Why High Quality DHA is So Important
Sunday, February 22, 2009
Byron J. Richards, Board Certified Clinical Nutritionist
DHA is the most biologically useful omega 3 fatty acid. The purpose of this brief review is to explain the extreme value of DHA to your health.
Fish Oil is now recognized as an important nutrient for the prevention of heart arrhythmias1 that lead to sudden death. These omega 3 oils have significant scientific proof that they can extend your life. They are also a superior nutrient to assist fat-related calorie burning. They promote the health of your white adipose tissue so that you can lose weight or maintain a healthy weight more easily, as well as helping you not become type II diabetic2.
What are Omega 3 Essential Fatty Acids and How Much Do You Need?
Omega 3 essential fatty acids are a unique type of fat that cannot be produced by your body from other fats and thus must come from your diet. All cell membranes in your body can use them to regulate health, and minimally they are needed for growth – which is the original reason for them being termed essential.
The length of an omega 3 fatty acid, in terms of its carbon spine, is very important. The shorter omega 3 is called α-linolenic acid (ALA). It is 18 carbons long with three unsaturated bonds (starting at the 3rd carbon – thus the name omega 3). ALA is the type that is found in non-animal omega 3 oils such as flax3, chia seeds, perilla, and walnuts. Another 18 carbon omega 3 is called stearidonic acid, and this time has four unsaturated bonds. Black current seed oil is a rich source of stearidonic acid.
Fish oil is composed of two main types of omega 3 oils, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These oils are longer in length (EPA is 20 carbons, DHA is 22) and they have more unsaturated bonds (EPA has 5, DHA has 6). The number of unsaturated bonds in an essential fatty acid is also important, as these are points of interaction in your metabolism.
DHA is by far the most biologically active4 omega 3 oil, due to its length and the number of unsaturated bonds it possesses. It is the dominant type that is found in your cell membranes. DHA, not EPA, is the primary fatty acid associated with cardiovascular health5 and improved circulation.
Plant-based omega 3 oils can be converted to DHA by your body’s enzyme system; however, this process is inefficient. Research shows that ALA is made into DHA at only a 2 – 5 % rate, meaning it is an inferior source of omega 3 oils for cardiovascular health.
When animals are range raised then the ALA omega 3 in the grass they eat is converted by the animal to EPA and DHA and stored in their fat. Most of the animals in the American food supply do not eat grass and have little omega 3 oils in their fat, leaving fatty fish as the main dietary source of DHA omega 3 oil. Fish have their own problems, meaning they are prone to accumulate mercury, PCBs, and other fat soluble toxins. Farm raised fish are not raised in cold, deep ocean waters, and therefore do not make as much fatty insulation to protect against the cold, and thus have lower levels of EPA and DHA.
Our food supply is lacking in high quality DHA, compared to our evolutionary diet. Making matters worse, omega 3 oils, which are anti-inflammatory in nature, are overwhelmed by the widespread use of pro-inflammatory omega 6 oils such as soy oil, corn oil, sunflower oil, and cottonseed oil. The historical ratio of omega 6 to omega 3 is 4:1. The typical American diet can be as high as 30:1 in favor of omega 6. Too much omega 6 oil blocks the enzymatic conversion of ALA to DHA. And today, most soy and corn oil is genetically modified with toxins spliced into the DNA of the food, making them even more pro-inflammatory.
Government guidelines for omega 3 consumption are 1600 milligrams per day for men and 1100 milligrams per day for women. Another scale used suggests a range of 0.6% – 1.2% of total energy (1300 – 2600 mg for a 2000 calorie diet). No guidelines are given for the amount of the very important DHA. Since ALA may not be converted to DHA, the government guidelines are somewhat useless.
Studies with a combination of EPA and DHA show that 1000 mg per day (600 EPA/400 DHA) is adequate to protect against a second heart attack6. However, a higher level of change occurs at doses in the 3000 – 4000 mg range (1800-2400 EPA/1200-1600 DHA), such as significantly lower triglycerides7, lower blood pressure, less sticky platelets, lower inflammation, and improved vascular function (important for changing cardio risk factors and losing weight).
The Need for High Quality DHA
DHA is the key biologically active essential fatty acid that you want to make sure you get in adeqaute amounts. Specific amounts of DHA have been extensively tested in humans.
In patients with persistently elevated triglycerides8 2160 mg of DHA lowered their triglycerides by 27% within three months and sustained that reduction at six months, whereas half that dose did not. 1560 mg of DHA has been shown to improve heart rate variability in overweight adults9 and do the same for athletes10. Having better heart rate variability is a main way to stop cardiovascular-related death, as well as to be able to exercise healthier.
In a four ounce serving of salmon or tuna you will get about 2,000 mg of EPA and DHA (1200 mg of EPA and 800 mg of DHA). Japanese men consuming this amount of fish every day have half the rate of heart disease and twice the blood levels of essential fatty acids, compared to Japanese men living in America.
A study in Alzheimer’s patients with 1700 mg of DHA proved significant uptake and incorporation of DHA into cells membranes and significant inflammation reduction. In fact, DHA is known to boost brain cell health and protection by a variety of mechanisms, even protecting against Parkinson’s.
This data means that if you have cardio risk factors, especially if you are overweight, have high blood pressure, elevated triglycerdies, or cognitive decline, a highly protective dose of DHA is in the 1500 – 2000 mg a day range. Data shows that 2000 mg of DHA11 optimizes plasma levels, though does in the range of 400012 – 600013 mg of DHA per day have been tested in humans. If your problems are less concerning, you can benefit from 400 – 1000 mg of DHA per day.
In my opinion everyone at any age should have at least 100 – 300 mg of DHA per day, as part of a healthy diet, just to meet basic nutritional needs and help prevent obesity (many Americans are lacking). Smaller doses of fish oil have been proven to improve circulation in even healthy young people, meaning that it is likely to help prevent the slow and gradual decline that accompanies the wear and tear of aging by maintaining more optimal health.
The amount of DHA in fish oil will vary from 10% - 20% of most formulations. Thus, in traditional fish oil capsules you will need 5000 – 10,000 mg of fish oil (5 to 10 capsules), to get 1000 mg of DHA. These capsules also contain larger amounts of EPA than DHA. EPA can actually get in the way of DHA getting into your brain, EPA is not the primary oil needed for health benefits, and EPA is a primary blood thinner (meaning you can bruise too easily before you get to a dose that really helps).
When I design dietary supplements I use a special fish oil raw material that is 50% DHA and 10% EPA, so that you can get the higher levels of the beneficial DHA without getting too much of the blood thinning EPA. The material I use is also molecularly distilled, meaning any mercury, PCBs, or other toxins have been removed.
Even the very conservative Mayo Clinic has come out and said that Americans should be taking fish oil for the prevention and treatment of cardiovascular disease.
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