Amino acids are nitrogen compounds that serve the organism as building blocks for proteins. Proteins are involved in numerous bodily functions and are therefore essential for life. Our body can only partially produce the required amino acids itself: So-called essential nitrogen compounds must be supplied with food.
Relevant for the body functions are their properties: There are acidic and alkaline amino acids. Since the human blood has a pH value of over seven, corresponding protein building blocks are of particular importance. Because our body wants to keep this value as constant as possible.
To explain: pH values above seven are alkaline, those below are acidic. A downward deviation from the normal value, therefore, means that the organism is over-acidified. Such an imbalance of the acid-base balance can impair our health, nutritionists and naturopaths agree. They, therefore, advise against an acid-heavy diet.
This is especially true for senior citizens. Foods containing alkaline amino acids can possibly counteract some typical complaints in old age.
Proteinogenic amino acids and their importance
An amino acid is called proteinogenic if it is necessary for the construction of the body’s own proteins. The human genome contains 20 such protein building blocks.
Proteins ingested with food are broken down into the individual building blocks via the digestive tract. These are then available to the organism to produce the required proteins. How well they can be utilised depends in particular on the source of the protein or the amino acids it contains.
Division of the protein building blocks into three classes
We distinguish between essential, semi-essential and non-essential amino acids.
Non-essential is any amino acid that your body can produce itself in the required amount. The only requirement is an average balanced diet.
An amino acid is essential when it is absolutely necessary to take it in through food: the body cannot produce it itself, so an insufficient supply will inevitably lead to a deficiency.
If we are in good health, our body is able to produce semi-essential amino acids from the essential ones itself. Stress, illness or other unfavourable circumstances can impair this ability. Then the organism is also dependent on the intake with food.
If a protein source contains all essential building blocks in an optimal composition, it is called complete.
For a balanced supply, the DGE (German Society for Nutrition) recommends that adults consume an average of 0.8 grams of protein per kilogram of body weight per day.
Our age and constitution can influence the optimal amount. A combined requirement coverage from vegetable and animal protein sources is considered balanced.
The human organism has an alkaline environment
Our blood normally has a pH value between 7.35 and 7.44. It is therefore slightly alkaline which is ideal for many functions in the organism. The body has its own buffer systems to maintain the alkaline environment as constantly as possible. However, if the amino acid content of the food is generally more acidic than alkaline, the buffer systems may be overstrained.
The transport of oxygen and nutrients via the blood and thus the entire metabolism suffers from fluctuations.
Specifically, this concerns among other things our
- electrolyte balance
- cell supply
- nervous system as an impulse conductor
- muscle activity
The tasks of alkaline amino acids
Our body needs these alkaline amino acids:
- Arginine (non-essential)
- Lysine (essential)
- Histidine (semi-essential)
The amino acid arginine is produced by a healthy organism itself. It contributes to the dilation of the blood vessels and thus counteracts clumping and circulatory disorders. In addition to your own production, you benefit from arginine in walnuts, peanuts, oats, whole grain rice, poultry, pork and beef.
The organism is urgently dependent on the supply of the amino acid lysine. In particular, it is involved in enzyme formation and hormone balance, immune stability and tissue regeneration. Lysine is found in peanuts, lentils, soybeans, tuna, shrimps and pork, among others.
Histidine is used for histamine formation. It is particularly important for immune function and the digestive tract. A healthy adult organism produces histidine itself. It can also be obtained from foods such as lentils, wheat germ, salmon and tuna.
Completeness is important
Nutritionists stress the importance of alkaline proteinogenic building blocks, as they consider hyperacidity of the organism to be partly responsible for some chronic diseases.
However, your body basically needs every essential amino acid regardless of its pH value.
A balanced diet helps to maintain the acid-base balance:
Ideally, the pH of our blood should be in the above-mentioned range between 7.35 and 7.44.
Buffer systems of the organism compensate for fluctuations
The so-called carbonic acid-bicarbonate system is active in human blood. It stimulates the breakdown of excess acids, which keeps the pH value stable. Haemoglobin, the red blood pigment, is also involved. The acidic substances are broken down into individual components, with the majority being exhaled as carbon dioxide through the lungs. Increased, deep breathing, for example during sporting activities, promotes acid expulsion via the lungs.
Another important buffer system is found in the kidneys to excrete acids with the urine. If you drink a lot of water or unsweetened tea, this process is encouraged. Intestinal activity, muscle activity and perspiration also contribute to the breakdown of acids.
Acidosis – the hyperacidity of the body
We distinguish between acute metabolic acidosis and latent acidosis. The risk of latent acidosis arises if we eat a too acidic diet for a long period of time. If the acid content of the food is permanently too high, the body’s buffer systems may no longer be sufficient.
Latent means that the pH value of the blood is slightly shifted into the acidic environment. Our bodily functions can thus still be maintained overall. On the other hand, a balanced supply of all necessary nutrients to the cells is no longer guaranteed. All in all, a latent over-acidification, in the long run, leads to our metabolism and metabolic processes being impaired.
Due to the increased acid excretion via the kidneys, latent acidosis can be detected by a low pH value in the urine.
The body’s own buffering of acids is dependent on minerals and an alkaline amino acid is usually more mineral-rich than an acidic one. This means that with latent acidosis the body needs more minerals. However, it receives less of these substances if we eat a predominantly acidic diet. Therefore, alkaline foods are increasingly recommended to regulate mineral balance.
A purely nutrition-related acute metabolic acidosis is quite unlikely: a more rapid shift of the pH value into the acidic range occurs. The buffer systems of our body normally prevent such a shift.
The cause can be chronic renal insufficiency, which impairs acid excretion. A diabetic coma is another risk factor.
Alkaline amino acids: Food for health-conscious people
It is a common misconception that a person simply needs to consume a lot of protein-containing food to ensure a balanced supply. It depends on the quality of the protein – more precisely on the amino acid composition.
In order to be able to use them optimally in the body, high bioavailability is advantageous. It must also contain all the relevant building blocks for the important endogenous proteins. This applies especially to essential and, under certain circumstances, semi-essential amino acids as well as those of an alkaline nature.
The views of nutritionists and practical tips on food composition are not always in agreement.
Scientifically recognized is the “Potential Renal Acid Load“, PRAL for short. This value describes the acid excretion of individual foods via the kidneys and thus the acid load of the body. A negative PRAL value indicates an excess of bases, a high value an excess of acid.
Since the body’s own buffer systems work on an alkaline basis and alkaline foods have a deacidifying effect, the following applies: Acidic foods contribute to the consumption of alkaline reserves.
However, acid does not refer to the taste, but to the chemical properties!
Consider individual constitution and nutrient quality
The PRAL value alone is nevertheless insufficient as a guideline value. For the actual acid-base balance and the right nutrition other factors play a role:
- If you are regularly active in sports, excess acid is increasingly reduced through breathing and muscle activity.
- Take in a lot of liquid, preferably water, and support the acid reduction via the kidneys.
Older people, who are naturally more prone to bone loss, have a less active buffer system than young people. They should eat more alkaline food, according to the German Association for Independent Nutrition (UGB).
How a balanced diet positively influences us
Studies confirm a link between acid-base balance and osteoporosis, informs the UGB: Even a slight, longer-lasting hyperacidity promotes the breakdown of bone substance.
This is due to the loss of minerals that the body obtains from the bones, among other things, for the purpose of acid excretion. The cartilage structure and the connective tissue as a supporting apparatus can also be affected.
Furthermore the UGB: As early as 2004, the World Health Organisation (WHO) and the Food and Agriculture Organisation (FAO) confirmed that bone resorption and the associated disturbance of the calcium balance are related to protein intake. They, therefore, recommend that acid-forming foods should be enjoyed in moderation. This also applies to rheumatic and gout diseases, which are associated with increased acid excretion.
Do you follow a predominantly alkaline diet?
These findings should be of particular interest to older people: A balanced diet to regulate the acid-base balance could counteract typical ailments in old age such as osteoporosis.
WHO and FAO, therefore, recommend reducing the consumption of acid-forming foods such as meat.
Besides osteoporosis, this could have a positive effect on other complaints:
- cardiovascular disorders
- high blood pressure
- connective tissue weakness
- muscle loss
- circulatory disorders
The connection has not yet been scientifically clarified. However, nutrition researchers agree that a constant pH value is important for the regulation of bodily functions. It should always be slightly alkaline. They, therefore, recommend that people should preferably eat foods with alkaline amino acids.
This is especially true when latent acidosis is already known and with increasing age when the risk of certain diseases increases. As a guideline for a balanced ratio, nutritionists often give about two-thirds alkaline or vegetable amino acids. Acidic or animal amino acids may be integrated into our diet to one third.
If you would like to eat health-consciously, just pay attention to the following
- to reduce the consumption of meat,
- restrict alcohol and sugary foods, and
- regularly consume fresh vegetables and fruit.
If you learn to cope better with stress, exercise regularly and drink enough, you will also contribute to a balanced amino acid metabolism.