liveonearth | Sugar and Depression (Reply)

British psychiatric researcher Malcolm Peet
cross-cultural analysis of the relationship between diet and mental illness
finding: strong link betw high sugar consumption and risk of depression and schizophrenia
2004 STUDY
http://www.ncbi.nlm.nih.gov/pubmed/15123503?dopt=Abstract
higher national dietary intake of refined sugar and dairy products
-->worse 2-year outcome of schizophrenia
high national prevalence of depression<--low dietary intake of fish and seafood
he writes of two mechanisms by which sugar may cause depression: BDNF and inflammation

BDNF SUPPRESSION
sugar suppresses activity of a key growth hormone in the brain called BDNF
BDNF levels are critically low in both depression and schizophrenia
BDNF promotes the health and maintenance of neurons in the brain
plays a vital role in memory function, triggers growth of new connections between neurons
critically low in both depression and schizophrenia
both syndromes often lead to shrinkage of key brain regions over time
(chronic depression-->brain damage)
evidence from animal models suggests that low BDNF can trigger depression

BDNF: MORE from wikipedia
Brain-derived neurotrophic factor
second neurotrophic factor to be characterized after NGF
a protein of the "neurotrophin" family of growth factors
related to "Nerve Growth Factor", NGF
neurotrophic factors are found in the brain and the periphery
expressed in: retina, CNS, motor neurons, kidneys, prostate???
BDNF acts on certain neurons of CNS and PNS
supports survival of existing neurons
encourages growth and differentiation of new neurons and synapses: neurogenesis
active in the hippocampus, cortex, and basal forebrain
(learning, memory esp long term, and higher thinking)
the vast majority of neurons in the mammalian brain are formed prenatally
parts of the adult brain can still grow new cells from stem cells: neurogenesis
mice born without the ability to make BDNF suffer developmental defects in CNS and sensory NS
usu die soon after birth
exercise increases secretion of BDNF at the mRNA and protein levels in the rodent hippocampus

LOW BDNF LEVELS
related to:
depression
schizophrenia, OCD
Alzheimer's (low levels may allow beta amyloid deposition)
Huntinton's
Rett syndrome,
dementia
anorexia nervosa and bulimia nervosa
epilepsy associated with genetic polymophism re: BDNF
?? autism???

HIGH LEVELS
can induce a change to an opiate-dependent-like reward state
when expressed in the ventral tegmental area in rats
high BDNF and Substance P assoc w/ increased itching in eczema

STRESS LOWERS BDNF IN RATS
stress & corticosterone-->decreased expression of BDNF in rats
if chronic-->atrophy of the hippocampus and other limbic structures
this happens in humans suffering from chronic depression
rats bred to be heterozygous for BDNF-->also atrophy of hippocampus

THINGS THAT INCREASE EXPRESSION OF BDNF IN BRAIN
excitatory neurotransmitter glutamate
voluntary exercise
caloric restriction
intellectual stimulation
curcumin
antidepressants
electroconvulsive therapy
sleep deprivation
antidepressants and electroconvulsive therapy reverse the atrophy process

BDNF INFLUENCES REELIN SIGNALING
regulates neuronal migration and positioning in developing brain
modulates neural plasticity in adult
enhances the induction and maintenance of long-term potentiation
stimulates dendrite and dendritic spine development
regulates the continuing migration of neuroblasts generated in adult neurogenesis sites like subventricular and subgranular zones
found in the brain, spinal cord, blood, and other body organs and tissues
implicated in pathogenesis of several brain diseases
lowered expression found in schizophrenia and psychotic bipolar disorder
psychotropic medication affects RELN expression
some science contradicts the epigenetic hypothesis explaining level change
total lack of reelin causes a form of lissencephaly
may play a role in Alzheimer's disease, temporal lobe epilepsy, and autism

TWO: EATING SUGAR CAUSES INFLAMMATION
chronic inflammation disrupts immune function, hurts brain
-->increased risk of heart disease, diabetes, arthritis, some forms of cancer
-->linked to a greater risk of depression and schizophrenia
(inflam also caused by trans fats and lowered by omega 3's)

INFLAMMATION IN PREGNANCY
Puerperal women are vulnerable to inflam effects because their levels of proinflammatory cytokines significantly increase during the last trimester of pregnancy, also they experience sleep disturbance, postpartum pain, may have past or current psychological trauma
best remedy: breastfeeding, naturally eases stress and modulates the inflammatory response

ANTISOCIAL BEHAVIOR
reduced sugar diet helps
Dr. Russell Blaylock
excessive insulin release-->hypoglycemia-->brain secretes high levels of glutamate
-->agitation, depression, anger, anxiety, panic attacks, increased in suicide risk

TWO STUDIES
FIRST
1985 study in Journal of Abnormal Psychology
reducing sugar intake had a positive impact on emotions
pts distressed at baseline
after 2-wk dietary change symptoms declined
diet change: high protein, low carb diet void of sucrose and caffeine
MMPI or POMS profiles reflected a more stable and less distressed individual
SECOND
Los Angeles Probation Department Diet-Behavior Program: Am Empirical Analysis of Six Institutional Settings
published in 1983
before and after comparison of 1,382 juveniles detained in three juvenile halls
and before-after comparison of 289 juveniles who were confined in three juvenile camps
dietary modifications: lower the daily consumption of sugar in all six settings
in the halls: 44% reduction in the incidence of antisocial behavior found over 3 mo
in the camps: 25% reduction in antisocial behavior during the 9 mo after the implementation

SOURCES
http://en.wikipedia.org/wiki/Brain-derived_neurotrophic_factor

Mercola
http://articles.mercola.com/sites/articles/archive/2009/12/22/How-Eating-Sugar-Can-Cause-Mental-Illness.aspx

Stephen Ilardi, Ph.D.
author of article in Psychology Today July 23, 2009: How to beat depression without drugs
http://www.psychologytoday.com/blog/the-depression-cure/200907/dietary-sugar-and-mental-illness-surprising-link
author of book: The Depression Cure
associate professor of psychology at U of Kansas
clinical researcher specializing in the treatment of depression

The British Journal of Psychiatry May 2004;184:404-8
http://www.ncbi.nlm.nih.gov/pubmed/15123503?dopt=Abstract
International variations in the outcome of schizophrenia and the prevalence of depression in relation to national dietary practices: an ecological analysis.
Peet M.
Swallownest Court Hospital, Aughton Road, Sheffield S26 4TH, UK. malcolmpeet@yahoo.com
BACKGROUND: Dietary variations are known to predict the prevalence of physical illnesses such as diabetes and heart disease but the possible influence of diet on mental health has been neglected. AIMS: To explore dietary predictors of the outcome of schizophrenia and the prevalence of depression. METHOD: Ecological analysis of national dietary patterns in relation to international variations in outcome of schizophrenia and prevalence of depression. RESULTS: A higher national dietary intake of refined sugar and dairy products predicted a worse 2-year outcome of schizophrenia. A high national prevalence of depression was predicted by a low dietary intake of fish and seafood. CONCLUSIONS: The dietary predictors of outcome of schizophrenia and prevalence of depression are similar to those that predict illnesses such as coronary heart disease and diabetes, which are more common in people with mental health problems and in which nutritional approaches are widely recommended. Dietary intervention studies are indicated in schizophrenia and depression.
PMID: 15123503 [PubMed - indexed for MEDLINE]