What fruits are most acidic

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Acidic foods

Acid foods are foods that contain enough acid to have a pH of 4.6 or lower. Acidic foods can be processed safely in a boiling water canner, usually without added acid (lemon juice, vinegar or citric acid). This is necessary to control botulinum bacteria. Acidity may be natural, as in most fruits, or added, as in pickled food. Low-acid canned foods are not acidic enough to prevent the
growth of these bacteria. Acid foods contain enough acid to block their growth, or destroy them more rapidly when heated. The term "pH" is a measure of acidity; the lower its value, the more acid the food. The acidity level in foods can be increased by adding lemon juice, citric acid, or vinegar.

Low Acid Foods

Low-acid foods have pH values higher than 4.6 up to 6.9. (non-acidic, or alkaline foods have pH values of 7.0 or greater) .They include red meats, seafood, poultry, milk, and all fresh vegetables except for most tomatoes. Most mixtures of low-acid and acid foods also have pH values above 4.6 unless their recipes include enough lemon juice, citric acid, or
vinegar to make them acid foods. Acid foods have a pH of 4.6 or lower. They include fruits, pickles, sauerkraut, jams, jellies, marmalades, and fruit butters.

Although tomatoes usually are considered an acid food, some are now known to have pH values slightly above 4.6. Figs also have pH values slightly above 4.6. Therefore, if they are to be canned as acid foods, these products must be acidified to a pH of 4.6 or lower with lemon juice or citric acid. To be safe, we simply recommend always adding 2 tablespoons of lemon juice to each quart of tomatoes or tomato products. Properly acidified tomatoes and figs are acid foods and can be safely processed in a boiling-water canner.

Acidity and botulism

Botulinum spores are very hard to destroy at boiling-water temperatures; the higher the canner temperature, the more easily they are destroyed. Therefore, all low-acid foods should be sanitized at temperatures of 240° to 250° F, attainable with pressure canners operated at 10 to 15 PSIG. PSIG means "pounds per square inch of pressure as measured by gauge". The more familiar "PSI" designation is used hereafter. At temperatures of 240° to 250° F, the time needed to destroy bacteria in low-acid canned food ranges from 20 to 100 minutes.

The exact time depends on the kind of food being canned, the way it is packed into jars, and the size of jars. When it is even possible*, the time needed to safely process low-acid foods in a boiling-water canner ranges from 7 to 11 hours; the time needed to process acid foods in boiling water varies from 5 to 85 minutes. Note: * in many cases, no amount of water bath canning will kill the type of bacteria present, because the temperatures never rise high enough.

Summarizing, low acid or non-acidic foods must be:

• pickled,
• frozen,
• dried or
• canned in a pressure canner (where there is a safe recipe determined for them - there is no safe recipe for canning pumpkins and squash)

Below is a summary of foods by pH.  For a comprehensive list of the pH values of many fruits and vegetables, including some specific varieties, see this page.

Foods can be acid because they are:

1. naturally acid foods
2. foods that have acid, such as vinegar or lemon juice, added
3. fermented foods, such as sauerkraut. During the fermentation process bacteria produce an acid.

Naturally acidic foods include most fruits, such as:

• apples
• berries
• blackberries
• blueberries
• cranberries
• peaches
• pears
• raspberries
• strawberries

Tomatoes are borderline - and must be considered a special case, with acid added!

Low Acid or Non-acidic Foods

These are considered to be LOW acid foods:

Certain fruits:

• figs,
• Asian pears,
• melons,
• bananas,
• dates,
• papaya,
• ripe pineapple,
• persimmons

Almost ALL vegetables, such as:

• asparagus
• beans
• corn
• cucumbers
• garlic
• green beans
• greens (lettuce, kale, collards, spinach, etc.)
• onions
• peas
• pumpkins
• squash (summer or winter varieties)

Acidic foods are those that typically have a pH of 4.6 or lower. Experts are divided on whether acidic foods actually induce metabolic acidosis in a healthy body. According to one school of thought, excessive consumption of acidic foods may be linked to poor bone health, urinary stones, and development of diseases such as arthritis. 

Some researchers also believe that acidic foods are more likely to produce metabolic acidosis in people with compromised kidney function, a condition characterized by decreased blood levels of bicarbonate, specifically 22 mEq/L.

10 foods high in acid

1. Dairy products, including cheese
2. Processed foods that are high in sodium, such as packaged crackers
3. High-sodium condiments such as soy sauce, steak sauce, and barbecue sauce
4. Fish
5. Seafood
6. Fresh red meats
7. Processed meats
8. Starchy foods such as wheat
9. Carbonated beverages such as soda
10. Drinks that are high in phosphorus (or phosphoric acid) such as beer and hot chocolate made from cocoa

Some acidic foods such as citrus fruits may be acidic based on their pH levels, but they have an alkalizing effect on the body. It is therefore OK to have these fruits daily unless you have gastroesophageal reflux disease (GERD)—reflux of food from the stomach into the esophagus. Citrus foods are known to trigger GERD.

What is acidity?

Acidity of foods or body fluids is determined by their pH value. The pH values fall between 0 and 14. The lower the pH, the more acidic. The higher the pH, the more alkaline. Some experts believe that having more alkaline foods and beverages and fewer acidic ones can help you prevent the development of chronic diseases including cancer and delay the signs of aging. However, evidence supporting this claim is insufficient.

Your ideal blood pH is between 7.35 and 7.45, which is slightly alkaline. Your kidneys and lungs work constantly to keep your body pH at this optimal level, irrespective of the food you eat.

• pH of 0: Most acidic
• pH of 7: Neutral
• pH of 14: Most basic, or alkaline

Can metabolic acidosis be prevented through diet?

Your body has an inherent control mechanism that helps regulate your pH levels. However, metabolic acidosis can occur, especially in people with chronic diabetes or kidney disease. Certain drugs if taken in high doses or for longer durations can also cause metabolic acidosis.

Consuming a moderate amount of acidic foods with plenty of fruits and vegetables is unlikely to cause metabolic acidosis and problems caused by metabolic acidosis.

Healthy habits, such as avoiding carbonated drinks and replacing meat with plant-based sources of protein help prevent too much acidity in the body. Replacing meat with poultry can also help you maintain ideal pH levels of the blood and urine.

Eating a balanced diet that includes whole grains, nuts, seeds, dairy products, fruits, and vegetables is a great way to maintain a healthy acid-base balance.

Medically Reviewed on 10/26/2021

References

Image Source: Darios44 / Getty Images Pizzorno J, Frassetto LA, Katzinger J. Diet-induced acidosis: Is it real and clinically relevant? British Journal of Nutrition. Cambridge University Press; 2010;103(8):1185-1194. Bonjour J-P. Nutritional disturbance in acid–base balance and osteoporosis: A hypothesis that disregards the essential homeostatic role of the kidney. British Journal of Nutrition. Cambridge University Press; 2013;110(7):1168-1177.

Metabolic Acidosis: Resources for Patients. https://www.kidney.org/atoz/content/metabolic-acidosis/patient