Why not Cocoa Flavanols for Autism?

  

Judging by my blog statistics, lots of people are interested in broccoli (Sulforaphane) to treat autism.  Thanks to the patents held by Johns Hopkins, you can expect to hear much more about Sulforaphane in the coming years.

Meanwhile, Columbia University and Mars, the chocolate people, have released a study showing that “flavanoids” in cocoa can do wonders for memory loss in older people.  In effect, they can restore memory in 60 years olds to where it was 20 or 30 years earlier.

If you take a step back and look at what is known by science about oxidative stress and antioxidants, all will become much clearer.

Oxidative Stress Pioneers

In an earlier post we met Paul Talalay, a German-American, who worked at Johns Hopkins.  He specializes in foods that protect you from cancer.  He is Mr Broccoli. 

It turns out that perhaps the real pioneer in this field is a 100% German, called Helmut Sies, who also studies foods that act as antioxidants and nutrients that provide protection from cancer.  We have his very detailed diagram below, that explains the relationship between many of the factors involved in oxidative stress.  I wish I had found it earlier.  I added the six outer boxes.

If you want to read clever studies about this subject, just include Helmut Sies in your search; for example “selenium Helmut Sies”.

Redox Pioneer: Professor Helmut Sies

On this graphic you will see GSH (Glutathione).  When you take NAC (N-acetylcysteine) you directly raise the level of GSH.  When eat broccoli you activate Nrf2, which is a Redox switch, just under the traffic light in the graphic.

When you eat certain flavonoids, like Cocoa, or carotenoids like lycopene (found in tomatoes), you again promote the anti-oxidative free radical scavenger effect.  Look in the blue boxes under diet.

Not on the diagram, we also have flavonolignans which are natural phenols composed of a part flavonoid and a part lignan. As pointed out in a comment in the last post by Seth Bittker, one interesting  flavonolignan is Silibinin, which has anti-oxidant and chemoprotective effects

Note the presence of (Coenzyme) Q10 in the yellow box.  This is part of the mitochondrial cocktail suggested by Dr Kelley from Johns Hopkins for regressive autism.  Q10 is depleted by statins.

Glutathione peroxidases, in the yellow box, are also very interesting.  These are selenium-containing enzymes.  GPx (x goes from 1 to 8)  catalyze the reduction of H₂O₂ and organic hydroperoxides to harmless products. This function helps to maintain membrane integrity and to reduce further oxidative damage to molecules such as lipids and lipoproteins with the associated increased risk of conditions such as atherosclerosis.  It appears GP₁ may be defective in autism and this is contributes to increased oxidative stress.  This area has been well studied due to its impact on heart disease.  You appear to be able to counter the lack of GPx with yeast-bound selenium, other forms of selenium do not work, due to a lack of bioavailability. A post will appear just on Selenium.

There are several other potent (exogenous) antioxidants that we have come across:-

• Alpha lipoic acid also known as ALA or Tioctic acid (found  in Dr Kelley’s cocktail)
•   L-Carnosine (studied by Dr Chez )
•  Vitamin C (suggested by many, including Dr Kelley)

Another day, another anti-oxidant

In human health, two well used anti-oxidant drugs are Alpha lipoic Acid (ALA,  also known as Tioctic acid) and N-acetyl cysteine (NAC).  They share many similar effects.

•       Potent antioxidant
•       Increase insulin sensitivity
•       Improve memory in those with mild cognitive          impairment
•       May lower blood pressure
•       Improve behavior in autism

NAC is widely used to treat Chronic obstructive pulmonary disease (COPD) and ALA is used to treat diabetic neuropathy. Perhaps they could be interchanged

·        NAC has a chemoprotective effect
·        ALA has been shown to induce cell cycle arrest in  human breast cancers      cells

Back to Cocoa Flavanols and Mars

This flurry of activity was driven by a well publicized study done at Columbia University Medical Center (CUMC), using a high cocoa flavanol concentration drink provided by Mars.

Dietary cocoa flavanols reverse age-related memory decline

   

In the CUMC study, 37 healthy volunteers, ages 50 to 69, were randomized to receive either a high-flavanol diet (900 mg of flavanols a day) or a low-flavanol diet (10 mg of flavanols a day) for three months. Brain imaging and memory tests were administered to each participant before and after the study. The brain imaging measured blood volume in the dentate gyrus, a measure of metabolism, and the memory test involved a 20-minute pattern-recognition exercise designed to evaluate a type of memory controlled by the dentate gyrus.
The high-flavanol group also performed significantly better on the memory test. “If a participant had the memory of a typical 60-year-old at the beginning of the study, after three months that person on average had the memory of a typical 30- or 40-year-old,” said Dr. Small. He cautioned, however, that the findings need to be replicated in a larger study—which he and his team plan to do.

This is very impressive.  But how do the other anti-oxidants compare?

Well, without funding from Mars, researchers only managed the money to test ALA and NAC on mice; but as you might expect, the result was similar.

The antioxidants alpha-lipoic acid and N-acetylcysteine reverse memory impairment and brain oxidative stress in aged SAMP8 mice

Chronic administration of either LA or NAC improved cognition of 12-month-old SAMP8 mice in both the T-maze footshock avoidance paradigm and the lever press appetitive task without inducing non-specific effects on motor activity, motivation to avoid shock, or body weight. These effects probably occurred directly within the brain, as NAC crossed the blood-brain barrier and accumulated in the brain. Furthermore, treatment of 12-month-old SAMP8 mice with LA reversed all three indexes of oxidative stress. These results support the hypothesis that oxidative stress can lead to cognitive dysfunction and provide evidence for a therapeutic role for antioxidants.

Cocoa Flavanols are good for your heart

This is also good news, but it does seem that antioxidants are generally very good for your heart.

First cocoa.

In this study blood pressure, glucose, insulin and cholesterol were all markedly affected for the better by the cocoa as was cognitive function.

This is great;  but it is what Helmut Sies has been telling the world for many years.

Benefits in Cognitive Function, Blood Pressure, and Insulin Resistance Through Cocoa Flavanol Consumption in Elderly Subjects With Mild Cognitive Impairment

The Cocoa, Cognition, and Aging (CoCoA) Study

Abstract—Flavanol consumption is favorably associated with cognitive function. We tested the hypothesis that dietary flavanols might improve cognitive function in subjects with mild cognitive impairment. We conducted a double-blind, parallel arm study in 90 elderly individuals with mild cognitive impairment randomized to consume once daily for 8 weeks a drink containing _990 mg (high flavanols), _520 mg (intermediate flavanols), or _45 mg (low flavanols) of cocoa flavanols per day. Cognitive function was assessed by Mini Mental State Examination, Trail Making Test A and B, and verbal fluency test. At the end of the follow-up period, Mini Mental State Examination was similar in the 3 treatment groups (P_0.13). The time required to complete Trail Making Test A and Trail Making Test B was significantly (P_0.05) lower in subjects assigned to high flavanols (38.10_10.94 and 104.10_28.73 seconds, respectively) and intermediate flavanols (40.20_11.35 and 115.97_28.35 seconds, respectively) in comparison with those assigned to low flavanols (52.60_17.97 and 139.23_43.02 seconds, respectively). Similarly, verbal fluency test score was significantly (P_0.05) better in subjects assigned to high flavanols in comparison with those assigned to low flavanols (27.50_6.75 versus 22.30_8.09 words per 60 seconds). Insulin resistance, blood pressure, and lipid peroxidation also decreased among subjects in the high-flavanol and intermediate-flavanol groups. Changes of insulin resistance explained _40% of composite z score variability through the study period (partial r2_0.4013; P_0.0001). To the best of our knowledge, this is the first dietary intervention study demonstrating that the regular consumption of cocoa flavanols might be effective in improving cognitive function in elderly subjects with mild cognitive impairment. This effect appears mediated in part by an improvement in insulin sensitivity.

There are more cocoa studies:-

Enhancing dentate gyrus function with dietary flavanols improves cognition in older adults  The effect of acute consumption of a flavonol-rich cocoa drink on cerebral vasomotor reactivity in African Americans

Mars Cocoa Science website

Cocoa Flavanols as a therapy for Autism

Based on the work of Helmut Sies and the trials funded by Mars, it is pretty obvious that 1,000mg of cocoa flavanols a day would very likely have a marked effect on someone with autism, assuming that is they were not already taking NAC, ALA, Carnosine, Broccoli, Sulforaphane or Selenium.  500 mg should also have an effect.

Choice of antioxidant

The question is what is the ultimate treatment for oxidative stress in autism?

I guess this will depend on exactly what type of autism you have (regressive or not), to what extent you have a mitochondrial dysfunction and whether you have any genetic dysfunction related to oxidative stress.

What works best in Billy, may be suboptimal in Charlie, but still much better than nothing at all.

It looks to me that NAC and ALA will likely be the most potent antioxidants.

If you live in the US, you can buy cocoa flavanols in standardized doses from Mars.  One capsule = 125mg of cocoa flavanols.   I have to add that I am far more inclined to believe Mars, than those supplement companies out there.  You can buy tablets saying they contain 50 mcg of Selenium, but what do they really contain? 

You can also buy “high flavanol” raw (non-alkalized) cocoa powder in big bags.  This lighter brown cocoa has lost far less of the flavonoids in the processing process.  In theory, a 5g teaspoon of the very best one will contain (on a good day) 415 mg of flavavols.

Mars are only supplying their CocoaVia products in North America, so if you want to try cocoa flavanols you have a few options:-

·        8.5 teaspoons of standard raw cocoa  (content will vary widely)

                or

·        1.2 teaspoons of “Chococru” upmarket raw cocoa

                or

·        4 capsules of CocoaVia from Mars  

Each of the above should give you 500mg of cocoa flavanols, which would look like a good starting point.  As with NAC, the studies show that the benefit increases the more you take, but the extra benefit drops off.

If somebody in the US tries CocoaVia, do let us know the result.

Not surprising, Mars tell us on the label that the product is not intended for children.  I do not suppose they ever thought of it being an autism therapy either.

I do like the idea of the redox switch, Nrf2, which Sulforaphane is known to activate.  I also like the idea of the enzyme GP₁ that acts as catalyst in the oxidation/reduction process.

The science is around 20 years old and nobody has yet figured it all out;  they probably will not conclusively do so in the next 20 years either.

Food for thought!

Sulforaphane (Broccoli) for Cancer, Autism and COPD

A reference to the other Broccoli

One advantage this blog has is that it looks at the comorbidities of autism, so we are aware of useful findings in related areas.  So it then does not come as a big surprise when a therapy effective in related areas also helps with autism.

One of the most useful is asthma.  Chronic obstructive pulmonary disease (COPD) is a related condition, brought on by smoking or pollution.  It kills 3 million people a year; COPD is made much worse by chronic oxidative stress.  We saw in an earlier post that oxidative stress stops the asthma drugs from working.  The current treatment for oxidative stress in COPD is N-acetyl cysteine (NAC).  I recall they are still looking for a better treatment; perhaps the search is over.  (see later).

We also saw that there is already some overlap between “emerging” research findings in cancer and those in autism. These include:-

·        PAK1, mTOR (Rapamycin), Wnt signaling

·        Ivermectin treatment for Leukemia and Autism

·        Quercetin and NAC aiding recovery for specific cancers and helping some in autism

For twenty years researchers have known about the potential cancer fighting benefits of Sulforaphane, which is produced by a chemical reaction when you eat fresh broccoli that was only lightly cooked.

In the intervening years vast amounts of research has been going on to tinker with broccoli to maximize/harness the potential health benefit, and also to develop related synthetic drugs (analogs of Sulforaphane) like Sulforadex.

Twenty years later, and a vast amount of broccoli supplement pills later, not many people have benefitted.  When you look into the matter, it really is rather bizarre.

Fresh raw broccoli was found to contain large amounts of both Glucoraphanin and an enzyme called Myrosinase.  When you eat the raw broccoli the Glucoraphanin and Myrosinase react to produce a potent substance called Sulforaphane, which seems to have numerous positive effects.  A powerful anti-oxidative process is triggered that was shown to have a strong anti-cancer effect.

The problem is that myrosinase from broccoli is not stable; when you cook it, freeze it, or process it, you lose it.  So, soggy cooked broccoli, crisp frozen broccoli and almost all the broccoli pills on the market have no myrosinase and therefore no Sulforaphane will be produced.

There have been numerous studies showing this and also a few clever ideas to get around it have been investigated.

Sulforaphane is itself also unstable and has to be used immediately or kept frozen.

Johns Hopkins and Sulforaphane

Sulforaphane was discovered in 1992 at Johns Hopkins and much related research still comes from there.  They hold the key patents and indeed went as far as to try to stop other people growing/selling broccoli sprouts.  They have developed a way to produce Sulforaphane in the laboratory and then it is freeze dried and kept frozen at -20 Celsius.

Cancer research

The cancers where Sulforaphane has shown promise include:-

§  Carcinogen detoxification

• Tumor progression and activity
• Stomach cancer
• Skin tumors
• Breast cancer
• Prostate cancer
• Colon cancer
• Bladder cancer
• Impact on developing or developed cancers

COPD

What caught my attention was a paper from 2008 by Peter Barnes, one of only two Englishmen on my Dean’s list and the only one that lives there.

Defective Antioxidant Gene Regulation in COPD: A Case for Broccoli

This has been followed up and there is now a Phase 2 clinical trial of Sulforaphane for treatment of COPD.

Broccoli Sprout Extracts Trial (BEST)

Barnes is my kind of scientist.  He has noted that the most potent, safe antioxidant to treat COPD is NAC (N-acetyl cysteine) but he wanted more, and has been on the look-out for years for a stronger, but safe, alternative.  He concluded that

“It has been difficult to find new more effective antioxidants that are not toxic. A more attractive approach may be to restore Nrf2 levels to normal through inhibiting the action of Keap1. This has been achieved in vitro and in vivo by isothiocyanate compounds, such as Sulforaphane, which occur naturally in broccoli”

And finally to Autism

So the recent big news that Sulforaphane was remarkable successful in a small trial at Massachusetts General Hospital (MGH) and Johns Hopkins maybe should not be such a surprise.

Sulforaphane treatment of autism spectrum disorder (ASD)

Autism spectrum disorder (ASD), characterized by both impaired communication and social interaction, and by stereotypic behavior, affects about 1 in 68, predominantly males. The medicoeconomic burdens of ASD are enormous, and no recognized treatment targets the core features of ASD. In a placebo-controlled,double-blind, randomized trial, young men (aged 13–27) with moderate to severe ASD received the phytochemical sulforaphane (n = 29)—derived from broccoli sprout extracts—or indistinguishable placebo (n = 15). The effects on behavior of daily oral doses of sulforaphane (50–150 μmol) for 18 wk, followed by 4 wk without treatment, were quantified by three widely accepted behavioral measures completed by parents/caregivers and physicians: the Aberrant Behavior Checklist (ABC), Social Responsiveness Scale (SRS), and Clinical Global Impression Improvement Scale (CGI-I). Initial scores for ABC and SRS were closely matched for participants assigned to placebo and sulforaphane. After 18 wk, participants receiving placebo experienced minimal change (<3.3%), whereas those receiving sulforaphane showed substantial declines (improvement of behavior): 34% for ABC (P < 0.001, comparing treatments) and 17% for SRS scores (P = 0.017). On CGI-I, a significantly greater number of participants receiving sulforaphane had improvement in social interaction, abnormal behavior, and verbal communication (P = 0.015–0.007). Upon discontinuation of sulforaphane, total scores on all scales rose toward pretreatment levels. Dietary sulforaphane, of recognized low toxicity, was selected for its capacity to reverse abnormalities that have been associated with ASD, including oxidative stress and lower antioxidant capacity, depressed glutathione synthesis, reduced mitochondrial function and oxidative phosphorylation, increased lipid peroxidation, and neuroinflammmation.

What surprised me was just how big an impact the Sulforaphane had and the fact that these are very serious researchers, unlike many others.

Since we are talking about a therapy that has a strong anti-oxidant connection I compared the trial results from the Stanford NAC trial, with those from the Sulforaphane trial at MGH.

Monty, aged 11 with ASD, responded almost immediately to NAC and so of course I am interested in any additional, even overlapping, therapy.

For anyone interested, the following table shows the results from the NAC study:-

The data shows a large drop in irritability and hyperactivity and a moderate improvement in stereotypy, compulsions and SIB.  On the Social Responsiveness Scale, the people on NAC dropped by 18 , versus a drop of 6 for the placebo group.

Now we have the results from the Sulforaphane (broccoli) study.

On the Social Responsiveness Scale (SRS) , the people on Sulforaphane dropped by 20, versus a drop of 2 for the placebo group.

Moving on to the Aberrant Behavior Checklist (ABC) we can compare the improvement in four sub-categories:-

NAC               Sulforaphane

Irritability                 -9.7                     -4

Lethargy                  -4.2                     -4.5

Stereotypy              -3.5                      -2.7

Hyperactivity           -11                      -4.8

Now these figures are averages.  In reality you are likely either a responder or non-responder, nobody is likely to be Mr. Average.

I found these results very encouraging, albeit less so than the NAC trial.  The Sulforaphane trial was conducted among young adults whereas NAC was trialed on children.  You might expect children to be more responsive, since their autism tends to be less controlled than it tends to be in adulthood.

Since both trials are drawn from a population with behavioral autism and not any biological specific dysfunction both groups will likely include people with :-

·        Classic early onset autism caused by multiple genetic and epigenetic (environmental) hits

·        Mitochondrial disease triggered regressive autism, with no inherent prior dysfunction

·        Single gene disorders, probably never identified

Any trial with responders > 30% is therefore very interesting.  This trial was much better than that.

Now, both classic autism and Mitochondrial disease triggered regressive autism are associated with oxidative stress.  People with classic autism do seem to respond to NAC, whereas some people with Mitochondrial disease do not.

In the NAC trial the dose was stepped up every 4 weeks  (0.9g 1.8g 2.7g).  In the Sulforaphane trial the dose remained the same but the effect grew.

So the method of action of both drugs may be similar, but it is not identical.  NAC is a ”primary anti-oxidant”, in that NAC and its end product Glutathione (GSH) are themselves anti-oxidants.   

Sulforaphane appears to be a “secondary anti-oxidant”, it activates Nrf2 which then triggers a set of reactions that promotes an anti-oxidant response.  So it is logical that there is a time delay.

But after week 18, Sulforaphane treatment was stopped and at week 22 all benefit had been lost.

So we can conclude, even though these are two different trials with different groups of people, that if anything NAC looks more potent than Sulforaphane.

The question is whether Sulforaphane plus NAC would be even better than NAC (or Sulforaphane) alone.

  

Mode of Action

I know that NAC is a “direct” anti-oxidant and it is a precursor for glutathione (GSH); its effect is almost immediate, whereas the MGH researchers inform us that Sulforaphane became effective over a matter of weeks.  We know that Sulforaphane activates a transcription factor, Nrf2 in the cell. Once activated, Nrf2 then translocates to the nucleus of the cell, where it aligns itself with the antioxidant response element (ARE) in the promoter region of target genes. The target genes are associated with process which assists in regulating cellular defences. Such cytoprotective genes include that for glutathione (GSH).

So it is clear that both NAC and Sulforaphane will affect the level of the boy’s most important antioxidant glutathione (GSH).

That may possibly be the end of the story.

Science does tell us that Sulforaphane has many other effects that may also be beneficial in autism.  They do seem to have an effect in cancer and some do relate to reversing epigenetic “errors”.  Classic autism is also likely triggered, in part, by epigenetic “markers” on undamaged parts of the DNA.  Any method of selectively removing these markers and turning genes “off” that were “on” in error and vice versa is very interesting.

Sulforaphane’s effect in cancer appears to be more than just an antioxidant.  Research has shown that it is indeed active epigenetically (switching on and off genes).

The logical next step would be to test NAC vs Sulforaphane vs (NAC + Sulforaphane).

Since we live in an imperfect world, rather than wait half a century for a clinical trial, you might have to do a home trial.

In the next post we will see how to make Sulforaphane at home.

As is often the case, it is not as simple as buying some on Amazon.

Sulforaphane survives for 30  minutes outside the freezer and almost all broccoli supplements have been shown to have no active Myrosinase.  Without this enzyme almost no Sulforaphane will be produced, no matter how many broccoli tablets you take.

This reminds me of people buying oxytocin over the internet.  If it is not kept chilled, by the time it arrives at your place, a few days later, it will be totally inactive and so ineffective.  You will have wasted your money and perhaps falsely concluded that oxytocin is ineffective.

This is how the Sulforaphane is made by Johns Hopkins:-

Preparation of Sulforaphane-Rich Broccoli Sprout Extracts.

Sulforaphane rich broccoli sprout extract (SF-BSE) was prepared by the Cullman Chemoprotection Center at The Johns Hopkins University essentially as described in Egner et al. In brief, specially selected broccoli seeds were surface-disinfected and grown (sprouted) for 3 d in a commercial sprouting facility under controlled light and moisture conditions. A boiling water extract was prepared, filtered, cooled, and treated with the enzyme myrosinase (from daikon sprouts) to convert precursor glucosinolates to isothiocyanates, and

then lyophilized at a food processing facility (Oregon Freeze Dry, Albany, OR). The lyophilized powder (216 μmol SF/g powder) was encapsulated into #1 gelcaps by ALFA Specialty Pharmacy (Columbia, MD); each capsule contained 50 μmol SF (232 mg of SFBSE); placebo capsules were filled with microcrystalline cellulose.

The powders (bulk and capsules) were maintained at approximately

−20 °C and repeatedly checked for microbial contaminants and SF

titer before conveyance to the study site pharmacy (Massachusetts

General Hospital) to be dispensed to patients.

  

Thanks to all the research done on Sulforaphane/broccoli as chemoprotective agent, all the pieces of the puzzle exist.  My first choice would always be the stable analog of Sulforaphane, but it is not yet available and will no doubt be ultra expensive.  So I will work with second best.

The nice people at Johns Hopkins did reply to my questions, so I think I have figured out what I needed to know.

                                           How to make Sulforaphane at home

NAC for Long Term Use in Autism

One of the post popular subjects on this blog is the use of NAC (N-acetyl cysteine) for autism. There are numerous earlier posts explaining how and why it works.

Just look up NAC in the index by subject; there are 19 posts, for those with plenty of time. (the labels function just gives the recent posts)

NAC was shown in a clinical trial at Stanford to be an effective treatment for autism.  You might have expected that this would be quickly followed by further research, but since NAC is widely available as a cheap supplement, there is not much financial incentive for further research.  Without that research, mainstream doctors will never prescribe it.

Beginner's guide to NAC 

Highly respected researchers have shown that in many types of autism, oxidative stress is present and considered that NAC might be an effective therapy.

In the past, some DAN-type doctors have used NAC, but the Stanford trial was the first mainstream trial for autism.

For oxidative stress in asthma and in particularly severe types, like COPD, NAC has long been used.  Oxidative stress stops asthma drugs from working, which is why NAC is used.

In autism, as in asthma, it appears that oxidative stress is a long term condition.  NAC controls oxidative stress, but it does not cure it.

Just as asthma research has shown that smoking triggers irreversible oxidative stress, the same appears to be true for autism.  NAC will rebuild the level of body’s own antioxidant, GSH, but as soon as you stop taking the NAC, oxidative stress reappears.  Many years after people quit smoking, the asthma research showed that oxidative stress remains, and so the asthma drugs do not work.

Will NAC be effective?

In cases of classic autism, NAC has been effective for almost everyone who has given me feedback.

The effect is usually noticed as being a reduction/elimination of stereotypy/stimming and obsessive compulsive behavior.  Other people have seen a reduction in aggression and even in sleeping problems.  The reduction in stereotypy makes way for good behaviours, like increased speech and better mood.

Some types of autism are not associated with oxidative stress; anecdotally, it seems to be some regressive types of autism.

When effective, NAC should change behaviour within a couple of days.  Equally, when you stop taking it, the same behaviours should return with a day or two.  This is a good way to check that you are not just imagining the effect.

NAC has “stopped working”

After a period of months you may find, as I did, that NAC has “stopped working”.  If this happens, most likely it is not that NAC has stopped working, but rather that something else has started working and is making the autism worse.  You need to identify what has happened, treat it, and then NAC will appear to start working again.

Possible reasons for NAC appearing to stop working include:-

·        Effect of an allergy (pollen or food)
·        Flare-up in an existing auto-immune disease
·        New auto-immune condition

For example, if the person has a history of GI problems and these get worse just as NAC “stops working”, you would know what to do.

NAC dosage

From what people tell me, in a three year old children 600mg once per day is effective.

In older children higher doses, going up to 2,400 mg or 3,000 mg are being used. 

There will come a point where increasing NAC will have no further behavioural effect and then there will be more likelihood of side effects.

You can experiment to find the lowest effective dose.  It is logical to split larger doses over the day, to maximize effectiveness and minimize any side effects.

In my son (33kg/73 lbs) I give 1,200mg at breakfast, 600mg at lunch and 600mg in the evening.  I started about 20 months ago.

Quality of NAC

There is both cheap NAC in gelatin capsules and foil-packed NAC.  Over time NAC will react with the air and lose its potency; as this happens a smell of rotten eggs is produced.  The foil-packed NAC is called Fluimucil in Europe and PharmaNAC in the US.

Side effects

Almost everything has side effects of some kind, but in the doses used for autism, NAC does not seem to cause anything troubling to occur.  

NAC will also reduce homocysteine, which is linked to various heart problems in adults.  As an antioxidant, NAC will also help remove any metals that should not be present. NAC has also been shown to improve outcomes in some types of cancer.