acid and alkaline foods
Image left: acid-producing foods. Image right: alkaline-producing foods.

The acid alkaline balance

Sound Consumer | October 2009

by Dr. Candace McNaughton, N.D.

(October 2009) — Foods can be categorized as carbohydrates, proteins and fats, but they also can be classified by how we process them. Our bodies transform nearly all foods into acids or alkaline bases, and we need a balance to be healthy.

Too many acid-producing foods cause a chronic condition called acidosis — meaning the body becomes too acidic, which can lead to osteoporosis, muscle deterioration, kidney stones, and inflammation.

Fish, meat, poultry, eggs, cheese, milk and grains generally produce acids, while fruit, vegetables, tubers and nuts generally cause blood to be more alkaline. For good health, your body should be slightly alkaline. This is easy to achieve by consuming more alkaline-producing foods and dietary supplements.

Not surprisingly, the typical Western diet, heavy with acid-producing meat and refined foods, is highly acidic. This was not always so. A diet that was more alkaline than acidic was the norm throughout most of human evolution.

High in fruit and vegetables and low in grains and dairy, virtually all pre-agricultural diets were more alkaline than acidic. The human genome hardly has changed over time so, genetically, our bodies still are adapted for more alkaline-producing foods.

Too much protein makes us acidic

Research clearly shows that a diet high in protein leads the body to produce excess acid -and that a diet high in plant foods leaves the body neutral or alkaline1,2. A German study of 720 children showed that those eating more fruits and vegetables produced less acid than those eating more meats, dairy, eggs and grains. Those with higher fat intakes also produced more acid3.

So, if we eat a lot of animal protein and few vegetables, we would be slightly acidic all the time4. Salt also can increase blood acidity — even in normal dietary amounts5. Diabetes6, excess alcohol consumption7, dehydration8, strenuous exercise9 and even the normal process of aging10 contribute to acidosis as well.

What does an acidic body mean to me?

* Score is net acid load in mEq/418 kJ32.
Acid-producing foods Score*
Fish 14.6
Meat 12.4
Poultry 7.8
Eggs 7.3
Shellfish 7.3
Cheese 3.3
Milk 1.3
Cereal Grains 1.1
Neutral foods Score*
Beans -0.4
Base-producing foods Score*
Nuts -1.1
Fresh fruit -5.2
Potatoes -5.4
Mushrooms -11.2
Carrots -17.1
Vegetable fruits -17.5
Leafy greens -23.4
Plant stalks -24.9

Being in a state of mild acidosis may contribute to many health problems. In a study at the University of Chicago, participants consumed a low carbohydrate, high protein diet for six weeks. They all produced more acid in their urine and showed signs of increased risk of kidney stone formation and bone loss11.

Since the body uses minerals from bone to moderate body acid, a state of mild acidosis over a long period may lead to low bone density. Studies show that low bone density may even be related to a 'normal' high protein diet12.

In a Swiss study, volunteers were put on an acid-forming diet or a base-forming diet including bicarbonate mineral water. The acid-forming diet resulted in increased release of calcium and markers of bone breakdown in urine, which was not seen in subjects on the base-forming diet13.

A state of acidosis affects hormones, which control the function of organs and affect such diverse processes as growth and development and reproduction14,15. Excess acid also leads to loss of muscle mass in older adults16 and can produce damaging oxidants and increased inflammation17.

Interstitial cystitis is a condition much like a bladder infection but no infection can be found. People experience all the pain and irritation but antibiotics don't help. Dietary changes, including avoidance of acidic foods, have been associated with reduction in symptoms of interstitial cystitis18.

In a number of studies, smoking, coffee and soda consumption, and a diet low in vegetables (all acid-promoting factors) are associated with greater risk for bladder cancer. Consumption of mineral water has been associated with a decreased risk for bladder cancer19.

How do I tell if I'm acidic?

It's not always easy to tell if your body is acidic. Blood is kept in a very tight pH range by the body's natural buffer systems — the body employs no fewer than seven systems to balance blood and body pH! These include the kidneys, lungs, colon and skin.

But here's the problem: keeping an acidic body at a normal or near-normal blood pH means that the buffer systems are being utilized and therefore a strain is being put on the system. The most obvious — and dangerous — examples are those of protein breakdown in muscles and minerals coming from the bones.

Many people use pH papers to tell if their urine or saliva are acidic but there are a few problems with this. First, urine is most healthy when it is slightly acidic. Second, the pH papers marketed for sale with alkalizing products may have adjusted the scale on the package so that they mark normal levels as abnormal.

For example, a package can say that urine with pH 6 is acidic. It is acidic, but this is a normal acceptable pH for urine. Also, the kidneys make many changes to urine as it comes out of the body and it may not accurately reflect the body's state. Saliva seems to be a better bet, but is not the whole picture. Remember that the body may correct pH of the blood successfully while tissues are sacrificing themselves to keep the blood levels normal.

It's necessary to look at many factors to diagnose if your body is acidic, including lab testing and any conditions or diseases you may have. The best way has not yet been established but I expect that over the next few years, the medical community will find a firm way to diagnose mild long-term acidosis. It must be diagnosed by a doctor, as many of us will have these conditions and may not be in an acid state.

Low normal levels or downward trends in tests can indicate an acidic state in the body. A rough way to estimate acid production is to look at animal protein versus vegetables in your diet. If you have a lot more animal protein than veggies, or if you drink a lot of coffee or alcohol, you may be acidic20.20.

Possible solutions

Small diet changes

Eating more vegetables is an easy way to alkalize the system. The potassium in vegetables helps to reduce body acidity — it is alkalizing.

In a study done at Tufts University, 384 older men and women were found to have greater lean body mass (mostly muscle) if they had higher potassium diets21. Remember that when the body is acidic, one of the things it does to achieve a balance is to break down protein from the muscles.

The most acid-producing foods are fish, meat, poultry, eggs and dairy. Grains are acid-producing, but are a 1 on the scale where meat is a 12.

Base-producing foods include plant stalks (such as broccoli stems), leafy greens, vegetable fruits (tomatoes and bell peppers), and root vegetables. Fruit is base-producing but is a -5 on the scale whereas leafy greens are a -23. You may be surprised to know that lemons and citrus are alkalizing. Beans are somewhere in the middle and remain a great source of protein22.

It's important to remember that protein is essential for health. Aim for 15-20 grams of protein per meal and fill the rest of your plate with vegetables for a healthy acid-base balance. (One cup of yogurt or 1/2 cup of tofu contains 10 grams of protein.)

Many athletes are told to increase protein dramatically when working out, but strenuous exercise23 and excessive protein intake both lead to an acidic condition of the body and can strain the kidneys. It's a good idea to get some extra protein when you're working out often but taking in 100-200 grams at every meal may cause an acidic condition.

Big diet changes

Sometimes, eating a good diet and following the basic recommendations isn't enough. You may need to count grams of protein and fat, or milligrams of sodium in your diet. Adding a greens supplement containing powdered chlorella, spirulina, wheatgrass or alfalfa can help to alkalize the body. (PCC carries several greens supplements.) You may need to see a doctor familiar with mild acidosis for a proper diagnosis, monitoring and detailed diet advice.


Supplementing with minerals is a stronger way to balance body acidity. A study comparing calcium citrate and calcium carbonate supplementation in postmenopausal women found that calcium citrate decreased markers of bone breakdown both in blood and urine, whereas calcium carbonate did not. Otherwise, their performance was similar in improving bone health24. Sodium bicarbonate has been studied extensively with mixed results25.

Potassium citrate has shown positive results. In one study, women with osteoporosis given potassium citrate had increased bone density significantly after a year26- something very difficult to achieve! It's important to follow the recommended doses on labels because it's possible to get too much potassium. If calcium is a concern because of kidney stones, potassium citrate is a great alternative.

Minerals reduce acidity and give your body's buffering systems a break. Systemic alkalization has been shown to help with osteoporosis27, asthma symptoms28, brain damage after stroke29, preventing kidney stones30, cancer 31, and other conditions. Much more research needs to be done.

The big picture

Dietary advice undoubtedly is confusing and trying to balance acid- and alkaline-producing foods may seem like one more thing to worry about. There are various factors which can make us acidic and can lead to harmful health conditions.

But by balancing protein with plenty of vegetables and by supplementing with greens and concentrated minerals if necessary, we should be able to alkalize our bodies and prevent bone and muscle loss and many other ailments we've come to associate with aging.

Candace McNaughton, N.D., is a clinician at Pure Wellness Centers in Seattle’s Capitol Hill neighborhood specializing in detoxification. She’s an accomplished writer and speaker; her focus in research is acidosis and inflammation. E-mail her at with questions.

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