Amino Acids: How Much In A Day Should I Take?

How much amino acid should I take a day to refer to the advisable and healthy amounts? It can be the limit per day to avoid adverse effects brought by too much intake of amino acids. What are amino acids? Amino acids are the building blocks of protein. They provide various essential functions for the

amino acids written on chalk board with different foods

How much amino acid should I take a day to refer to the advisable and healthy amounts? It can be the limit per day to avoid adverse effects brought by too much intake of amino acids.

What are amino acids?

Amino acids are the building blocks of protein. They provide various essential functions for the normal functioning of the nervous system, muscles, formation of nails and hair, and organs. They are divided into two groups – essential amino acids (they can’t be produced by your body and must be obtained from foods) and the non-essential acids (they can be produced by your body).

Essential Amino Acids Non-Essential Amino acids
Histidine Alanine
Arginine Isoleucine
Aspartic acid Asparagine
Lysine Leucine
Methionine Cysteine
Phenylalanine Glutamic acid
Threonine Glutamine
Tryptophan Glycine
Valine Proline
Tyrosine Serine

How much amino acids should I take a day

The calculation for weight in kg

RDI of the essential amino acid per kilogram of weight X Weight (pounds)

For Histidine

RDI  = 14 mg X 60 kg (or 132 pounds) = 840 mg

The calculation for weight in pounds

RDI of the essential amino acid per kilogram of weight X weight (in kg) / 2.2

For Histidine

RDI = 14 mg X (132  / 2.2) = 840 mg

You can do this calculation for the rest of the essential amino acids

The US recommends the following daily allowances for each 1 kg or 2.2 pounds of body weight. 

  • Histidine – 14 mg
  • Isoleucine – 19 mg
  • Leucine – 42 mg
  • Lysine – 38 mg
  • Methionine – 19 mg
  • Phenylalanine – 33 mg
  • Threonine – 20 mg
  • Tryptophan – 5 mg
  • Valine – 24 mg

According to these sources: Harvard School of Public health and the University of Arizona, the following are the daily intakes of amino acids that you should take for each gram of protein you are eating.

  • Histidine – 18 mg
  • Isoleucine – 25 mg
  • Methionine and cysteine – 25 mg
  • Leucine – 55 mg
  • Lysine – 51 mg
  • Phenylalanine and Tyrosine – 47 mg
  • Threonine – 27 mg
  • Tryptophan – 7 mg
  • Valine – 32 mg

A desirable amount of protein-based on the grams of protein intake

Various researchers in Canada used a method named Indicator Amino Acid Oxidation (IAAO) that bases the desirable amino acid amount on the protein consumed

Milligram for each gram of protein
Histidine (no data)
Isoleucine 4 mg
Leucine 13 mg
Lysine 19 mg
Methionine 37 mg
Phenylalanine 42 mg
Threonine 47 mg
Tryptophan 48 mg
Valine 55 mg

National Academy of Sciences RDI

The recommended daily intake for amino acids also depends upon age and gender as set by the National Academy of Sciences (NAS). 

recommended intake of amino acids by age

For the Non-Essential Amino acids

Currently, the Daily Recommended Intake does not provide data for the non-essential amino acids.

What are its adverse effects?

Kidneys have to work hard

Kidneys play a vital role in regulating acids in the body and thus are susceptible to excessive amino acids. Some amino acids are basic while others are acidic. A high-protein diet can be acidic.

Consuming a high-protein diet can make your kidneys work extra hard to keep it balanced. Because your body doesn’t store extra amino acids it will be broken down and eliminated once you eat take too much. A higher intake of amino acids will result in higher levels of ammonia and urea – thus the kidney will double its effort to filter blood.

Can cause side effects

According to the Mayo clinic, Arginine can cause abdominal pain, gout, airway inflammation, allergic symptoms, bloating and diarrhea, gastrointestinal problems, and nausea. Arginine can worsen allergies and asthma and if you have those conditions use amino acid supplements with caution.

Since amino acids form the building blocks of protein, eating too much of it can lead to bad breath, weight gain, diarrhea, constipation, dehydration, heart disease, kidney damage, and increased risks of cancer. 

Individual effects for each cited amino acids

  • Tryptophan – According to this report, there were no side effects of tryptophan to humans.
  • Phenylalanine – According to these reports, there were no side effects of incrementing doses.
  • Lysine – There were no reported adverse effects of incremented doses to infants according to this report.
  • Histidine – When obese human subjects were given dosages of 24 to 64 grams per day of histidine, there was a reported increase in painful eyes, nausea, anorexia, urinary zinc, drowsiness, weakness and headache, poor memory, mental confusion, and depression. On the other hand, there were no side effects that showed when a 4.5 gram per day of histidine was used as a treatment for chronic uremia, rheumatoid arthritis, and obesity. 
  • Methionine – This amino was reported as among the most toxic in higher dosages. Higher intake of methionine led to failed pregnancies, hemosiderin accumulation, liver damage, and growth depression in animals. On the other in humans, there was also an adverse effect such as hepatic dysfunction, vomiting, and nausea. Further, dosages of 10 to 20 grams per day given orally up to 2 weeks resulted in functional psychosis in schizophrenic patients.

What is the normal intake?

The recommended amount depends upon the number of factors such as health, gender, activity, age, and gender. For people, with little activity, health professionals recommend up to 0.8 grams for every kilo of body weight. Most experts agree that healthy adults can eat 2 grams of protein for each of their body weights for a longer period.

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