Acid versus Alkali

Filed in Articles and Presentations on June 20, 2014

A healthy mealA large marketing industry has been built up around the concept of acid diets and alkali diets and misleading statements concerning the effects on the human body.  So I thought this week’s article would address this topic.

An acid is a substance which has the capacity to react with metal oxides, hydroxides and carbonates producing compounds which are salts.   Another way of describing acids is a substance which can donate a proton and accept a proton.  A hydrogen atom has one electron and when this is lost in a reaction then you get a proton.  So the basic structure of an acid has is a  single carboxyl group (COOH).

Acids are most commonly recognised by their smell – vinegar is a basic acetic acid. Another example particularly of concern in Ontario and the Great Lakes is Acid rain.  The burning of sulphur containing fuels creates sulphur dioxide which reacts to with air and water to produce sulphuric acid.  Sulphuric acid can combine with ammonia which neutralises the acid.  Ammonia is found in urine in animals and humans but this mechanism enables cattle to survive polluted air.

An excess in the body,  usually from eating an inappropriate diet, causes an excess of hydrochloric acid ‘heartburn’ which is then relieved by purchasing products called anti acids which is often composed of magnesium hydroxide thus neutralising the acid and consequent discomfort.

As acids have the capacity to donate a proton and thus form bonds they can link up with substances which are typically called bases ( ie accept the proton ) which neutralise acids.   Water can be both a base and an acid!   Water soluble bases are called alkalis.  These concepts of acid and alkali are measured by the Ph scale.   This scale was invented by a Danish biochemist working for the Carlsberg company making beer.   The role of acid and bacteria is very important in the production of beer ( as in the human gut ) so this scale was invented as a means to measure the fermentation process of yeast.  A Ph scale in the body is typically measured from 5-8 with 5 representing a very acid solution and anything above 7 an alkaline solution. For practical purposes water is considered to be neutral at 7.0 Ph.

Within the body your acid/alkali balance is tightly regulated by the kidneys and hormones such as ADH ( anti diuretic hormone ).  When a urinalysis is done you will see that Ph is recorded between 5-9 on most tests.   If you are off the scale either end of these numbers you will be very ill and likely to risk mortality as the acid/alkali balance is critical to human life.  Anything above 7.8 is incompatible with human life ie very alkali.

I will try to simplify the process.   When you begin the process of eating and drinking, the body reacts immediately via a hugely complex sophisticated mechanism to balance the acid and alkali intake irrespective of what you put in your mouth.   The initial step is with the salivary glands and via the sight, smell, taste, chewing senses and thus initiating the processes of digestion, secretion and absorption.  Salt and water are excreted in the mouth to enable food to move into the stomach where hydrochloric acid and pepsins are secreted by the walls of the stomach to break down the food, to kill microbes, break the bonds in proteins for absorption and liquidise food.  Amylase secreted in the mouth breaks down carbohydrates but the gastric acid in the stomach destroys amylase.

As I explained earlier, acids can be made more alkali by donating protons to bases like water. The stomach produces about 2 litres of hydrochloric acid a day but this is regulated by the effects of four controlling chemical messengers – gastrin, histamine, acetylcholine, somatostatin. So in the case of a food which is predominantly a protein the concentration of acid in the stomach is very high and inhibits any further secretion of acid ( hydrogen ions ) but as food enters the stomach the store of acid decreases in preparation for entry into the duodenum by binding the hydrogen ions to protein to make them more alkali or rather less acidic. When acid levels fall gastrin, histamine and acetylcholine initiate a process which increases the formation of more hydrochloric acid.   The duodenum does not function very well if food is highly acidic as it inhibits the next stage absorptive processes. Thus as the acid level falls the valve into the duodenum is activated.

Proteins are further broken down in the small intestine by pancreatic enzymes.  The pancreas secretes bicarbonate which neutralises hydrochloric acid entering the small intestine from the stomach.  Fats are deemed like proteins, to be highly acidic and insoluble in water.  The pancreas secretes lipase which enables emulsification and water  to act as a base in the acid exchange together with bile salts.  The pancreas itself generates four enzymes which further enable the body to breakdown food for its own benefit.  Trypsin, carboxypeptides, lipase, amylase, and ribonuclease.

All food may be described as acidic but some foods are more acidic than others and thus require higher or lower concentrations of secreting chemicals to be processed.  Steak with its high protein content is highly acidic and oranges while tasting acidic only contain a small amount of citric acid which is a weak acid and thus can be easily broken down into an alkaline solution.  If any part of this complicated chemical pathway is impaired then it leads to disease.  It is at this point that dietary modification can be beneficial to enable the impairments to be resolved.   When H.Pylori, a bacteria, which is present in all our guts, gets out of control, ulcers get formed through its attachment to the mucosal surfaces of the stomach/duodenum, which secretes excessive acid as a defense mechanism to protect itself.  Symptom relief from the pain is provided by drugs such as proton pump inhibitors as they reduce the level of stomach acid generated by the body in its normal feedback cycle. Slippery elm powder will do the same job without creating a side effect of PPI’s which is to increase the risk of exposing the body to harmful bacteria normally destroyed by high levels of stomach acid while allowing the mucosal surfaces to heal.  At this time it would be easier on your body to eat foods which are less acidic i.e vegetables, fruits rather than large amounts of protein, fats or starches.   At the end of the day all three food groups proteins, fats, carbohydrates ( sugars ) are needed by the body.

In diabetes the function of the pancreas is impaired so its ability to secrete the enzymes needed to breakdown protein and starch is reduced thus if you have diabetes a much larger proportion of your food intake should be vegetables rather than high protein and starch.   Protein and fats take a much longer digestive time due to the more complicated metabolic pathways required compared to vegetables and fruits.  Thus it is best to start a meal with protein rather than veggies unless they are composed of bitter substances which stimulate the digestive enzymes such as arugala, chicory, fennel, dandelions and so on.

As is evident from the role of water acting as an acid or a base; drinking 2 litres a day helps the digestive system significantly to work properly and maintains hydration of tissues.

The vast majority of digestive disorders arise from inappropriate diets – colon cancer from large amounts of sugar and protein, diabetes from sugars, liver cirrhosis from alcohol and so on. Nothing to do with acid vs alkali diets.   The moral of the story is eat sensibly a balance of all three food groups in small quantities two to three times a day!

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