Summary: Cognitive decline begins early in life with accelerated neurodegeneration. Take realistic steps now to protect brain health.

A study just published in The Lancet offers evidence that cognitive decline starts becoming apparent as early as age 45. The authors set out to…

“…estimate 10 year decline in cognitive function from longitudinal data in a middle aged cohort and to examine whether age cohorts can be compared with cross sectional data to infer the effect of age on cognitive decline.”

They assessed 5,198 men and 2,192 women, aged 45-70 at the beginning of cognitive testing in 1997-9 for memory, reasoning, vocabulary, and phonemic and semantic fluency three times over 10 years. Their data confirm an early loss of cognitive function:

“All cognitive scores, except vocabulary, declined in all five age categories (age 45-49, 50-54, 55-59, 60-64, and 65-70 at baseline), with evidence of faster decline in older people. In men, the 10 year decline, shown as change/range of test×100, in reasoning was −3.6% in those aged 45-49 at baseline and −9.6% in those aged 65-70. In women, the corresponding decline was −3.6% and −7.4%.”

A strategy to protect brain health begins with finding out the individual’s specific needs according to the biological basics. Fundamentals that apply equally to adults are listed in the Parents’ Guide To Brain Health. The authors conclude with the important observation:

“Cognitive decline is already evident in middle age (age 45-49).”

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Summary: cholesterol plays critical roles in cell membranes and steroid hormone production. This study associates low LDL cholesterol with worse cognitive performance. As expected, the effect is amplified by inflammation. Care should be taken to apply a balanced approach to cholesterol lowering therapies.

A truly fascinating study was just published in the journal Neurobiology of Aging investigating lipoproteins and loss of cognitive function. The authors state:

“The aim of this study was to examine the associations between high-density lipoprotein (HDL) and low-density lipoprotein (LDL) cholesterol, triglycerides, and cognition and focus on the modifying effect of inflammation.”

They collected biological and cognitive data on 1003 persons ≥ 65 years of age over 6 years of follow-up, measuring cognition with the Mini-Mental State Examination (general cognition), Auditory Verbal Learning Test (memory), and Coding Task (information processing speed). High HDL was associiated with better memory performance, but their data seem to suggest the importance of sufficient LDL cholesterol in brain neuronal membranes:

“We found an independent association between high HDL cholesterol and better memory performance. In addition, low LDL cholesterol was predictive of worse general cognitive performance and faster decline on information processing speed.”

Not at all surprisingly they found that inflammation compounds the adverse effects of low LDL:

“Furthermore, a significant modifying effect of inflammation (C-reactive protein, α-antichymotrypsin) was found. A negative additive effect of low LDL cholesterol and high inflammation was found on general cognition and memory performance.”

And since high triglycerides are commonly provoked by the high insulin levels due to insulin resistance which also have deleterious effects on the brain…

“Also, high triglycerides were associated with lower memory performance in those with high inflammation.”

The authors conclude by suggesting that HDL, LDL and inflammatory indicators can be used as predictors of poor cognitive function:

“Thus, a combination of these factors may be used as markers of prolonged lower cognitive functioning.”

This compels us to use caution and see the ‘big picture’ when designing strategies to manage lipids—care should be taken to not suppress LDL cholesterol to too low a level.

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Summary: Neuroinflammatory signaling molecules are elevated in bipolar disorder patients compared to controls. Marked increases in proinflammatory cytokines are also observed in the brains of teen suicide victims. Brain inflammation, immune system dysregulation and the loss of self-tolerance are key factors in the management of BP and major depression.

A paper just published in the Journal of Psychiatric Research offers further evidence for the role of neuroinflammation resulting from immune system dysregulation in bipolar disorder. The authors state:

“Bipolar disorder (BD) is associated with considerable higher chronic medical comorbidities, overweight and obesity. Adipokines are adipocyte-derived secretory factors which have functions in immune response and seem to be associated with both BD and overweight. The aim of this study was to evaluate the plasma levels of adipokines (adiponectin, resistin and leptin) and TNF-α and its receptors (sTNFR1 and sTNFR2) in BD overweight patients in comparison with overweight controls.”

The authors measured plasma levels of adiponectin, resistin, leptin, TNF-α and TNF-α soluble receptors in thirty bipolar patients along with thirty controls matched by age, gender and body-mass index (BMI). The subjects were also assessed by Mini-International Neuropsychiatric Interview, Young Mania and Hamilton Depression rating scales. What did the data show?

“BD patients presented increased plasma levels of adiponectin, leptin and sTNFR1.”

This is but one drop in a sea of emerging evidence for the role of brain inflammation and immune dysregulation in neuropsychiatric disorders that clinicians should consider in comprehensive case management. The authors conclude:

“This study provides further support to the hypothesis of the immune/inflammatory imbalance in BD.”

Another study in the same journal documents a marked increase in proinflammatory cytokines in the frontal lobes of teenagers attempting suicide. The authors observe:

“”Proinflammatory cytokines play an important role in stress and in the pathophysiology of depression—two major risk factors for suicide. Cytokines are increased in the serum of patients with depression and suicidal behavior; however, it is not clear if similar abnormality in cytokines occurs in brains of suicide victims.”

So they evaluated 24 teenage suicide victims and 24 matched normal control subjects for gene and protein expression levels of the proinflammatory cytokines interleukin (IL)-1β, IL-6, and tissue necrosis factor (TNF)-α in the prefrontal cortex (PFC). Again we see the markers for brain inflammation:

“Our results show that the mRNA and protein expression levels of IL-1β, IL-6, and TNF-α were significantly increased in Brodmann area 10 (BA-10) of suicide victims compared with normal control subjects.”

This is the deepest biological expression of the loss of self-tolerance in these disorders. Autoimmune inflammatory conditions require evaluation of all the known underlying causal factors that may contribute to the loss of self and chemical tolerance in order to design the most helpful treatment plan. The authors conclude:

“These results suggest an important role for IL-1β, IL-6, and TNF-α in the pathophysiology of suicidal behavior and that proinflammatory cytokines may be an appropriate target for developing therapeutic agents.”

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Summary: The use of selective serotonin reuptake inhibitors (SSRIs, such as Prozac®, Celexa®, Lexapro®, Luvox® and Paxil®) taken during pregnancy—especially the first trimester—appears to increase the risk of autism spectrum disorders. There are evidence-based alternatives to SSRIs that support brain health without putting the fetus at risk.

A study recently published in the journal Archives of General Psychiatry draws attention to a risk of autism spectrum disorders (ASDs) born to mothers who took SSRI antidepressants during their pregnancy. The authors observe:

“The prevalence of autism spectrum disorders (ASDs) has increased over recent years. Use of antidepressant medications during pregnancy also shows a secular increase in recent decades, prompting concerns that prenatal exposure may contribute to increased risk of ASD.”

Therefore they set out to…

“…systematically evaluate whether prenatal exposure to antidepressant medications is associated with increased risk of ASD.”

In order to do so they compared the data for 298 children with ASD to 1507 randomly selected control children, along with the data for both their mothers. Their findings support a cautionary approach to the prenatal use of SSRIs:

“Prenatal exposure to antidepressant medications was reported for 20 case children (6.7%) and 50 control children (3.3%). In adjusted logistic regression models, we found a 2-fold increased risk of ASD associated with treatment with selective serotonin reuptake inhibitors by the mother during the year before delivery (adjusted odds ratio, 2.2), with the strongest effect associated with treatment during the first trimester (adjusted odds ratio, 3.8).”

In other words, the increase in risk for the whole year before delivery was 220%, but limiting the investigation to the first trimester it was 380%. Interestingly…

“No increase in risk was found for mothers with a history of mental health treatment in the absence of prenatal exposure to selective serotonin reuptake inhibitors.”

Meaning that it wasn’t a history of mental health treatment the year before delivery but specifically the use of SSRIs that accounted for the increased risk of ASDs. The authors conclude:

“Although the number of children exposed prenatally to selective serotonin reuptake inhibitors in this population was low, results suggest that exposure, especially during the first trimester, may modestly increase the risk of ASD. The potential risk associated with exposure must be balanced with the risk to the mother or fetus of untreated mental health disorders.”

This would be a troubling dilemma were it not for the fact that therapies supporting brain health are available to treat depression. Serotonin production and signaling, when indicated, can be supported in a physiological and sustainable manner that promotes the brain health of mother and fetus. A categorization and description of key resources that applies to adults as well as children is available in the Parents’ Guide To Brain Health.

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Summary: chronic inflammation due to immune system dysregulation, with or without a diagnosed autoimmune disease, plays a fundamental role in chronic depression. This offers sustainable and evidence-based treatments for depression and brain health.

The authors of an important paper published in Current Immunology Reviews state:

…current antidepressants do not effectively target all of the pathological processes that are responsible for the major symptoms of depression…However, in recent years greater attention has been directed to the inter-relationship between the brain and peripheral organs (the” body-mind” connection) in which changes in the endocrine and immune systems play a major role in the pathological changes that occur in depression. Thus inflammation is beginning to emerge as a major contributing factor not only to depression and other major psychiatric disorders…”

Two major ways that immune dysfunction promotes depression are emphasized: the direct effect of inflammation on the brain, and the brain effects of the hormonal response to inflammation. Regarding the former:

“…in the past 30 years or so that clinical and experimental evidence has been obtained clearly demonstrating that aspects of both cellular and humoral immunity were dysfunctional in major depression…in particular the pro- and anti-inflammatory cytokines…Such clinical observations suggest that proinflammatory cytokines contribute to the major symptoms of depression and now forms the basis of the inflammation, cytokine or inflammatory response hypothesis of depression.”

It’s now known that peripherally derived inflammatory cytokines have access to the brain, including areas involved in depression…

“Once in the brain, the proinflammatory cytokines activated both neuronal and non-neuronal (for example, the microglia, astrocytes and oligodendroglia) cells via the nuclear factor-kappa-beta (NF-kB) cascade in a similar manner to that occurring in the peripheral inflammatory response…

Also, the production of serotonin and dopamine is adversely affected by inflammation:

“Recently much attention has been paid to the activation of the tryptophan-kynurenine pathway by these cytokines whereby tryptophan is shunted from the synthesis of serotonin to that of kynurenine…clearly this is an important mechanism whereby serotonergic function is decreased in depression. The activity of the dopaminergic system is also reduced in response to inflammation. For example, IFN reduces the synthesis of dopamine by decreasing the concentration of the co-factor tetrahydrobiopterin (BH4)…As IFN increases the synthesis of nitric oxide by activating the BH4 dependent enzyme nitric oxide synthase in the microglia it seems likely that the reduction in dopaminergic function is linked to the increase in nitric oxide. This gaseous neurotransmitter is known to activate the glutamatergic system which, when this exceeds physiologically limits, enhances apoptosis and neurodegeneration.”

In other words, an increase in inflammatory cytokines derails the production of serotonin and dopamine, and activates the excitatory (glutamatergic) system to the point of cell death.

Additionally, proinflammatory cytokines activate the HPA (hypothalamo-pituitary-adrenal) axis causing excessive cortisol production which is lethal to brain cells at high levels…

“In addition to the modulation of neurotransmitter function, proinflammatory cytokines contribute to the major symptoms of depression by activating the HPA axis by increasing the release of CRF, thereby contributing to hypercortisolaemia, a feature of major depression. The mechanism whereby the cytokines induce hypercortisolaemia involves a decreased sensitivity of the glucocorticoid receptors thereby leading to glucocorticoid resistance…”

The inflammation model also sheds light on the role of stress in depression:

“…as major depression is often accompanied by inflammatory diseases (such as irritable bowel syndrome, type 2 diabetes, arthritis and autoimmune disorders) that can activate the peripheral and central inflammatory response, it is possible that such inflammatory disorders initiate the inflammatory changes that precipitate depression….[But] it is evident that inflammation also occurs in depressed patients who are not suffering from concurrent inflammatory disorders. Thus the increased vulnerability of depressed patients to psychosocial stress is probably the key factor that leads to the activation of the immune and endocrine axes in depression. It is known, for example, that even the relatively mild acute stress of public speaking causes an increase in NF-kB activity, a key element in the induction of the inflammatory cascade. In this regard, it is also known that patients with major depression frequently show an enhanced responsiveness of IL-6 and NF-kB to an antigen challenge…such changes appear to be associated with activation of the microglia thereby suggestion that the inflammatory changes are also occurring in the brain.”

In other words, patients with major depression have a more pronounced inflammatory response to substances to which they are sensitized or allergic to (antigens). This is in addition to an increased immune and hormonal response to psychosocial stress.

Of special significance for the use of heart rate variability analysis for evaluation of the autonomic nervous system and therapies that increase parasympathetic tone…

“The mechanism whereby psychological stress influences both the peripheral and central inflammatory cascade is co-ordinated by the autonomic nervous system. Thus the release of noradrenaline and adrenaline following the activation of the sympathetic system results in the activation of both alpha and beta adrenoceptors on immune cells thereby initiating the release of proinflammatory cytokines, via the activation of the NF-kB cascade, particularly on macrophages and monocytes in peripheral blood…Conversely stimulation of the parasympathetic system has the opposite effect on the stress induced inflammatory response…It is possible that the anti-depressant-like action of vagal nerve stimulation, occasionally used to treat resistant depression, is associated with such an anti-inflammatory action.”

Brain inflammation associated with depression actually causes the death of brain cells (apoptosis):

“Thus in major depression, the prolonged activation of the inflammatory network in the brain results in a decrease in neurotrophins, leading to reduced neuronal repair, a decrease in neurogenesis, and an increased activation of the glutamatergic pathway that contributes to neuronal apoptosis, oxidative stress and the induction of apoptosis in astrocytes and oligodendrocytes.”

On top of all this, inflammation causes the biochemical pathway that produces serotonin from tryptophan to converted to the production of neurotoxins instead through the tryptophan-kynurenine pathway and the production of quinolinic acid.

“As both the cytokines and cortisol are raised in major depression, it is not surprising to find that the tryptophan-kynurenine pathway is increased….Kynurenine hydroxylase metabolises kynurenine first to 3-hydroxykynurenine and then to 3-hydroxyanthranilic acid and quinolinic acid. This pathway is increased in depression and dementia…In chronic depression…the activated microglia produce an excess of the neurotoxin…Furthermore quinolinic acid can cause apoptosis of the astrocytes. This results in a reduction in the metabolic and physical buffer to the neurons that is usually provided by the astrocytes and thereby further exposes the neurons to the neurodegenerative actions of quinolinic acid.”

Inflammation in the brain over the long term causes neurodegeneration that appear as brain shrinkage:

“The structural changes observed in the brain of patients with chronic depression lends support to the neurodegenerative hypothesis of depression. It is known that there is a shrinkage of the hippocampus in patients with major depression and a decrease in the number of astrocytes and a neuronal loss in the prefrontal cortex and in the striatum. Such changes could be the consequence of chronic low grade inflammation in which the proinflammatory cytokines, nitric oxide, prostaglandin E2 and other inflammatory mediators play key roles; the cytokines are known to induce the cyclo-oxygenase and nitric oxide sythase pathways in the brain and thereby increase the inflammatory insult. The inhibition of neurotrophin synthesis in the brain by glucocorticoids, and the neurotoxic action of quinolinic acid, add further to the impact of the inflammatory changes.”

There are indications that patients who respond poorly to neurotransmitter-manipulating medications have markers for increased inflammation:

“Further evidence for the relationship between inflammation and depression is provided by the observation that depressed patients with a history of partial or lack of response to antidepressant treatments have elevated plasma concentrations of IL-6 and acute phase proteins that persist despite antidepressant treatment. It has been suggested that patients who are resistant to conventional antidepressant treatment possess abnormal alleles of the IL-1 and TNF genes, and possibly for T-cell function.”

Moreover, even when there is some relief from a depressed mood or anxiety with these medications…

“…there is abundant clinical evidence that the available antidepressants…are far less effective in treating the memory and cognitive dysfunction (fatigue, psychomotor retardation) that commonly affect middle aged and elderly depressed patients.”

There is mounting evidence that modulating inflammation can improve the inflammatory response:

“There are already indications from the clinical literature that TNF antagonists…reduce the symptoms of depression in a variety of patients with autoimmune diseases…the mood state of the patients improving before the signs of improvement of the autoimmune disorder…IL-10, and insulin-like growth factor that has prominent anti-inflammatory activity, have been shown to attenuate the depressive-like behaviour in rodents induced by an inflammatory challenge.”

IL-10 is increased by correcting suboptimal levels of vitamin D.

“Perhaps the most obvious step to the reduction of inflammation both centrally and peripherally is to reduce the activity of the prostenoid pathway and thereby reduce the synthesis of inflammatory prostaglandins such as PGE2.”

This is exactly what is accomplished by correcting an omega-3 fatty acid deficiency with a low 3:6 ratio.

The best chance for a sustainable program for helping depression by treating the inflammation is to determine with the appropriate tests why the excessive inflammation is happening in the first place. Then physiological and sustainable treatments can address those underlying causes properly. That brings up the very large topic of the functional management of autoimmune disease and chronic inflammation, a subject of many posts here and deserving of a weighty textbook. See posts forthcoming in the next week on the role of gastrointestinal inflammation as a contributing cause and treatment target for depression and the effectiveness of the omega-3 fatty acid EPA as a PGE2 reducer for depression.

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Summary: chronic low-grade inflammation is both a damaging result of and a fundamental cause promoting obesity. Management of both weight loss programs and the medical complications of obesity should address the inflammatory component.

An important paper was recently published in the Journal of Clinical Investigation that discusses the role of inflammation in obesity, obesity-related disorders, and metabolic dysfunction. The chronic inflammatory response associated with obesity is has been termed metainflammation:

“Over the past decade, the search for a potential unifying mechanism behind the pathogenesis of obesity-associated diseases has revealed a close relationship between nutrient excess and derangements in the cellular and molecular mediators of immunity and inflammation. This has given birth to the concept of “metainflammation” to describe the chronic low-grade inflammatory response to obesity.”

The authors describe characteristics of the metainflammation of obesity:

“The chronic nature of obesity produces a tonic low-grade activation of the innate immune system that affects steady-state measures of metabolic homeostasis over time. Childhood obesity may place individuals at risk for lifelong metainflammation, since inflammatory markers are elevated in obese children as young as 3 years old. Superimposed on this chronic inflammation are recurrent acute episodes of nutrition-related immune activation induced by nutrient availability (fasting or high-fat meals)…Non-biased assessments of gene expression networks in adipose tissue identify a robust pattern of overexpressed inflammatory genes associated with obesity and metabolic disease and enriched for macrophage genes…While transient inflammatory states such as sepsis can have multi-organ effects, few other chronic inflammatory diseases are characterized by the features of pancreatic, liver, adipose, heart, brain, and muscle inflammation as is seen in obesity.”

Importantly, inflammation itself induces insulin resistance that further promotes obesity:

“Multiple inflammatory inputs contribute to metabolic dysfunction, including increases in circulating cytokines, decreases in protective factors (e.g., adiponectin), and communication between inflammatory and metabolic cells. For example, direct and paracrine signals from M1 classically activated macrophages can impair insulin signaling and adipogenesis in adipocytes…Similar effects on adipocyte inflammation and glucose transport are generated by signals from activated conventional T cells such as IFN-γ. In parallel, dysregulated macrophage-myocyte and macrophage-hepatocyte signaling can influence insulin sensitivity.”

They discuss the fascinating observation that obesity is associated with an imbalance of immune regulation characterized by the dominance of Th1 (cell-mediated, with a classical proinflammatory macrophage activation state = M1) over Th2 (antibod-mediated, M2) immune inflammatory activity:

“While ATMs [adipose tissue macrophages] likely assume a number of states along the M1/M2 spectrum depending on fat depot location and nutritional status, increasing adiposity results in a shift in the inflammatory profile of ATMs as a whole from an M2 state to one in which classical M1 proinflammatory signals predominate.”

Most importantly there are a number points where we may intervene to ‘perturb the system’ in the direction of more balanced immune function, thus reducing inflammation and supporting weight loss:

“…maintaining metabolic homeostasis requires a balanced immune response and an integrated network of multiple cell types. Adipose tissue also contains potent tolerogenic CD4+ Tregs that are downregulated by obesity, a potential initiating event in metainflammation. Likewise, there appear to be innate systems by which nutrient signals are utilized to self-limit inflammation. For example, the obesity-induced increase in expression of GPR120, an omega-3 fatty acid (FA) receptor on macrophages capable of attenuating M1 macrophage activation and increasing M2 gene expression, limits inflammation…”

Also of great interest is the role of brain inflammation in promoting obesity:

“The effects of brain inflammation on the metabolic function of peripheral tissues are broad. Independent of obesity, hypothalamic inflammation can impair insulin release from β cells, impair peripheral insulin action, and potentiate hypertension. Many of these effects are generated by signals from the sympathetic nervous system, which is also capable of inducing inflammatory changes in adipose tissue in response to neuronal injury…The dynamic interplay between hypothalamic inflammation and obesity suggest additional targets for antiinflammatory therapies in obesity. A key extension of these observations is the potential that antiinflammatory pathways may counteract these CNS inflammatory events and improve leptin sensitivity.”

Obesity must be understood as an active agent, both as cause and result, in the web of chronic inflammation. The greatest clinical success in managing weight loss and chronic inflammatory disorders comes from determining and treating the pro-inflammatory factors involved according to each individual case.

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There has been a burst of papers drawing further attention to the damage that glucose and insulin dysregulation does to the brain. A study just published in the journal Neurology investigates specifically…

“…the association between glucose tolerance status defined by a 75-g oral glucose tolerance test (OGTT) and the development of dementia.”

The authors subjected 1,017 community-dwelling dementia-free subjects 60 years and older to an oral glucose tolerance test, then followed them for 15 years. The outcome measure was clinically diagnosed dementia. What did their data show?

The age- and sex-adjusted incidence of all-cause dementia, Alzheimer disease (AD), and vascular dementia (VaD) were significantly higher in subjects with diabetes than in those with normal glucose tolerance. These associations remained robust even after adjustment for confounding factors for all-cause dementia and AD, but not for VaD (all-cause dementia: adjusted hazard ratio [HR] = 1.74; AD: adjusted HR = 2.05; VaD: adjusted HR = 1.82). Moreover, the risks of developing all-cause dementia, AD, and VaD significantly increased with elevated 2-hour postload glucose (PG) levels even after adjustment for covariates, but no such associations were observed for fasting plasma glucose (FPG) levels: compared with those with 2-hour PG levels of <6.7 mmol/L [120.6 mg/dl], the multivariable-adjusted HRs of all-cause dementia and AD significantly increased in subjects with 2-hour PG levels of 7.8 to 11.0 mmol/L [140.4 to 198 mg/dl] or over, and the risk of VaD was significantly higher in subjects with levels of ≥11.1 mmol/L [199.8 mg/dl].”

This is striking. The risk of all-cause dementia doubled for those with diabetes, and there was a significant increase in the risk of all-cause dementia and Alzheimer’s disease with a 2 hour post-glucose load level of 140.4 mg/dl or more. Moreover, fasting glucose levels did not reveal the danger that was disclosed only by the functional OGTT. I always risk desensitizing my patients to the damage done to the brain by glucose and insulin dysregulation; better to let the authors’ conclusion do the talking:

“Our findings suggest that diabetes is a significant risk factor for all-cause dementia, AD, and probably VaD. Moreover, 2-hour PG levels, but not FPG levels, are closely associated with increased risk of all-cause dementia, AD, and VaD.”

Meanwhile, a time study just published in the journal Diabetic Medicine also examines the association of diabetes with Alzheimer’s disease. The authors’ intent was to determine…

“…whether diabetes mellitus influences functional status in patients with Alzheimer’s disease.”

They studied 608 community-dwelling patients with Alzheimer’s disease, assessing diabetes at the beginning. Functional status was examined twice yearly with the Activities of Daily Living scale. Each patient also had a baseline functional disability determined if their Activities of Daily Living score was less than 6. Decreases in these metrics over four years of follow-up exams was used to define worsening of functional disability due to AD. Their data also reveal the ruination of the brain by glucose intolerance:

“At baseline, diabetes was present in 63 participants (10.4%) and, compared with those without diabetes, was associated with functional impairment [age- and sex-adjusted OR = 2.73]. After controlling for confounders, the association remained significant [OR = 2.04]. Follow-up demonstrated a significant interaction between duration of Alzheimer’s disease and diabetes, which was associated with progression of functional impairment in patients who had been diagnosed with Alzheimer’s disease for less than 1 year, but not in those who had been diagnosed with Alzheimer’s disease for more than 1 year. Abnormal one-leg balance, polymedication and obesity seem to be important factors explaining the association between diabetes and functional status.”

Clinicians (non-neurologists), how often do you check one-leg balance? The authors’ data suggests that a year after a clear-cut Alzheimer’s diagnosis the damage is too extensive to discriminate the effect of diabetes, thus they conclude:

“At baseline, the presence of diabetes significantly increases the risk of functional disability in patients with Alzheimer’s disease; our longitudinal data confirm that in patients with a recent diagnosis of Alzheimer’s disease (but not in those who have had Alzheimer’s disease for longer than 1 year), diabetes continues to worsen functional status.”

Regarding mechanisms, an interesting paper just published in Current Diabetes Reviews examines recent findings illuminating the link between IGF-1 signaling and diabetes-associated dementia. The authors state:

“Patients with type 2 diabetes (T2DM) have a two- to three-fold increased risk for Alzheimer’s disease (AD), the most common form of dementia. Vascular complications might explain partially the increased incidence of neurodegeneration in patients with T2DM. Alternatively, neuronal resistance for insulin/insulin-like growth factor-1 (IGF-1) might represent a molecular link between T2DM and AD, characterizing AD as “brain-type diabetes”.”

They describe recent research findings that suggest decreased IGF-1 signaling (IIS) in the brain is a compensatory attempt to reduce the accumulation of toxic β-amyloid (Aβ):

“According to this hypothesis, brains from AD patients showed substantially downregulated expression of the Insulin receptor (IR), the IGF-1 receptor (IGF-1R), and the insulin receptor substrate (IRS) proteins…suggesting that decreased IIS [insulin/IGF-1 signaling] might be involved in the pathogenesis of both T2DM and AD. In contrast, type 2 diabetic patients suffering from AD accumulate less β-amyloid (Aβ) compared to non-diabetic AD patients raising the question, whether the changes in IIS are cause, consequence, or compensatory counterregulation to neurodegeneration. Recent data in C. elegans showed that reducing IIS decreases Aβ toxicity. This effect is accomplished via two transcription factors…suggesting that Insulin/IGF-1 transmitted signals influence Aβ proteotoxicity.”

This important point should not go unnoticed by those who are contemplating therapies that increase IGF-1—they may increase risk factors for Alzheimer’s disease and dementia.

And another paper recently published in Neurology highlights the damage done to the brain by advanced glycation end products due to poor glucose tolerance. The authors observe:

“Several studies report that diabetes increases risk of cognitive impairment; some have hypothesized that advanced glycation end products (AGEs) underlie this association. AGEs are cross-linked products that result from reactions between glucose and proteins. Little is known about the association between peripheral AGE concentration and cognitive aging.”

They studied 920 elders without dementia, 495 with diabetes and 425 with normal glucose, and examined baseline AGE concentration by urine pentosidine in association with performance on the Modified Mini-Mental State Examination (3MS) and Digit Symbol Substitution Test (DSST) at baseline and repeatedly over 9 years. What did the data show?

“On both tests, there was a more pronounced 9-year decline in those with high and mid pentosidine level [more AGEs] compared to those in the lowest tertile. Incident cognitive impairment was higher in those with high or mid pentosidine level than those in the lowest tertile.”

We are probably just beginning to understand the ways that glucose and insulin regulation, whose profound leverage on the physiology is evolutionarily preserved from relatively primitive organisms to humans, has on the brain. Regarding damage done by excessive glucose interaction with tissues, it is not necessary for glucose dysregulation to have progressed to diabetes as the authors conclude:

“High peripheral AGE level is associated with greater cognitive decline in older adults with and without diabetes.”

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Biological systems respond differently to high and low amounts of the same substances and to continuous and intermittent application of the same stimuli. Hormesis is very important to understand for designing programs for medical treatment, exercise, weight loss and more. As stated in a paper published in the journal Ageing Research Reviews:

“Hormesis is a term used by toxicologists to refer to a biphasic dose–response to an environmental agent characterized by a low dose stimulation or beneficial effect and a high dose inhibitory or toxic effect. In the fields of biology and medicine hormesis is defined as an adaptive response of cells and organisms to a moderate (usually intermittent) stress. Examples include ischemic preconditioning, exercise, dietary energy restriction and exposures to low doses of certain phytochemicals.”

In other words, something that can be damaging or toxic at a higher dose may elicit a beneficial response at a lower one. This applies to calorie restriction and exercise as well as medicines. Research on hormesis has advanced in the past decade:

“Recent findings have elucidated the cellular signaling pathways and molecular mechanisms that mediate hormetic responses which typically involve enzymes such as kinases and deacetylases, and transcription factors such as Nrf-2 and NF-κB. As a result, cells increase their production of cytoprotective and restorative proteins including growth factors, phase 2 and antioxidant enzymes, and protein chaperones.

Thus plants from vegetables to wine grapes subject to moderate stress produce a richer yield of beneficial substances, and…

“A better understanding of hormesis mechanisms at the cellular and molecular levels is leading to and to novel approaches for the prevention and treatment of many different diseases.”

Intermittent caloric restriction is emerging as an effective and practical method for  successful long term weight loss and the longevity promoting effects of diet (see the earlier post on intermittent versus continuous calorie restriction and weight loss). Understanding the principle of hormesis is at the core of the Lapis Light Program for Weight Loss and Gene Modulation. As stated in another paper in the same journal:

“Reducing energy intake by controlled caloric restriction or intermittent fasting increases lifespan and protects various tissues against disease, in part, by hormesis mechanisms that increase cellular stress resistance.”

Regarding brain health in particular the author of another paper notes:

“It is likely that the capacity of the brain to remain healthy during aging depends upon its ability to adapt and nurture in response to environmental challenges. In these terms, main principles involved in hormesis can be also applied to understand relationships at a higher level of complexity such as those existing between the CNS and the environment.”

And yet another paper on aging in general beautifully articulates the practical meaning of hormesis:

“Hormesis in aging is represented by mild stress-induced stimulation of protective mechanisms in cells and organisms resulting in biologically beneficial effects. Single or multiple exposure to low doses of otherwise harmful agents, such as irradiation, food limitation, heat stress, hypergravity, reactive oxygen species and other free radicals have a variety of anti-aging and longevity-extending hormetic effects. Detailed molecular mechanisms that bring about the hormetic effects are being increasingly understood, and comprise a cascade of stress response and other pathways of maintenance and repair. Although the extent of immediate hormetic effects after exposure to a particular stress may only be moderate, the chain of events following initial hormesis leads to biologically amplified effects that are much larger, synergistic and pleiotropic. A consequence of hormetic amplification is an increase in the homeodynamic space of a living system in terms of increased defence capacity and reduced load of damaged macromolecules. Hormetic strengthening of the homeodynamic space provides wider margins for metabolic fluctuation, stress tolerance, adaptation and survival. Hormesis thus counter-balances the progressive shrinkage of the homeodynamic space, which is the ultimate cause of aging, diseases and death. Healthy aging may be achieved by hormesis through mild and periodic, but not severe or chronic, physical and mental challenges, and by the use of nutritional hormesis incorporating mild stress-inducing molecules called hormetins. The established scientific foundations of hormesis are ready to pave the way for new and effective approaches in aging research and intervention.”

An interesting paper published in the journal Molecular Neurobiology examines the hormetic effects of caloric restriction on the extremely important process of neuroplasticity.

“Aging is associated with the decline of cognitive properties. This situation is magnified when neurodegenerative processes associated with aging appear in human patients. Neuronal synaptic plasticity events underlie cognitive properties in the central nervous system.”

The authors comment on the hormetic effects of intermittent caloric restriction on the aging brain and nervous system:

“Caloric restriction (CR; either a decrease in food intake or an intermittent fasting diet) can extend life span and increase disease resistance. Recent studies have shown that CR can have profound effects on brain function and vulnerability to injury and disease. Moreover, CR can stimulate the production of new neurons from stem cells (neurogenesis) and can enhance synaptic plasticity, which modulate pain sensation, enhance cognitive function, and may increase the ability of the brain to resist aging.”

As in all other systems of the body…

“The beneficial effects of CR appear to be the result of a cellular stress response stimulating the production of proteins that enhance neuronal plasticity and resistance to oxidative and metabolic insults; they include neurotrophic factors, neurotransmitter receptors, protein chaperones, and mitochondrial biosynthesis regulators.”

The authors of a paper published in the journal Neurochemical Research also consider the role of hormesis in neuroprotection and brain aging.

“The predominant molecular symptom of aging is the accumulation of altered gene products. Moreover, several conditions including protein, lipid or glucose oxidation disrupt redox homeostasis and lead to accumulation of unfolded or misfolded proteins in the aging brain. Alzheimer’s and Parkinson’s diseases or Friedreich ataxia are neurological diseases sharing, as a common denominator, production of abnormal proteins, mitochondrial dysfunction and oxidative stress, which contribute to the pathogenesis of these so called “protein conformational diseases”. The central nervous system has evolved the conserved mechanism of unfolded protein response to cope with the accumulation of misfolded proteins. As one of the main intracellular redox systems involved in neuroprotection, the vitagene system is emerging as a neurohormetic potential target for novel cytoprotective interventions. Vitagenes encode for cytoprotective heat shock proteins (Hsp) Hsp70 and heme oxygenase-1, as well as thioredoxin reductase and sirtuins.”

Furthermore…

“Nutritional studies show that ageing in animals can be significantly influenced by dietary restriction. Thus, the impact of dietary factors on health and longevity is an increasingly appreciated area of research. Reducing energy intake by controlled caloric restriction or intermittent fasting increases lifespan and protects various tissues against disease.”

A fascinating study recently published in the Journal of Surgical Research examines the hormetic benefits of short-term preoperative caloric restriction on the response to surgical trauma. The authors state:

“Lifespan extension is achieved through long-term application of dietary restriction (DR), and benefits of short-term dietary restriction on acute stress and inflammation have been observed….We hypothesized that short-term DR in humans reduces the acute phase response following a well defined surgical trauma.”

They randomized thirty live kidney donors to either 30% preoperative dietary restriction followed by 1 d of fasting or a 4 d ad libitum diet prior to surgery. In addition to white blood cell subsets and numbers, they measured serum cytokine production after stimulation of whole blood with lipopolysaccharide (LPS). An excellent response to short-term caloric restriction was documented:

“A clear trend towards lower numbers of postoperative circulating leukocytes was observed in the DR group. IL-8 serum levels were significantly higher in the DR group over the first 6 postoperative days. After LPS stimulation, significantly less TNF-α was produced by blood obtained postoperatively compared with preoperative blood from the DR group. This was not observed in the control group.”

In other words, the short-term caloric restriction group expressed a much ‘better’ (less damaging) inflammatory response to surgical trauma compared to the control group. This begs for more research into the adoption of short-term or intermittent caloric restriction as the standard of care in preparation for surgery.

The phenomenon of hormesis in biology is a vast subject that every clinician must be familiar with to most effectively calibrate the dose of a wide range of interventions from medicines and supplements to exercise, caloric restriction and therapies that stimulate the body by the use of hands, needles or any other sensory-based modality—even subtle aspects of counseling and imagery. It is fundamental to our system of weight loss and gene modulation.

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Numerous times over the past couple decades I’ve regrettably had to contradict a colleague when a patient has been told that their serum levels of vitamin B12 are adequate and supplementation is not warranted. A study just published in the journal Neurology offering yet more evidence that serum vitamin B12 levels within the typical normal range can mislead about serious consequences of B12 deficiency in the brain. The authors’ intent was to…

“…investigate the interrelations of serum vitamin B12 markers with brain volumes, cerebral infarcts, and performance in different cognitive domains in a biracial population sample cross-sectionally.”

They examined serum markers of vitamin B12 in relation to neuropsychological tests of 5 cognitive domains and brain MRI studies obtained on average 4.6 years later among 121 older community dwelling adults. The data paint an important picture:

“Concentrations of all vitamin B12–related markers, but not serum vitamin B12 itself, were associated with global cognitive function and with total brain volume. Methylmalonate levels were associated with poorer episodic memory and perceptual speed, and cystathionine and 2-methylcitrate with poorer episodic and semantic memory. Homocysteine concentrations were associated with decreased total brain volume. The homocysteine-global cognition effect was modified and no longer statistically significant with adjustment for white matter volume or cerebral infarcts. The methylmalonate-global cognition effect was modified and no longer significant with adjustment for total brain volume.”

In other words, the decrease in total brain volume due to vitamin B12 insufficiency appeared to the mediating the impact on function of the markers besides homocysteine (also associated with brains infarcts)—and serum B12 did not correlate with the MRI or cognitive testing results. For lay readers, your brain can be shrinking with concomitant loss of cognitive function due to B12 insufficiency and the blood test for B12 can still appear normal. The authors’ conclusion needs to become common knowledge among all practitioners:

“Methylmalonate, a specific marker of B12 deficiency, may affect cognition by reducing total brain volume whereas the effect of homocysteine (nonspecific to vitamin B12 deficiency) on cognitive performance may be mediated through increased white matter hyperintensity and cerebral infarcts. Vitamin B12 status may affect the brain through multiple mechanisms.”

Note: methylmalonate (methylmalonic acid) in urine or serum, while not perfect, are practicable. This study also adds more evidence to the importance of homocysteine and brain health.

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It’s long been known that the herb feverfew (Tanacetum parthenium) can reduce the frequency and intensity of migraine attacks if taken ahead of time on a regular basis, but alternatives to triptan medications for acute application are in short supply. Therefore I’m glad to see a study just published in Headache: The Journal of Head and Face Pain offering evidence that the novel sublingual preparation of feverfew plus ginger LipiGesic M™ can rapidly abort or ameliorate a migraine headache. The authors state:

“Therapeutic needs of migraineurs vary considerably from patient to patient and even attack to attack. Some attacks require high-end therapy, while other attacks have treatment needs that are less immediate. While triptans are considered the “gold standard” of migraine therapy, they do have limitations and many patients are seeking other therapeutic alternatives. In 2005, an open-label study of feverfew/ginger suggested efficacy for attacks of migraine treated early during the mild headache phase of the attack.”

Pursuant to this they designed the double-bind placebo-controlled study reported here that included 60 patients who self-treated 221 attacks of migraine with either the sublingual feverfew/ginger preparation or placebo. Additionally…

“All subjects met International Headache Society criteria for migraine with or without aura, experiencing 2-6 attacks of migraine per month within the previous 3 months. Subjects had <15 headache days per month and were not experiencing medication overuse headache. Inclusion required that subjects were able to identify a period of mild headache in at least 75% of attacks. Subjects were required to be able to distinguish migraine from non-migraine headache.”

Subjects were randomized to receive either sublingual feverfew/ginger or a matching placebo, and told (but not required) to initiate treatment as soon as they recognized that a migraine was starting. What were the results?

“Sixty subjects treated 208 evaluable attacks of migraine over a 1-month period; 45 subjects treated 163 attacks with sublingual feverfew/ginger and 15 subjects treated 58 attacks with a sublingual placebo preparation…At 2 hours, 32% of subjects receiving active medication and 16% of subjects receiving placebo were pain-free. At 2 hours, 63% of subjects receiving feverfew/ginger found pain relief (pain-free or mild headache) vs 39% for placebo. Pain level differences on a 4-point pain scale for those receiving feverfew/ginger vs placebo were −0.24 vs −0.04 respectively. Feverfew/ginger was generally well tolerated with oral numbness and nausea being the most frequently occurring adverse event.”

This is clearly palliative treatment rather than therapy designed to address the underlying causes of migraine (see forthcoming posts regarding the functional medicine approach to migraine). However, an effective palliative that is wholesome and free of serious side-effects as implied in the authors’ conclusion is welcome news:

“Sublingual feverfew/ginger appears safe and effective as a first-line abortive treatment for a population of migraineurs who frequently experience mild headache prior to the onset of moderate to severe headache.”

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