Posted by Andrea Lewis
Carnosine, which is concentrated in the brain and muscle tissues, is a dipeptide of the amino acids beta-alanine and histidine. And while carnosine, in its whole dipeptide form, is only found in meat, both of its constituents are found in a wide variety of plant foods. This is the most logical explanation for how animals like cows, turkeys, chickens and pigs come to have so much in their tissues, especially when one considers how carnosine in meat is broken down and used in the body.
Carnosine Digestion and Synthesis
Upon digestion, carnosine is broken down in the gastrointestinal tract into its constituents. Yes, some intact carnosine does escape the GI tract freely but that small amount is quickly broken down in the blood by the enzyme carnosinase. Carnosinase hydrolyzes carnosine and other dipeptides containing histidine into their constituent amino acids. In other words, after consuming meat, all of the carnosine that was ingested is converted to beta-alanine and histidine. Then, oddly enough, the amino acids are converted back to carnosine in the muscles and used or transported where needed. The entire process of carnosine synthesis is not entirely understood, but it’s worth noting that consuming carnosine from meat is unnecessary, as it will be converted into beta-alanine and histidine anyway, both of which are available in many raw whole foods.
Carnosine’s main claim to fame is its ability to inhibit AGE (Advanced Glycation End) products, which is valuable for treating and preventing a range of diseases. This benefit is largely responsible for carnosine’s other health benefits and uses:
- Heart health
- Kidney health
- Eye health
- Improved cognitive function
- Autism Spectrum Disorder
Carnosine has been shown to reduce and protect against oxidative stress in the body, making it an excellent anti-oxidant. This anti-oxidant protection extends to pH buffering and electrolyte support, which is highly beneficial to heart health. The heart is a fast twitch muscle that demands a lot of energy, but it does not get the same amount of rest as the other fast twitch muscles in the body. The heart must always be active or, obviously, we die. As a result, the heart requires more carnosine to engage in faster, efficient muscle contractions. Heart tissue must also have the right electrolyte balance, pH buffers, and plenty of antioxidants to manage daily demands at an optimal level; carnosine helps to provide all of the above. Studies have shown that individuals with myocardial infarction, bundle branch blocks, angina, congestive heart failure (CHF), and other cardiomyopathies may benefit from increasing their intake of carnosine. One such study, ‘β-Alanine and orotate as supplements for cardiac protection’, published in the journal Open Heart, showed that carnosine, synthesized in the body from beta-alanine, is indeed more concentrated in fast twitch muscles, like the heart, and can help protect against cardiac issues, such as congestive heart failure.
Diabetics tend to have elevated levels of oxidative stress stemming from their condition. Diabetics also tend to have pronounced issues with atherosclerosis and kidney disease, because diabetes causes a stiffening of tissues as a result of excess AGEs in the body; that excess has been linked to a lack of carnosine. The same holds true for some optical issues. Carnosine helps protect the eye from oxidative damage of the lens and retina. One animal study, in particular, demonstrated that carnosine protected the retina from restriction in blood supply (oxygenation) when the eye tissue was under increased intraoccular pressure, which reduces the risk for glaucoma. Carnosine is also available in an eye drop solution for those at risk for glaucoma and cataracts. For more information on that topic, Google ‘carnosine eye drops’, there are a lot of blogs and research papers on the topic.
Carnosine has been studied extensively in the muscles and brain tissues, because that’s where it’s concentrated. In regards to brain and neurological health, carnosine has been shown to be of great help in preventing and reversing cognitive decline. And it’s affect on the brain and muscles appears more perceptible in the elderly. One study in particular, ‘Anserine and carnosine supplementation in the elderly: Effects on cognitive functioning and physical capacity’, published in the Archive of Gerontology and Geriatrics, Sept-Oct. 2014, showed that while cognitive function and physical capacity increased, BMI, blood pressure and heart rate improved during the 13-week study, in which fifty-one subjects were given Chicken meat extract containing CRC components (2:1 ration of anserine to carnosine). FYI, anserine is also a dipeptide that contains beta-alanine and histidine. A quote from the study, “After supplementation Body Mass Index (BMI) decreased significantly (p<0.05) in the CRC group performance comparing the placebo group. In two of six Senior Fitness Test the scores increased significantly (p<0.05) in CRC group comparing to the placebo group. The perceived exertion differed significantly (p<0.05) at the baseline and after follow up at the CRC group. The mean values of the Short Test of Mental Status (STMS) scores showed the significant (p<0.04) increase only in CRC group, in the subscores of construction/copying, abstraction and recall. Conducted anserine and carnosine supplementation in the elderly brings promising effects on cognitive functioning and physical capacity of participants. However, further studies are needed.”
Another study, entitled ‘Carnosine Treatment for Gulf War Illness: A Randomized Controlled Trial’, published in the Journal of Health Sciences, Vol. 5, No. 3, 2013, showed that carnosine was also able to treat cognitive and some physical issues in gulf war veterans. “About 25% of 1990-1991 Persian Gulf War veterans experience disabling fatigue, widespread pain, and cognitive dysfunction termed Gulf War illness (GWI) or Chronic Multisymptom Illness (CMI). A leading theory proposes that wartime exposures initiated prolonged production of reactive oxygen species (ROS) and central nervous system injury. The endogenous antioxidant L-carnosine (B-alanyl-L-histidine) is a potential treatment since it is a free radical scavenger in nervous tissue. To determine if nutritional supplementation with L-carnosine would significantly improve pain, cognition and fatigue in GWI, a randomized double blind placebo controlled 12 week dose escalation study involving 25 GWI subjects was employed.
“L-carnosine was given as 500, 1000, and 1500 mg increasing at 4 week intervals. Outcomes included subjective fatigue, pain and psychosocial questionnaires, and instantaneous fatigue and activity levels recorded by ActiWatch Score devices. Cognitive function was evaluated by WAIS-R digit symbol substitution test.
“Carnosine had 2 potentially beneficial effects: WAIS-R scores increased significantly, and there was a decrease in diarrhea associated with irritable bowel syndrome. No other significant incremental changes were found. Therefore, 12 weeks of carnosine (1500 mg) may have beneficial cognitive effects in GWI. Fatigue, pain, hyperalgesia, activity and other outcomes were resistant to treatment.”
Carnosine has the ability to cross the blood-brain barrier, the brain’s security system, which is essentially a network of blood vessels that only permit essential nutrients to enter while blocking other substances. This has been an obstacle to treating many neurological issues, including seizures and Autism Spectrum Disorder. In animal studies, carnosine has been shown to improve management of seizures, acting as an anticonvulsant. One study, published in Brain Research, November 6, 2008, examined the effect of carnosine on epilepsy in rats. The epileptic episodes were induced by penicillin. The scientists ascertained that “These findings indicate that carnosine has an anticonvulsant effect on penicillin-induced epilepsy in rats. Thus, our data support the hypothesis that carnosine may be a potential anticonvulsant drug for clinical therapy of epilepsy in the future.” Later studies supported their findings. An article published in Nutrition Review, April 19, 2013, reported that carnosine improved language skills and behavior in children with ASD (Autistic Spectrum Disorder). “Researchers treated 31 autistic children, ranging from 3 to 12 years in age, with either 400 mg of L-Carnosine, twice a day, or a placebo, for 8 weeks. At the end of the study the children treated with L-Carnosine showed significant improvements in behavior, socialization, and communication, as well as increases in language comprehension based on CARS (Childhood Autism Rating Scale), vocabulary tests (E/ROWPVT) and biweekly parent reports. In the conclusion to their report the researchers state, “Oral supplementation with L-Carnosine resulted in demonstrable improvements in autistic behaviors, as well as increases in language comprehension that reached statistical significance.” … the researchers report that L-Carnosine may improve receptive language, auditory processing, socialization, awareness of surroundings, and even help fine motor planning and expressive language when compared to placebo. Responses are usually seen between one to eight weeks after beginning treatment.” The study referenced in the article is titled ‘Double-blind, placebo-controlled study of L-carnosine supplementation in children with autistic spectrum disorders’, and was published in the Journal of Child Neurology, November 17, 2002.
What About Histidine?
All of the carnosine studies I found (including those mentioned and quoted above) used either beta-alanine supplements, l-carnosine supplements or carnosine extracted directly from poultry, but histidine is also required for synthesis of carnosine in the body. I assume, because the nutrient is so prevalent in such a wide variety of foods, that the researchers saw no need to use a histidine supplement as part of their carnosine research studies when using beta-alanine supplements. Histidine can be found in both animals and plants, as well as every tissue in the human body; even the myelin sheaths that coat nerve cells and ensure the transmission of messages from the brain to various parts of the body contain histidine. So, whether one is a vegan, vegetarian or carnivore, they are sure to get sufficient amounts of histidine in their diet.
Best Whole Food Sources of Beta-Alanine
- Soy beans / soy nuts
- Turnip greens
- White mushrooms
- Laver seaweed
- Spirulina seaweed
Best Whole Food Sources of Histidine
- Green peas
- soybean sprouts
- Mustard Greens
- Sweet corn
- Bamboo shoots
- Daikon (Japanese radish)
- Okra pods
- Head lettuce / Butter lettuce
- Lotus root
- Chinese chives
- Green sweet peppers
- Chinese cabbage
Obviously, there are far more histidine-rich whole foods than beta-alanine-rich whole foods, and I didn’t even list half of the whole foods that contain histidine. Apparently, most foods contain histidine, including those used to feed livestock and, of course, the livestock themselves. And it’s worth noting that histidine, in addition to being half of the peptide bond that forms carnosine and its pivotal role in the formation of protein, has demonstrated a variety of therapeutic properties both anecdotally and in clinical studies; those properties include reducing the effects of stress and chronic conditions like rheumatoid arthritis, treating certain types of sexual dysfunction, fighting fatigue and preventing anemia. In any case, it’s good to know that one can indeed get all of the benefits of carnosine and its constituent elements as a raw vegan.