L-carnosine is naturally produced by the body. It is a dipeptide of the amino acids histidine and beta-alanine. L-carnosine is concentrated in areas which require a lot of energy, such as the muscles, brain, liver, kidneys, and heart.
This amino acid has a number of antioxidant properties. Consequently it has been the subject of a lot of research. Specifically, scientists have been intrigued to ascertain if this non-essential amino acid can help to reverse the aging process1. Other areas of research focus on the effects of carnosine in disease treatment and exercise productivity.
Studies have found that as the body ages, concentrations of carnosine begin to decline2, 3, 4. However, the body’s requirement for this amino acid does not diminish. This is where dietary sources of l-carnosine become increasingly important to keep the body functioning at an optimal level.
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L-carnosine and aging
One of the major roles of l-carnosine is to help the body met the metabolic demands of energy production and allocation. In young bodies this amino acid is found in high concentrations to support high energy-demanding tissues.
As the body ages l-carnosine concentrations decline for a couple of reasons. Firstly, the body makes less of this amino acids. Secondly, l-carnosine becomes more susceptible to destruction in older bodies. Studies have shown that people experiencing unnaturally accelerated aging due to conditions such as metabolic syndrome and diabetes have a much lower production rate of l-carnosine and this amino acid is destroyed at a faster rate5.
For these reasons scientists have been trying to determine if increasing carnine concentrations can help to slow down or reverse the aging process. There have been many studies focusing on the anti-aging properties of this amino acid. In culture dishes, l-carnosine has been shown to reduce the aging of human cells6, 7. This amino acid has also been found to extend the lifespan of rotifers, fruit flies, and mice8, 9, 10, 11, 12.
How does l-carnosine fight the aging process?
This amino acid is not just any ordinary antioxidant molecule. Although it is not the most powerful antioxidant, it does target six molecular aging mechanisms and can increase longevity. Areas where carnosine is an effective anti-aging agent include:
Oxidation – Stress on the cells and tissues cased by oxidation is one of the leading causes of aging. Carnosine helps to minimise this by scavenging free radicals, reducing DNA damage13.
Glycation – This is the formation of glucose compounds containing various enzymes and proteins that cause aging. These glycated molecules induce oxidative stress and enhance inflammatory responses that accelerate the aging process. 14, 15.
Cross-linking – The combination of oxidation and glycation causes ineffective cross-linked proteins. These abnormalities are dealt with naturally through structures known as proteasomes. However, as the body ages cross-linked proteins accumulate as proteasomal degradation declines. Carnosine can help to eliminate cross-linked proteins. 16, 17.
Mitochondrial dysfunction – As the body becomes increasingly exposed to oxidative stress mitochondrial dysfunction increases and this speeds up the aging process. However, studies show that carnosine can help to alleviate these problems18, 19.
Excess metals – Excess metals in the body are toxic and known to be linked to diseases such as Parkinson’s and Alzheimer’s. Carnosine will bind to copper, iron, and zinc ions to help ride the body of these excess metals20.
Telomere shortening – Telomeres are repeated DNA sequences located at the ends of chromosomes. They act like a ‘molecular clock’ and become shorter with every cycle of cell reproduction. The cells die when telomeres become too short and this increases the aging process. Carnosine slows down the rate of shortening21
L-carnosine and exercise performance
Carnosine itself is not often taken as a performance enhancing supplement. However, beta- alanine supplements are often taken by body builders and athletes.
This is because this amino acid will combine with histidine to help boost carnosine levels and buffer against muscle acidity and subsequent fatigue22, 23. A diet containing carnosine, histidine and beta-alanine protein rich foods may help to improve athletic performance.
L-carnosine, diabetes and associated health problems
Carnosine has been found to be in lower concentrations in the cells of people with diabetes24. This is believed to be due to elevated gylcation and subsequent protein cross-linking. Studies have found that carnosine can reduce blood pressure and blood glucose levels in animals with diabetes25.It has also been found that this amino acid stabilises the membranes of red blood cells to protect them against harmful gycation byproducts and can delay the onset of diabetes26, 27. For people at risk of developing Type 2 diabetes or those already suffering from this disease, increasing carnosine levels may have multiple health benefits:
- L-carnosine reduces glycation and oxidation of low-density lipoprotein (LDL) which can lower the risk of diabetes-induced atherosclerosis28, 29.
- L-carnosine safeguards kidney cells from the damaging effects of high glucose, reducing the risk of nephropathy30.
- L-carnosine stops blood vessel damage associated with diabetic retinopathy, helping to protect vision31.
- L-carnosine reduces the risk of diabetic induced cataracts by minimizing protein cross-linking in the eye lenses32.
L-carnosine and cardiovascular health
Carnosine is highly concentrated in the heart. This amino acid helps to protect against ischemia (restricted blood flow) and subsequent heart attacks33. Carnosine safeguards the arteries from gylcation and oxidation, which are key factors in the development of atherosclerosis.
This amino acid also allows the arteries to relax by regulating calcium ions, further supporting a healthy heart function34. Consequently, carnosine is a very important amino acid when it comes to supporting cardiovascular health and protecting against heart disease.
L-carnosine and cognitive function
Brain tissue contains a high concentration of carnosine to reduce glycemic, nitrosative, and oxidative stress35, 36. These processes cause inflammation and detrimental cross-linking proteins, including those associated with Alzheimer’s disease. Not only will maintaining healthy carnosine levels help to minimise these harmful effects, it also assists with reducing toxicity caused by metal irons in certain brain areas.
Studies have shown that people suffering from Alzheimer’s and other neurodegenerative problems have significantly lower concentrations of carnosine in their brain tissue37, 38. It’s uncertain if this deficiency is causing the disease or as a result of the disease progression. Either way, many researchers believe that carnosine supplementation will reduce disease-causing cellular toxicity and possibly help to prevent Alzheimer’s and Parkinson’s diseases.
Symptoms of a l-carnosine deficiency
Carnosine deficiencies are rare and do not normally occur in healthy people. Generally a deficiency in this amino acid would only occur due to a genetic defect that prevents its synthesis and transport.
However, some people on low protein diets or are malnourished can be predisposed to a carnosine deficiency. Symptoms of a carnosine deficieny may include reduced muscle tone, developmental delays in babies and children, nerve tissue degradation, and tremors.
Dietary sources of l-carnosine
Protein-rich foods have a high concentration of carnosine. The best sources of this amino acid are poultry, pork and beef. Vegetarian sources rich in alanine and histidine to produce carnosine include nuts, seeds, watercress, brewer’s yeast, brown rice, whole grains, avocado, beans, bran, corn, legumes, mushrooms, and spirulina.
There are plenty of dietary supplements with carnosine. Up to 100mg of l-carnosine per day is usually considered safe. However, it is very important to consult with a health professional before taking any supplement. This will help to determine if there are any underlying health concerns which prohibit supplementation.
L-carnosine is a very important amino acid. It is a potent antioxidant and a powerful anti-aging agent. Studies have demonstrated that carnosine has many health benefits and can protect against heart diseases, diabetes, declining cognitive function and other associated aliments. This amino acid is also important for exercise and overall vitality.
Although deficiencies are rare, illness and/or poor diet may lead to a decline in carnosine availability. A healthy balanced diet and carnosine supplementation may help to better protect health and well-being.
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