result in a positive number. To clarify, this is because a larger number subtracted from a smaller results in a positive result. Therefore, foods high in protein and phosphorus will typically have a positive PRAL number. 

If potassium, magnesium, and calcium totals are higher than protein and phosphorus levels that food will have a negative PRAL score. This is because a smaller number subtracted from a larger number equates to a negative number. 

Examples of How PRAL Scores Result in Negative or Positive Numbers

Below are two examples of how both a negative and positive PRAL score is calculated.

Steak

Three ounces of a cooked steak will have a positive PRAL number of about 47. You can see how the protein and phosphorus numbers are higher than the calcium, potassium, and magnesium content of this food.

  • Protein for PRAL =  0.49 x 95.5 g protein (PRO) = 46.795
  • Phosphorus for PRAL = 0.037 x 197 mg phosphorus (PHOS) = 7.289
  • Potassium for PRAL = 0.021 x 307 mg potassium (K) = 6.447
  • Magnesium for PRAL = 0.026 x 22.2 mg magnesium (Mg) = 0.5772
  • Calcium for PRAL 0.013 x 4.3 calcium mg (Ca) = 0.0559

PRAL of steak =  46.795 (PRO) + 7.289 (PHOS) – 6.447 (K) – 0.5772 (Mg) – 0.0559 (Ca) 

PRAL of steak = 47.0039

Spinach

The PRAL of a cup of raw spinach will come out to about negative 2.9. This is because the spinach subtracts the smaller protein and phosphorus levels from the larger potassium, magnesium, and calcium content. Below is a breakout of how the higher potassium, magnesium, and calcium levels are what give spinach a lower PRAL score.

  • Protein for PRAL =  0.49 x 2.1 g protein (PRO) = 1.029
  • Phosphorus for PRAL = 0.037 x 14.7 mg phosphorus (PHOS) = 0.5439
  • Potassium for PRAL = 0.021 x 167 mg potassium (K) = 3.507
  • Magnesium for PRAL = 0.026 x 23.7 mg magnesium (Mg) = 0.6162
  • Calcium for PRAL 0.013 x 29.7 calcium mg (Ca) = 0.3861

PRAL of spinach =  1.029 (PRO) + 0.5439 (PHOS) – 3.507 (K) – 0.6162 (Mg) – 0.3861(Ca) 

PRAL of spinach = -2.9364

For anyone who hates math, you may be dreading having to compute the PRAL score formula but luckily you don’t have to do anything. You can just look at the list below.

How PRAL Value Foods Differ From pH Levels

So Unlike pH, the higher the PRAL number, the more acid is produced from that food or diet. A negative PRAL value indicates that food will produce a base when consumed. 

Metabolic Acidosis and Kidney Function 

Balance is key when it comes to acid levels in the body. However, too much can be bad for health. Firstly, acid is naturally produced from metabolic processes like respiration and digestion. The lungs and kidneys are responsible for making sure body pH or acid levels don’t get too high.  

Diets high in PRAL foods can also lead to high acid production. A study in the American Journal of Clinical Nutrition indicated that protein intake leads to high acid levels in those with poor kidney function. This is because they will have trouble clearing acid from the body and it will accumulate in the blood. Subsequently, high levels of acid lead to metabolic acidosis.

Metabolic acidosis in CKD is common. It can affect about 15 to 19% of patients. Risk also increases with age.

However, one way to look out for acidosis is to keep track of your acid levels. This is done by having your doctor monitor the carbon dioxide in your blood. 

Serum bicarbonate is the lab used to check for acidosis. Normal levels are 22 to 29 mEq/L. Metabolic acidosis occurs when bicarbonate levels drop under 22 mEq/L.

Metabolic Acidosis can lead to the following health problems:

  • Increased bone loss (osteoporosis)
  • Muscle loss
  • High blood sugar
  • Death

Moreover, signs and symptoms of metabolic acidosis include the following: 

  • Long and deep breaths
  • Fast heartbeat
  • Headache
  • Confusion
  • Weakness 
  • Fatigue
  • Nausea and vomiting
  • Loss of appetite

Similarly, those with kidney dysfunction and metabolic acidosis are also at risk for developing kidney disease. Read more about the renal function panel here.

High Acid to Alkaline Diet: A Treatment for Acidosis

Acidosis is a very serious and scary condition. But there is something you can do to treat it. Some research indicates taking sodium bicarbonate (baking soda) or sodium citrate pills will help increase the levels of the base in your body. 

The idea behind using baking soda and alkali supplements is that they will fill your body with base. More base will neutralize the excess acid. It should also protect your kidneys from further wear and tear. To note, this treatment is not recommended unless your healthcare professionals give you the go-ahead to try it out yourself.

It’s important to know that self-treating with baking soda may cause other problems. Just one teaspoon of baking soda has 1,259 milligrams of sodium – more than half a day’s worth. Sodium bicarbonate tabs, though, have just 178 milligrams sodium per tablet.

However, an easier way to lower the risk for metabolic acidosis would be to just start incorporating more alkaline foods into the diet. 

Low PRAL and Foods on the Alkaline Diet 

As we discussed earlier, the lower the PRAL value the less acid produced. Foods on the alkaline diet produce base when digested by the body. This leads to a lower pH and alkaline environment. Simply, the more alkaline your diet the lower your acid levels. So implementing an alkaline diet can lead to less pressure on the kidneys.

Low PRAL alkalinity-promoting foods include fruits and vegetables. Similarly, these foods are higher in potassium, magnesium, and calcium. These nutrients are what help the body produce more bicarbonate or base.

PRAL Alkaline Foods vs. Acidic foods

You may be thinking, “wait for a second! Lemon is an acidic food, will this cause me to produce acid?” That answer is no. To clarify, acidic foods are different from alkaline foods. 

There are foods with a low pH. Therefore, the acid produced by the body from high PRAL foods should not be confused with foods that have a low pH. 

Acidic foods can be tolerated by the body because they are neutralized by the hydrochloric acid in the stomach during digestion. Therefore, foods like lemons and tomatoes can be both acidic and alkaline at the same time. 

Foods with a higher pH (bases) can also be a high PRAL food. For example, red meat, cheese, has a pH of around 5 or 6.

To get a better idea of how foods impact PRAL look at this acid-alkaline chart.

PRAL Acid-Alkaline Chart

The PRAL acid-alkaline chart breaks down foods by how much acid and base (alkaline) they produce. The lower the number the more base there is. Therefore, you want to look for low and negative numbered PRAL foods to include in your diet. 

PRAL Acid Foods

Below is a list of acid-producing foods measured in milliequivalents of acid per day (mEq/day).

FoodFood GroupPRAL Value (mEq/day)
Low-fat vanilla yogurtDairy and Egg0.1727
Whipped creamDairy and Egg0.175
Low-fat milk (1% fat)Dairy and Egg0.1833
Whole milk (3.25% fat)Dairy and Egg0.2128 
Instant oatmeal (appleCereals Grains and Pasta0.2338
Beef gravy soupsSauces and Gravies0.2861
Whipped salted butterDairy and Egg 0.3575
SaccharinSweets0.3766
Chocolate fudge with nuts Sweets0.3782 
Fat-free sour creamDairy and Egg 0.44 
Vanilla ice creamSweets0.496
MayonnaiseFats and Oils0.514 
English muffinsBaked 0.566 
Soy milkLegumes 0.576
Bulgur Cereal Grains and Pasta 0.5992
Tortilla chips Snacks0.6441
Chocolate Wafer BarSweets0.7469
Banana breadBaked 0.802
Pork and chicken lunch meat Sausages & Lunch Meats 0.8397 
White riceCereal Grains and Pasta0.9198 
Rice noodles Cereal Grains and Pasta0.9719
Buckwheat groatsCereal Grains and Pasta0.9812
Frozen Cheese lasagna Meals, Entrees, & side dishes1.6573
Raisin breadBaked1.75
Whole wheat breadBaked1.906
OystersFinfish & Shellfish1.9648
Oat bran Cereal Grains and Pasta2.8739
Buttermilk pancakesBaked2.999
Peanut butterLegumes3.2024
TofuLegumes3.4531
Cream cheese Dairy and Egg3.8525
PorkPork3.9957
Frozen turkey and gravyPoultry4.2072
LambLamb, Veal, and Game4.4118
Pork & turkey sausageSausages & Lunch Meats 4.4945 
CroissantsBaked4.528
Brown gravySauces and Gravies4.6716 
Pork pattiesPork 4.753
Granola Breakfast bars, Snacks 4.799 
Corned beefBeef4.8302 
No salt oil roasted mixed nuts Nuts 4.8898
VealLamb, Veal, and Game4.9628 
MackerelFinfish and shellfish 5.125 
AnchovyFinfish and shellfish 5.3895
Frozen cheese pizzaFast Foods5.5824 
Pacific herringFinfish and shellfish 5.6731
Low salt wheat crackersBaked 5.842 
Whole milk ricotta cheeseDairy and Egg6.1814 
HalibutFinfish and shellfish6.1919 
Salted cashewsNuts6.4219
CodFinfish and shellfish6.5249
HamSausages & Lunch Meats6.614 
Macaroni Cereal Grains and Pasta6.9256 
White riceCereal Grains and Pasta6.9808 
Turkey breastSausages & Lunch Meats7.3663
LobsterFinfish and shellfish7.439 
CouscousCereal Grains and Pasta7.6004 
Brazil nuts, unblanchedNuts8.1468 
Blue crabFinfish and shellfish8.3724 
Atlantic mackerelFinfish and shellfish8.417 
Pine nutsNuts8.7121 
Oven-roasted chicken breast (fat-free)Sausages & Lunch Meats8.7281
Raw tunaFinfish and shellfish9.186 
Wild riceCereal Grains and Pasta9.3967 
Egg, wholeDairy and Egg9.4162 
Pastrami (98% fat-free)Sausages & Lunch Meats9.781
Beef ribsBeef 9.8355 
Roasted turkeyPoultry10.491 
Brie cheeseDairy and Egg11.0195
Atlantic salmon  Finfish and shellfish11.114 
Rye Cereal Grains and Pasta11.9514 
Durum wheatCereal Grains and Pasta12.2622 
Ground porkPork12.4381 
Ground beef, (90% lean) Beef 12.5339
VealLamb, Veal, and Game12.6367
Light canned tuna no saltFinfish and shellfish12.7089 
Camembert cheese Dairy and Egg13.05
Roasted chickenPoultry13.8479
Mozzarella cheese (part-skim milk)Dairy and Egg16.4904
Low-calorie lemonade (aspartame)Beverages 18.393 
Swiss cheeseDairy and Egg21.2867
Reduced calorie (aspartame)Sweets74.592
PuddingSweets85.3939 
Baking phosphateBaked270.164

Acid-Producing Foods Do Not Need to be Avoided

Rather, think of this as a balancing act. When adding foods mentioned above, it will be beneficial to balance them with alkaline foods listed below.

For example, -10 + 4 = -6. There is still a “positive” value in this equation, however the end result is still negative.

PRAL Neutral Foods

Below is a list of neutral foods measured in milliequivalents of acid per day (mEq/day).

FoodServing SizeFood GroupPRAL Value
Cod liver fish oil1 tbspFats and OIls0

PRAL Alkaline Foods

Below is a list of alkaline foods measured in milliequivalents of acid per day (mEq/day).

FoodFood GroupPRAL Value
ParsleyVegetables-108.647
CorianderSpices and Herbs-99.4853 
ChervilSpices and Herbs -92.4 
BasilSpices and Herbs -85.3627 
Celery flakesVegetables-84.464
Dried parsleySpices and Herbs -81.4902 
Dried Oriental radishesVegetables-74.552
Dill weedSpices and Herbs -74.5146
TarragonSpices and Herbs -64.5107
ChivesVegetables-59.815
TomatoesVegetables-58.3551 
Dried spearmintSpices and Herbs -55.4223
Sweet green peppersVegetables-52.33
Sweet red peppersVegetables-52.33 
OreganoSpices and Herbs -49.767
MarjoramSpices and Herbs -49.3026 
SeaweedVegetables-46.8031 
TurmericSpices and Herbs -46.6693
LeeksVegetables-39.016 
MolassesSweets-38.554
RosemarySpices and Herbs -37.4338 
Paprika Spices and Herbs -36.3376
ThymeSpices and Herbs -35.4831 
Pasilla peppersVegetables-35.3725
FennelSpices and Herbs -35.371
CelerySpices and Herbs -34.7177 
Dill seed Spices and Herbs -33.1908 
Apricots dehydratedFruits & Fruit Juices-33.071 
CuminSpices and Herbs -31.9771
ClovesSpices and Herbs -31.5888 
BananasFruits & Fruit Juices-29.7609 
Black pepperSpices and Herbs -25.3975
GingerSpices and Herbs -24.5502
CinnamonSpices and Herbs -23.7569
Coriander seedSpices and Herbs -23.2097 
ShallotsVegetables-22.754
CardamomSpices and Herbs -22.5736
Shiitake mushroomsVegetables-20.2168
Beet greens (cooked)Vegetables-19.5627 
Lima beansLegumes -18.3206
AniseedSpices and Herbs -18.175
Carob flourLegumes -18.1082
Canned tomato pasteVegetables-17.6662 
Bay leaf Spices and HerbsSpices and Herbs  -17.1611 
Beet greens (raw)Vegetables-16.748 
Fresh RosemarySpices and Herbs -16.4511 
Dried Litchis Fruits & Fruit Juices-16.272 
Dried PeachesFruits & Fruit Juices-16.2001 
Dried peeled chestnuts Nuts-16.0431 
ThymeSpices and Herbs -15.5676 
Dill weed Spices and Herbs -15.4946 
YamsVegetables-15.1183 
French beans Legumes -14.4771 
Raisins Fruits & Fruit Juices-14.4592 
Roasted pumpkin seedsNuts-14.3325 
Dried persimmonsFruits & Fruit Juices-14.2998 
Dried currantsFruits & Fruit Juices-14.2918
Dried figsFruits & Fruit Juices-14.058 
Dried unpeeled ChestnutsNuts-13.8949 
Medjool datesFruits & Fruit Juices-13.6711 
Black beansLegumes -13.58
Lemon grass (citronella)Vegetables-12.9592 
PeppermintSpices and Herbs -12.6495 
Taro rootVegetables-12.5929 
White beansLegumes -12.5801 
Pine nutsNuts-12.4117 
Swiss chardVegetables-12.3768
Boiled chestnutsNuts-12.374 
Fermented tofuLegumes -12.3655
Deglet datesFruits & Fruit Juices-11.9065 
Spinach Vegetables-11.8446 
Dehydrated apples Fruits & Fruit Juices-11.5772
Pink beansLegumes -11.5406
ParsleySpices and Herbs-11.1267
Kidney beansLegumes -11.0587 
Black bean soupLegumes -11.0475
KaleVegetables-10.737
PurslaneVegetables-10.722
Mustard spinach Vegetables-10.331
Cooked spinach Vegetables-10.2887 
Banana chipsSnacks-10.267
Dried Chinese chestnutsNuts-10.1082 
Wasabi Vegetables-10.074
Basil Spices and Herbs -10.0124 
Spearmint (fresh)Spices and Herbs -10.0109
Water chestnuts Vegetables-9.962
Bamboo shoots (cooked)Vegetables-9.9373
Cilantro (coriander)Vegetables-9.6683 
Pinto beansLegumes -9.5952 
Raw plantainsFruits & Fruit Juices-9.585
Hyacinth beansLegumes-9.508 
Dried pearsFruits & Fruit Juices-9.3937 
Cooked plantainsFruits & Fruit Juices-9.1999 
Northern beansLegumes-9.0656 
Pinto beansVegetables-9.059 
Peaches (dehydrated)Fruits & Fruit Juices-9.0131
Grapefruit juiceFruits & Fruit Juices-8.7247 
Winter squash, Vegetables-8.6619
Russet potatoesVegetables-8.6483 
Cranberry beans Legumes-8.6303 
AvocadosFruits & Fruit Juices-8.6116
CowpeasVegetables-8.6085 
Kidney beans Legumes-8.4118
HorseradishVegetables-8.362
KaleVegetables-8.337
Chicory greensVegetables-8.328
Sweet potatoVegetables-8.1881
Apples (dried)Fruits & Fruit Juices-8.1863
Swiss chardVegetables-8.144
Bamboo shoots (raw)Vegetables-7.983
Dandelion greensVegetables-7.939
Ginger root Vegetables-7.8912
ArugulaVegetables-7.8628 
Chinese cabbageVegetables-7.4486
FennelVegetables-7.3154
Turnip greens (raw)Vegetables-7.203
BananasFruits & Fruit Juices-6.9369 
GuavasFruits & Fruit Juices-6.8335
Agar (seaweed)Vegetables-6.7404
Mustard greensVegetables-6.691
Adzuki beansLegumes-6.6607
KaleVegetables-6.615 
RhubarbFruits & Fruit Juices-6.519
Collards frozen uncookedVegetables-6.3629
Collards cookedVegetables-6.3267
Prickly pearsFruits & Fruit Juices-6.3123
KiwifruitFruits & Fruit Juices-6.1249
Dried figsFruits & Fruit Juices-6.0692
Endive Vegetables-6.0115
ZucchiniVegetables-6.0011
ParsnipsVegetables-5.882
Jerusalem artichokesVegetables-5.767
Roasted salted soybeansLegumes-5.7452
ParsnipsVegetables-5.7422
CarrotsVegetables-5.7103
WatercressVegetables-5.689
Passion-fruit juiceFruits & Fruit Juices-5.6599
White beansLegumes-5.6403
Kiwi fruitFruits & Fruit Juices-5.6194
Pumpkin Vegetables-5.607
OkraVegetables-5.587
GuavasFruits & Fruit Juices-5.5638
PapayasFruits & Fruit Juices-5.4851
Beets (raw) Vegetables-5.3621
Burdock root Vegetables-5.3523
Green hot chili peppersVegetables-5.342
CurrantsFruits & Fruit Juices-5.232
Oriental radishes (cooked)Vegetables-5.2237
Chinese broccoli (cooked)Vegetables-5.1734
Yellow snap beansVegetables-5.1579
Crushed canned tomatoesVegetables-5.1274
Coconut waterNuts-5.1192
Brussel sproutsVegetables-5.1038
Prune juiceFruits & Fruit Juices-5.0921
Passion fruit juice Fruits & Fruit Juices-5.0787
Cantaloupe melonFruits & Fruit Juices-5.0694
Chinese cabbage (raw) Vegetables-5.047 
Celery, raw Vegetables Vegetables-5.0399
Red hot chili peppersVegetables-5.0347
ScallionsVegetables-4.9863
Turnip greens (cooked)Vegetables-4.9844
Beets (cooked) Vegetables-4.9818
Globe or french ArtichokesVegetables-4.9697
White radishesVegetables-4.89
Mustard cabbageVegetables-4.889
White beansLegumes-4.8846
Figs (raw) Fruits & Fruit Juices-4.8835
HorseradishSpices and Herbs -4.8708
Kelp Vegetables-4.8218
PomegranatesFruits & Fruit Juices-4.7945
Canned carrot juiceVegetables-4.7885
ChivesVegetables-4.7557
RadicchioVegetables-4.7463
Elderberries  Fruits & Fruit Juices-4.7376
CabbageVegetables-4.7231
Chinese cabbage (raw) Vegetables-4.676 
Green onions Vegetables-4.67
Canned tomatoes wedgesVegetables-4.6569 
Passion-fruitFruits & Fruit Juices-4.624 
Cabbage Vegetables-4.6104 
ShallotsVegetables-4.596
Broccoli raabVegetables-4.5283
Portabella mushroomsVegetables-4.519 
Honeydew melonFruits & Fruit Juices-4.4544 
CauliflowerVegetables-4.4408 
LongansFruits & Fruit Juices-4.4401 
Apricots (raw)Fruits & Fruit Juices-4.331
Tomatillos (raw) Vegetables-4.3256 
Lemon peelFruits & Fruit Juices-4.313 
Baby carrotsVegetables-4.3034 
Red cabbageVegetables-4.2933 
Crimini mushroomsVegetables-4.211
BroccoliVegetables-4.1968 
CollardsVegetables-4.0975 
Yellow raw tomatoesVegetables-4.0608 
Toasted coconut meatNuts-3.973
BroccoliVegetables-3.9692 
Orange with peelFruits & Fruit Juices-3.939 
Cherries (sweet)Fruits & Fruit Juices-3.8206 
NutmegSpices and Herbs -3.7574 
QuincesFruits & Fruit Juices-3.663 
Orange juiceFruits & Fruit Juices-3.657
KumquatsFruits & Fruit Juices-3.6078 
OrangesFruits & Fruit Juices-3.581
CauliflowerVegetables-3.5095 
TangerinesFruits & Fruit Juices-3.1421
Green leaf lettuceVegetables-3.1406
PeachesFruits & Fruit Juices-3.1161 
West Indian cherryFruits & Fruit Juices-3.087
NectarinesFruits & Fruit Juices-3.0516
Cherries (sour)Fruits & Fruit Juices-3.03
MangosFruits & Fruit Juices-2.9831
Red leaf lettuceVegetables-2.9803 
Strawberries (frozen)Fruits & Fruit Juices-2.9103 
BlackberriesFruits & Fruit Juices-2.8039
Coconut meatNuts-2.6773 
Garlic Vegetables-2.6466 
PlumsFruits & Fruit Juices-2.622 
Strawberries (fresh)Fruits & Fruit Juices-2.5427
CucumberVegetables-2.4265 
Raspberries Fruits & Fruit Juices-2.407 
Celery rootVegetables-2.389
LitchisFruits & Fruit Juices-2.3623 
PineappleFruits & Fruit Juices-2.3354 
Pinto beansVegetables-2.3335 
PearsFruits & Fruit Juices-2.2048 
Asparagus Vegetables-2.193 
Lime juiceFruits & Fruit Juices-2.1232
Apples (raw)Fruits & Fruit Juices-1.9206
Wakame seaweedVegetables-1.3373 
BlueberriesFruits & Fruit Juices-1.0444 
Goat milkDairy and Egg-0.5386 
Macadamia Nuts-0.4579 
CranberriesFruits & Fruit Juices-1.3729
TapiocaCereal Grains and Pasta-0.1649
QuinoaCereal Grains and Pasta-0.191 
Chamomile teaBeverages-0.241
Tofu yogurt Legumes-0.44 

PRAL Food Groups to Make Eating Easier

Having to check the individual foods may be quite timely. However, to make it easier, we are also providing you with food groups that have different effects on acid production. Below are various food groups that will increase, decrease, and moderately elevate PRAL.

Food Groups That Increase PRAL (Acid Producing Foods)

Firstly, food groups that increase PRAL include:

Food Groups That Moderately Elevate PRAL

Secondly, food groups that moderately elevate PRAL include the following:

  • Cereals grains and pasta
  • Eggs and dairy
  • Some fats and oil
  • Baked items
  • Finfish and shellfish

Food Groups that Lower PRAL (Base Producing Foods)

Lastly, foods groups that lower PRAL are:

  • Vegetables
  • Fruits
  • Beans and legumes
  • Some nuts

Low PRAL Renal Diet Guidelines

Picking out individual PRAL food and foods groups may be time-consuming. However, an easier way to decrease your acid levels is by following these renal diet guidelines. 

Increase your consumption of fruits and vegetables that are good for kidney health. The key to lowering your acid production will be to eat more foods that make base. Therefore, tating a large number of fruits and vegetables is an easy way to ensure this.

Change the types of protein you consume. As you can see protein foods produce a high PRAL value. This means more acid. The more acid in your diet, the harder your kidneys will be working. So swap out some animal proteins for lower PRAL plant proteins.

Limit your servings of high PRAL proteins. Animal protein foods can do to a number on your kidneys. Even just reducing protein portion sizes can lower the amount of acid that is being produced. A good rule of thumb is having about 3 oz. Or look at the portion in relation to the size of your palm. If it’s bigger than your hand then you should scale back on the size.

PRAL Diet Comparisons

If you are feeling overwhelmed by having to pick out low PRAL foods here are some diets you can try to ensure you are getting enough low PRAL foods.

Dietary Approaches to Stop Hypertension DASH Diet

The Dietary Approaches to Stop Hypertension or DASH diet was designed to help lower blood pressure. It is a heart-healthy low sodium diet with a lot of low PRAL fruits, vegetables, and plant proteins. It also recommends whole grains and healthy fats. High PRAL animal proteins and saturated fats are allowed in moderation. Nuts, seeds, beans, peas, and sweets are also limited to specific servings during the week. See the serving breakout below:

  • Grains: 6 – 8 servings per day
  • Meats, poultry, and fish: 6 or fewer servings per day
  • Vegetables: 4 – 5 servings per day
  • Fruit: 4 – 5 servings per day
  • Low-fat or fat-free dairy products: 2–3 servings per day
  • Fats and oils: 2 – 3 servings per day
  • Sodium: 1,500 – 2,300 mg per day
  • Nuts, seeds, dry beans, and peas: 4–5 servings per week
  • Sweets: 5 or fewer servings per week

The Mediterranean Diet

The Mediterranean Diet is another meal plan offering a lot of low PRAL foods. This eating plan has been devised to help improve heart health, diabetes, and brain function.

It is based on the regular consumption of olive oil as a main source of fat. It incorporates a lot of whole grains, fruits, vegetables, legumes, tree nuts, and seeds. 

Animal proteins, fish, seafood, and dairy are allowed in moderation. Red meat and other meat products are limited to about two times a week. 

PRAL Considerations for Kidney Disease

Though a diet high in fruits and vegetables can improve health, those with kidney conditions like CKD need to be mindful of certain nutrients in their diet. If you need to restrict potassium, phosphorus, and other electrolytes, be sure to limit your intake of foods containing these nutrients.

Alkaline Supplements vs Low PRAL Foods

Like with all health conditions there are many products on the market offering a quick fix to lower acid levels. Don’t be fooled by these marketing tactics. There is little research indicating these products can work. Worse yet they may even cause harm. 

One popular product is alkaline water. This drink contains a large amount of base. Just like when there is too much acid, an excess in base in the blood can result in alkalosis. Alkalosis is when the body’s pH becomes elevated. Signs of alkalosis include:

  • Nausea
  • Vomiting
  • Hand tremors
  • Muscle twitching
  • Tingling in the extremities
  • Face confusion
  • Decrease calcium 

The best way to avoid acidosis or alkalosis is by having a varied diet of low PRAL foods. If you do find an alkaline product you are interested in it is best to talk to your doctor before trying it.

Summary

As discussed, the potential renal acid load or PRAL value is a number calculated by how nutrients in food metabolize into acid in the blood. The higher the PRAL value the more acid that is produced. Therefore, eating a diet full of high PRAL foods can put you at risk for metabolic acidosis. Consequently, this condition can lead to many metabolic disorders including insulin resistance, diabetes, heart disease, and high blood pressure. 

The kidneys work to clear acid production but those with kidney dysfunction will have a harder time getting rid of acid in the blood. Therefore, there is a higher risk for metabolic acidosis with kidney issues. Following a low PRAL diet can prevent acid build-up and preserve kidney function. Eating foods that produce more base such as fruits and veggies, swapping out animal proteins for low PRAL plant proteins, and eating smaller servings of animal protein can also help kidney function. 

Supplements and medications recommended for increasing the alkalinity in the blood can be tempting to try but caution should be taken with these as they may cause more harm than good. It is best to talk to your doctor before taking any low PRAL supplements.

Want to see how your PRAL your diet is?

Interested in seeing where your diet falls in the PRAL values? I highly recommend you check out Cronometer Pro. The Cronomteter Gold membership (only $40 per year!) can tell you your daily PRAL values based on your logged meals. And I’ve got a special discount code for you start tracking today!

Example of nutrient balances tracked in Cronometer Gold plan. Includes omega-6:omega-3 ratio, zinc:copper ratio, potassium:sodium ratio, calcium:magnesium ratio, and PRAL alkalinity from foods logged.
Example of nutrient balances in Cronometer, including PRAL alkalinity score from all foods logged per day!

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4 thoughts on “PRAL: Understanding Potential Renal Acid Load for Kidney Disease”

  1. The equation you show to calculate PRAL does not show any steps that could create a negative score, and yet your refer to a negative score being a base. Did you leave something out to simplify this? Can you please explain?

    1. The calculation will be negative with the subtracted numbers (potassium, magnesium, and calcium) are larger than the positive numbers (protein and phosphorus). (here’s that section). From the example of spinach, we see that the amount of protein and phosphorus is lower than the amount of potassium, magnesium, and calcium, which is why there is a negative result. The number from that equation tells us how much acid is produced: a positive number produces acid and a negative number balances out acid. I hope this helps! 🙂

  2. Jen,
    I have heard of negative PRAL foods through Alison Lopez on the plant powered kidney page. I had messaged her because I didn’t fully understand it. She tried to explain it to me. She said that she eats only negative PRAL foods. I have several questions:
    1. I am stage 5 GFR 13 now. I also have Metabolic Acidosis and take a sodium bicarb pill twice a day.
    Will this help me to control the metabolic acidosis?
    2. What does it mean when the chart tells the food and the negative PRAL value it doesn’t give the amount should be eaten.
    3. Is it okay to confine yourself to just negative PRAL or should you have both negative and positive and just make sure your total number for the day ends up in the negative?
    Thank you for all you do for kidney warriors. Always researching to help us live better. You are a blessing. I still haven’t found a renal dietician near me. My insurance paid for me to see a regular registered dietician, but that didn’t prove to be helpful…I don’t think she had training for renal patients. I keep reading what you post and trying to glean information from your PPK group and DADVICEtv.

    1. Hi Nona! I’ll answer your questions as best as I can here.
      1) PRAL can help with metabolic acidosis. It’s not just about eating the “negative” foods- it’s about how your daily balance ends up. -10+6 still makes a -4 result, even with a positive number in the equation. When there’s medication already involved, it’s very important to discuss your plan with the prescribing physician.
      2) It’s based on the amount in the food. The serving size can go up, but all the values will then adjust accordingly. The end result will still make the negative or positive number.
      3) There is no evidence that relying solely on the negative foods is beneficial. Many foods that are good for us have a net positive number – we can just offset that positive with a food on the negative side.
      This is a very complex aspect of the kidney diet. I highly recommend Cronometer for a food tracker that includes PRAL values for each day. Hopefully that will help give you some guidance on how your PRAL levels are coming out on a bigger picture! Thanks so much for your kind words and support! 🙂

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