Alkaline vs Acidic foods – Understanding the pH content of foods

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Amongst other classifications, foods can also be divided into alkaline and acidic types. Which type is better for you and why?

What is pH balance?

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The human body has many different mechanisms that help to maintain its equilibrium in order to attain optimal functioning. Of these mechanisms, pH is one of the most important balance systems in the body. pH stands for “potential” of “hydrogen”. It refers to the amount of hydrogen ions present in a solution. The higher the number of H+ ions, the more acidic is the solution. Similarly, the lower the number of H+ ions, the more alkaline is the solution. Water is a neutral solution with a pH of 7. A pH of 6.9 or less is considered acidic and a pH over 7 is considered alkaline.

Blood has a pH range of 7.35 - 7.45. This implies that the normal pH of blood is slightly alkaline. A slight deviation in the pH range of blood can have a detrimental effect. A shift in pH towards the acidic range, i.e. a pH of less than 7, can lead a person to coma, while a shift towards the alkaline range, pH more than 7.45, can cause convulsions. The stomach, in comparison to the rest of the body has an acidic environment with a pH of 1.35 - 3.5, due to the presence of hydrochloric acid that helps in the digestion of food.

Food and pH levels

Your diet has the most important effect on the natural pH of the body. Stress is an equally important factor that causes pH change. Typically, our diet comprises more of acidic foods, in the form of processed and refined foods, but ideally the intake of alkaline foods should be higher. In order to attain the right pH balance, the body creates a buffer system, which involves cushioning the body and removing unwanted acids. It is a chemical process to protect the body from the harm done by acids. Changes in pH balance affect many body functions namely:

  • Digestive system - Acidity or acid reflux is due to high acid content.
  • Gynaecological concerns - Maintaining a specific pH balance is important for conception and vaginal health.
  • Skeleton system - As bones are a reserve of calcium and magnesium, high acid content leads of demineralization of bones.
  • Enzyme function - Various enzymes in the body are involved in the metabolic processes. The functions of enzymes are dependent on electrolytes and electrolytes are in turn dependent on the body’s pH.

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For the human body, an alkaline environment is better suited for immunological health, good enzymatic action and repair mechanism. But the body, unavoidably produces acids:

- During exercise for instance, lactic acid is produced.

- Exhalation of CO2 is a form of acid removal.

- Immune and stress responses also generate acids.

As the body produces acids on its own, a diet that is more alkaline should be consumed.

Food or diet is termed acidic or alkaline by the ash it produces when the food is burnt in a bomb calorimeter (an apparatus used to measure the calorific value of food).

Alkaline and acidic foods

The list of alkaline and acidic foods given below is based on the theory of impact of food on the body after it has been consumed, viz. whether it has an acidifying or an alkalizing effect in the body after consumption.

List of alkaline and acidic foods



Highly alkaline Cucumber, spinach, parsley, broccoli, all sprouts Highly acidic Alcohol, coffee, black tea, sweetened fruit juice, honey, jam, jelly, chicken, eggs, pork, milk, colas, soda
Moderately alkaline Beetroot, all bell peppers, cabbage, lettuce, onion, ginger, tomato, lady finger, mustard leaves, lemon Moderately acidic Fresh juice, mayonnaise, apple, banana, grapes, mango, orange, peach, pineapple, brown rice, oats, wheat, ketchup, butter
Mildly alkaline Cauliflower, carrot, peas, coconut. Mildly acidic Chana, Rajma, plums, watermelons, soyabean.

Acidic foods cannot be completely avoided, but it is important to try and consume them in moderation.

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Written by Misha Sharma, Nutritionist

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