top of page

Download and Fill-Out
New Patient Paperwork Here

Do Vegetarians Need Amino Acid Supplements?


Client Question:“I have a friend who says vegetarians specifically need to supplement L-citrulline, glycine, and L-lysine. What do you suggest?”


Understanding Amino Acids

L-citrulline, glycine, and L-lysine are all amino acids, which are the building blocks of protein. The human body uses amino acids to build and repair tissues, produce hormones and enzymes, and support overall metabolic health.


There are 21 amino acids in total, divided into two categories:

  1. Essential Amino Acids: These must be obtained from the diet.

  2. Non-Essential Amino Acids: These can be made by the body, so dietary intake is not required.

Out of the 21 amino acids, only nine are essential.


The Nine Essential Amino Acids

A common mnemonic used to remember them is “PVT TIM H(a)LL”:

  1. Phenylalanine

  2. Valine

  3. Threonine

  4. Tryptophan

  5. Isoleucine

  6. Methionine

  7. Histidine

  8. Leucine

  9. Lysine


What About L-Citrulline, Glycine, and Lysine?

  • L-citrulline and glycine are non-essential amino acids. A healthy body produces all that it needs, so supplementation is generally unnecessary.

  • Lysine is an essential amino acid, meaning it must come from the diet.


Lysine plays an important role in:

  • Connective tissue health

  • Energy and fat metabolism

  • Calcium and fluid balance


While lysine is essential, supplementation is not necessary. Supplementation has been associated with gastrointestinal distress and neurological issues.


Do Vegetarians Need to Supplement Lysine?

No, not if they are eating enough calories and protein. Lysine is present in small amounts in many foods and in larger amounts in plant-based staples, including:

  • Soy products (tofu, tempeh, edamame)

  • Legumes (beans, lentils, peas)

  • Quinoa

  • Nuts and seeds


If someone is meeting their overall protein needs, they are almost certainly meeting their lysine needs as well.


Approximate lysine requirements:

  • Infants: ~60 mg per kg of body weight

  • Adults: ~30 mg per kg of body weight


This amount is easily met with normal food intake — for example, a single cup of cooked beans provides a substantial portion of daily lysine needs.


How Much Protein Do We Actually Need?

According to the World Health Organization, a healthy adult needs approximately: 0.8 grams of protein per kilogram of body weight per day


For Example:

  • A 170-lb (77 kg) male needs about 62 grams/day

  • A 140-lb (64 kg) female needs about 51 grams/day


These amounts are readily achievable through a balanced diet, including plant-based, vegetarian and vegan diets.


Take-Home Message

  • Most Americans consume more than enough protein, often far more than required.

  • There has never been a documented case of protein deficiency in a healthy individual who is consuming adequate calories.

  • True protein deficiency is seen in cases of starvation, severe illness (such as advanced cancer), or major trauma (e.g., extensive burns).


Special Populations to Be Mindful of Protein Intake

  • Children: Young children often consume many of their calories from juices, sodas, and sweetened drinks, which contain no protein. Encourage water in sippy cups and structured meals rather than constant snacking.

  • Older Adults: Aging is associated with reduced appetite and decreased efficiency in protein digestion and absorption. Many older adults rely heavily on tea, biscuits, or other processed snack foods, which may lead to inadequate protein intake. Being intentional about including protein-rich foods is important in this stage of life.


Bottom Line

Vegetarians and vegans or other plant-based diets do not need to supplement individual amino acids when eating a well-planned, calorie-adequate diet. Whole foods provide all essential amino acids in sufficient quantities — without the risks associated with unnecessary supplementation.


To Your Abundant Health,

Dana West, RDN, LD


Dana West, RDN, LD thrives on helping her amazing clients get a new lease on life by embracing health and conquering disease, one step at a time, so they can start living with renewed energy and enthusiasm, doing all the things they love to do again.

You can get a new lease on life too, in her upcoming Energize and Thrive: A Virtual Retreat for Vibrant Living.

If you’re an individual in serious overwhelm with your health, lacking energy and experiencing fatigue and poor sleep, this retreat will have you reclaiming your life and thriving in all the things you love again.

Wanna come? Details here!

798 Madison 8645

Huntsville, AR 72740

479-363-6585


 
 
 

Comments

bottom of page