Aspartame. Is it more ‘Die’ than ‘Diet’?

A link came around tonight on my Facebook feed about aspartame: “Aspartame is linked to Leukemia and Lymphoma in new Landmark Study on Humans” (http://worldtruth.tv/aspartame-is-linked-to-leukemia-and-lymphoma-in-new-landmark-study-on-humans/)

I’ve seen these sorts of articles come around on social media before, usually in the form of an alternative health website hysterically exaggerating an irrelevant or pseudoscientific study, trying to prove some point about the evils of western medicine or society, or get more internet traffic through sensationalist click-bait.

And I’d heard the whole aspartame-causes-cancer thing before. I’d heard that there was maybe some evidence in animal studies, but that there was no definitive link in humans.

So just from the title, before I’d even read the article, my sceptical mind was primed to expect the opposite of the articles eye-catching headline.  I started searching the literature to see if there was any evidence to prove me right.

The first research article I came across that wasn’t on rats was from the American Journal of Clinical Nutrition in 2012, “Consumption of artificial sweetener – and sugar-containing soda and risk of lymphoma and leukemia in men and women” [1]. It was an impressive study in terms of its numbers and its quality. It was drawn from the data of the Nurses Health Study and the Health Professionals Follow-Up Study, which were both prospective studies (which follow a large number of subjects over a long time to see who gets the disease in question, rather than starting with who has the disease in question and trying to work backwards trying to ascertain causes, which is much less reliable). Both studies also had a large number of subjects which increased their statistical power, and made their findings more robust.

The results didn’t look very good for aspartame. There was a clear-cut increase in the risk of Non-Hodgkins Lymphoma for men who consumed two or more serves per day of diet drinks containing aspartame (Relative Risk: 1.69; 95% Confidence Interval: 1.17, 2.45; P-trend = 0.02) and Multiple Myeloma for men who consumed one or more serve per day of diet drinks containing aspartame (RR: 2.02; 95% CI: 1.20, 3.40). However, there was no change in the risks for women who consumed aspartame.

The results certainly caught me a little off guard. Perhaps there was some truth to the alternative website’s assertions after all. Interestingly enough, the study that the worldtruth.tv site reviewed was the same article I’d found. I was guilty of making a snap judgement, and I had to remind myself not to always jump to conclusions.

Still, even though the article wasn’t sensationalist click-bait, some unanswered questions remained. Why was the risk only found in men? Was there a real association, and if so, why the difference. Should we extrapolate this finding like worldtruth.tv did and justifiably ask “will future, high-quality studies uncover links to the other cancers in which aspartame has been implicated (brain, breast, prostate, etc.)?”

In terms of the gender difference, the authors of the original study did have a theory: “We hypothesized that the sex differences we observed may have been due to the recognized higher enzymatic activity of alcohol dehydrogenase type I (ADH) in men, which possibly induced higher conversion rates from methanol to the carcinogenic substrate formaldehyde.” In support of this theory, they looked at the risk of leukaemia and lymphoma in those aspartame users who were drinkers vs the aspartame users who weren’t. Ethanol stops the metabolic conversion of aspartame to formaldehyde, so if their theory was on the right track, those aspartame users who also drank alcohol would have a lower risk. As it turns out, their data was supportive, with aspartame non-drinkers having an increased risk for Non-Hodgkins Lymphoma (RR: 2.34; 95% CI: 1.46, 3.76; P-trend = 0.004) compared with aspartame users who also drank (RR: 0.96; 95% CI: 0.48, 1.90; P-trend = 0.99) [1].

However, despite the findings of Schernhammer et al, a more recent large prospective trial published in the Journal of Nutrition last year found there was no association between soft-drinks of any variety and blood cancers, including those containing aspartame [2].

So the jury is still out on aspartame. Based on what we currently know, if you’re a woman, then there’s no risk of developing leukaemia or lymphoma from drinking diet drinks. If you’re a man, there’s also probably no risk, but a glass or two of alcohol a day would probably make sure of that. Although the best advice is probably to not bother drinking diet drinks at all. The best diet drink is still plain old water, which has virtually no associated risks, is much cheaper, and probably tastes a whole lot better.

References

  1. Schernhammer, E.S., et al., Consumption of artificial sweetener- and sugar-containing soda and risk of lymphoma and leukemia in men and women. Am J Clin Nutr, 2012. 96(6): 1419-28 doi: 10.3945/ajcn.111.030833
  2. McCullough, M.L., et al., Artificially and sugar-sweetened carbonated beverage consumption is not associated with risk of lymphoid neoplasms in older men and women. J Nutr, 2014. 144(12): 2041-9 doi: 10.3945/jn.114.197475
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Dr Caroline Leaf – Feed your children manure???

Screen Shot 2015-03-19 at 11.27.57 pm

I was entertained somewhat by Dr Leaf’s latest Facebook post this evening. In it, there was a pairing of water and a pot-plant, and sugary drinks and a child, with the words, “If you give this (water) to your plants? Why give this (sugary beverages) to your children.”

Without looking too closely, one might think that Dr Leaf was making a good point. Water is good, and sugar is bad, right?

With just a little more thinking, one can see that the metaphor is pretty weak. Plants aren’t children. Following the same logic of the metaphor, I should feed my children manure instead of food, since it’s clearly good enough for the pot-plant.

What is worrying about this post is Dr Leaf’s linking of diet with our Christian morals. Dr Leaf tries to link the concept of drinking water to the worship of God, because your body is a temple, and “Whether you eat or drink, or whatever you do, do it all for the glory of God.” (1 Corinthians 10:31). By logical extrapolation, Dr Leaf is therefore saying that drinking Coke is dishonouring God and the temple he gave for you. If you drink Coke, then you’re a bad Christian.

Though that’s really only Dr Leaf’s interpretation, because the scripture that she quotes isn’t talking about the composition of the food you eat but about it’s relationship to the sacrifice to idols. As far as I was aware, Coke isn’t used in any worship of idols before it’s bottled and distributed. So really, I don’t think whether you drink coke or other sodas will have any bearing on your relationship with God.

Perhaps Dr Leaf would have better spent her time outlining the studies that back up her overly dramatic statement “that sugary drinks like soda and processed orange juice can cause neurochemical havoc in your brain” rather than just hoping people will take her at her word.

Lets be real … no one in their right mind is encouraging children to have more sugar, mainly because of the excess calories, and not the hysterical notion of “neurochemical havoc”. Dr Leaf’s trying to get it right, but her poor metaphor, and the linking of ones diet to ones honouring of God probably went a step too far.

It would be nice if Dr Leaf could reexamine her knowledge of nutritional science and the scriptures that she uses so that she doesn’t weaken her credibility with such posts in the future.

Dr Caroline Leaf and the 98 Percent Myth

Dr Caroline Leaf believes that nearly all our diseases come from our thoughts.

Dr Caroline Leaf believes that nearly all our diseases come from our thoughts.

In the hustle and bustle of daily life, most people wouldn’t stop to consider what makes people sick.  In my profession, I get a front row seat.

In the average week, I get to see a number of different things.  Mostly “coughs, colds and sore holes” as the saying goes, although there are some rarer things too.  And sometimes, people present with problems that aren’t for the faint of heart (or stomach – beware of nail guns is all I can say).

Normally, the statistics of who comes in with what doesn’t make it beyond the desk of the academic or health bureaucrat.  The numbers aren’t as important as the people they represent.

But to Dr Caroline Leaf, Communication Pathologist and self-titled Cognitive Neuroscientist, the numbers are all important.  To support her theory of toxic thoughts, Dr Leaf has stated that “75 to 98% of mental and physical (and behavioural) illness comes from one’s thought life” [1: p37-38].  She has repeated that statement on her website, on Facebook, and at seminars.

As someone with a front row seat to the illnesses people have, I found such a statement perplexing.  In the average week, I don’t see anywhere near that number.  In general practices around Australia, the number of presentations for psychological illnesses is only about eight percent [2].

But Australian general practice is a small portion of medicine compared to the world’s total health burden.  Perhaps the global picture might be different?  The World Health Organization, the global authority on global health, published statistics in November 2013 on the global DALY statistics [3] (a DALY is a Disability Adjusted Life Year).  According to the WHO, all Mental and Behavioural Disorders accounted for only 7.2% of the global disease burden.

You don’t need a statistics degree to know that seven percent is a long way from seventy-five percent (and even further from 98%).

Perhaps a large portion of the other ninety-three percent of disease that was classified as physical disease was really caused by toxic thoughts?  Is that possible?  In short: No.

When considered in the global and historical context, the vast majority of illness is related to preventable diseases that are so rare in the modern western world because of generations of high quality public health and medical care.

In a recent peer-reviewed publication, Mara et al state, “At any given time close to half of the urban populations of Africa, Asia, and Latin America have a disease associated with poor sanitation, hygiene, and water.” [4] Bartram and Cairncross write that “While rarely discussed alongside the ‘big three’ attention-seekers of the international public health community—HIV/AIDS, tuberculosis, and malaria—one disease alone kills more young children each year than all three combined. It is diarrhoea, and the key to its control is hygiene, sanitation, and water.” [5] Hunter et al state that, “diarrhoeal disease is the second most common contributor to the disease burden in developing countries (as measured by disability-adjusted life years (DALYs)), and poor-quality drinking water is an important risk factor for diarrhoea.” [6]

Diarrhoeal disease in the developing world – the second most common contributor to disease in these countries, afflicting half of their population – has nothing to do with thought.  It’s related to the provision of toilets and clean running water.

We live in a society that prevents half of our illnesses because of internal plumbing.  Thoughts seem to significantly contribute to disease because most of our potential illness is prevented by our clean water and sewerage systems.  Remove those factors and thought would no longer appear to be so significant.

In the same manner, modern medicine has become so good at preventing diseases that thought may seem to be a major contributor, when in actual fact, most of the work in keeping us all alive has nothing to do with our own thought processes.  Like sanitation and clean water, the population wide practices of vaccination, and health screening such as pap smears, have also significantly reduced the impact of preventable disease.

Around the world, “Recent estimates of the global incidence of disease suggest that communicable diseases account for approximately 19% of global deaths” and that “2.5 million deaths of children annually (are) from vaccine-preventable diseases.” [7] Again, that’s a lot of deaths that are not related to thought life.

Since 1932, vaccinations in Australia have reduced the death rate from vaccine-preventable diseases by 99% [8].  Epidemiological evidence shows that when vaccine rates increase, sickness from communicable diseases decrease [9: Fig 2, p52 & Fig 8, p67].

Population based screening has also lead to a reduction in disease and death, especially in the case of population screening by pap smears for cervical cancer.  Canadian public health has some of the best historical figures on pap smear screening and cervical cancer. In Canada, as the population rate of pap smear screening increased, the death rate of women from cervical cancer decreased.  Overall, pap smear screening decreased the death rate from cervical cancer by 83%, from a peak of 13.5/100,000 in 1952 to only 2.2/100,000 in 2006, despite an increase in the population and at-risk behaviours for HPV infection (the major risk factor for cervical cancer) [10].

And around the world, the other major cause of preventable death is death in childbirth.  The risk of a woman dying in childbirth is a staggering one in six for countries like Afghanistan [11] which is the same as your odds playing Russian Roulette.  That’s compared to a maternal death rate of one in 30,000 in countries like Sweden.  The marked disparity is not related to the thought life of Afghani women in labour.  Countries that have a low maternal death rate all have professional midwifery care at birth.  Further improvements occur because of better access to hospital care, use of antibiotics, better surgical techniques, and universal access to the health system [11].  Again, unless one’s thought life directly changes the odds of a midwife appearing to help you deliver your baby, toxic thoughts are irrelevant as a cause of illness and death.

Unfortunately for Dr Leaf, her statement that “75 to 98 percent of mental, physical and behavioural illnesses come from toxic thoughts” is a myth, a gross exaggeration of the association of stress and illness.

In the global and historical context of human health, the majority of illness is caused by infectious disease, driven by a lack of infrastructure, public health programs and nursing and medical care.  To us in the wealthy, resource-rich western world, it may seem that our thought life has a significant effect on our health.  That’s only because we have midwives, hospitals, public health programs and internal plumbing, which stop the majority of death and disease before they have a chance to start.

Don’t worry about toxic thoughts.  Just be grateful for midwives and toilets.

References

1.         Leaf, C.M., Switch On Your Brain : The Key to Peak Happiness, Thinking, and Health. 2013, Baker Books, Grand Rapids, Michigan:

2.         FMRC. Public BEACH data. 2010  [cited 16JUL13]; Available from: <http://sydney.edu.au/medicine/fmrc/beach/data-reports/public%3E.

3.         World Health Organization, GLOBAL HEALTH ESTIMATES SUMMARY TABLES: DALYs by cause, age and sex, GHE_DALY_Global_2000_2011.xls, Editor 2013, World Health Organization,: Geneva, Switzerland.

4.         Mara, D., et al., Sanitation and health. PLoS Med, 2010. 7(11): e1000363 doi: 10.1371/journal.pmed.1000363

5.         Bartram, J. and Cairncross, S., Hygiene, sanitation, and water: forgotten foundations of health. PLoS Med, 2010. 7(11): e1000367 doi: 10.1371/journal.pmed.1000367

6.         Hunter, P.R., et al., Water supply and health. PLoS Med, 2010. 7(11): e1000361 doi: 10.1371/journal.pmed.1000361

7.         De Cock, K.M., et al., The new global health. Emerg Infect Dis, 2013. 19(8): 1192-7 doi: 10.3201/eid1908.130121

8.         Burgess, M., Immunisation: A public health success. NSW Public Health Bulletin, 2003. 14(1-2): 1-5

9.         Immunise Australia, Myths and Realities. Responding to arguments against vaccination, A guide for providers. 5th ed. 2013, Commonwealth of Australia, Department of Health and Ageing, Canberra:

10.       Dickinson, J.A., et al., Reduced cervical cancer incidence and mortality in Canada: national data from 1932 to 2006. BMC Public Health, 2012. 12: 992 doi: 10.1186/1471-2458-12-992

11.       Ronsmans, C., et al., Maternal mortality: who, when, where, and why. Lancet, 2006. 368(9542): 1189-200 doi: 10.1016/S0140-6736(06)69380-X

Dr Caroline Leaf – Contradicted by the latest research

This is my most popular post by far.  I truly appreciate the support and interest in this post, but I’ve discovered and documented a lot more about Dr Leaf’s ministry in the last two years.  I welcome you to read this post, but if you’d like a more current review of the ministry of Dr Caroline Leaf, a new and improved version is here:
Dr Caroline Leaf – Still Contradicted by the Latest Evidence, Scripture & Herself

* * * * *

Mr Mac Leaf, the husband of Dr Caroline Leaf, kindly took the time to respond to my series of posts on the teachings of Dr Leaf at Kings Christian Centre, on the Gold Coast, Australia, earlier this month. As I had intended, and as Mr Leaf requested, I published his  reply, complete and unabridged (here).

This blog is my reply.  It is heavily researched and thoroughly referenced.  I think it’s fair to say that while Dr Leaf draws her conclusions from some scientific documents, there is more than enough research that contradicts her statements and opinions.  I have only listed a small fraction, and only on some of the points she raised.

In fairness, the fields of neurology and neuroscience are vast and rapidly expanding, and it is impossible for one person to cover all of the literature on every subject.  This applies to myself and Dr Leaf.  However, I believe that the information I have read, and referenced from the latest peer-reviewed scholarly works, do not support Dr Leaf’s fundamental premises.  If I am correct, then the strength and validity of Dr Leaf’s published works should be called into question.

As before, I welcome any reply or rebuttal that Dr Leaf wishes to make, which I will publish in full if she requests.  In the interests of healthy public debate, and encouraging people to make their own informed decisions on the teachings of Dr Leaf, any comments regarding the response of Mr Leaf, Dr Leaf or myself, are welcome provided they are constructive.

This is a bit of a lengthy read, but I hope it is worthwhile.

Dear Mr Leaf,

Thank you very much for taking the time out to reply to some of the points raised in my blog.  I am more than happy to publish your response, and to publish any response you wish to make public.

ON INFORMED DECISIONS

I published my blog posts to open up discussion on the statements made by Dr Leaf at the two meetings that I attended at Kings Christian Centre on the Gold Coast.  As you rightly point out, people should be able to make informed decisions.  A robust discussion provides the information required for people to make an informed choice.  Any contributions to this discussion from either yourself or Dr Leaf would be most welcome.

I apologise if you interpreted my blogs as judgemental, or if you believe there are any misunderstandings.  You may or may not have read my final two paragraphs from the third post, in which I acknowledged that I may have misunderstood where she was coming from, but that I would welcome her response.  If there were any misunderstandings, it is likely because Dr Leaf did not make any attempt to reference any of the statements she made on the day.  You may argue that she was speaking to a lay audience, and referencing is therefore not necessary.  However, I have been to many workshops for the lay public by university professors, who have extensively referenced their information during their presentations.  A lay audience does not preclude providing references.  Rather, it augments the speakers authority and demonstrates the depth of their knowledge on the subject at hand.

YOUR DEFENCE

It’s interesting that you feel the need to resort to defence by association, and Ad Hominem dismissal as your primary counter to the points I raised.

Can you clarify how attending the same university as Dr Christaan Barnard, or a Nobel laureate, endorses her arguments or precludes her from criticism?  I attended the University of Queensland where Professor Ian Frazer was based.  He developed the Human Papilloma Virus vaccine and was the 2006 Australian of the Year.  Does that association enhance my argument?

Can you also clarify why a reference from a colleague was preferred to letting Dr Leaf’s statements and conclusions speak for themselves?  Dr Amua-Quarshie’s CV is certainly very impressive, no doubt about that, although he doesn’t list the papers he’s published.  (I’m assuming that to hold the title of Adjunct Professor, he’s published peer-reviewed articles.  Is he willing to list them, for the record?)

Whatever his credentials, his endorsement means very little, since both Dr Leaf and Dr Amua-Quarshie would know from their experience in research that expert opinion is one of the lowest forms of evidence, second worst only to testimonials [1].  Further, both he and Dr Leaf are obviously close friends which introduces possible bias.  His endorsement is noteworthy, but it can not validate every statement made by Dr Leaf.  Her statements should stand up on their own through the rigors of critical analysis.

On the subject of evidence, disparaging your critics is not a substitute for answering their criticism.  Your statement, “By your comments it is obvious that you have not kept up to date with the latest Scientific research” is an assumption that is somewhat arrogant, and ironic since Dr Leaf is content to use superseded references dating back to 1979 to justify her current hypotheses.

DR LEAF’S EVIDENCE

In the blog to which you referred, Dr Leaf makes a number of statements that are intended to support her case.  These include the following.

“A study by the American Medical Association found that stress is a factor in 75% of all illnesses and diseases that people suffer from today.”  She fails to reference this study.

“The association between stress and disease is a colossal 85% (Dr Brian Luke Seaward).”   But again, she fails to reference the quote.

“The International Agency for Research on Cancer and the World Health Organization has concluded that 80% of cancers are due to lifestyles and are not genetic, and they say this is a conservative number (Cancer statistics and views of causes Science News Vol.115, No 2 (Jan.13 1979), p.23).”  It’s good that she provides a reference to her statement.  However, referencing a journal on genetics from 1979 is the equivalent of attempting to use the land-speed record from 1979 to justify your current preference of car.  The technology has advanced significantly, and genetic discoveries are lightyears ahead of where they were more than three decades ago.

“According to Dr Bruce Lipton (The Biology of Belief, 2008), gene disorders like Huntington’s chorea, beta thalassemia, cystic fibrosis, to name just a few, affect less than 2% of the population. This means the vast majority of the worlds population come into this world with genes that should enable the to live a happy and healthy life. He says a staggering 98% of diseases are lifestyle choices and therefore, thinking.”  Even if it’s true that Huntingtons, CF etc account for 2% of all illnesses, they account for only a tiny fraction of genetic disease.  And concluding that the remaining 98% must therefore be lifestyle related is overly simplistic.  It ignores the genetic influence on all other diseases, other congenital, and environmental causes of disease.  I will fully outline this point soon.

Similarly, “According to W.C Willett (balancing lifestyle and genomics research for disease prevention Science (296) p 695-698, 2002) only 5% of cancer and cardiovascular patients can attribute their disease to hereditary factors.”  Science is clear that genes play a significant role in the development of cardiovascular disease and most cancers, certainly greater than 5%.  Again, I will discuss this further soon.

“According to the American Institute of health, it has been estimated that 75 – 90% of all visits to primary care physicians are for stress related problems (http://www.stress.org/americas.htm). Some of the latest stress statistics causing illness as a result of toxic thinking can be found at: http://www.naturalwellnesscare.com/stress-statistics.html”  These websites not peer-reviewed, and both suffer from a blatant pro-stress bias.

You’ll also have to forgive my confusion, but Dr Leaf also wrote, “Dr H.F. Nijhout (Metaphors and the Role of Genes and Development, 1990) genes control biology and not the other way around.”  So is she saying that genes DO control development?

EVIDENCE CONTRADICTING DR LEAF

Influence Of Thought On Health

Dr Leaf has categorically stated that “75 to 98% of all illnesses are the result of our thought life” on a number of occasions.  She repeated the same statement in her most recent book so it is something she is confident in.  However, in order to be true, this fact must be consistent across the whole of humanity.

And yet, in a recent peer-reviewed publication, Mara et al state, “At any given time close to half of the urban populations of Africa, Asia, and Latin America have a disease associated with poor sanitation, hygiene, and water.” [2]  Bartram and Cairncross write that “While rarely discussed alongside the ‘big three’ attention-seekers of the international public health community—HIV/AIDS, tuberculosis, and malaria—one disease alone kills more young children each year than all three combined. It is diarrhoea, and the key to its control is hygiene, sanitation, and water.” [3]  Hunter et al state that, “diarrhoeal disease is the second most common contributor to the disease burden in developing countries (as measured by disability-adjusted life years [DALYs]), and poor-quality drinking water is an important risk factor for diarrhoea.” [4]

Toilets and clean running water have nothing to do with stress or thought.  We live in a society that essentially prevents more than half of our illnesses because of internal plumbing, with additional benefits from vaccination and population screening.  If thoughts have any effect on our health, they are artificially magnified by our clean water and sewerage systems.  Remove those factors and any effects of thought on our health disappear from significance.  Dr Leaf’s assertion that 75 to 98% of human illness is thought-related is a clear exaggeration.

Let me be clear – I understand the significance of stress on health and the economy, but it is not the cause of 75-98% of all illnesses.  I’m not sure if there is a similar study in the US, but the latest Australian data suggests that all psychological illness only counts for 8% of visits to Australian primary care physicians [5].

In terms of cancer, I don’t have time to exhaustively list every cancer but of the top four listed in the review “Cancer Statistics 2013” [6] , here are the articles that list the gene x environment interactions:

  1. PROSTATE – There are only two risk factors for prostate cancer, familial aggregation and ethnic origin. No dietary or environmental cause has yet been identified [7].  It is most likely caused by multiple genes at various loci [8].
  2. BREAST – Genes make up 25% of the risk factors for breast cancer, and significantly interacted with parity (number of children born) [9].
  3. LUNG/BRONCHUS – Lung cancer is almost exclusively linked to smoking, but nicotine addiction has a strong hereditary link (50-75% genetic susceptibility) [10].
  4. COLORECTUM – Approximately one third of colorectal cancer is genetically linked [11].

So the most common cancer is not linked to any environmental factors at all, and the others have genetic influences of 25% to more than 50%.  This is far from being 2% or 5% as Dr Leaf’s sources state.

Also in terms of heart disease, the INTERHEART trial [12] lists the following as significant risk factors, and I have listed the available gene x environment interaction studies that have been done on these too:

  1. HIGH CHOLESTEROL – Genetic susceptibility accounts for 40-60% of the risk for high cholesterol [13].
  2. DIABETES – Genetic factors account for 88% of the risk for type 1 diabetes [14].  There is a strong genetic component of the risk of type 2 diabetes with 62-70% being attributable to genetics [15, 16].
  3. SMOKING – nicotine addiction has a strong hereditary link (50-75% genetic susceptibility) [10].
  4. HYPERTENSION – While part of a much greater mix of variables, genetics are still thought to contribute between 30% and 50% to the risk of developing high blood pressure [17].

So again, while genes are a part of a complex system, it is clear from the most recent evidence that genetics account for about 50% of the risk for cardiovascular disease, which again is a marked difference between the figures that Dr Leaf is using to base her assertions on.

Atrial Natriuretic Peptide

I am aware of research that’s studied the anxiolytic properties of Atrial Natriuretic Peptide.  For example, Wiedemann et al [18] did a trial using ANP to truncate panic attacks.  However, these experiments were done on only nine subjects, and the panic attacks were induced by cholecystokinin.  As such, the numbers are too small to have any real meaning.  And the settling is completely artificial.  Just as CCK excretion does not cause us all to have panic attacks every time we eat, ANP does not provide anxiolysis in normal day to day situations.  Besides, if ANP were really effective at reducing anxiety, then why do people suffering from congestive cardiac failure, who have supraphysiological levels of circulating ANP [19] , also suffer from a higher rate of anxiety and panic disorders than the general population? [20]

The Heart As A Mini-Brain

As for Heartmath, they advance the notion of the heart being a mini-brain to give themselves credibility.  It’s really no different to an article that I read the other day from a group of gut researchers [21] – “‘The gut is really your second brain,’ Greenblatt said. ‘There are more neurons in the GI tract than anywhere else except the brain.’”  The heart as a mini-brain and the gut as a mini-brain are both figurative expressions.  Neither are meant to be taken literally.  I welcome Dr Leaf to tender any further evidence in support of her claim.

Hard-Wired For Optimism

As for being wired for optimism, the brain is likely pre-wired with a template for all actions and emotions, which is the theory of protoconsciousness [22].  Indeed, neonatal reflexes often reflect common motor patterns.  If this is true, then the brain is pre-wired for both optimism and love, but also fear.  This explains the broad role of the amygdala in emotional learning [23] including fear learning.  It also means that a neonate needs to develop both love and fear.

A recent paper showed that the corticosterone response required to learn fear is suppressed in the neonate to facilitate attachment, but with enough stress, the corticosterone levels build to the point where amygdala fear learning can commence [24].  The fear circuits are already present, only their development is suppressed.  Analysis of the cohort of children in the Bucharest Early Intervention Project showed that negative affect was the same for both groups.  However positive affect and emotional reactivity was significantly reduced in the institutionalised children [25].  If the brain is truly wired for optimism and only fear is learned, then positive emotional reactivity should be the same in both groups and the negative affect should be enhanced in the institutionalised cohort.  That the result is reversed confirms that neonates and infants require adequate stimulation of both fear and love pathways to grow into an emotionally robust child, because the brain is pre-wired for both but requires further stimulation for adequate development.

The Mind-Brain Link

If the mind controls the brain and not the other way around as Dr Leaf suggests, why do anti-depressant medications correct depression or anxiety disorders?  There is high-level evidence to show this to be true [26-28].  The same can be said for recent research to show that medications which enhance NDMA receptors have been shown to improve the extinction of fear in anxiety disorders such as panic disorder, OCD, Social Anxiety Disorder, and PTSD [29].

If the mind controls the brain and not the other way around as Dr Leaf suggests, why do some people with acquired brain injuries or brain tumours develop acute personality changes or thought disorders?  Dr Leaf has done PhD research on patients with closed head injuries and treated them in clinical settings according to her CV.  She must be familiar with this effect.

One can only conclude that there is a bi-directional effect between the brain and the stream of thought, which is at odds with Dr Leaf’s statement that the mind controls the brain and not the other way around.

FURTHER CLARIFICATION

One further thing.  Can you clarify which of Dr Leaf’s peer-reviewed articles have definitively shown the academic improvement in the cohort of 100,000 students, as you and your referee have stated?  And can you provide a list of articles which have cited Dr Leaf’s Geodesic Information Processing Model?  Google Scholar did not display any articles that had cited it, which must be an error on Google’s part.  If her theory is widely used as you say, it must have been extensively cited.

I understand that you are both busy, but I believe that I have documented a number of observations, backed by recent peer-reviewed scientific literature, which directly contradict Dr Leaf’s teaching.  I have not had a chance to touch on many, many other points of disagreement.

For the benefit of Dr Leaf’s followers, and for the scientific and Christian community at large, I would appreciate your response.

I would be grateful if you could respond to the points raised and the literature which supports it, rather than an Ad Hominem dismissal or further defense by association.

Dr C. Edward Pitt

REFERENCES

1. Fowler, G., Evidence-based practice: Tools and techniques. Systems, settings, people: Workforce development challenges for the alcohol and other drugs field, 2001: 93-107.

2. Mara, D., et al., Sanitation and health. PLoS Med, 2010. 7(11): e1000363.

3. Bartram, J. and Cairncross, S., Hygiene, sanitation, and water: forgotten foundations of health. PLoS Med, 2010. 7(11): e1000367.

4. Hunter, P.R., et al., Water supply and health. PLoS Med, 2010. 7(11): e1000361.

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