Carnitine–important, but confusing

Among those nutrients, or nutritional supplements, that continue to gain support from ongoing published research, is one that doesn’t get as much attention from the press as others–such as vitamin D, fish oil, CoQ10 or Ubiquinol, and calcium, for example. This is too bad, as the health benefits from many of the lesser know supplements is very impressive, and very important. The one that we want to remind you about, today, is L-Carnitine.

Why is L-Carnitine so important? Research has shown that L-Carnitine can be beneficial in many areas, including cardiovascular health, sports nutrition and energy, weight management, brain wellness, male fertility, infant nutrition, and restricted diets such as that of vegetarians.

L-Carnitine is a substance that is normally produced in our body, in the liver, that is essential for energy production and fat metabolism.

What caught our attention this past week, was some new research on carnitine’s ability to reduce muscle soreness and accelerate recover after exercise–even in older people.

Considerable research on carnitine’s role in sports nutrition already exists. In this area, it has been shown to delay the onset of fatigue, improve the recovery process, and optimize performance.

Studies have sown that L-Carnitine supplementation increases the peak treadmill running speed in marathon runners and increases VO2max in cyclists and long distance walkers.

Research shows that L-carnitine supplementation decreases lactic acid accumulation and spares glycogen and therefore plays a role in delaying fatigue during exercise.

And, most recently, clinical studies show that daily L-carnitine consumption prior to high intensity exercise significantly reduced muscle pain and decreased muscle damage in untrained subjects. In other words, this means that L-Carnitine supplementation can help in the recovery process. The protective effects might be partly due to enhancement of oxygen supply to the muscle via increased blood flow.

Until now, the effect of L-Carnitine on recovery after exercise had been done on younger people. The most recent study, published in Metabolism: Clinical & Experimental, showed that the same benefit occurred in older subjects. The average age was 48.7 years, and they tood 2 grams per day of L-Carnitine l-tartrate. Subjects were divided into two groups, with one getting a placebo.

Blood samples showed that L-carnitine supplementation significantly improved a range of biochemical markers, including purine metabolism, free radical formation, and muscle tissue disruption. The researchers wrote: “Such findings support the additional findings that l-carnitine l-tartrate significantly reduced muscle soreness immediately after the exercise workout and at 24 and 48 hours postexercise when compared with the placebo condition.”

Although the L-Carnitine did not affect the physical performance of the subjects, the researchers pointed out that “Carnipure [L-Carnitine l-tartratre] can play an important role in the diet of middle-aged women and men and positively affect their physical wellbeing,”

Now, another reason we wanted to talk about this is that choosing an L-Carnitine supplement can be a little confusing. This is the area, or course, where we try to help you. That is what Willner Chemists is all about. The problem is that there are many different forms of L-Carnitine on the market.

Why is this? Well, if you remember a few minutes ago, Dr. Podell ran down a list of the various health conditions and body systems that can be affected by L-Carnitine. Depending on which area of the body you are concerned with, you can choose a form of L-Carnitine that is optimized for that purpose.

Take brain wellness, for example. There are several applications for L-Carnitine in brain or central nervous system health. Because of its restorative and protective actions against aging and neurodegeneration, it can play a role in maintaining optimal brain function and reducing mental decline under certain conditions.

The acetyl derivative of L-Carnitine, Acetyl L-Carnitine, is the form to use for this purpose. Why? Because this form can cross the blood-brain barrier. It is also a source of acetyl groups, important to neurotransmitter and energy production.

Another special form of L-Carnitine supplement is GPLC. This is a propionyl ester of carnitine that includes a glycine component. Compared with other forms of carnitine, GPLC exhibits a special affinity for muscle tissues, including those of the heart and skeletal muscles. GPLC is a powerful antioxidant that scavenges free radicals – protecting against lipid peroxidation, assists in energy production – contributing to proper carbohydrate metabolism, improved muscle function and reduced lactic acid buildup during low-oxygen conditions such as exercise, and provides powerful support for peripheral arterial blood flow.

This form, GPLC, would be a good choice for those with cardiovascular concerns or even sports and exercise applications.

There are other forms as well. Tartrates and Fumarates. There is an Acetyl-L-Carnitine Arginate. One company, Jarrow Formulas, has a combination of Carnitine and CoQ10, while Doctor’s Best combines GPLC with CoQ10.

Perhaps in response to this challenging situation–having to choose from so many different products, Jarrow Formulas come out with one answer–a full spectrum carnitine combination product called CarnitAll 600.

As they describe it, “CarnitALL® is a full spectrum carnitine combination designed to impact various body tissues with the benefits of carnitine including the cardiac and skeletal muscles as well as mitochondrial function in brain, nerve, heart, liver and sperm cells, where various forms of L-Carnitine participate in metabolizing fatty acids into energy.”

It contains L-Carnitine Fumarate, Acetyl-L-Carnite Arginate, GPLC, and Acetyl-L-Carnitine Taurinate.

There are two companies that manufacture L-Carnitine, Sigma-Tau and Lonza. For more information, each has excellent information on their web sites:

http://www.aminocarnitines.com/index.asp

http://www.lonza.com/carnipure/en.html

You can also go to www.willner.com and select “carnitine” from the drop down menu under Library Quick Search.

*Note: The above information was taken from the opening radio script of our program, The Willner Window, on WOR & WGKA, broadcast on August 29th, 2010. . . . written by Don Goldberg

About Don Goldberg

Hello. I am what you might call a Nutritional Pharmacist. After college, I worked in the Pharmaceutical and Nutritional Industry, first in Quality Control, and then in Manufacturing and Product Development. Increasingly, as the years passed, I became more involved with nutritional supplements. I spent many years detailing physicians, herbalists, and homeopaths about nutritional and herbal therapies and products. In 1992, along with my friend Arnie Gitomer, I bought Willner Chemists, a well-established nutritionally oriented pharmacy. For the first time, I had an opportunity to communicate directly with the consumer, the patient, and the customer. I love it. This blog is an additional way for me to extend my personal views and opinions directly to you. You can also hear me on the radio, every Sunday, from 2 to 4 pm on WOR radio in NY (710 AM), or WGKA in Atlanta (920 AM). Or check our website, www.willner.com.
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3 Responses to Carnitine–important, but confusing

  1. Kate Berry says:

    Hi Mr. Goldberg,

    I’m a woman in her mid-30s, was raised a vegetarian and would say overall I’m pretty healthy. I’m on no medication but I’ve been under some long-term (2yrs) chronic stress and now my thyroid is “borderline low” (Hypothyroid – to the point where I can definitely tell in the way I feel, but also I’ve gained about 8 lbs.). I’ve recently started natural remedies including yoga, daily excersise and a natural Gaia Thyroid Support supplement with L-Tyrosine (300mg) to get me back on track.

    As a vegetarian, I’m also extremely interested in beginning a daily regimen of L-Carnitine l-tartratre. However, I’m doing research and it looks like my thyroid condition and supplement could adversely interact ? I guess my question is … should I avoid all together? ….Or is there a safe dosage of L-Carnitine l-tartratre that does NOT interact (maybe high dosages only will interact? ) …or maybe I could alter these two supplements on different days?

    If you have any information I would be very grateful! There is very little reliable, high quality information.

    Best,
    Kate

    • Don Goldberg says:

      I am not aware of any problem with taking L-Carnitine under these conditions. I do see that there have been a couple of studies using L-Carnitine in “hyperthyroidism.” The premise seems to be based on speculation that L-Carnitine might suppress thyroid function in some tissues. Is this the basis for your concern? I can only tell you that I see no references to this as a contraindication in the sources I consulted, and I doubt it would be a problem. But I am not a physician and you would have to get your doctor’s input if you remain concerned. Here is the abstract of the one study that may relate to this:
      J Clin Endocrinol Metab. 2001 Aug;86(8):3579-94.
      Usefulness of L-carnitine, a naturally occurring peripheral antagonist of thyroid hormone action, in iatrogenic hyperthyroidism: a randomized, double-blind, placebo-controlled clinical trial.
      Benvenga S, Ruggeri RM, Russo A, Lapa D, Campenni A, Trimarchi F.
      Source
      Cattedra & Sezione di Endocrinologia, Dipartimento Clinico-sperimentale di Medicina e Farmacologia, University of Messina School of Medicine, 98125 Messina, Italy. s.benvenga@me.nettuno.it
      Abstract
      Old studies in animals and unblinded studies in a few hyperthyroid patients suggested that L -carnitine is a periferal antagonist of thyroid hormone action at least in some tissues. This conclusion was substantiated by our recent observation that carnitine inhibits thyroid hormone entry into the nucleus of hepatocytes, neurons, and fibroblasts. In the randomized, double-blind, placebo-controlled 6-month trial reported here, we assessed whether 2 or 4 g/d oral L-carnitine were able to both reverse and prevent/minimize nine hyperthyroidism- related symptoms. We also evaluated changes on nine thyroid hormone-sensitive biochemical parameters and on vertebral and hip mineral density (bone mineral density). Fifty women under a fixed TSH-suppressive dose of L -T(4) for all 6 months were randomly allocated to five groups of 10 subjects each. Group 0 associated placebo for 6 months; groups A2 and A4 started associating placebo (first bimester), substituted placebo with 2 or 4 g/d carnitine (second bimester), and then returned to the association with placebo. Groups B2 and B4 started associating 2 and 4 g/d carnitine for the first two bimesters, and then substituted carnitine with placebo (third bimester). Symptoms and biochemical parameters worsened in group 0. In group A, symptoms and biochemical parameters worsened during the first bimester, returned to baseline or increased minimally during the second bimester (except osteocalcin and urinary OH-proline), and worsened again in the third bimester. In group B, symptoms and biochemical parameters (except osteocalcin and urinary OH-proline) did not worsen or even improved over the first 4 months; they tended to worsen in the third bimester. In both the A and B groups, the two doses of carnitine were similarly effective. At the end of the trial, bone mineral density tended to increase in groups B and A (B > A). In conclusion, L-carnitine is effective in both reversing and preventing symptoms of hyperthyroidism and has a beneficial effect on bone mineralization. Because hyperthyroidism depletes the body deposits of carnitine and since carnitine has no toxicity, teratogenicity, contraindications and interactions with drugs, carnitine can be of clinical use.

  2. Don Goldberg says:

    In response to the question about carnitine and thyroid medication:

    J Clin Endocrinol Metab. 2001 Aug;86(8):3579-94.

    Usefulness of L-carnitine, a naturally occurring peripheral antagonist of thyroid hormone action, in iatrogenic hyperthyroidism: a randomized, double-blind, placebo-controlled clinical trial.
    Benvenga S, Ruggeri RM, Russo A, Lapa D, Campenni A, Trimarchi F.

    Cattedra & Sezione di Endocrinologia, Dipartimento Clinico-sperimentale di Medicina e Farmacologia, University of Messina School of Medicine, 98125 Messina, Italy. s.benvenga@me.nettuno.it

    Abstract
    Old studies in animals and unblinded studies in a few hyperthyroid patients suggested that L -carnitine is a periferal antagonist of thyroid hormone action at least in some tissues. This conclusion was substantiated by our recent observation that carnitine inhibits thyroid hormone entry into the nucleus of hepatocytes, neurons, and fibroblasts. In the randomized, double-blind, placebo-controlled 6-month trial reported here, we assessed whether 2 or 4 g/d oral L-carnitine were able to both reverse and prevent/minimize nine hyperthyroidism- related symptoms. We also evaluated changes on nine thyroid hormone-sensitive biochemical parameters and on vertebral and hip mineral density (bone mineral density). Fifty women under a fixed TSH-suppressive dose of L -T(4) for all 6 months were randomly allocated to five groups of 10 subjects each. Group 0 associated placebo for 6 months; groups A2 and A4 started associating placebo (first bimester), substituted placebo with 2 or 4 g/d carnitine (second bimester), and then returned to the association with placebo. Groups B2 and B4 started associating 2 and 4 g/d carnitine for the first two bimesters, and then substituted carnitine with placebo (third bimester). Symptoms and biochemical parameters worsened in group 0. In group A, symptoms and biochemical parameters worsened during the first bimester, returned to baseline or increased minimally during the second bimester (except osteocalcin and urinary OH-proline), and worsened again in the third bimester. In group B, symptoms and biochemical parameters (except osteocalcin and urinary OH-proline) did not worsen or even improved over the first 4 months; they tended to worsen in the third bimester. In both the A and B groups, the two doses of carnitine were similarly effective. At the end of the trial, bone mineral density tended to increase in groups B and A (B > A). In conclusion, L-carnitine is effective in both reversing and preventing symptoms of hyperthyroidism and has a beneficial effect on bone mineralization. Because hyperthyroidism depletes the body deposits of carnitine and since carnitine has no toxicity, teratogenicity, contraindications and interactions with drugs, carnitine can be of clinical use.

    PMID: 11502782 [PubMed – indexed for MEDLINE]Free Article

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