Most supplements today are judged by how they compare to creatine. Anything that doesn't deliver noticeable results on the scale and in the gym in a few weeks is often written off as a worthless supplement.
However, some supplements deserve a closer and more objective look before that final decision is made. Carnitine is one of these supplements. Since no one has reported putting on 10 pounds of mass or 50 pounds on their squat using carnitine most fitness enthusiasts write it off. Dr. Gastelu believes this may be a mistake and makes a compelling argument for its inclusion in your supplement regimen.
These days, carnitine's many benefits are getting a lot of media attention, yet most people are still unsure how taking carnitine will improve their health or how much carnitine their bodies need. Whether you are one of those people or a veteran carnitine user who wants updated information, read on. This section will start you off on your quest for knowledge about this remarkable supplement.
Carnitine is a natural substance-a metabolite, or product of metabolism-that occurs in all living cells. Because the body produces it, it is not considered an essential nutrient and cannot be classified as a vitamin. Carnitine is not quite an amino acid either, although you may see it referred to as such in some magazine articles and promotional literature. From a chemist's point of view, carnitine is classified as a quaternary amine. But you only need to know that carnitine is a metabolite-a substance produced by your body.
Certain metabolites, such as carnitine, have been shown to have beneficial effects on the human body when ingested from dietary sources and in the form of supplements. Some health-care practitioners characterize carnitine as vitamin-like because it is an essential growth factor (required for growth) in infants. For adult humans, carnitine is considered to be a health-enhancing substance that falls into the semi-essential category-meaning that it plays an important role in optimum health and longevity but it is not absolutely necessary to supplement with this substance for survival.
You should note, however, that recent medical studies have found that carnitine may be essential for elderly people, as well as for people with metabolic carnitine deficiency condition-a condition in which the body does not produce enough carnitine to meet its metabolic demands.
You will often see carnitine referred to as L-carnitine in magazine articles and as an ingredient in dietary supplements. You may also see it preceded by the letter D. Like many substances that occur in nature, the carnitine molecule has two forms, which are mirror images of one another. Scientists use the letters L and D to distinguish between these two forms. It is important to note, however, that L-carnitine is the form that is active in your body, not D-carnitine. When purchasing carnitine supplements, always look for L-carnitine. Whenever you see the word carnitine in this book, it will be referring to L-carnitine unless the D form is specified.
Carnitine is primarily produced in the liver, brain, and kidneys through a series of biochemical steps. These biochemical steps are referred to as a synthetic pathway and function similarly to putting together a model in an assembly-line fashion. This pathway involves using biochemical building blocks and enzymes (substances that help put molecules together), which help the building blocks combine or link together as they move along the pathway to build the carnitine molecule. The synthesis of carnitine involves the amino acids lysine and methionine, as well as vitamin B3, vitamin B6, vitamin C, and iron.
Every living cell in your body contains many specialized structures called mitochondria, which perform a very vital cellular function-the production of energy. This is why mitochondria are often referred to as the "powerhouses" of the cells. Fatty acids are broken down in the mitochondria to produce energy for cell functions. While cells can also make energy from glucose and amino acids, the production of energy from fatty acids in the mitochondria is very important to your health.
The fatty acids that are delivered to the cells from the circulatory system need carnitine to carry them through the mitochondria's cell membrane. In fact, this is the main function of carnitine. From this information, it should be easy to understand how carnitine can help in fat loss: by shuttling more fatty acids into the cell's mitochondria to be used for energy, carnitine ensures that less fat gets stored as body fat.
Carnitine also functions to clear metabolic waste products out of the mitochondria. This function occurs after the carnitine molecule has delivered its fatty acid across the mitochondrial membrane. It then latches on to short-chain-fatty-acid waste products and shuttles them out of the mitochondria. This detoxification role of carnitine enables the mitochondria to continue its energy-producing function at peak output. If waste products were permitted to build up, the breakdown of fatty acids in the mitochondria would slow down and become impaired.
Researcher Noris Siliprandi and coworkers point out in their review of carnitine functions that carnitine can help clear out the metabolic byproducts that can accumulate in the mitochondria during exercise. This gives carnitine a dual role in energy production-shuttling fatty-acid energy building blocks, or substrate, into the mitochondria and shuttling metabolic-waste products of energy production out of the mitochondria.
What Can Carnitine Do For Me?
There is medical evidence suggesting that under certain circumstances and as you age, the body's production of carnitine slows. As this happens, the body's tissues-including the muscles, heart, and brain-will experience reduced carnitine content. This reduction lessens the capacity of heart muscle to produce energy, increasing the chances that these tissues will malfunction. In addition, the tissues richest in carnitine-those of the muscles and the heart-are unable to synthesize carnitine and must, therefore, get it from the blood as it is produced in other tissues, including the liver and kidneys. Both of these reasons are why it's important to make sure that you have adequate tissue levels of carnitine throughout your life. You can do this by taking supplemental carnitine.
Dietary sources of carnitine are mainly animal-derived products, such as beef, chicken, sheep, lamb, and rabbit. More specifically, carnitine comes from the muscles, kidneys, and livers of these animals. Plant sources of carnitine are limited. Moreover, the carnitine levels in them are very small. These plant sources include avocado, alfalfa concentrate, and wheat germ, which contain only less than 2 mg per 100 g of edible portions.
Nutritionists estimate that the average daily dietary intake of carnitine from food is about 100 to 300 mg for people who eat meat. Because vegetarians do not eat animal products, they have a much lower daily intake of carnitine.
Supplemental intake of carnitine can range from small amounts of about 50 mg contained in a multinutrient supplement to an intake of over 2 g per day in an individual supplement. Studies have shown that taking 500 mg per day of a carnitine supplement can increase the body's carnitine levels in tissues and blood. Higher amounts of carnitine are commonly used for therapeutic purposes.
Carnitine For Weight Loss
Losing and maintaining weight is a lifelong battle for millions of people in their quest for a leaner body and better health. Experts estimate that almost 30 million American adults are dieting to lose weight at any given time and an equal number are gaining it back. Research indicates that leading a lifestyle that boosts your body's usage of fat is the first step to lifelong weight management. Due to carnitine's essential role in fat metabolism, it is a prime nutrient for boosting your fat burning capacity.
There's much more to losing and controlling your weight than just taking a dietary supplement. People with weight problems need to adopt a lifestyle of proper dietary habits and a program of regular physical activity in their daily routine to help with lifelong weight control. Carnitine's role in fatty-acid metabolism can help with your weight loss efforts and can be an important part of your "lean-lifestyle" program. However, it is not meant to solve all of your weight problems on its own.
Carnitine's role in fatty-acid transport into cells' mitochondria for energy production helps in weight management by enhancing the rate at which your body uses fatty acids for energy production. This, in turn, increases the fat calories your body uses each day and decreases the amount being stored on your hips, waist, and other body parts. Carnitine ingestion can also increase your metabolic rate-the amount of energy you produce and the calories you use to produce it-which means you will burn more calories each day.
In 1997, researchers reported the results of a study that examined the effects of carnitine on weight loss in obese adolescent students aged thirteen to seventeen. The subjects were divided into two groups. Both groups received nutritional education, physical training, and controlled diets. The experimental group also took 2 g of L-carnitine per day and the control group took a placebo. At the end of the three-month study both groups of students lost weight, demonstrating that food control and exercise can result in weight loss. However, the group taking 2 g of L-carnitine per day lost an average of over 11 pounds of weight, while the group taking the placebo lost an average of about 1.5 pounds of weight. This study clearly demonstrated that L-carnitine supplementation caused a greater rate and total amount of weight loss. The L-carnitine treatment was well tolerated by the study subjects, with no side effects being observed.
In 1992, Gilbert Kaats and coworkers reported the results of their weight-loss study, which included the use of carnitine and other nutrients. A total of thirty women and ten men, ages nineteen to sixty-five, were recruited for the study. The study was designed to evaluate changes occurring in lean body mass, blood cholesterol levels, and resting metabolic rate, while subjects followed a program of moderate calorie restriction of 1,000 to 2,000 calories a day.
During the phase I, eight-week study period, dietary guidelines were followed by the subjects, but no supplements were taken. Not many changes were detected in body weight, blood serum cholesterol levels or resting metabolic rate during this period. During the phase II, eight-week part of the study, subjects added two fiber cookies and supplements containing 200 mg of L-carnitine and other nutrients, including 200 mcg of chromium, per day to their diets. At the end of phase II, researchers discovered an average loss of body fat of over 11 pounds and an 11-percent reduction in total serum cholesterol levels. Furthermore, they saw a 9-percent reduction in the blood serum levels of LDL-cholesterol (the so-called "bad" cholesterol), no loss of lean body mass, and maintenance of, or an increase in, resting metabolic rate.
Interviews with subjects after the study revealed that the addition of the fiber cookies and carnitine supplement helped them stick to their diets. Moreover, they found the increase in the rate of fat loss encouraging. It is interesting to note that three of the subjects doubled their metabolic rates during phase II.
One of these subjects followed a vegetarian diet and lost only 3.6 pounds of body fat during the first eight weeks and a substantial 16.5 pounds of body fat during the second eight weeks of the study. (Since dietary carnitine is supplied almost exclusively by animal proteins, vegetarians typically have low carnitine intakes from dietary sources.) It appears that the supplemental carnitine increased the vegetarian's rate of fat metabolism, resulting in an increased reduction in body fat. These studies demonstrate carnitine's powerful metabolic and fat-burning enhancing effects.
You can find many types of weight-loss aids in health food stores and pharmacies these days. When you begin picking up different products and reading the labels, you will notice that most of them contain similar ingredients. As you study these weight-loss aids more closely, you will begin to notice that they fall into a few general categories; however, there is no fixed number of dietary-supplement or diet-aid categories like there is with over-the-counter drug products.
Unofficially, these supplements and diet aids include products promoted as fat metabolizers, appetite controllers, fibers, fat absorbers, meal replacements, and combination products. Meal replacements come in the form of drinks, bars, cookies, and frozen dinners. You will commonly find carnitine as an ingredient in the more sophisticated meal-replacement products. Look for meal replacements that contain adequate protein and fiber, little or no sugar, and are loaded with vitamins, minerals, carnitine, and other nutrients.
Fiber supplements can play a role in appetite control, especially if you are one of the many people who have a stomach that empties quickly after you eat. In fact, researchers in the United Kingdom in the 1970s found that taking certain fibers, such as guar gum, before eating can make your stomach empty more slowly, helping with appetite control. These findings resulted in the development of many of the fiber weight-loss products now available.
More recently, a completely new breed of "animal fiber" weight-loss aids called chitosan or polyglucosamine have appeared on the shelves. These products boast a fat-absorbing effect, meaning that they lock on to fats in your meal and may prevent some of the fat from being absorbed by your body. So taking a fiber supplement along with carnitine and other nutrients can provide your body with added benefits.
A group of researchers published their findings on long-term weight loss in the Journal of the American Dietetic Association in April 1998. Nutritionist Siao Mei Shick and coworkers studied 355 adult women (average age of forty-five) and 83 adult men (average age of fifty) who lost weight and kept it off. Most of the subjects had lost weight under the supervision of a professional health-care practitioner or by using a commercial weight-loss program, in addition to an exercise program.
But, to keep the weight off, the women ate an average of 1,306 calories per day and the men ate an average of 1,685 calories per day. Both men and women maintained a fat intake of about 24 percent of their total caloric intakes. This supports the belief that if you wish to avoid regaining your lost weight you need to stick to a lifelong weight maintenance diet, taking into account your individual needs. Carnitine can be part of this plan.
Carnitine For Energy, Endurance & Power
If you exercise regularly or want to muster up enough energy to begin an exercise program, research shows that carnitine should be part of your daily diet. Carnitine helps your body become more energetic, and it can help reduce the aches and pains that may occur from exercise and athletics. If you are an endurance athlete, carnitine supplementation can improve your performance by helping to increase your speed for longer periods of time. Other athletes and "weekend warriors" can also experience benefits from carnitine intake because of its role in reducing the buildup of lactic acid in the muscles. When lactic acid builds up and accumulates in the muscles, fatigue sets in. If you are interested in learning more about these benefits read on to discover the interesting details about how carnitine works at making your body better at exercise and physical performance.
Some of the first studies measuring the effects of carnitine intake on physical performance detected a respiratory-quotient lowering effect. In simple terms, this means the body uses more fatty acids and less glucose, or blood sugar, for energy, resulting in a greater loss of body fat from exercise and diet. For competitive athletes, a lower respiratory quotient can mean greater endurance and an increase in the time it takes to become fatigued.
Medical studies have also shown that carnitine intake reduces lactic-acid levels in exercising muscles. As you perform strength exercises or sports, lactic acid - a metabolic byproduct of anaerobic metabolism - builds up in your muscles to a point where fatigue sets in. If you can delay this buildup, you can increase your total physical performance. For endurance athletes, such as long-distance runners, this means running a little faster for a little longer. For strength athletes, such as weightlifters, this means lifting more weight with more repetitions or being able to perform greater bursts of strength more times.
In 1989, medical researcher E. M. Gorostiaga and coworkers reported such results in the International Journal of Sports Medicine, in an article titled, "Decrease in respiratory quotient during exercise following L-carnitine supplementation." They found that administering 2 g per day of L-carnitine had a respiratory-quotient lowering effect and concluded that such a decrease suggests increased fatty-acid utilization and a probable muscle glycogen-sparing effect, meaning that fewer carbohydrates are used to produce energy. You see, the body always uses carbohydrates and fat to produce energy, but it has a more limited supply of carbohydrates, which, therefore, can become depleted during prolonged exercise (over 1.5 hours). When your carbohydrate store runs out, overall performance declines. So, by sparing your muscle-glycogen supplies, carnitine can help you work harder and longer.
In your daily life, you burn a mixture of approximately 40- to 45-percent fatty acids, 40- to 45-percent carbohydrates, and 10- to 15-percent amino acids for energy. These ratios change depending on your unique metabolism and the type and duration of exercise you are performing. Aerobic (oxidative) exercise uses more fat for energy, while anaerobic (nonoxidative) exercise uses more muscle glycogen. Your body's store of glycogen is small compared with its fat reserves, so it can become depleted after only a few hours of exercise or strenuous physical activity. And when your muscles and liver are depleted of their glycogen stores, your energy output, both physical and mental, is decreased.
Because liver glycogen supplies your brain with the glucose it needs for energy, when your liver glycogen levels are low or become depleted, your mental alertness and brain function will be impaired. And because glycogen is important for short-term bursts of strength, as well as for maintaining peak physical output in long-term endurance events, keeping your body's glycogen stores replenished is vital for peak physical and mental performance in all types of sports.
In 1990, L. Vecchiet and coworkers published their research findings on the influence of L-carnitine on maximal physical exercise in the European Journal of Applied Physiology. These researchers conducted a study using healthy men, aged twenty-two to thirty years, with similar lifestyles and physical conditioning. Experimental subjects took 2 g of L-carnitine ninety minutes before taking exercise tests. The researchers measured exercise performance and the amount of oxygen taken in of subjects exercising on a stationary cycle machine.
Beneficial effects of the single dose of carnitine were immediately detected. An increase in power output was observed, as well as an increase in total work performed. Blood concentrations of lactic acid were also reduced when the subjects took the dosage of 2 g of L-carnitine before exercise sessions.
When you exercise and progressively increase the time and intensity of your exercise sessions, muscle pain or soreness sometimes occurs a day or two later. This is called delayed onset muscle soreness (DOMS) by exercise physiologists, and is a common side effect of exercise or intensive physical work. Symptoms of DOMS include pain on movement, tenderness, and sensation of swelling and stiffness of the muscles. People who lift weights typically experience DOMS the day after grueling bouts of intense exercise. Cell damage and a complex series of biochemical changes are thought to contribute to DOMS. Impairment of energy metabolism is thought to render cells more susceptible to mechanical stress, which can result in more tissue damage from exercise.
Carnitine administration has been shown to protect muscle tissue from exercise-induced damage by means of stimulating vasodilatation, or blood circulation, resulting in a better blood supply to working muscles and improved clearance of toxic metabolic-waste products. In one study, Dr. Maria Giamberaridino gave six male subjects either 3-g of L-carnitine or a placebo per day for three weeks to find out if carnitine supplementation can help reduce DOMS. Subjects then performed exercises that have been determined to produce DOMS. In her study, Dr. Giamberaridino found that subjects experienced less DOMS during the periods when they were taking 3 g of L-carnitine per day than during the periods when they did not. This study indicates that L-carnitine has a protective effect against pain and damage from exercise.
Research indicates that when your muscles are loaded with carnitine, it can help reduce the breakdown of amino acids that make up your muscle proteins for energy production. So preventing the use of amino acids for energy reduces the breakdown of muscles. When you exercise, if your body uses amino acids for energy, breakdown of muscle mass invariably occurs. In addition to proper protein intake, higher amounts of carnitine in your muscles can deter the use of amino acids for energy production during exercise, and therefore help protect against muscle breakdown and damage.
When looking at the current medical studies, there are some gaps and inconsistencies in the carnitine/exercise research. In some scientific circles, this may stimulate debate and controversy. However, when the total body of carnitine research is examined, including carnitine's other beneficial health effects discussed in this article, taking carnitine supplements should be anything but controversial. What the research does conclude is that supplementation with carnitine in amounts from 1 to 4 gs per day is well tolerated for study periods of several weeks up to a year.
The research also reports on improvements in physical performance and a reduction in DOMS. Other studies show positive results and improvements with carnitine use, and although they may not be statistically significant, their findings may be significant to you. When you consider all of the current research on carnitine, the majority of scientific evidence is in favor of using carnitine as a performance-enhancing aid for fitness exercisers and competitive athletes and for the other uses discussed in this article.
To additionally help boost your energy levels, you should make sure that you are getting enough of all the essential nutrients in your diet, including vitamins, minerals, carbohydrates, protein, and unsaturated fats. Other energy-enhancing supplements you may want to incorporate into your supplemental regimen along with carnitine include coenzyme Q10, octacosanol, ginseng, and magnesium. Of course, you should read the available literature on these supplements before incorporating them into your nutritional plan. The Specialist in Performance Nutrtion course provides guidelines for determining specific nutritional requirements.
Note: This is part one, click here for part two!
Author: Daniel Gastelu, M.S., MFS
Reprinted with Permission. Copyright 2004 Daniel Gastelu. All rights reserved. This article is not intended to replace medical advice; consult your doctor for all matters related to your health.