|
2007/01/09, 11:06 PM
http://www.ericcressey.com/fishyadvice1.html
Fishy Advice: Part I
By Eric Cressey
If you're even remotely up-to-date on your nutrition-for-health reading, you're well aware of the benefits of fish oil. Moreover, if you're anything like me, you've also gone to great lengths--often to no avail--to convince people that they should be taking it even if it does sound "icky." In an effort to save you and I a lot of future time and energy, I've compiled the following for you to share with your relatives, mailman, proctologist, lunchlady, and anyone else with whom you associate that isn't currently "on da fish."
Based on undeniable scientific evidence and anecdotal evidence, I strongly encourage you to incorporate into your diet two specific omega-3 fatty acids: eicosapentaenoic acid (EPA) and docosahexanoic acid (DHA), commonly referred to as fish oils. EPA and DHA deficiencies have been linked to problems that include, but are certainly not limited to heart disease, hypertension, arthritis, cancer, immune disorders, chronic intestinal disorders, growth retardation, liver disorders, skin lesions, reproductive failure, visual problems, kidney disorders, and neurological disorders (1).
Dietary alpha-linolenic acid can be converted to EPA and DHA in the body for utilization as important raw materials in healthy cell membranes. Significant amounts of alpha-linolenic acid can be found in the following oils: flaxseed, soybean, hempseed, pumpkinseed, canola, wheat germ and walnut. Products such as margarine and shortening that are derived from these oils also contain modest amounts of alpha-linolenic acid. Some nuts and seeds-- butternuts, walnuts, pumpkinseeds, and flaxseeds-- and vegetables (soybeans) are good sources as well (1). However, the conversion of alpha-linolenic acid to EPA and DHA is quite inefficient; estimates place the conversion rates at less than 5-10% for EPA and 2-5% for DHA (2). Lifestyle factors can also negatively influence these conversions. There is also evidence to suggest that females are more efficient at converting linolenic acid than men; this is likely due to increased demands for EPA and DHA during pregnancy and lactation (3). Even if you eat plenty of the aforementioned foods regularly, you still might come up short on EPA and DHA because the fatty acid quality is often degraded due to the typical overprocessing that occurs in commercial production (4). As such, it is best to get your EPA and DHA directly whenever possible.
EPA and DHA are commonly referred to as fish oils because coldwater fish are by far the best sources. Although the terms EPA/DHA and fish oils are substituted for one another in writing and conversation, EPA and DHA are actually just two kinds of fatty acids contained in fish oils (5). These fish include, but are not limited to: salmon, mackerel, bluefish, tuna, mullet, herring, anchovy, and sardines. Infants receive plenty of EPA and DHA from their mothers' milk (1). Certainly, eating fish every day isn't appetizing for most people, and drinking human milk after the age of one is neither feasible nor socially acceptable! Plus, the typical vegetarian diet is extremely low in alpha-linolenic acid, so even if conversion was efficient, these individuals would still be coming up short (clinical studies have proven that vegetarians have insufficient levels of EPA and DHA) (2). Luckily, fish oil supplements in both liquid and softgel form are widely available to ensure that EPA and DHA requirements can be met easily.
EPA and DHA exert their most powerful effects in an anti-inflammatory role. Arachidonic acid, which is created out of the omega-6 fatty acids in our diets, serves as the building block for certain eicosanoids that control the synthesis of cytokines that are pro-inflammatory and immunoregulatory; when these cytokines are overproduced, chronic inflammatory diseases (and even septic shock) can result. Omega-3 fatty acids, on the other hand, inhibit the production of arachidonic acid--thus preventing the production of certain mediators of inflammation--and serve as the raw materials for a healthier class of eicosanoids with anti-inflammatory properties (6). Given how out-of-whack the typical diet is in terms of the omega-6: omega-3 ratio, it should come as no surprise that the world is as unhealthy as it is!
Here is some pretty impressive data on a variety of fronts:
Cardiovascular Health/Atherosclerosis/Hyperlipidemia/Hypertension:
An eleven year study of 20,557 male U.S. physicians showed that those who consumed fatty fish at least once per week were 52% less likely to suffer a sudden cardiac death than those who only ate it once per month or less (5).
The typical Greenland Eskimo diet is devoid of fruits and vegetables and very high in fats from animal sources: not your traditional "heart healthy diet." However, the Eskimos had far lower instances of coronary heart disease (CHD) than a Denmark population of nearly identical ethnical composition (same ancestors). The Eskimo and Danish diets both consisted of a high percentage of calories from fat (39% and 42%, respectively), so why didn't the Eskimos suffer from such CHD like the Danes and everyone else? The secret lay with the types of fat that the Eskimos were eating. The typical Danish diet consisted of 22% of total calories from saturated fat and less than 1% from omega-3 polyunsaturated fatty acids (PUFAs). Meanwhile, only 9% of total calories in the Eskimo diet came from saturated fat. Perhaps more importantly, 4.2% of the Eskimos' total calories came from omega-3 PUFAs (5). Similar trends are readily apparent in coastal villages of Korea and Japan and throughout Scandinavian countries. Not surprisingly, they all rely extensively on coldwater fish in their everyday lives. Need further proof? A recent comparison of two Japanese villages: one fishing, one farming, found that the farming village had eight times more atherosclerotic plaques than their fishing counterparts (7).
In a study of 59 patients with diagnosed heart disease, Durrington et al (2001) monitored the effects of 2 g daily of Omacor, a pharmaceutical grade fish oil concentrate. The researchers found that "there was a sustained significant decrease in serum triglycerides by 20-30% and in very low density lipoprotein (VLDL) cholesterol by 30-40% in patients receiving active Omacor at three, six, and 12 months compared either to baseline or placebo (8)."
Not only do fish oils lower serum triglycerides and, in high dosages and combination with dietary modifications, low density lipoprotein (LDL) cholesterol, but they also decrease arterial platelet collection, which can lead to dangerous clots (5).
Harper and Jacobsen (2001) reported that randomized clinical trials with fish oils "have demonstrated reductions in risk that compare favorably with those seen in landmark secondary prevention trials with lipid-lowering drugs (5)."
Following coronary artery bypass surgery with venous grafts, patients that receive 4 g per day of omega-3 fatty acids have a significantly lower risk of graft occlusion (obstruction/closure) (9).
Hypertension:
There are like 80 bizillion studies out there proving that fish oil reduces blood pressure (although you'll obviously derive greater benefits if you eat right and exercise, too). That said, 4 g omega-3 fatty acids per day is the minimum you'll need to see an improvement (9). You can expect not only reduced blood pressure, but also decreased vascular wall thickness (10). I've included a few more references (11-13) for those of you that either don't believe me or have a lot of time on your hands for extra reading.
Cardiac Arrhythmias:
There is significant backing for the assertion that fish oils' antiarrhymthic capacity is the most important. Without sufficient EFAs, the body is forced to make cell membranes out of saturated fatty acids, which yield membranes that are far less elastic. When cardiac cells are made from EFAs (and are thus appropriately elastic), the heart has an easier time returning to a resting state. However, the rigid cell membranes made from saturated fatty acids can cause arrhythmias and alter the cardiac muscle cell contraction (5).
Inflammatory Diseases of Joints and Connective Tissues:
In patients with degenerative and inflammatory joint diseases, supplementation with omega-3 fatty acids decreases both the "degradative and inflammatory aspects of chondrocyte metabolism, whilst having no effect on the normal tissue homeostasis (14)."
Chondrocytes are the building blocks of articular cartilage and work with the extracellular matrix of collagen and proteoglycans to dissipate forces. If the cartilage is constantly eroding due to chondrocyte degradation, the structure tends to soften as its water content increases. Interventions with omega-3 fatty acids are effective in reducing these negative trends and their related symptoms in most patients with osteoarthritis (15,16).
http://www.sherdog.net/forums/showthread.php?t=477258
Originally Posted by Charles Poliquin
For those of us interested in positively and optimally altering body composition and maximizing our training efforts, fish oils offer thirteen possible advantages:
1. Cell membrane health: EPA and DHA insure that cell membranes remain healthy. This means that the membranes are flexible and contain larger numbers of insulin receptors that are more receptive and responsive to circulating insulin. This results in decreased fat storage in the adipocytes (fat cells).
2. Fish oils turn on the lipolytic genes (fat burning genes).
3. Fish oils turn off the lipogenic genes (fat storage genes).
4. Fish oils diminish C-reactive proteins, a newly identified risk factor associated with various inflammatory diseases, including atherosclerosis, angina, coronary heart disease, heart attack, stroke, congestive heart failure, and diabetes. The DHA fraction of the fish oil seems to be one most responsible for that protective effect. DHA also has the best ability to reduce blood pressure.
5. Increase utilization of fat stores from the adipocytes.
6. Preferential utilization for energy production once stored in the adipocytes.
7. Reduced inflammation from physical training.
8. Pain management from the reduced inflammation.
9. EPA regulates blood supply to the brain which is essential in maintaining focus in weight training sessions. DHA is important in brain membranes, memory, and cognitive function.
10. Fish oils increase serotonin levels (the happy neurotransmitter). Therefore, fish oils will decrease incidence of depression, anxiety, panic attack, and reduce carbohydrate cravings.
11. Fish oils will improve your cardiovascular risk profile by lowering VLDL, triglycerides, homocysteine, fibrinogen, and increasing HDL levels. Combining fish oils with plant sterols will improve lipid levels even more than either alone.
12. Fish oils can also decrease blood pressure by several mechanisms. These include increases in the vasodilatory compound, nitric oxide, reducing vascular inflammation, blocking the constrictive elements in the vascular wall such as the calcium channels reducing blood viscosity, and inhibiting a blood vessel constrictor (thromboxane). Lipoprotein (a) is another CVD predictor that can be lowered by fish oils (a 19% reduction was seen with natural, stable fish oils and just 4% with a highly purified fish oil).
13. Fish oils are a great stress fighter. Supplementation with n-3 fatty acids inhibits the adrenal activation of steroids, aldosterone, epinephrine, and norepinephrine (catecholamines) elicited by a mental stress, apparently through effects exerted at the level of the central nervous system. Therefore, for the same amount of stress, one will produce fewer stress hormones if consuming fish oils on a regular basis.
http://www.t-nation.com/readTopic.do...dra?id=1371812
|
