Thursday, February 11, 2010

Does Tyrosine Supplementation for ADHD Actually Work? (Part 5)

Part 5 on a series of posts on Tyrosine supplements for ADHD Treatment

The amino acid tyrosine is often prescribed as an alternative strategy for treating ADHD, either alone (and often in the place of ADHD stimulant medications), or in combo with one or more medications for the disorder. But how effective is tyrosine really? Is it a valid ADHD treatment method, or just another theoretical supplement strategy that has only minimal positive effects on the disorder?

In the past four posts, we have examined the following metabolic pathway of tyrosine in the conversion process of this amino acid to the neuro-signaling chemicals dopamine, norepinephrine, and epinephrine (adrenaline) and the implications for this on the biochemical factors involved in the onset and treatment of attention deficit hyperactivity disorder.

  1. In part 1 of our series on ADHD and tyrosine supplementation, we did a quick overview of the above process, the connection between regional levels of these compounds listed above with regards to the neuro-chemistry of ADHD, and gave a general theoretical basis for tyrosine supplementation (based on its metabolic profile and some of tyrosine's biochemical products and pathways in the body). We also introduced the concept of the blood brain barrier, which is a biochemical barrier that controls the flow of chemical agents into and out of the brain. This blood brain barrier has numerous implications for drug design and therapeutics, and must be dealt with if we are to get the desired compounds, drugs and nutrients into the brain.

  2. In part 2 of the tyrosine and ADHD discussion, we looked at the enzyme Tyrosine Hydroxylase, and the dietary nutrients which were involved in making this enzyme run effectively. Some of the nutrient-based strategy were based on clinical trials, while others were more based on theory.

  3. Part 3 of the ADHD/tyrosine blog series centered around the merits of starting with tyrosine as a supplementation strategy vs. bypassing tyrosine and starting with the second compound in the above pathway, L-DOPA (also called Levodopa). L-DOPA is commonly used as a treatment agent in Parkinson's Disease (which has a moderate degree of overlap with ADHD as far as chemical happenings are concerned), but we investigated the pro's and cons of starting with this agent vs. starting with its precursor tyrosine for treating ADHD.

  4. and finally, Part 4 of the tyrosine postings zeroed in on the second major enzymatic step of the pathway, in which L-DOPA was converted to dopamine. This process is heavily dependent on a class of enzymes called aromatic amino acid decarboxylases, with the main enzyme of focus being a specific type called DOPA decarboxylase. In order for these enzymes to function, however, we discussed their dependence on a compound called pyridoxal phosphate (pyridoxal phosphate is an "active" form of Vitamin B6). We also looked at how competing amino acids and their products (namely the amino acid tryptophan and its product serotonin), actually share these enzyme systems and can interfere with the L-DOPA to dopamine conversion process and sabotage the effectiveness of the tyrosine-driven ADHD treatment strategy.
And now, for part 5: the conversion process of the neurochemical dopamine to another neurochemical, norepinephrine...

*Blogger's note:
What follows is a lengthy explanation of why dopamine and norepinephrine are so important for ADHD, and how they interact with specific proteins called "transporters" or "receptors" to regulate their overall levels in key "ADHD" brain regions. If you are short on time, you may want to bypass this long explanatory section which starts and ends with a triple asterisk (***).

------------------------------------------------------------------------------------------------
***Begin explanatory section on dopamine and norepinephrine and ADHD

It is important to note, first of all, that this dopamine to norepinephrine conversion is not universal throughout all of the body, or even throughout the whole central nervous system. In many regions of the brain and nervous system, the chemical conversion process and metabolism of tyrosine "stops" at dopamine. However, in other key regions, the necessary enzymes exist to continue on with this conversion process to norepinephrine (and even beyond in some cases).

First, we need to address the all-important question, however: Why is the conversion of dopamine to norepinephrine important with regards to treating ADHD? To answer this question, we must look at some of the neuro-biology (and neuro-genetics) of some of the mechanisms which regulate dopamine and norepinephrine function in the brain:

We have hinted elsewhere that both dopamine and norepinephrine (namely imbalances of these two neuro-signaling agents) play a major role in the pathology of ADHD and its symptoms in most cases. However, it is important to note one very important thing here: many of the studies implicating dopamine and norepinephrine in the pathology of ADHD are often concerned more with the transport process of these two signaling agents into and out of neuronal cells, and are often less concerned with the overall concentrations of these two chemicals in the body or even the central nervous system.

Of course there is some degree of overlap (a vast overall deficiency of dopamine or its precursors, for example, would probably put one at more risk of having a deficit of this chemical in the key target areas of the brain), but we must get past the thinking that incorrectly assumes that if we just boost overall levels of these compounds across the board, then these chemical imbalances will just work themselves out. This is simply not the case, and unfortunately, in this blogger's opinion, many advocates of supplementation instead of medications often fail to address this all-important issue of the transport process.

Among the many different ways of transporting dopamine and norepinephrine in and out of the neuronal cells, we must look at two key players: the receptors and the transporters.

#1) The receptors:

The receptors (in a nutshell), are located on the outside of a cell (in this case, the neuronal cells in the brain), and are the place where signaling agents such as dopamine, norepinephrine, histamine, etc. essentially "dock" onto the cell. Proper functioning of these receptors is especially important with regards to disorders such as ADHD. We have even looked at some of the specific genes which code for these receptors, and have analyzed how certain genetic forms of these "receptor genes" are often associated with a higher likelihood of having ADHD.

For example, some of the earliest posts on this blog looked at specific genes that coded for dopamine receptors, such as the Dopamine D4 receptor gene (DRD4) and the Dopamine D5 receptor gene (DRD5) . The DRD4 gene is believed to be one of the most "heavily" influencing genes out there with regards to ADHD genes, while the DRD5 gene, while showing a somewhat weaker genetic connection to ADHD overall, seems to show a bit more of a specific connection to the inattentive component of ADHD (as opposed to the hyperactive/impulsive component of the disorder).

With regards to genetics and chemical receptors for the neuro-chemical norepinephrine, it appears that there are also some genes which may affect this norepinephrine-receptor relationship. There is some evidence for a specific gene called ADRA1A. ADRA1A is a gene located on the 8th human chromosome, and is believed to code for a specific receptor of norepinephrine. In fact, there are some implications that having a particular form of this ADRA1A gene may even influence the effectiveness of medications such as clonidine (which is a drug often used to treat hypertension, but is sometimes used "off-label" as an ADHD treatment medication. Clonidine has a different mode of action than the typical stimulants, but has found some success as a second or third level treatment method for certain types of ADHD).

It is important to note that several of the most common ADHD medications target (either directly or indirectly) these transporters, which influences the overall balance of dopamine and norepinephrine in and out of cells.
In other words, if we want to truly replace drugs with nutrition for treating ADHD, we need to overcome this receptor problem (at least in theory). This is why (in the blogger's opinion) nutrition-based treatments often come up short, because while they may be able to influence production and overall levels of neuro-signaling agents such as dopamine and norepinephrine they are often nowhere near as chemically "potent" at modifying the transporter issues. If you're interested, an earlier post talked about some of the specific genes, receptors and transporters, and how some of these "ADHD genes" may even play a specific role on how we should dose ADHD medications.

#2) The transporters

Switching gears away from dopamine and norepinephrine receptors, we must also examine another important class of proteins which regulate dopamine and norepinephrine levels both inside and outside of neuronal cells. These are called "transporters". As their name suggests, these agents essentially go one step further in the process by shuttling neuro-signaling chemicals such as dopamine and norepinephrine both into and out of cells. In other words, these dopamine and norepinephrine tranporters also play a vital role in the process.

We can talk about these transporters all day (and we have, in other previous posts on this blog!), but for sake of brevity, I should just mention that specific genes for dopamine transporters (called the dopamine transporter gene or DAT), and for norepinephrine transporters (called the norepinephrine transporter gene or NET, however, it is also referred to by another completely different name: SLC6A2) both have been studied extensively with regards to their genetic influences on ADHD and related disorders. As mentioned earlier, these transporters often play major roles in medication responses, and may even be linked to co-occurring disorders in ADHD, such as bulimia, drug addiction, anxiety disorders, etc.

*In other words, these receptors and transporters (as well as the influences they carry on regulating neurochemical levels) are some of the main reasons why ADHD is believed to be so genetically influenced.***

-------------------------------------------------------------------------------------------------
***End explanatory section on the importance of regulating dopamine and norepinephrine levels in ADHD. The rest of the post is concerned with the dopamine to norepinephrine conversion process, and starts immediately below:



Here is a chemical representation of the dopamine to norepinephrine conversion process (don't worry if you're not a chemist, just look at some of the names of the compounds, enzymes and nutrients involved in the process, we will discuss all of these in thorough detail below):


From the above picture, we should note the two main components which need to be addressed in the dopamine to norepinephrine conversion process:
  1. The enzyme Dopamine Beta Hydroxylase, and
  2. The nutrient ascorbic acid (aka vitamin C), especially with its regard to oxygen (O2), as depicted above.
Dopamine Beta Hydroxylase enzyme: We have examined Dopamine Beta Hydroxylase (often abbreviated as DBH) several times in previous posts. The gene coding for the DBH enzyme (of which the gene shares the same name, "DBH") is located on the 9th human chromosome. This enzyme is responsible for adding a hydroxyl (-OH) group off of the dopamine molecule, which leaves us with the new neuro-chemical norepinephrine. Note that this is the second time in the overall conversion process of tyrosine to L-DOPA to dopamine to norepinephrine that an "OH" group was added, the first being the work of an "OH" onto the hexagon ring of tyrosine to convert it to L-DOPA (see first diagram in this blog post if this is confusing).

*Please note: It is important to note that oxygen is required for this step to work, as an oxygen atom is transferred from O2 to the dopamine molecule. In order for this chemical conversion to work, however, another agent (vitamin C) is required. This is where ascorbic acid (vitamin C) comes in
:

Ascorbic Acid (vitamin C):
We mentioned vitamin C in an earlier post, in that it can play a "helper" role in the conversion of tyrosine to L-DOPA, a process which utilizes the enzyme tyrosine hydroxylase. Tyrosine hydroxylase is dependent on iron, but the efficacy of the enzyme requires iron to operate in the "reduced" form as opposed to the "oxidized" form (the reduced form has iron in a "+2" positively charged state, and in the "oxidized" form, iron exists in the even more positively charged "+3" state. In nature how positively or negatively charged a certain element is can have drastic effects on its biological function. In the case of the tyrosine hydroxylase enzyme, and the metabolism of tyrosine, this is no exception). Much of this "helper" role of vitamin C was due to the ability of the vitamin to keep the iron in the desired "+2" state. Some studies have found this tyrosine hydroxylase enzyme to be significantly compromised in vitamin C deficient states (as in scurvy).

However, while tyrosine hydroxylase the enzyme Dopamine Beta Hydroxylase appears to be even more heavily dependent on vitamin C, as mentioned in an earlier blog entry titled: 10 Ways Vitamin C Helps Treat ADHD Symptoms (this was mentioned in point #9). For the conversion process of tyrosine to L-DOPA, much of vitamin C's usage was due to its antioxidant status, but for this dopamine beta hydroxylase enzyme, which is used to convert dopamine to norepinephrine, vitamin C is used more of as a "co-factor" or "helper" to the enzyme.

As mentioned above, vitamin C must be "sacrificed" to get the oxygen atom from the O2 molecule and onto the dopamine molecule to convert it to norepinephrine. The end result of this "sacrifice" is a different oxidized form of the vitamin, which is known as dehydroascorbate.

This brings up another important point. We have seen in the past how vitamin C is often an "altruistic" agent in ADHD treatment, in that it frequently sacrifices itself for the well-being of other nutrients of importance to ADHD. For example, we've spoken at length about the problem of oxidation of omega-3 fatty acids (since omega-3 supplementation is a common ADHD supplementation strategy, this damaging oxidation process can be quite severe if not controlled for), and how vitamin C can help in preventing omega-3 oxidation in ADHD treatment cases. Vitamin C often helps "recycle" other antioxidants such as vitamin E (which is much more fat-soluble than vitamin C, so it is often recommended for antioxidant treatment strategies for ADHD that vitamins C and E are used in tandem).

Please note, then, that since vitamin C is used in the dopamine to norepinephrine pathway, and that it is essentially "lost" in the process (unless it is returned to its native ascorbic acid form by another antioxidant, such as glutathione), it is crucial that we maintain adequate levels of vitamin C. Furthermore, since vitamin C is a water soluble vitamin, it gets removed from the system quite easily. Therefore, it is imperative that we maintain adequate pools of this vitamin through diet or supplementation. A rough estimate of daily vitamin C requirements can be found here.

However, since toxicity is rarely an issue with vitamin C (see the upper limits of the vitamin here, and note how much of a ceiling there is between the recommended levels and the upper limit), going slightly higher (i.e. 2 times the recommended amount) is rarely a problem. Therefore, this blogger personally recommends that since the vitamin is useful in at least 2 different parts of the tyrosine to dopamine and norepinephrine conversion process (involving both the tyrosine hydroxylase enzyme for the conversion of tyrosine to L-DOPA and the dopamine beta hydroxylase enzyme-driven conversion of dopamine to norepinephrine), those wishing to try tyrosine supplementation for ADHD should maintain adequate (if not slightly higher than "adequate") levels of the vitamin.

We will wrap up our discussion of tyrosine supplementation for treating ADHD in the next few blog posts. We will look briefly at the norepinephrine to epinephrine conversion process, but focus more on some of the potentially harmful side-products of tyrosine metabolism, including the potential buildup of the pro-inflammatory agent homocysteine. Finally, we will finish with a final post on the blogger's thoughts on the whole process, recap the different nutrients needed to optimize enzyme function for overall tyrosine metabolism, and look at possible ways in which, instead of being used completely in isolation, tyrosine supplementation could also be used as an adjunct or accessory treatment to common ADHD medications, possibly optimizing their function and improving their effectiveness in treating ADHD and related disorders.

Add to Technorati Favorites

37 comments:

shashank said...

Here is a link to more information about the genetics of Tyrosine Hydroxylase Deficiency that was prepared by our genetic counselor and which has links to some useful resources for those dealing with this condition: http://www.accessdna.com/condition/Tyrosine_Hydroxylase_Deficiency/769. There is also a phone number listed if you need to speak to a genetic counselor by phone. I hope it helps. Thanks, AccessDNA

adhd resource said...

Thanks for the information that you've share. I really appreciate it. Looking forward for more of your posts.

nickdrew said...

pretty useful information,thanks
come to my health and fitness community

Online Generic Viagra said...

A word of appreciation for you.The art of doing of writing things is excellent.Keep posting articles like these.A very good article post.I must appreciate you knowledge about the subject.Thanks for sharing the relevant stuff, I was searching since a very long time.

Generic Viagra said...

Nice Post, I appreciate with you and your work. Thanks for sharing...

Pearlie Guerrier said...

Vitamin C works like a wonder medicine. I don't think that there is any toxicity either but one should not take too much. Thank you for the rough estimate of the daily intake. I do need a guideline to follow.

forzest said...

This is very appreciative post. I must appreciate your knowledge very much. Thanks for introducing about it....

www.ciudad-real-3d.com said...

This can't work in fact, that is exactly what I consider.

Shingles Home Remedy said...

Thanks for share! Nice article and valuable info :)

santa barbara chiropractor - dr.zemella said...

There are many parents these days that take their children for chiropractic treatment and care. It has been observed that children can take advantage of this treatment method starting from birth till throughout the childhood. Handling a child with ADHD in your house can be a problematic work but it has been observed that chiropractic treatment can help a lot with the symptoms of ADHD.

Children suffering from the problem of ADHD or attention deficit/hyperactivity disorder can act out in various ways. They may control themselves, not obey commands and bully other children. These children might get violent and may have rough behavior like throwing things around.

According to a survey by American Chiropractic Association in 1991, the number of chiropractic patients of sixteen years of age and younger has increased to 8.5%. Chiropractic services is the most common alternative method of treatment performed on children and it is completely safe.

A study conducted in 1975 compared the effect of chiropractic treatment and drugs in children suffering from ADHD. The study showed that chiropractic services was twenty four percent more effective than normal drug prescription. It worked over the wide range of symptoms which are common in neurological dysfunction syndrome. So, chiropractic treatment works good with children having ADHD.

It has been observed that children who suffer from the problem of ADHD have successful results with chiropractic treatment. It has also been noticed that children who have vertebral subluxation and do not show any symptoms of ADHD should still have chiropractic services. The best method of treatment in case of ADHD is chiropractic services. It is completely natural and so it does not have any side effects. This makes it very safe for your child. With proper treatment and care, the symptoms of this condition can be helped to a great degree.


The effects of chiropractic services on children with learning and behavioral problems was investigated with 24 elementary and secondary level students, 12 receiving regular chiropractic treatment and 12 receiving medication. Results indicated that chiropractic treatment was more effective for the wide range symptoms common in the neurological dysfunction syndrome in which the following symptom areas were identified: attention span, hyperactivity, listening comprehension, reading comprehension, verbal output performance, writing output performance, following instructions, hand-eye coordination, overall coordination, effort, emotional maturity, behavior, and self-confidence.

The hands-on nature of the chiropractic services requires patients to visit the chiropractor a number of times. To be treated by the best chiropractor, a patient needs to go into the office. A chiropractor may provide acute, chronic, and/or preventive care thus making a certain number of visits sometimes necessary. Your doctor of chiropractic should tell you the extent of treatment recommended and how long you can expect it to last.

viagra blog said...

Excellent post.I want to thank you for this informative read, I really appreciate sharing this great post. Keep up your work.

comprar viagra said...

Super blog and nice to read. I really liked your blog and would like to know more about the topic. Thank you for the post.

write research paper for me said...

This is a very significant blog. Thanks for sharing your thoughts. Keep up the good job in posting very good topics.

Johan said...

Very low levels of iron supplement can make people tired quickly. Iron plays a great role in bone structure, haemoglobin and red blood cells. So when if you have diagnosis with deficiency anemia, use angstrom Iron supplement.

bedroom curtains said...

HI
ADHD treatments
I'm quite pleased with the information in this post. nice and useful!
thank you!

Helan said...

Thank you for sharing this interesting information. My son was recently diagnosed with ADHD so I am looking for all the information I can about it. One website I have come across in my research is http://onlineceucredit.com/edu/social-work-ceus-td. It has been very helpful.

Teenage Bedroom said...

Good day
ADHD treatments
Creative ideas turn out to be quite qualified in terms of you're posting. I wish you best of luck with your articles.

sleeper sofa said...

Hello
ADHD treatments
Wonderful! Can I merely say what a relief to uncover someone who essentially knows what they’re speaking about on the internet?

sports handicapping services said...

how good these sites with much good info thanks

Winnifred said...

In my view everyone have to glance at it.

canadian viagra said...

I enjoyed reading your articles. This is truly a great read for me. I have bookmarked it and I am looking forward to reading new articles.Keep up the good work!

buy kamagra said...

Excellent website. Lots of useful information here. I am sending it to a few friends ans also sharing in delicious. And obviously, thanks for your effort!

essay editor said...

That might have been just the right one to appeal!

Roderick Parker said...

Thank you so much for providing plenty of useful content. I have bookmarked your site and will be without doubt coming back. Once again, I appreciate all your work and also providing a lot vital tricks for your readers.
Green coffee 800

Anna Swiderski said...

I have been talking about this subject a lot lately with my mother so hopefully this will get him to see my point of view.
Green coffee 800

Debra Robertson said...

Have you ever considered adding more videos to your blog posts to keep the readers more entertained? I mean I just read through the entire article of yours and it was quite good but since I'm more of a visual learner,I found that to be more helpful well let me know how it turns out! I love what you guys are always up too. Such clever work and reporting! Keep up the great works guys I've added you guys to my blogroll. This is a great article thanks for sharing this informative information.. I will visit your blog regularly for some latest post.
Green coffee 800

Tina said...

This post was great, thanks. If you need more info on a drug intervention then you should check out Ken he’s got great experience.

john0812smith said...

And so what’s the solution due to this crippled living? Nicely there are lots of medical treatments along with methods obtainable that is conceived over the time period simply by medical doctors along with medical experts. But these kind of treatment options try to cause you to artificially fertile through additional components along with these kind of methods are generally definitely high-priced in every aspects. The actual achievements price of from any of the treatment options can be not necessarily established. And once solution fails, this not only breaks persons emotionally however they additionally disheartenment of actually to How To Get Pregnant.



Anonymous said...

ADHD (not a disorder) is based on amazons doing the work of two people. It is really sad that scientists have not looked at this angle.

Greek amazons, Dahomey amazons and many amazons around the world did the work of two or three people. These genes will be passed down on to boys and girls.
So what you will get is two or three lots of intelligence, two or three lots of sensitives, two or three lots of energy, two or three lots of strengths, two or three lots of inquisitiveness, two or three lots of anger, two or three lots of resentment, different type of smell etc. It all stems of the lifestyle that existed.
Attention deficit should be selective attention - their environment historically was rich and if you are walking through the forest at speed, you will have learned over generations to select the correct noise or stimulus to really listen to. If you were in the forest you needed to be sensitive to your environment. Watery conversation may not be a trigger to their minds. Since the ancestors did the work of two people, they will have two or three lots of deep stimulus. It should be People from the Working path verses people from the social path. People from the social path have low and medium stimulus whilst people from the working path an exemptionally. high stimulus. Floism

Obat Kutil Kelamin Herbal said...

goodnight ..

Obat Kutil Pada Bibir Vagina said...

goodnight all..

Hanna Willimas said...

I have read on many websites about the ADHD meditation and its treatment, I think Tyrosine can be helpful for better future of ADHD meditation. You can read this helpful resource to know more about ADHD treatment. ADHD Meditation Education

Web Designing Companies said...

From this blog i got the actual information and full details regarding vitamin D levels and ADHD.It having well explanation about it.
Web Designing Companies | Website Development Companies

Website Design Company said...

This is really very good blog to allay the suspicions regarding Tyrosine Supplementation for ADHD Actually Work.
Web Design Company Bangalore | Responsive Web Design Services

saransh khanna said...


Great post, thanks for sharing..


Web Design India


Wordpress Development Company

Bryan Avoti said...

Glad to read this blog post on ADD Treatments. I was browsing the web for ADHD/ADD treatment in panama city beach and luckily i found this blog. This blog is truly tremendous.

Thiago daLuz said...

Thanks for putting this together. I was on ADHD medication when I was little, and only recently have begun researching it. My cousin is considering something like this for her son. I'm helping her look at alternatives to things like Adderall. Thiago | https://www.mindmilq.com/