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. In this article, we will cover what PRAL is, how its measured, and how kidney patients can use PRAL to protect kidney function.
Table of Contents
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.
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, foods high in hydrogen are acidic and have a pH of less than 7.
Anything low in hydrogen will be a base and have a ph greater than 7.
To give you some examples, water is neutral at 7 a pH of seven. Stomach acid is very acidic and has a pH of 2.
Coconut has a pH of about 6. Celery has a pH of 6. Apples have a pH of 4. Lemons have a pH around 2.
In other words, the lower the pH the more acidic the food.
This is the opposite of the PRAL value. Foods with a positive PRAL value will produce more acid.
Remember what PRAL is – the value of the result of digestion of a food. Not the hydrogen of the food itself, but what happens in the body.
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 (grams)) + (0.037 x phosphorus (mg))
– (0.021 x potassium (mg)) – (0.026 x magnesium (mg)) – (0.013 x calcium (mg))
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
Use our PRAL Calculator
Below is a space where you can plug in the values described to calculate the PRAL of a food, meal, or entire day.
Try it out and let us know what you think.
PRAL Calculator
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 are more likely to 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 Negative and Positive PRAL Scores
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. This means it produces acid.
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 means it is alkaline or acid-reducing in the body.
The spinach has less protein and phosphorus amounts compared to the larger potassium, magnesium, and calcium values.
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.
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.
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 fall below 22 mEq/L.
Complications
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.
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. Nonetheless, they have PRAL values upwards of positive 20!
To get a better idea of how foods impact PRAL, look at this acid-alkaline chart below.
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).
| Food | Food Group | PRAL Value (mEq/day) |
|---|---|---|
| Low-fat vanilla yogurt | Dairy and Egg | 0.1727 |
| Whipped cream | Dairy and Egg | 0.175 |
| Low-fat milk (1% fat) | Dairy and Egg | 0.1833 |
| Whole milk (3.25% fat) | Dairy and Egg | 0.2128 |
| Instant oatmeal (apple cinnamon) | Cereals Grains and Pasta | 0.2338 |
| Beef gravy soups | Sauces and Gravies | 0.2861 |
| Whipped salted butter | Dairy and Egg | 0.3575 |
| Saccharin | Sweets | 0.3766 |
| Chocolate fudge with nuts | Sweets | 0.3782 |
| Fat-free sour cream | Dairy and Egg | 0.44 |
| Vanilla ice cream | Sweets | 0.496 |
| Mayonnaise | Fats and Oils | 0.514 |
| English muffins | Baked | 0.566 |
| Soy milk | Legumes | 0.576 |
| Bulgur | Cereal Grains and Pasta | 0.5992 |
| Tortilla chips | Snacks | 0.6441 |
| Chocolate Wafer Bar | Sweets | 0.7469 |
| Banana bread | Baked | 0.802 |
| Pork and chicken lunch meat | Sausages & Lunch Meats | 0.8397 |
| White rice | Cereal Grains and Pasta | 0.9198 |
| Rice noodles | Cereal Grains and Pasta | 0.9719 |
| Buckwheat groats | Cereal Grains and Pasta | 0.9812 |
| Frozen Cheese lasagna | Meals, Entrees, & side dishes | 1.6573 |
| Raisin bread | Baked | 1.75 |
| Whole wheat bread | Baked | 1.906 |
| Oysters | Finfish & Shellfish | 1.9648 |
| Oat bran | Cereal Grains and Pasta | 2.8739 |
| Buttermilk pancakes | Baked | 2.999 |
| Peanut butter | Legumes | 3.2024 |
| Tofu | Legumes | 3.4531 |
| Cream cheese | Dairy and Egg | 3.8525 |
| Pork | Pork | 3.9957 |
| Frozen turkey and gravy | Poultry | 4.2072 |
| Lamb | Lamb, Veal, and Game | 4.4118 |
| Pork & turkey sausage | Sausages & Lunch Meats | 4.4945 |
| Croissants | Baked | 4.528 |
| Brown gravy | Sauces and Gravies | 4.6716 |
| Pork patties | Pork | 4.753 |
| Granola Breakfast bars, | Snacks | 4.799 |
| Corned beef | Beef | 4.8302 |
| No salt oil roasted mixed nuts | Nuts | 4.8898 |
| Veal | Lamb, Veal, and Game | 4.9628 |
| Mackerel | Finfish and shellfish | 5.125 |
| Anchovy | Finfish and shellfish | 5.3895 |
| Frozen cheese pizza | Fast Foods | 5.5824 |
| Pacific herring | Finfish and shellfish | 5.6731 |
| Low salt wheat crackers | Baked | 5.842 |
| Whole milk ricotta cheese | Dairy and Egg | 6.1814 |
| Halibut | Finfish and shellfish | 6.1919 |
| Salted cashews | Nuts | 6.4219 |
| Cod | Finfish and shellfish | 6.5249 |
| Ham | Sausages & Lunch Meats | 6.614 |
| Macaroni | Cereal Grains and Pasta | 6.9256 |
| Turkey breast | Sausages & Lunch Meats | 7.3663 |
| Lobster | Finfish and shellfish | 7.439 |
| Couscous | Cereal Grains and Pasta | 7.6004 |
| Brazil nuts, unblanched | Nuts | 8.1468 |
| Blue crab | Finfish and shellfish | 8.3724 |
| Atlantic mackerel | Finfish and shellfish | 8.417 |
| Pine nuts | Nuts | 8.7121 |
| Oven-roasted chicken breast (fat-free) | Sausages & Lunch Meats | 8.7281 |
| Raw tuna | Finfish and shellfish | 9.186 |
| Wild rice | Cereal Grains and Pasta | 9.3967 |
| Egg, whole | Dairy and Egg | 9.4162 |
| Pastrami (98% fat-free) | Sausages & Lunch Meats | 9.781 |
| Beef ribs | Beef | 9.8355 |
| Roasted turkey | Poultry | 10.491 |
| Brie cheese | Dairy and Egg | 11.0195 |
| Atlantic salmon | Finfish and shellfish | 11.114 |
| Rye | Cereal Grains and Pasta | 11.9514 |
| Durum wheat | Cereal Grains and Pasta | 12.2622 |
| Ground pork | Pork | 12.4381 |
| Ground beef, (90% lean) | Beef | 12.5339 |
| Veal | Lamb, Veal, and Game | 12.6367 |
| Light canned tuna no salt | Finfish and shellfish | 12.7089 |
| Camembert cheese | Dairy and Egg | 13.05 |
| Roasted chicken | Poultry | 13.8479 |
| Mozzarella cheese (part-skim milk) | Dairy and Egg | 16.4904 |
| Low-calorie lemonade (aspartame) | Beverages | 18.393 |
| Swiss cheese | Dairy and Egg | 21.2867 |
| Reduced calorie (aspartame) | Sweets | 74.592 |
| Pudding | Sweets | 85.3939 |
| Baking powder (phosphate) | Baked | 270.164 |
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).
| Food | Serving Size | Food Group | PRAL Value |
| Cod liver fish oil | 1 tbsp | Fats and OIls | 0 |
PRAL Alkaline Foods
Below is a list of alkaline foods measured in milliequivalents of acid per day (mEq/day).
| Food | Food Group | PRAL Value |
|---|---|---|
| Parsley | Vegetables | -108.647 |
| Coriander | Spices and Herbs | -99.4853 |
| Chervil | Spices and Herbs | -92.4 |
| Basil | Spices and Herbs | -85.3627 |
| Celery flakes | Vegetables | -84.464 |
| Dried parsley | Spices and Herbs | -81.4902 |
| Dried Oriental radishes | Vegetables | -74.552 |
| Dill weed | Spices and Herbs | -74.5146 |
| Tarragon | Spices and Herbs | -64.5107 |
| Chives | Vegetables | -59.815 |
| Tomatoes | Vegetables | -58.3551 |
| Dried spearmint | Spices and Herbs | -55.4223 |
| Sweet green peppers | Vegetables | -52.33 |
| Sweet red peppers | Vegetables | -52.33 |
| Oregano | Spices and Herbs | -49.767 |
| Marjoram | Spices and Herbs | -49.3026 |
| Seaweed | Vegetables | -46.8031 |
| Turmeric | Spices and Herbs | -46.6693 |
| Leeks | Vegetables | -39.016 |
| Molasses | Sweets | -38.554 |
| Rosemary | Spices and Herbs | -37.4338 |
| Paprika | Spices and Herbs | -36.3376 |
| Thyme | Spices and Herbs | -35.4831 |
| Pasilla peppers | Vegetables | -35.3725 |
| Fennel | Spices and Herbs | -35.371 |
| Celery | Spices and Herbs | -34.7177 |
| Dill seed | Spices and Herbs | -33.1908 |
| Apricots dehydrated | Fruits & Fruit Juices | -33.071 |
| Cumin | Spices and Herbs | -31.9771 |
| Cloves | Spices and Herbs | -31.5888 |
| Bananas | Fruits & Fruit Juices | -29.7609 |
| Black pepper | Spices and Herbs | -25.3975 |
| Ginger | Spices and Herbs | -24.5502 |
| Cinnamon | Spices and Herbs | -23.7569 |
| Coriander seed | Spices and Herbs | -23.2097 |
| Shallots | Vegetables | -22.754 |
| Cardamom | Spices and Herbs | -22.5736 |
| Shiitake mushrooms | Vegetables | -20.2168 |
| Beet greens (cooked) | Vegetables | -19.5627 |
| Lima beans | Legumes | -18.3206 |
| Aniseed | Spices and Herbs | -18.175 |
| Carob flour | Legumes | -18.1082 |
| Canned tomato paste | Vegetables | -17.6662 |
| Bay leaf Spices and Herbs | Spices and Herbs | -17.1611 |
| Beet greens (raw) | Vegetables | -16.748 |
| Fresh Rosemary | Spices and Herbs | -16.4511 |
| Dried Litchis | Fruits & Fruit Juices | -16.272 |
| Dried Peaches | Fruits & Fruit Juices | -16.2001 |
| Dried peeled chestnuts | Nuts | -16.0431 |
| Thyme | Spices and Herbs | -15.5676 |
| Dill weed | Spices and Herbs | -15.4946 |
| Yams | Vegetables | -15.1183 |
| French beans | Legumes | -14.4771 |
| Raisins | Fruits & Fruit Juices | -14.4592 |
| Roasted pumpkin seeds | Nuts | -14.3325 |
| Dried persimmons | Fruits & Fruit Juices | -14.2998 |
| Dried currants | Fruits & Fruit Juices | -14.2918 |
| Dried figs | Fruits & Fruit Juices | -14.058 |
| Dried unpeeled Chestnuts | Nuts | -13.8949 |
| Medjool dates | Fruits & Fruit Juices | -13.6711 |
| Black beans | Legumes | -13.58 |
| Lemon grass (citronella) | Vegetables | -12.9592 |
| Peppermint | Spices and Herbs | -12.6495 |
| Taro root | Vegetables | -12.5929 |
| White beans | Legumes | -12.5801 |
| Swiss chard | Vegetables | -12.3768 |
| Boiled chestnuts | Nuts | -12.374 |
| Fermented tofu | Legumes | -12.3655 |
| Deglet dates | Fruits & Fruit Juices | -11.9065 |
| Spinach | Vegetables | -11.8446 |
| Dehydrated apples | Fruits & Fruit Juices | -11.5772 |
| Pink beans | Legumes | -11.5406 |
| Parsley | Spices and Herbs | -11.1267 |
| Kidney beans | Legumes | -11.0587 |
| Black bean soup | Legumes | -11.0475 |
| Kale | Vegetables | -10.737 |
| Purslane | Vegetables | -10.722 |
| Mustard spinach | Vegetables | -10.331 |
| Cooked spinach | Vegetables | -10.2887 |
| Banana chips | Snacks | -10.267 |
| Dried Chinese chestnuts | Nuts | -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 |
| Raw plantains | Fruits & Fruit Juices | -9.585 |
| Hyacinth beans | Legumes | -9.508 |
| Dried pears | Fruits & Fruit Juices | -9.3937 |
| Cooked plantains | Fruits & Fruit Juices | -9.1999 |
| Northern beans | Legumes | -9.0656 |
| Pinto beans | Vegetables | -9.059 |
| Peaches (dehydrated) | Fruits & Fruit Juices | -9.0131 |
| Grapefruit juice | Fruits & Fruit Juices | -8.7247 |
| Winter squash, | Vegetables | -8.6619 |
| Russet potatoes | Vegetables | -8.6483 |
| Cranberry beans | Legumes | -8.6303 |
| Avocados | Fruits & Fruit Juices | -8.6116 |
| Cowpeas | Vegetables | -8.6085 |
| Kidney beans | Legumes | -8.4118 |
| Horseradish | Vegetables | -8.362 |
| Kale | Vegetables | -8.337 |
| Chicory greens | Vegetables | -8.328 |
| Sweet potato | Vegetables | -8.1881 |
| Apples (dried) | Fruits & Fruit Juices | -8.1863 |
| Swiss chard | Vegetables | -8.144 |
| Bamboo shoots (raw) | Vegetables | -7.983 |
| Dandelion greens | Vegetables | -7.939 |
| Ginger root | Vegetables | -7.8912 |
| Arugula | Vegetables | -7.8628 |
| Chinese cabbage | Vegetables | -7.4486 |
| Fennel | Vegetables | -7.3154 |
| Turnip greens (raw) | Vegetables | -7.203 |
| Bananas | Fruits & Fruit Juices | -6.9369 |
| Guavas | Fruits & Fruit Juices | -6.8335 |
| Agar (seaweed) | Vegetables | -6.7404 |
| Mustard greens | Vegetables | -6.691 |
| Adzuki beans | Legumes | -6.6607 |
| Kale | Vegetables | -6.615 |
| Rhubarb | Fruits & Fruit Juices | -6.519 |
| Collards frozen uncooked | Vegetables | -6.3629 |
| Collards cooked | Vegetables | -6.3267 |
| Prickly pears | Fruits & Fruit Juices | -6.3123 |
| Kiwifruit | Fruits & Fruit Juices | -6.1249 |
| Dried figs | Fruits & Fruit Juices | -6.0692 |
| Endive | Vegetables | -6.0115 |
| Zucchini | Vegetables | -6.0011 |
| Parsnips | Vegetables | -5.882 |
| Jerusalem artichokes | Vegetables | -5.767 |
| Roasted salted soybeans | Legumes | -5.7452 |
| Parsnips | Vegetables | -5.7422 |
| Carrots | Vegetables | -5.7103 |
| Watercress | Vegetables | -5.689 |
| Passion-fruit juice | Fruits & Fruit Juices | -5.6599 |
| White beans | Legumes | -5.6403 |
| Kiwi fruit | Fruits & Fruit Juices | -5.6194 |
| Pumpkin | Vegetables | -5.607 |
| Okra | Vegetables | -5.587 |
| Guavas | Fruits & Fruit Juices | -5.5638 |
| Papayas | Fruits & Fruit Juices | -5.4851 |
| Beets (raw) | Vegetables | -5.3621 |
| Burdock root | Vegetables | -5.3523 |
| Green hot chili peppers | Vegetables | -5.342 |
| Currants | Fruits & Fruit Juices | -5.232 |
| Oriental radishes (cooked) | Vegetables | -5.2237 |
| Chinese broccoli (cooked) | Vegetables | -5.1734 |
| Yellow snap beans | Vegetables | -5.1579 |
| Crushed canned tomatoes | Vegetables | -5.1274 |
| Coconut water | Nuts | -5.1192 |
| Brussel sprouts | Vegetables | -5.1038 |
| Prune juice | Fruits & Fruit Juices | -5.0921 |
| Passion fruit juice | Fruits & Fruit Juices | -5.0787 |
| Cantaloupe melon | Fruits & Fruit Juices | -5.0694 |
| Chinese cabbage (raw) | Vegetables | -5.047 |
| Celery, raw Vegetables | Vegetables | -5.0399 |
| Red hot chili peppers | Vegetables | -5.0347 |
| Scallions | Vegetables | -4.9863 |
| Turnip greens (cooked) | Vegetables | -4.9844 |
| Beets (cooked) | Vegetables | -4.9818 |
| Globe or french Artichokes | Vegetables | -4.9697 |
| White radishes | Vegetables | -4.89 |
| Mustard cabbage | Vegetables | -4.889 |
| White beans | Legumes | -4.8846 |
| Figs (raw) | Fruits & Fruit Juices | -4.8835 |
| Horseradish | Spices and Herbs | -4.8708 |
| Kelp | Vegetables | -4.8218 |
| Pomegranates | Fruits & Fruit Juices | -4.7945 |
| Canned carrot juice | Vegetables | -4.7885 |
| Chives | Vegetables | -4.7557 |
| Radicchio | Vegetables | -4.7463 |
| Elderberries | Fruits & Fruit Juices | -4.7376 |
| Cabbage | Vegetables | -4.7231 |
| Chinese cabbage (raw) | Vegetables | -4.676 |
| Green onions | Vegetables | -4.67 |
| Canned tomatoes wedges | Vegetables | -4.6569 |
| Passion-fruit | Fruits & Fruit Juices | -4.624 |
| Cabbage | Vegetables | -4.6104 |
| Shallots | Vegetables | -4.596 |
| Broccoli raab | Vegetables | -4.5283 |
| Portabella mushrooms | Vegetables | -4.519 |
| Honeydew melon | Fruits & Fruit Juices | -4.4544 |
| Cauliflower | Vegetables | -4.4408 |
| Longans | Fruits & Fruit Juices | -4.4401 |
| Apricots (raw) | Fruits & Fruit Juices | -4.331 |
| Tomatillos (raw) | Vegetables | -4.3256 |
| Lemon peel | Fruits & Fruit Juices | -4.313 |
| Baby carrots | Vegetables | -4.3034 |
| Red cabbage | Vegetables | -4.2933 |
| Crimini mushrooms | Vegetables | -4.211 |
| Broccoli | Vegetables | -4.1968 |
| Collards | Vegetables | -4.0975 |
| Yellow raw tomatoes | Vegetables | -4.0608 |
| Toasted coconut meat | Nuts | -3.973 |
| Broccoli | Vegetables | -3.9692 |
| Orange with peel | Fruits & Fruit Juices | -3.939 |
| Cherries (sweet) | Fruits & Fruit Juices | -3.8206 |
| Nutmeg | Spices and Herbs | -3.7574 |
| Quinces | Fruits & Fruit Juices | -3.663 |
| Orange juice | Fruits & Fruit Juices | -3.657 |
| Kumquats | Fruits & Fruit Juices | -3.6078 |
| Oranges | Fruits & Fruit Juices | -3.581 |
| Cauliflower | Vegetables | -3.5095 |
| Tangerines | Fruits & Fruit Juices | -3.1421 |
| Green leaf lettuce | Vegetables | -3.1406 |
| Peaches | Fruits & Fruit Juices | -3.1161 |
| West Indian cherry | Fruits & Fruit Juices | -3.087 |
| Nectarines | Fruits & Fruit Juices | -3.0516 |
| Cherries (sour) | Fruits & Fruit Juices | -3.03 |
| Mangos | Fruits & Fruit Juices | -2.9831 |
| Red leaf lettuce | Vegetables | -2.9803 |
| Strawberries (frozen) | Fruits & Fruit Juices | -2.9103 |
| Blackberries | Fruits & Fruit Juices | -2.8039 |
| Coconut meat | Nuts | -2.6773 |
| Garlic | Vegetables | -2.6466 |
| Plums | Fruits & Fruit Juices | -2.622 |
| Strawberries (fresh) | Fruits & Fruit Juices | -2.5427 |
| Cucumber | Vegetables | -2.4265 |
| Raspberries | Fruits & Fruit Juices | -2.407 |
| Celery root | Vegetables | -2.389 |
| Litchis | Fruits & Fruit Juices | -2.3623 |
| Pineapple | Fruits & Fruit Juices | -2.3354 |
| Pears | Fruits & Fruit Juices | -2.2048 |
| Asparagus | Vegetables | -2.193 |
| Lime juice | Fruits & Fruit Juices | -2.1232 |
| Apples (raw) | Fruits & Fruit Juices | -1.9206 |
| Wakame seaweed | Vegetables | -1.3373 |
| Blueberries | Fruits & Fruit Juices | -1.0444 |
| Goat milk | Dairy and Egg | -0.5386 |
| Macadamia | Nuts | -0.4579 |
| Cranberries | Fruits & Fruit Juices | -1.3729 |
| Tapioca | Cereal Grains and Pasta | -0.1649 |
| Quinoa | Cereal Grains and Pasta | -0.191 |
| Chamomile tea | Beverages | -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:
- Beef
- Sweets
- Pork
- Poultry
- Lamb, veal, and game
- Baked items
- Some nuts
- Alcohol and beer
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 goods
- 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.
Add More Negative PRAL Foods
The key to lowering your acid production will be to eat more foods that make base. Therefore, eating a large number of fruits and vegetables is an easy way to ensure this.
It will be important to consume more of the negative PRAL nutrients (potassium, magnesium, and calcium) over the positive PRAL nutrients (protein and phosphorus).
If your doctor and dietitian have directed you to follow a potassium restriction, try adding more volume of low-potassium fruits and vegetables. Be sure to discuss how long the restriction will be in place for as well!
Acidosis can also increase potassium levels. Therefore, considering gradually increasing potassium levels (with approval and monitoring by your healthcare team) may be an effective solution.
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 such as beans, legumes, and even tofu.
While tofu is slightly positive, adding negative PRAL vegetables like green and red peppers can result in a negative PRAL dish. ( +3 + -53 = -50! PRAL negative!)
Limit Servings of High/Positive PRAL Animal 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.
Animal protein foods are generally high in both protein and phosphorus, as well as lower in calcium and magnesium. They do still have potassium.
Thinking of the PRAL equation, it makes sense that animal proteins will add acid because of the resulting positive PRAL values.
If you are still including animal proteins, a good rule of thumb is sticking to about a 3 ounce serving.
This is approximately the size of a standard playing card deck, or the size of an average adult palm. If it’s bigger than your palm, then you should consider scaling back on the portion.
Avoid added phosphates
Since phosphorus is one of the nutrients that makes a food more PRAL positive, limit or avoid added phosphates. This is generally a great way to keep kidneys healthy for many reasons!
To find added phosphates, look at a food’s ingredient list. Any ingredient that has the letters PHOS included is a sign there’s added phosphates. For example, colas tend to have PHOSphoric acid in their ingredients.
No ingredients list? If that’s because it’s a whole, natural food – like an apple – it’s naturally free of phosphate additives!
If it’s a packaged food without an ingredient list, be cautious. See if you can contact the manufacturer to get an ingredient list to be safe.
Learn more about a low phosphorus diet here.
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 breakdown 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.
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
However, research on alkaline water has yet to show concrete benefits in a healthy population, let alone the CKD population.
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 or dietitian 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 Gold. The Cronometer 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!
*This is an affiliate link in which we receive a very small commission, at no expense to you. Thank you for your support!
Jen Hernandez is a registered dietitian and board-certified specialist in renal nutrition. She has nearly a decade of experience with kidney disease patients in all stages - from stage 1 through kidney transplant. Jen writes on the blog of Plant-Powered Kidneys to help reach and teach more kidney patients about how they can enjoy more foods in a plant-based diet while protecting kidney health.
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?
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! 🙂
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.
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! 🙂
You stated under Section 4 that ‘Compounds that contain a lot of hydrogens are acidic and have a pH of less than 7. But then you wrote ‘the higher the pH the more acidic’. I’m sorry…I thought it was the other way around. Am I confused?
Good catch! That is an error – it should say the lower the pH the more acidic. It’s the opposite from PRAL, where the higher a PRAL value is, the more acidic it is. It’s been corrected. Thank you so much for letting me know!
I’ve been using Cronometer and have found it to be an amazing eye opener. I know negative is positive, but what is an acceptable PRAL range? Somedays my PRAL is positive, but is low.
Thanks for all the wonderful information you share!
Hi Rebecca! It depends on the individual. There’s not a certain number that everyone should qualify for, but it can be a great way to set your own nutrition goals. Look at the trends and your “average” to get an idea of where you’re hitting most days. No one is perfect, so some days will be harder. But the average can give an idea of where you’re at and help you set a goal. This is a great topic to discuss with your own healthcare team, too, who can give you specific targets and ranges to aim for. 🙂
Hi! Is there an easy way to calculate the PRAL in a recipe? For example, I found recipes for almond flour blueberry muffins and almond flour pancakes I want to try. Do I need to calculate the PRAL for each individual ingredient or is there a way to calculate it based upon the nutritional values for each finished product? Also, are you familiar with Lee Hull’s book Stopping Kidney Disease? Thanks!
We recommend using a system like Cronometer, which you would enter the recipe ingredients and it would provide you with a nutrition breakdown. The article mentions the benefits of Cronometer as well. And yes, I am familiar with it. 🙂
Hi am a lover of Cronometer…while I don’t track all my foods at every meal, having discovered how to manage my diet, I couldn’t do without it. It makes it so simple. Worth the money!
I guess my other question, to the universe, is how come the various Acid and Alkaline tables that provide columns in a spectrum of Way bad Acid to Way good Alkaline, why are some foods in different columns in different lists?
Thank you for this article – it’s brilliant.
Thanks so much, KK! I can’t answer to what other articles are doing, but ours are based on content from the USDA Food Database and the PRAL calculation noted in the article. Perhaps some other articles are talking about pH? (Which, for the record, is definitely different!)
I bought Cronometer but I can’t figure out how it shows the PRAL SCORE. Can anybody tell me how to do it?
Thanks,
Ginny
Hi Virginia! The PRAL score is available in the Gold Plan. You’ll find it in the analysis area with the rest of the nutrition details for your day and meal.
Hello Virginia,
I use the Cronometer App religiously on a daily basis on my IPad. However I found the only way for me to activate the PRAL meter to show up in the App was to go online and sign in to my account from a regular computer. I don’t recall the actual steps but I remember it was in settings. You can find the steps you need to take with a google search. Good luck.
Login to the web site for cronometer. Click “Settings” then click “Display” at the bottom in the section “Nutrient Balances” put a check mark in the box for “PRAL Alkalinity”.
There is no save button. The change should occur immediately. Now check the app and it should now be in “Nutrient Balance” Gage area.
Scroll to the very bottom. If it’s not there, go to your settings and select PRAL. easy peasy!
Hi Jen, My kidney doctor prescribed allopurinol because I have high uric acid. Is uric acid related to PRAL? Will the allopurinol adjust my PRAL to be closer to neutral or should I be worried that my uric acid levels are consistently high on my labs? He has never mentioned the term PRAL, but he did suggest to cut out meat and go vegetarian. Thank you.
Hi Sharon! Thanks for your patience in my responses. In a way, uric acid can be related to PRAL because of our food choices. Foods that have a lot of purines, which is then converted to uric acid, can also be acidic and increase PRAL. Allopurinol is to help lower uric acid, but won’t have an effect on PRAL. Making changes to your diet including adding more fruits and vegetables can help both uric acid and PRAL values. And if your kidney doctor is discussing vegetarian diet with you (and you’re interested), keep that conversation going! I hope this helps. 😊
Hi Sharon. My uric acid was high and was causing intense pain in my feet. At times the pain was so bad I was crawling around my house because I couldn’t walk. I found out I had Gout due to the uric acid build up in my kidneys. After getting a steroid shot and a 6 day prescription of steroid pills I went home and started researching. I found there are foods that help lower that acid and the ones that really stuck out to me were asparagus and bing/tart cherries either fresh or in juice form as they are alkaline. I located Tart Red Cherry Juice not from concenstrate from Trader Joes. I purchased black/bing cherries at the store and would eat a bowl full a day. I also drink 3/4-1 cup of the tart cherry juice every morning. I have not had any more problems with the Gout in my feet. I’ve also been able to get off my prescription reflux meds and to to OTC which are easier on my kidneys. Hope this helps you.
Looking at the equations, the units don’t seem to cancel.
Can you verify that the application of the equation is to: 1. get the total grams of each food you are going to eat, and multiply them by the mEq score shown? 2. Sum all the foods you will be eating. 3. Positive number is bad, 0 or negative number is good?
Hi James! The technical units of PRAL are milliequivalents (mEq) per day. Positive numbers mean there is more acidity and negative numbers means there is more alkalinity (or less acidity). So negative is “positive” or good for the kidneys. 😊
You should check your data table, I am finding conflicts in the information. As examples “White Rice” and “Pinto Beans”. You have different numbers is different locations. I don’t think that is correct, a food should not very in PRAL based on what it’s classification is.
You’re right! Thank you for catching this error, James. I have corrected them. 😅
I was wondering the PRAL score of olive oil? Also fyi basil is listed twice in the table with much different PRAL values.
PRAL of olive oil is zero, so it’s neutral! 👍🏼
The pH given for apples is wrong. Otherwise looks like a good article thanks 🙂
There’s pH and then there’s PRAL – they’re different values 😉
Is there a connection of the ph of my urine and co2 of my blood. Can i do urine test and get any useful information please send answer to my email just in case I end up not finding my way back here.
Yes, urine tests can be very helpful for kidney health! Be sure to review the results with your healthcare team to get the best, most comprehensive results review that will be specific to your kidney health.
You mention chloride having an influence, but not in what way. I cannot find anything about chloride and PRAL using Google, are you sure it is relevant?
Hi Kelly! Higher chloride can be associated with lower alkalinity. Here’s another article about it: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3269186/
Hi, I drink 2 tablespoons of Apple Cider Vinegar. How will that affect my PRAL.
Hi Donald, thanks for reaching out. I can’t say how it will affect any individual’s PRAL values. Apple cider vinegar (or ACV) is most studied around topics like weight loss and blood sugar control. Apple cider vinegar itself doesn’t have a PRAL value (remember- it’s based on the amount of nutrients like protein, phosphorus, and magnesium.. none of which are in apple cider vinegar). I hope this article gives you more information about ACV!
Pine nuts showing up in both tables as good and bad :/
Ah, good catch and thank you for bringing that to our attention! We have corrected it. Pine nuts are more acidic, so it’s important we have the right info.
Hi
Your PRAL formula is incorrect. You inadvertently added 2 minus signs to the alkaline components.
Your formula:
– (- 0.021) x potassium (mg/day) – (- 0.026) magnesium (mg/day) – (- 0.013) x calcium (mg/day).
It should read:
– (0.021) x potassium (mg/day) – (0.026) magnesium (mg/day) – ( 0.013) x calcium (mg/day)
Thanks so much for bringing that to our attention, John. We have corrected it AND added in a PRAL calculator!
Thank you for introducing me to Cronometer. Subscribed and have been using it for a few days. If you have kidney disease (I’m stage 3a CKD) you need the Gold version of this app to manage your kidney-friendly diet. The breadth and depth of this apps features is a real relief for a frustrated new CKD patient. Looking forward to Wednesday’s Zoom
Thanks again
I’m so happy to hear that! Hope you liked the class. 😊
6 or fewer servings of meat or fish per day under the DASH diet, 6 servings at 3 oz would equal 18 oz for the day?
Thanks for this article, so helpful!
It’s one-ounce portions that they speak to. So six ounces per day. That may be a big change for some. Glad you find the articles helpful, Jim!