CARNITINE

beef steakCarnitine is made in the body from the essential amino acids L-lysine and methionine.  This conversion requires niacin (B3), vitamin B6, vitamin C, and iron. Carnitine (L-Carnitine) is essential for energy production in the cell:
 – It enables activated fatty acids to enter the mitochondria.
 – Beta-oxidation of the fatty acids in the cell to produce ATP (the major energy source of our cells).
 – Modulation of acyl-CoACoA ratio.
 – Energy storage in the cell as acetylcarnitine
 – Detoxification by removal of poorly metabolized acyl groups excreting them as carnitine esters.

Carnitine has been known to lower triglycerides and cholesterol in those who are relatively low in carnitine. 

 

SYMPTOMS OF DEFICIENCY

In children, the major symptoms of carnitine deficiency are related to the decreased energy of muscles leading to heart failure in severe cases and weakness of major muscles affecting the ability to walk or other gross motor skills in the very young child.  The impaired lipid metabolism of carnitine deficiency results in lipid accumulation in skeletal muscle, heart, and liver.  This results in muscle weakness and fatigue. 

Due to the great needs for oxygen in the heart and brain, times of stress (illness in the ICU, any heart compromise) and times of memory challenge (Alzheimer’s, depression,  Autism spectrum, etc.) may benefit from carnitine support. At the cellular level, carnitine levels drop quickly when there is a lack of oxygen.

Since carnitine is the shovel that gets energy into the cell, fatigue and weakness should be considered possible signs of carnitine deficiency. Due to the rapid changes in blood levels at any given time, blood levels, while suggestive of an issue when low, are rarely helpful.  Rather than a muscle biopsy for carnitine levels, I prefer to use micronutrient testing MNT (www.spectracell.com).

 

FOOD SOURCES                                                
                                                                         mg
Beef (4 ounces)                                        56-162
Whole milk (1 cup)                                            8
Fish      (4 ounces)                                         4-7
Chicken            (4 ounces)                             3-5 
Cheese (2 ounces)                                           2
Whole wheat bread (2 slices)                        0.2
Asparagus (1/2 cup)                                       0.1                  

Adults who eat meat and other animal products typically get 60-180 mg a day of carnitine. Vegans average 10-12 mg daily.

 

SAFETY AND TOXICITY

At daily doses exceeding 3 grams a day, supplements can cause nausea, vomiting, abdominal cramps, diarrhea, and a fishy body odor. In children, I have occasionally seen stomach upset at doses as low as 250 mg, which can be reduced if taken with food. There are rare reports of muscle weakness in uremic patients and seizures in patients with seizure disorders. 

There is no established RDA or upper limit of tolerability, however I would limit supplementation doses to:
Infants              1            25 mg twice a day
Children                       250 mg twice a day
Teen & adults               500 mg twice a day

Carnitine should only be taken as L-carnitine, and there seems to be a benefit of taking Coenzyme Q10 and pantothenate with carnitine, especially if those nutrients are low or borderline. 

Here are some related links that you may enjoy reading:

Carnitine Biosynthesis in Mammals…

Systemic Primary Carnitine Deficiency…

Carnitine Deficiency in Chronic Critical Illness…

Carnitine Deficiency Disorders in Children… 

National Institutes of Health Carnitine Fact Sheet…

 

 

Dr. Paul

 

 

 

 

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