Is
it true that each food that you eat can cause your blood to become more alkaline
or acidic?
The
answer is: not really. The pH of your blood is tightly regulated by a complex
system of buffers that are continuously at work to maintain a range of 7.35 to
7.45, which is slightly more alkaline than pure water.
If
the pH of your blood falls below 7.35, the result is a condition called acidosis,
a state that leads to central nervous system depression. Severe acidosis - where
blood pH falls below 7.00 - can lead to a coma and even death.
If
the pH of your blood rises above 7.45, the result is alkalosis. Severe alkalosis
can also lead to death, but through a different mechanism - alkalosis causes all
of the nerves in your body to become hypersensitive and over-excitable, often
resulting in muscle spasms, nervousness, and convulsions; it's usually the convulsions
that cause death in severe cases.
The
bottom line is that if you're out and about, your body is doing an adequate job
of keeping your blood pH somewhere between 7.35 to 7.45, and the foods that you
are eating are not causing any wild deviations of your blood pH.
So
what's up with all the hype about the need to alkalize your body? And what's to
be made of the claim that being too acidic can cause osteoporosis, kidney stones,
and a number of other undesirable health challenges?
As
usual, the answers to such questions about human health can be found by understanding
basic principles of human physiology. So let's take a look at the fundamentals
of pH and how your body regulates the acid-alkaline balance of its fluids on a
moment-to-moment basis.
pH
is a measure of how acidic or alkaline a liquid is. With respect to your health,
the liquids involved are your body fluids, which can be categorized into the following
two main groups:
Intracellular
fluid, which is the fluid found in all of your cells. Intracellular fluid
is often called cytosol, and makes up about two-thirds of the total amount of
fluid in your body.
Extracellular
fluid, which is the fluid found outside of your cells. Extracellular
fluids are further classified as one of two types:
Plasma,
which is fluid that makes up your blood.
Interstitial
fluid, which occupies all of the spaces that surround your tissues. Interstitial
fluid includes the fluids found in your eyes, lymphatic system, joints, nervous
system, and between the protective membranes that surround your cardiovascular,
respiratory, and abdominal cavities.
Your
blood (plasma) needs to maintain a pH of 7.35 to 7.45 for your cells to function
properly. Why your cells require your blood to maintain a pH in this range to
stay healthy is beyond the scope of this article, but the most important reason
is that all of the proteins that work in your body have to maintain a specific
geometric shape to function, and the three-dimensional shapes of the proteins
in your body are affected by the tiniest changes in the pH of your body fluids.
The
pH scale ranges from 0 to 14. A liquid that has a pH of 7 is considered to be
neutral (pure water is generally considered to have a neutral pH). Fluids that
have a pH below 7 - like lemon juice and coffee - are considered to be acidic.
And fluids that have a pH above 7 - like human blood and milk of magnesia - are
considered to be alkaline.
It's
important to note that on the pH scale, each number represents a tenfold difference
from adjacent numbers; in other words, a liquid that has a pH of 6 is ten times
more acidic than a liquid that has a pH of 7, and a liquid with a pH of 5 is one
hundred times more acidic than pure water. Most carbonated soft drinks (pop) have
a pH of about 3, making them about ten thousand times more acidic than pure water.
Please remember this the next time you think about drinking a can of pop.
When
you ingest foods and liquids, the end products of digestion and assimilation of
nutrients often results in an acid or alkaline-forming effect - the end products
are sometimes called acid ash or alkaline ash.
Also,
as your cells produce energy on a continual basis, a number of different acids
are formed and released into your body fluids. These acids - generated by your
everyday metabolic activities - are unavoidable; as long as your body has to generate
energy to survive, it will produce a continuous supply of acids.
So
there are two main forces at work on a daily basis that can disrupt the pH of
your body fluids - these forces are the acid or alkaline-forming effects of foods
and liquids that you ingest, and the acids that you generate through regular metabolic
activities. Fortunately, your body has three major mechanisms at work at all times
to prevent these forces from shifting the pH of your blood outside of the 7.35
to 7.45 range.
These
mechanisms are:
Buffer
Systems
Carbonic
Acid-Bicarbonate Buffer System
Protein
Buffer System
Phosphate
Buffer System
Exhalation
of Carbon Dioxide
Elimination
of Hydrogen Ions via Kidneys
It's
not in the scope of this article to discuss the mechanisms listed above in detail.
For this article, I only want to point out that these systems are in place to
prevent dietary, metabolic, and other factors from pushing the pH of your blood
outside of the 7.35 to 7.45 range.
When
people encourage you to "alkalize your blood," most of them mean that you should
eat plenty of foods that have an alkaline-forming effect on your system. The reason
for making this suggestion is that the vast majority of highly processed foods
- like white flour products and white sugar - have an acid-forming effect on your
system, and if you spend years eating a poor diet that is mainly acid-forming,
you will overwork some of the buffering systems mentioned above to a point where
you could create undesirable changes in your health.
For
example, your phosphate buffer system uses different phosphate ions in your body
to neutralize strong acids and bases. About 85% of the phosphate ions that are
used in your phosphate buffer system comes from calcium phosphate salts, which
are structural components of your bones and teeth. If your body fluids are regularly
exposed to large quantities of acid-forming foods and liquids, your body will
draw upon its calcium phosphate reserves to supply your phosphate buffer system
to neutralize the acid-forming effects of your diet. Over time, this may lead
to structural weakness in your bones and teeth.
Drawing
on your calcium phosphate reserves at a high rate can also increase the amount
of calcium that is eliminated via your genito-urinary system, which is why a predominantly
acid-forming diet can increase your risk of developing calcium-rich kidney stones.
This
is just one example of how your buffering systems can be overtaxed to a point
where you experience negative health consequences. Since your buffering systems
have to work all the time anyway to neutralize the acids that are formed from
everyday metabolic activities, it's in your best interest to follow a diet that
doesn't create unnecessary work for your buffering systems.
Acid
and Alkaline-Forming Effects of Common Foods
Generally
speaking, most vegetables and fruits have an alkaline-forming effect on your body
fluids.
Most
grains, animal foods, and highly processed foods have an acid-forming effect on
your body fluids.
Your
health is best served by a good mix of nutrient-dense, alkaline and
acid-forming foods; ideally, you want to eat more alkaline-forming foods than
acid-forming foods to have the net acid and alkaline-forming effects of your diet
match the slightly alkaline pH of your blood.
The
following lists indicate which common foods have an alkaline-forming effect on
your body fluids, and which ones result in acid ash formation when they are digested
and assimilated into your system.
Foods
that have a Moderate to Strong Alkaline-Forming Effect
Foods
that have a Moderate to Strong Acid-Forming Effect
Alcohol Soft drinks (pop) Tobacco Coffee White sugar Refined
Salt Artificial sweeteners Antibiotics (and most drugs) White flour
products (including pasta) Seafood White vinegar Barley Most boxed
cereals Cheese Most beans Flesh meats Most types of bread
Please
note that these lists of acid and alkaline-forming foods are not comprehensive,
nor are they meant to be.
If
you're eating mainly grains, flour products, animal foods, and washing these foods
down with coffee, soda, and milk, you will almost certainly improve your health
by replacing some of your food and beverage choices with fresh vegetables and
fruits.
The
primary purpose of this article is to offer information that explains why I believe
that you don't need to take one or more nutritional supplements for the sole purpose
of alkalizing your body. Your body is already designed to keep the pH of your
body fluids in a tight, slightly alkaline range.
The
ideal scenario is to make fresh vegetables and fruits the centerpieces of your
diet, and to eat small amounts of any other nutrient-dense foods that your appetite
calls for and that experience shows your body can tolerate.
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