Anti-Inflammatory Diet

All health care starts with diet. My recommendations for a healthy diet are here:
Anti-Inflammatory Diet and Lifestyle.
There are over 190 articles on diet, inflammation and disease on this blog
(find topics using search [upper left] or index [lower right]), and
more articles by Prof. Ayers on Suite101 .

Thursday, November 20, 2008

Brain Arachidonic Acid: Alzheimer’s, Bipolar, Parkinson’s

A recent review article on brain lipid metabolism discussed the results obtained by looking at how the major omega-6 fatty acid, arachidonic acid is imported and used in brain tissue. Arachidonic acid conversion to inflammatory prostaglandins was monitored by extracting lipids from rat brains after a variety of treatments. Similarly, isotopes (13C) of fatty acids were imaged by PET scans in patients treated for Alzheimer’s, bipolar disorder and Parkinson’s disease.

The major findings on brain arachidonic acid (AA, omega-6) and docosahexaenoic acid (DHA, omega-3) are:

  • Ca. 5% of daily dietary AA and DHA are converted to make prostaglandins in the brain. Converted AA and DHA are rapidly replaced by serum AA and DHA.
  • Brain DHA and AA metabolisms are independent.
  • AA and DHA are rapidly circulated into phospholipids (R2 on the diagram) on the endoplasmic reticulum, move to the cytoplasmic membrane (see diagram, gray and white strands) removed by phospholipase A2 in synapses, converted to prostaglandins, leukotrienes, etc., or recycled to phospholipids. Enzymes that catalyze these reactions are usually different for DHA and for AA.
  • Drugs used to treat bipolar disorder (lithium, carbamazepine, valproic acid, lamotrigine) lower AA conversion in rats, but do not affect DHA conversion.
  • Experimentally induced brain inflammation or neurotoxicity increases AA conversion, but not DHA conversion to prostaglandins.
  • An omega-3 fatty acid deficient diet also increases AA, but not DHA conversion.
  • More AA is converted in Alzheimer’s patients. This is consistent with increased inflammation and neurotoxicity in postmortem examinations.
  • Mice that have been genetically manipulated to eliminate alpha-synuclein, a protein implicated in Parkinson’s disease, also show an increase in AA conversion and a decrease in DHA conversion.

Interpretation: Inflammation in the brain is separate from the rest of the body, but is the foundation of many brain disorders, including Alzheimer’s disease, bipolar disorder and Parkinson’s disease. In these disorders, arachidonic acid is rapidly converted into inflammatory prostaglandins and leukotrienes. Drugs that reduce symptoms, reduce AA conversion.

A diet rich in omega-3 DHA and reduced omega-6 arachidonic acid reduces the symptoms of these diseases -- an anti-inflammatory diet and lifestyle should be the first line of defense against brain/mental disorders.

reference:
Rapoport SI. 2008. Brain arachidonic and docosahexaenoic acid cascades are selectively altered by drugs, diet and disease. Prostaglandins Leukot Essent Fatty Acids. Oct 28. [Epub ahead of print]

2 comments:

Greg Marlow said...

Is it possible that hyponatremia and its resulting swelling of the brain could cause an inflamation response? 10% of hospital admissions to mental wards suffer from this condition. I suspect that many more actually suffer from transient hyponatremia that is not diagnosed upon admission.

Dr. Art Ayers said...

Greg,
I would be surprised if the body has such poor control of salt balance that brain swelling results. It would seem more likely to be a blood pressure problem associated with brain inflammation. My impression is that the blood brain barrier is breached by inflammation permitting further compromise of the brain tissue by errant members of the immune system including marauding macrophages harboring bacteria and endotoxins. I think that most of these mental presentations would be well treated with an aggressive anti-inflammatory diet and perhaps antibiotics.