Omega-3 Fatty Acids, Antioxidants and Cancer

It is hard to sort out the inflammatory effects of short/long-chain omega-6 and omega-3 fatty acids. Vegetable antioxidants make the picture even worse. The absolute, as well as relative amounts, of the various types of fatty acids make a difference. It also now appears that oxidation prior and during digestion may be important to the impact of polyunsaturated fatty acids (PUFAs). The source (perhaps even the meal composition) of the PUFAs was as important as omega-3 versus omega-6, for common, short chain PUFAs.

In some studies, omega-3 PUFAs, such as the short-chain alpha linolenic acid (ALA) common in flax seed or the long-chain fish oil FUFAs, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), reduced cancer in human and mice. Earlier work in cell cultures showed that all of PUFAs suppressed the growth of cancer cells.

A large French study (reference below) began in 1993. Approximately 100,000 women between the ages of 40 and 65 volunteered to provide dietary and breast malignancy information and ca. 75,000 qualified for the study (the French component of EPIC, European Investigation of Cancer and Nutrition) . The dietary data provided information on the fatty acid composition of meals and revealed who was eating vegetable antioxidants and vitamins.

Major findings:

• Neither omega-6 nor omega-3 fatty acids were related directly to breast cancer risk.
• Long chain omega-3 fatty acids (EPA and DHA) reduced breast cancer in the group of women with the highest consumption of omega-6 PUFAs.
• High LA or ALA consumption in the form of vegetable oils or vegetables reduced cancer incidence.
• High LA or ALA consumption in the form of processed foods or nuts was associated with a higher incidence of breast cancer.
• Longer chain PUFAs were not associated with increased risk, regardless of source.

What does this mean?

• The source of the PUFA is of paramount importance. This study may apply more specifically to cancers and less to other inflammation-based degenerative diseases. The general anti-inflammatory diet may need refinement. I would suggest the following additions:
• Retain the preference for the more omega-3 friendly olive oil or perhaps flax oil versus the omega-6 rich vegetable oils (corn, soy, safflower), but focus on freshness and do not heat these oils.
• The data seem to be in favor of saturated fats for cooking. That means a shift to coconut oil.
• Vegetable antioxidants may be most important in the gut during digestion. Do these antioxidants even enter the blood stream? Certainly some alkaloids get to the brain, but much of the impact of the less mobile, large molecules may be restricted to the gut.
• An extension of this discussion may be to encourage eating more leafy vegetables with meat. That may be the paleo-diet connection.

reference:
Thiébaut AC, Chajès V, Gerber M, Boutron-Ruault MC, Joulin V, Lenoir G, Berrino F, Riboli E, Bénichou J, Clavel-Chapelon F. 2009. Dietary intakes of omega-6 and omega-3 polyunsaturated fatty acids and the risk of breast cancer. Int J Cancer. Feb 15;124(4):924-31.

Where’s the Aspirin?

Aspirin is the traditional anti-inflammatory agent. Many of us grew up with the quintessential doctoring phrase, “Take two aspirin and call me in the morning.” Aspirin stops inflammation in several ways. Like all drugs, it interacts with many different proteins/enzymes. In fact it interacts so intimately with the inflammatory system that it suggests that the process of inflammation may require an aspirin-like molecule to function normally.

Aspirin Binds to Multiple Enzymes of Inflammation

Aspirin is observed to reduce inflammation. That means that ingested aspirin tablet dissolve in the stomach and pass through the intestines into the blood stream and subsequently bath cells of the blood and the endothelium that lines the blood vessels. In order to reach the blood stream, the aspirin must pass through the intestinal cells. That passage requires binding to a protein transport molecule.

Cells responding to an inflammatory signal (NFkB, transcription factor is activated) synthesize enzymes that release unsaturated fatty acids (ARA, EPA, DHA) from membrane phospholipids (PLA2, phospholipase A2), form a cyclic epoxide from the fatty acid (prostaglandin H2 synthase 2, also called cyclooxygenase 2, COX-2).

Aspirin binds to the inhibitor that normally inactivates NFkB and prevents NFkB activation that is required for inflammation. Aspirin also binds to PLA2 and prevents fatty acid release and thereby blocks activation of inflammation. Aspirin also binds to COX-2 and blocks the production of inflammatory prostaglandins from ARA. But that is not all that aspirin does.

Inflammation Resolution Uses Aspirin-COX-2 Interaction

The strange interaction that makes aspirin suspicious is that aspirin doesn’t just interfere with the action of enzymes, it subtly changes their specificity. Thus aspirin chemically transfers its acetyl group (CH3-COOH-) to an amino acid in the active site of COX-2 to produce a new group of anti-inflammatory lipoxins from ARA, EPA and DHA.

This raises the question of whether aspirin is a natural dietary modulator of inflammation. Recall that aspirin was initially obtained from willow (Salix) bark. Unfortunately, the data are conflicting. Initial research indicated that grains (naturally inflammatory) lacked aspirin, but many herbs, spices and leafy vegetables (naturally anti-inflammatory) contained aspirin. Subsequent tests refuted this work. It would be consistent with observations that some dietary components are anti-inflammatory, but candidate acetyl donors have not been identified.

Speculative acetyl candidates may include the menthol relatives, such as menthyl acetate (figure). Peppermint oil, which contains mostly menthol with some menthyl acetate, is more effective in the treatment of inflammatory bowel disease than most pharmaceuticals prescribed to treat the condition. This anti-inflammatory activity may be due in part to the aspirin-like chemical structure and function of the menthyl acetate. Also note that acetic acid/vinegar is sometimes suggested as a cure-all. This activity may be a consequence of its formation of ester linkages with alcohols that have structures similar to menthol.

Large Dose Aspirin as Cancer Treatment

The potent anti-inflammatory effects of aspirin have been compromised, because inflammation is an essential developmental activity. Thus, the integrity of the gut, for example, requires modest production of inflammatory prostaglandins and a pill of aspirin can disrupt gut tissue. Large doses of aspirin cannot be given orally. Intravenous administration of large doses of aspirin, however, is possible and the impact on process that require inflammation is dramatic.

Anecdotal evidence indicates that large dose aspirin is able to disrupt cancers, because proliferation of cancer cells requires NFkB activation and other inflammatory responses. High doses of aspirin also cause other potentially dangerous complications, such as short-circuiting oxidative phosphorylation of mitochondria and increasing nitric oxide free radical production. Still, the impact of high dose aspirin on some diseases is so amazing that it is being actively and carefully pursued.

What’s the Opposite of Inflammation?

I want to commemorate the writing of my 100th article on Blogspot by discussing a new insight into inflammation.

I have been searching the last several years for an anti-inflammatory system to balance inflammation. Now I realize that there is no opposite to inflammation. There is only completion of inflammation to return to the original state. Inflammation is a process that includes resolution or recovery from the defensive, destructive state of immunological activity.

Inflammation is the martialling of resources for battle by offloading lymphocytes from the blood stream, engaging the enemy by triggering the release of toxic secretory vesicles from leukocytes, and cleaning up the carnage by macrophages engulfing cellular fragments. Each step in the inflammatory process induces the next step until there is a return to the origin. Inflammation is not balanced by anti-inflammatory processes.

Inflammation is triggered by molecules characteristic of viruses, bacteria or fungi binding to membrane receptors (TLRs). The result is activation of the inflammatory transcription factor, NFkB (illustrated holding DNA), that turns on the expression of dozens of genes that code for cytokines (IL-1, IL-6, TNF) and enzymes (COX-2) that produce signal compounds. Among the signal compounds are the inflammatory eicosanoids (PGE2) produced from the omega-6 fatty acid arachidonic acid (ARA).

The complex signaling pathways that lead to PGE2 synthesis subsequently initiate transcription of genes that code for the enzymes that make lipoxins (resolvins and protectins) from eicosapentanaenoic acid (EPA) and docosahexaenoic acid (DHA). EPA and DHA are the two omega-3 fatty acid components of fish oil and a shortage of these dietary components blocks the next step, resolution of inflammation.

The lipoxins reduce the permeability of blood vessels, stop the offloading of lymphocytes, reduce responsiveness to inflammatory cytokines, recruit phagocytic macrophages to clean up debris and orchestrate a return to quiescence of the inflammatory system. Without adequate lipoxins, inflammation continues.

An interesting footnote to this discussion is the impact of aspirin on inflammation. Aspirin binds to the enzyme (COX-2) that converts ARA to inflammatory prostaglandins and leukotrienes. Acetylation of COX-2 by aspirin stops inflammatory eicosanoid synthesis and shifts the synthesis to anti-inflammatory lipoxins. Even ARA is used to make anti-inflammatory lipoxins in the presence of aspirin. This shift to anti-inflammatory signaling may occur naturally in the small intestines in response to aspirin-like compounds in vegetables. This would be a transitory response similar to taking aspirin with a meal. More constant use of aspirin would disrupt the normal and necessary actions of the inflammatory signaling to maintain the integrity of the gut.

Excess of dietary omega-6 oils and deficiency in omega-3 fatty acids corrupts inflammatory signaling by eliminating recovery and produces chronic inflammation. Another name for chronic inflammation is obesity/metabolic syndrome. Chronic inflammation is the foundation for the degenerative, autoimmune and cancer diseases that are so prevalent today.

Fortunately a shift to an anti-inflammatory diet and lifestyle provides a simple solution to chronic inflammation.

[Note added: Perhaps the opposite of anti-inflammatory is immunosuppressed, as in high use of omega-3 oils can increase the risk of tuberculosis of influenza.]

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]

Osteopetrosis

Bones like stones, that is osteo-petrosis. It is the opposite of osteoporosis, porous bones. Osteopetrosis is a disruption of bone metabolism so that mineralization by osteoblasts predominates over demineralization by osteoclasts.

Mice lacking almost all genes, i.e. knockout mice, are now available. To determine which body tissues require the inflammatory transcription factor, NFkB, NFkB knockout mice were engineered and their characteristics were carefully analyzed. Their bones kept mineralizing and mineralizing and mineralizing. NFkB function was required for the development and function of osteoclasts, the macrophage-derived cells that remove bone.

Inactivation of osteoclasts or inhibition of osteoclast development by bisphenols, such as Boniva, leads to a minor version of osteopetrosis. Killing osteoclasts leads to a reversal of osteoperosis. An omega-3 fatty acid deficient diet leads to osteoporosis in mice.

Omega-3 fish oil has been used to reduce inflammation induced bone loss associated with many diseases, e.g. arthritis, periodontitis and osteoporosis. In a recent study (below) the fish oils, DHA and EPA were added to mouse macrophages in culture and the impact on differentiation into osteoclasts was analyzed. DHA was more effective than EPA in reducing NFkB activation and TFA response leading to macrophage differentiation. The omega-6 fatty acid, ALA, enhanced osteoclast differentiation, consistent with many animal and human studies that show that the high omega-6 fatty acid content of such common vegetable oils as corn, soybean and safflower, are inflammatory and presumably encourage osteoporosis.

Osteoporosis increase in our population has paralleled the increase in use of omega-6 vegetable oils, and the increase in chronic inflammation. The first step in treating osteoporosis should be a shift to an anti-inflammatory diet lacking these vegetable oils. Olive oil is much safer.


Rahman MM, Bhattacharya A, Fernandes G. 2008. Docosahexaenoic acid is more potent inhibitor of osteoclast differentiation in RAW 264.7 cells than eicosapentaenoic acid. J Cell Physiol. 214:201-9.

Inflammation Score

Most people need some feedback to monitor the impact of their diet and exercise on their health. I tried to point out some of the major contributors to chronic inflammation with a little check list. See how you score (choose one of the list for each category) and give me your feedback on the how you think each part contributes to inflammatory diseases.

Fat Content ____
lean 0
extra abdominal fat 4
obese 8

Carbs ____
small meals, no cereal for breakfast 0
fistful of starch with each meal 2
pasta/rice/potato as a meal 4

HFCS ____
high fructose corn syrup banned from your diet 0
don’t avoid HFCS, but avoid soft drinks 2
have replaced sucrose with HFCS, enjoy soft drinks 4

Unsaturated Fats ____
have removed vegetable oils (except olive oil) from your kitchen 0
use canola oil 2
have replaced saturated fats with corn oil 4

Trans fats ____
eat no trans fats 0
avoid trans fats on your chips 2
don’t know what trans fats are 4

Fish oil ____
supplement with two or more fish oil (DHA/EPA) capsules per day 0
eat at least two helpings of oily fish per week 2
avoid all fish products 4

Antioxidants ____
know that coffee, tea and chocolate are good sources of vegetable antioxidants 0
eat five servings of fruits and veggies 0
take vitamin C supplement, because you avoid veggies 2
avoid veggies; meat and potatoes type 4

Exercise ____
take a stroll after meals and maintain your muscle mass 0
run when you feel guilty 2
couch potato 4

If you smoke, add an extra 15 points

Add ‘em up. How much are you stoking the inflammation furnace?
0-5 Cool! You will never look your age.
6-10 You are getting warm. Hope that you don't have any genetic predispositions to disease.
11-15 You may postpone inflammatory illness until middle age. The flame is lit. Pick your disease.
16-25 If you aren’t showing a chronic disease, you will soon.
26+ You can reverse your disease symptoms with the inflammatory diet and exercise.

Eating Rules -- Omega-3

Fish oils are anti-inflammatory and are most effective when other vegetable oils are avoided, but are eaten in a meal in which other fats stimulate bile production.

Omega-3 fatty acid rules:

• Avoid vegetable oils in general -- corn is very bad, soy is bad and canola is not too bad
• Only olive oil is acceptable
• Flax oil is too short and still has omega-6 fatty acids -- most labeling is misleading
• Saturated fat in butter and eggs is ok and safer than vegetable oil
• More symptoms of inflammation means more fish oil supplements are needed
• Take fish oil supplements with meals and preferably fatty foods to stimulate bile

Explanation: The omega-3 fatty acids that count are those that are essential, i.e. the body can’t make them, EPA (C20) or DHA (C22), or that can be produced from ALA (C18). EPA and DHA can be converted into anti-inflammatory prostaglandins by COX, the enzyme that is blocked by aspirin. COX also converts omega-6 fatty acids into inflammatory prostaglandins. Unfortunately the corresponding short omega-6 fatty acids block the elongation of the short omega-3 ALA. For this reason, supplementing most vegetable oils, that are rich in omega-6 oils, with even high levels of omega-3 fatty acids, will still leave the vegetable oils inflammatory. In most cases the only alternatives are eating more fatty fish than you would normally eat or fish oil supplements.

Most people have found that without any symptoms of inflammation two gram capsules per day of combined EPA-DHA fish oil meet requirements for health. Two more capsules should be added per day for obesity and two more for other symptoms of inflammation, e.g. arthritis, allergy, etc. Spread the supplements over multiple meals. Eating the fish oil with other fat-rich food will improve absorbance in the gut by stimulating the release of bile -- capsules on their own will just slip on past. I would recommend an empirical approach -- start with two capsules a day and see if your symptoms lessen within a week. If not, increase by two more capsules a day and monitor your symptoms. The severity of your inflammatory inputs will determine how much fish oil is required. Other sources of omega-6 oils will sabotage the anti-inflammatory benefits of the omega-3 fatty acids supplements. Saturated fats and cholesterol are not as much of a problem as the omega-6 fatty acids (and of course trans fats.)

Obesity is a particular problem, because the fat is a source of omega-6 fatty acids that were eaten when your diet was worse. You will continue to pay for previous dietary errors. For this reason, a diet rich in olive oil is helpful, because fat stored from this oil will be low in omega-6 fatty acids that could be troublesome in the future. This may be a significant component of the benefit of the Mediterranean diet.