Are acidic foods harmful to health? Good and bad acidic foods

acidic foods
Are acidic foods harmful to health?

Are acidic foods harmful to health? Good and bad acidic foods

If the acids are concentrated and the alkalinity of the blood decreases, the person is exposed to all kinds of cases that lead to eczema, water pox, chronic bronchitis, colds, acidosis, gastrointestinal disorders, gout, rheumatism, and other diseases. 
The study of the chemical functions of the body is one of the greatest areas in which nutrition science is studied. Nutrition science explains the interaction of nutrients and other substances in food with respect to health maintenance, growth, reproduction, and disease of the organism. It also includes food intake, assimilation, absorption, catabolism, biosynthesis, and excretion. In our pursuit of strength and activity, we freely consume large quantities of food that deposit acid waste in the blood, so we must know what acidic foods and alkaline foods are?

Acidic foods: Good or bad?

Recently, some researchers have claimed that acidic foods are harmful to health. Consequently, many people have chosen to avoid or eliminate acidic foods from their diet. In this article, we will discuss how the acidic foods you eat can affect your body and we will present the claims and investigate the evidence so that people can help in determining whether low-acid or acid-free food is the right choice for them. First of all, we should be aware of some background information, before deciding whether avoiding acid foods is beneficial or not, as to how acidic and basic substances interact with the body. Let's see what the acid is and how it acts when it comes to our food. When we look into the acid-base definition, we get, the quantity of acidity and basicity is described as PH level measurement. Each one is extreme in food and drinks on the pH scale or measurement of the acidity or alkalinity of the compounds. PH values can range from 0 to 14, PH value in distilled water or neutral substances is 7. Other types of water may be slightly different pH values with impurity or minerals. Anything below pH 7 is acidic, while anything above ph7 is basic.

How acidic foods affect the body?

PH levels in the body
We should know, when our body becomes very acidic, there are three ways to balance the pH level at the optimum level. To balance the pH level, the respiratory system will increase the breathing rates removing carbon dioxide from the body. Our blood uses the chemical compounds which are called buffers, to reduce acid, as well as kidneys, use them to remove the acid by urinating and play an important role in inactivating and neutralizing acid in the blood. While our body is designed to neutralize a lot of acids, these systems are forced to work hard and can often take a toll on our health. There are different pH levels in various parts of the human body. Within the digestive system, pH values are highly acidic to slightly alkaline. Differences in pH levels within the various organs and body fluids allow them to complete their special work. In any direction, the pH level in the blood more than these limits will greatly reduce the metabolic processes within the body. Human blood with pH from 7.35 - 7.45 should be slightly alkaline. Symptoms of acidosis, or very low on pH scale; irritability, moodiness, depression, dyspepsia,  poor digestion, poor skin, and headaches. Bacteria and viruses grow in the acidic environment by making patients difficult to recover and easy to get sick.

The acid-ash hypothesis

The acid-ash hypothesis is a therapeutic and medical hypothesis that states that excessive acidic diets are bad for overall health, and as a result, there may be many recognizable health effects, including increased risk of osteoporosis. The foods that are metabolized from the body are left behind as chemical residues known as "ash". When combined with the body's fluid, it can form either acid or alkali, which can cause an interaction in the body. For this reason, some attention has been received in the secular society and lay community, and has been used to support the heresy or fad diet known as an alkaline diet. According to the hypothesis, to reduce the pH level of the blood, foods containing acid-forming substances, cause accumulation of acid. The body then compensates for this loss by filtering alkaline metals, especially calcium, from the bone and exerting in the urine. Supporters of the acid-ash hypothesis claim that regular and long-term consumption of acid-producing foods increases the risk of mineral bone, increasing the risk of conditions like osteoporosis. The hypothesis also states that the acid-ash is produced by meat, chicken, cheese, fish, eggs, and grains. While alkaline ash is produced by vegetables and fruits excluding prunes, cranberries, and plums. Since the designation of acid or alkaline ash depends on residues remained on combustion rather than food acidity.  Foods such as citrus, which is generally acidic, actually considered alkaline-producing agents in the diet.

effects of acidic foods
Are acidic foods harmful to health?

Acid-base homeostasis

Acid-base homeostasis is the balanced regulation of the pH of the extracellular fluid in the body and is essential for normal physiology, function and cell metabolism. Proponents of the acid-ash hypothesis claim that the diet affects the blood pH level. However, the body's buffering system strictly regulates blood pH in the process called acid-base homeostasis. The importance of this regulation is certified by various physiological derangements which occur when the plasma pH is either high or low. The proper balance between the acid and the base in the extracellular fluids is very important for the body's general physiology and cellular metabolism.
The pH of intracellular and extracellular fluids should be maintained at a stable level. Generally, the systemic acid-base balance is well regulated with artery pH between 7.36 and 7.44; Intracellular pH is normally around 7.2. For example, chronic metabolic acidosis can be associated with the progress of low bone density, muscle wasting,  nephrolithiasis, and progression of CKD (1–3). At a cellular level, many essential cellular functions, transmembrane transport processes, and metabolic enzymes are highly pH sensitive. Although this review will address systemic pH regulation and role of a kidney, individual cells also have different mechanisms to control their intracellular pH. Examples of the buffer are; calcium stored in bones, proteins, or other mechanisms through which the body resists the pH change in the bloodstream.

The following mechanisms are mainly involved in this process:

Respiratory compensation
 Alveolar ventilation normally eliminates approximately 15 mol CO2 per day that is produced from normal cellular oxidative metabolism and maintains around 40 mmHg arterial PCO2. It normally increases or decreases in CO2 production. Breathing rate increases when acid levels are high. It breaks the carbonic acids into water and carbon dioxide in the blood. The process, including the exhaust of CO2, generally returns blood pH at the normal level.

Renal compensation
 The kidneys have the predominant role of regulating the systemic HCO3− concentration and hence, the metabolic component of the acid-base balance. 
There are two components in the work of the kidneys, almost all filtered bicarbonates (HCO3) and generation of new bicarbonates to change the normal place of consumption by pathologic acids. This production of new bicarbonates is done by net acid immersion. In other words, the kidneys produce bicarbonate ions, which neutralize acid within the blood and make new HCO3− by excreting acid.

These two mechanisms are very effective in balancing the acid and base grounds that it is almost impossible to have any effect on the blood pH for a person's diet. A blood pH level that decreases to pH 7.35 leads to serious health issues in lung or kidneys. This condition, termed acidosis, causes a build-up of acid in the tissues and fluids and can be fatal if left untreated.

Clinical trials

Many researchers have investigated this claim by measuring whether alkalizing salts reduce urinary calcium excretion and found in their studies that taking alkalizing salts will directly reduce the acidity of the blood. This reduction would stop the body's need to leach calcium from the bones, meaning that it would excrete the less amount of calcium in the urine. But, it was later realized, however, that a decrease in the amount of calcium leached from the bones was not responsible for this drop in urinary calcium.  Instead, it was because potassium blocked the absorption of enough calcium in the blood. Being fewer calcium levels in the blood leads to the less calcium existence in urine to filter.
Other clinical trials cited in the review directly investigated whether taking alkalizing salts benefits to bone health. At the starting point, two small studies suggested that these salts can actually maintain healthy bones and reduce the risk of osteoporosis in the body. However, more rigorous, longer-term, randomized controlled trials failed to show any benefit of alkalizing salts. Consequently, the scientific compatibility is that an alkaline diet does not take advantage of bone health with starting positive results due to random chance or placebo effects.


The most common reason people may choose to avoid acidic foods is due to concerns that they may cause or aggravate certain digestive disorders, such as acid reflux gastroesophageal reflux disease. Foods containing acid-forming substances are:
Alcohol, carbonated drinks, coffee, black tea, vinegar, yeast, meat, dairy,  artificial sweeteners, grains, sunflower and pumpkin seeds, tobacco, nuts, and refined table salt. These all substances are low on the pH scale, or highly acidic. Highly processed and fast foods are too. Consumption of these food items and drinks forces the body to fight to reduce the abundance of acid and neutralize it.


Foods that show alkalinity, or 'base-forming' foods, are considered to prevent the effects of acid abundance in the body. These foods contain most of the fruits and vegetables. Even citrus fruits, that are actually acidic in the beginning, can disturb the upper gastric disorders. These conditions can also be increased by high food in fat. Triggers of acid reflux and GERD are known for the following foods: Apples, grapes, oranges, peaches, pineapple, oily and greasy, full-fat dairy, creamy sauces or salad dressings, tomatoes, high-fat foods, fried, lemons, limes, animal fats, and lard and strawberries. They all are moderately acidic. Obviously, these are the best choice of processed foods but take them in moderation. Brown rice, wheat bread, goat cheese, and butter are all in this category as well.


Green juices, lemons, plant milk (rice, coconut, almond), all greens, avocado, broccoli, and beans are all moderately to highly alkaline. Consuming these foods will reduce the need for the acid neutralizing systems of the body to be overworked. Decreasing the acid level in the body can help improve overall health and energy states. If you’re struggling to get all the healthy and appropriate foods into your routine, We have mentioned here enough quantity for you and introduced you to the alkaline goodness of green juices and plant milk.

Take away

Unlike the acid-ash hypothesis, there is no evidence to suggest that acidic foods are harmful to health. It is not possible to change blood pH through diet alone. A blood pH that is highly acidic or alkaline indicates a serious medical problem. Despite this, the so-called basic diet that contains fruits and vegetables is abundant in vitamins, minerals, and antioxidants. People can get many benefits for their overall health by increasing the intake of these foods. However, these benefits are not related to changes in blood pH. Those who benefit from a low acidity diet are those people who are considered acidic foods leading to upper gastric disease.

By: Mahtab Alam Quddusi

Journal Reference:
-British Journal of Nutrition,    10.1017/S0007114513000962

The Scientific World

The Scientific World is a Scientific and Technical Information Network that provides readers with informative & educational blogs and articles. Site Admin: Mahtab Alam Quddusi - Blogger, writer and digital publisher.

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