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DHA – An Overview

September 13th, 2009

From UMM.EDU.com:

Docosahexaenoic acid (DHA)
Overview:
Docosahexaenoic acid (DHA) is an omega-3 fatty acid. It is found in cold water fatty fish and fish oil supplements, along with eicosapentaenoic acid (EPA). Vegetarian sources of DHA come from seaweed. DHA is essential for the proper functioning of our brains as adults, and for the development of our nervous system and visual abilities during the first 6 months of life. In addition, omega-3 fatty acids are part of a healthy diet that helps lower risk of heart disease. Our bodies naturally produce small amounts of DHA, but we must get the amounts we need from our diet or supplements. Most people in the Western world do not get enough omega-3 fatty acids in their diet.

Uses:
Attention-Deficit Hyperactivity Disorder (ADHD)

Because omega-3 fatty acids are needed for children’s brains to develop properly, researchers have examined whether fish oil might reduce ADHD symptoms. So far, results have been mixed. One study showed fish oil might help, but many patients dropped out of the study before it was completed.

Depression

Although some studies have shown that fish oil reduces symptoms of depression, it isn’t clear whether DHA alone has the same effect. Other studies suggest it may be EPA which has the positive effect on depression.

Heart Disease

Fish oil appears to have positive effects on existing heart disease. It also may lower the risk for developing heart disease. Omega-3 fatty acids found in fish oil help lower triglycerides (fats in the blood), lower blood pressure, reduce the risk of blood clots, improve the health of arteries, and reduce the amount of arterial plaque (which narrows arteries and causes heart disease).

Infant Development

DHA plays a crucial role in the growth and development of the central nervous system as well as visual functioning in infants.

Rheumatoid Arthritis

Several small studies indicate that fish oil may help reduce symptoms and inflammation associated with rheumatoid arthritis. However, it does not stop the progression of the disease.

Menstrual Pain

Fish oil appears to reduce the pain of menstrual cramps when taken on a regular basis (not just when menstruating).

Raynaud Syndrome

Several studies show that high doses (12 g) of fish oil can reduce sensitivity to cold in the fingers and toes of people with Raynaud syndrome. Take doses this high only under a doctor’s supervision.

Lupus

Two small studies suggested that fish oil reduced fatigue and joint pain associated with lupus.

Dietary Sources:
DHA is found in cold water fatty fish, including salmon, tuna (bluefin tuna have up to five times more DHA than other types of tuna), mackerel, sardines, shellfish, and herring. Although some of these fish contain low levels of mercury, the Food and Drug Administration has found that consuming several servings of fish each week poses no risk to healthy people and conveys many health benefits. Women who are pregnant or planning to become pregnant should avoid Atlantic mackerel, shark, swordfish, and tilefish. They should also limit consumption of white albacore tuna to under 6 oz. per week. (High-quality fish oil supplements made by manufacturers who test for mercury and other toxins do not pose the same risk of mercury contamination. Read labels carefully and check for purity, or ask your doctor to help you find the best quality DHA supplement.) For infants, breast milk from a well-nourished mother contains significant amounts of DHA, while infant formula may not have any DHA. Read labels carefully to find a brand that does.

Available Forms:
DHA is available as a supplement in two common forms:

Fish oil capsules [which contain both DHA and EPA (eicosapentaenoic acid), another omega-3 fatty acid]
DHA extracted from algae (which contains no EPA)
How to Take It:
Pediatric

Breast-fed infants should receive enough DHA if the mother gets enough of this fatty acid.
Adult

Most studies have used 1,000 – 2,500 mg of DHA per day.
In the diet: 2 – 3 servings of fatty fish per week, which corresponds to 1,250 mg EPA and DHA per day.
Fish oil supplements: 3,000 – 4,000 mg standardized fish oils per day. Read the label to check levels of DHA and EPA, which are not the same as mg of fish oil. Higher doses are generally considered safe, but people who take blood-thinning medication or people who have hemophilia should check with their doctors to determine a safe dose.
Pregnant women: 200 mg DHA per day
Algal-derived DHA supplements: 200 mg per day
Some fish oil supplements also contain vitamin E to maintain freshness.

Precautions:
Fish oil capsules contain both DHA and EPA. Supplements containing EPA may not be recommended for infants or small children because they upset the balance between DHA and EPA during early development. Pregnant women should talk to their doctor before taking fish oil supplements.

Fish oil capsules may cause minor side effects, such as loose stools, abdominal discomfort, and belching. In addition, they may prolong bleeding time slightly. If you take blood-thinning medication, talk to your doctor before taking fish oil.

Possible Interactions:
Blood Pressure Medication — DHA may lower blood pressure, so it could make the effects of prescription blood pressure medication stronger.

Anticoagulants (blood thinners) — EPA in fish oil supplements may increase bleeding time, so fish oil could make the effects of these drugs stronger. The same does not appear to be true of DHA alone.

Diabetes medications — Theoretically, fish oil supplements may lower levels of glucose in the blood and could make effects of diabetes drugs stronger. If you have diabetes, talk to your doctor before taking fish oil.

Aspirin — In combination with aspirin, fish oil could be helpful in the treatment of some forms of coronary artery disease. However, this combination may also increase the risk of bleeding. Talk to your doctor to see if this combination is right for you.

Cyclosporine — Omega-3 fatty acids may reduce some of the side effects associated with cyclosporine therapy, which is often used to reduce rejection in transplant recipients. Talk to your doctor before adding any new herbs or supplements to your existing medication regimen.

DHA – Unraveling Natures Gift

September 11th, 2009

By David Perlmutter, MD, FACN, ABIHM

Perhaps no other “brain nutrient” is receiving as much attention lately as is docosahexaenoic acid (DHA). And with good reason. Scientists have been aggressively studying this critically important brain fat for the past several decades for at least three important reasons.

1. BRAIN BUILDER

First, more than two thirds of the dry weight of the human brain is fat, and of that fat, one quarter is DHA. In the brain, DHA, along with other important fats like phosphatidylserine (PS) and phosphatidylcholine (PC), is an important building block for the membranes surrounding brain cells. This includes the areas where one brain cell connects to another (synapse) so DHA gets to the heart of brain activity. So, from just a structural point of view, DHA plays a fundamental role – that is, it is involved directly in the transmission of information from one neuron to the next.
2. INFLAMMATION REGULATOR

Second, DHA is one of nature’s important regulators of inflammation. Inflammation is ultimately responsible for a large number of brain maladies – like Alzheimer’s, Parkinson’s, ADHD, and multiple sclerosis, to name a few. DHA naturally reduces the activity of the COX-2 enzyme and as such, acts a lot like the so-called “COX-2 inhibitor” medications now on the market. Activity of the COX-2 enzyme turns on the production of damaging chemical mediators of inflammation, so naturally inhibiting the enzyme helps put out the fire.
3. GENETIC STIMULATOR

The third, and perhaps the most exciting activity of DHA is its role in modulating gene expression. This seemingly simple structural fat actually has the power to turn on specific genes, unlocking our DNA and allowing certain proteins to be manufactured.

Brain Derived Neurotrophic Factor (BDNF) is one such protein. The functions of BDNF in the human brain are compelling. In brain development, BDNF helps orchestrate the production, synaptic connection and selective pruning of brain cells and their connections.

As we age, BDNF helps maintain our brain cells, fosters their repair when damaged, and what is most exciting, actually stimulates the growth of new brain cells in the human brain. The long held dogma that we couldn’t grow new brain cells has now been overthrown as research now demonstrates that humans possess the ability for brain cell renewal throughout our entire lifetimes, and this activity is under the guidance of BDNF. And again, it is DHA among all other dietary fats, that helps stimulate BDNF.

Dr. Stephen Cunnane of the University of Toronto goes so far as to credit DHA with a pivotal role in the evolution of the human brain. Anthropologists have long wondered why the human brain weighs nearly twice as much as our earliest human relative, Homo habilus from two million years ago.

Cunnane states, “Anthropologists and evolutionary biologists usually point to things like the rise of language and tool-making to explain the massive expansion of early hominid brains. But this is a Catch-22. Something had to start the process of brain expansion and I think it was early humans eating clams, frogs, bird eggs, and fish from shoreline environments. This is what created the necessary physiological conditions for explosive brain growth.”

“Homo habilus… needed the gene activation from DHA to make the evolutionary leap.”

Our earlier ancestors inhabited savannahs and forests and therefore had little exposure to food sources rich in brain-boosting DHA. It is only when Homo bilus migrated to shorelines of rivers and lakes which, were common in the prehistoric Rift valley, that DHA rich marine foods were consumed.

This is a powerful example of environmental influences (DHA rich food) affecting genetic expression. So early Homo habilus was genetically predisposed to the development of a larger more powerful brain, but needed the gene activation from DHA to make the evolutionary leap.

DHA provides life changing advantages for the developing child’s brain – including improved cognitive function, enhanced visual acuity and hand-eye coordination, as well as a reduced risk for ADD/ADHD, behavioral issues, and depression.

Exploration into the role of this critically important nutrient in the adult has only just begun. The benefits include a lower risk of dementia, Alzheimer’s disease, depression, and more. There are also advantages unrelated to brain health such as improved cardiovascular function, lowered levels of triglycerides, and reduced risk of macular degeneration.

In the past, fish consumption has been advocated as a meaningful way to increase DHA availability, but well founded concern regarding mercury and PCB exposure from fish consumption makes alternative sources of DHA more attractive.

Nutritional supplements containing DHA from non-fish sources (marine algae) are becoming widely available. In addition, because of the burgeoning science supporting the fundamental role of DHA in brain health, various food manufacturers are now incorporating DHA derived from algae into a variety of food products ranging from infant formula to cereal bars.

Because DHA enriched foods are entering the marketplace, I believe, there will be a dramatic effect on the brain health and function of our population. The marketing efforts designed to support these products will surely raise the public’s awareness of this fundamental nutrient supporting my contention that DHA is to the brain what calcium is to the bones.

Omega Fatty Acid Balance Can Alter Immunity And Gene Expression

June 2nd, 2009

From ScienceDaily.com:

For the past century, changes in the Western diet have altered the consumption of omega-6 fatty acids (w6, found in meat and vegetable oils) compared with omega-3 fatty acids (w3, found in flax and fish oil). Many studies seem to indicate this shift has brought about an increased risk of inflammation (associated with autoimmunity and allergy), and now using a controlled diet study with human volunteers, researchers may have teased out a biological basis for these reported changes.

Anthropological evidence suggests that human ancestors maintained a 2:1 w6/w3 ratio for much of history, but in Western countries today the ratio has spiked to as high as 10:1. Since these omega fatty acids can be converted into inflammatory molecules, this dietary change is believed to also disrupt the proper balance of pro- and anti- inflammatory agents, resulting in increased systemic inflammation and a higher incidence of problems including asthma, allergies, diabetes, and arthritis.

Floyd Chilton and colleagues wanted to examine whether theses fatty acids might have other effects, and developed a dietary intervention strategy in which 27 healthy humans were fed a controlled diet mimicking the w6/w3 ratios of early humans over 5 weeks. They then looked at the gene levels of immune signals and cytokines (protein immune messengers), that impact autoimmunity and allergy in blood cells and found that many key signaling genes that promote inflammation were markedly reduced compared to a normal diet, including a signaling gene for a protein called PI3K, a critical early step in autoimmune and allergic inflammation responses.

This study demonstrates, for the first time in humans, that large changes in gene expression are likely an important mechanism by which these omega fatty acids exert their potent clinical effects

Fatty acids and fishy questions

May 17th, 2009

While valid debates rage over declining fish stocks, where should consumers look to find omega-3s?

From 2Canada.com:

It’s been a controversial couple of weeks for our friends from the deep blue sea. Two weeks ago, the Journal of the Canadian Medical Association published an analysis that not only called into question the purported benefits of omega-3 fatty acids, but also criticized the use of fish oils as ecologically unsustainable. Just days later, the International Society for the Study of Fatty Acids and Lipids (ISSFAL) issued a research summary confirming that omega-3s from plant sources such as flaxseed cannot be converted efficiently enough in the human body to offer any significant benefit, making marine sources of omega-3s our best bet for fighting disease.

Unfortunately, this kind of contradictory advice tends to generate frustration for consumers, who end up feeling pulled in different directions (“When will you people get your stories straight?” is a common complaint). The odd thing about this story, though, is that it turns out both sides make a good point. (Life is never simple, is it?) So let’s sift through all the talk and see if health-conscious consumers can have their omega-3s and keep eating them, too.

A QUICK REFRESHER ON OMEGA-3S

Omega-3 fatty acids are an essential type of fat thought to confer a variety of health benefits. Along with their counterparts, omega-6 fatty acids, omega-3s need to be consumed through food, as they cannot be manufactured in the body. Once inside the body, omega-3s are incorporated into cell membranes, making them more fluid, while also sending signals that reduce inflammation throughout the body. Ultimately, they seem to make our joints less stiff, our arteries more flexible and our brains healthier.

It’s generally accepted that our diet contains both lower levels of omega-3s than those of our ancestors, as well as higher levels of omega-6s. Since omega-3s are largely obtained from fish, while omega-6s are available through numerous types of plant oils (such as sunflower and safflower oils) that are commonly used in food processing, it has been estimated that we consume far more omega-6 than omega-3 fatty acids. The result, in theory, is a higher proportion of pro-inflammatory signals being sent through our body, making us more prone to heart disease, cancer, diabetes and other chronic ailments.

Within the family of omega-3s, there are actually different sub-types, which — at least in theory — can be interconverted. One, known as alpha-linolenic acid, or ALA, is found primarily in plant sources, such as flaxseed, walnuts and canola oil, while others, known as eicosapentaenoic acid, or EPA, and docosahexaenoic acid, or DHA, are generally only available from fish and marine-derived sources.

ALA TO DHA: LOST IN TRANSLATION

The controversy addressed in the ISSFAL statement surrounds the conversion of ALA to DHA (DHA is essentially the endpoint of omega-3 metabolism in humans). For years, evidence has been mounting that our bodies simply do not convert ALA to DHA, even though we theoretically have the enzymes to do so. In reality, the amount of ALA that finally becomes DHA — and therefore can be useful to our bodies –is estimated to be close to zero. While ISSFAL wasn’t breaking any new ground with their statement, their point is that the evidence is convincing enough that we should be focusing on consuming “pre-formed” DHA, rather than relying on ALA sources to get us our omega-3s. (Note, however, that ground flaxseed can potentially provide numerous other health benefits from its fibre and lignan content — in other words, it’s worth more to us than just its ALA.)

BUT WHAT ABOUT THE FISH?

If we go by the recommendations of numerous internationalhealth-related organizations, not only do we need to get our omega-3s from the sea, we need to get a couple of servings per week to prevent heart disease, and even more if we already have heart disease or high triglycerides. Since eating that much fish is not palatable for everyone, the next step for many is to take a fish oil supplement.

This is where the CMAJ analysis takes exception: Its authors argue that, with global fish stocks on the brink of collapse, it is irresponsible to recommend an increase in fish consumption, especially since (as they argue) the evidence to support the benefits of fish is not clear. They point to numerous large-scale analyses of fish and fish oil use that have shown an inconclusive or marginal benefit of fish to heart health, in particular, not to mention other medical conditions.

ALTERNATIVES — FOR TIMES WHEN THERE AREN’T ENOUGH FISH IN THE SEA

While getting into the details over the various analyses of the benefits of fish is beyond the scope of this column, there are still enough researchers and medical organizations that believe omega-3s are good for us that it makes sense to look into alternatives to reduce pressure on the fish population. As author Taras Grescoe outlined in his acclaimed 2008 book, Bottomfeeder, smaller, bottom-feeding fish, such as sardines, herring and anchovies are not only rich sources of omega-3 fatty acids, but their rapid reproduction rates allow their populations to regenerate faster than larger fish. While not the most popular choices for North American eaters, Grescoe maintains that there are plenty of ways to enjoy these more eco-friendly fish.

Beyond the bottomfeeders, there is another, growing alternative to fish-based omega-3s: DHA from algae. Now available in supplemental form, as well as added to various food products, algal DHA is considered a far more sustainable means of getting your omega-3s while bypassing fish entirely. Having said that, there is limited research in algal DHA (we assume it works just as well as the fish form), but for now, it looks to have a bright future.

Finally, I think it’s worth mentioning again that, just because some of something is good, does not mean that more is better. While eating fish a couple of times per week seems to be good for your health, eating large, predatory fish on a regular basis or eating fish on a daily basis and taking vast amounts of fish oil supplements puts more pressure on our fish stocks, likely outweighing any health benefits the fish provide you. As always, exercising moderation is likely the best path to follow.

- Jennifer Sygo is a dietitian in private practice at Cleveland Clinic Canada (clevelandcliniccanada.com), which offers executive physicals, prevention and wellness counselling and personal health care management in Toronto.

Fish Oil Protects Against Diseases Like Parkinson’s

April 26th, 2009

Dr. Perlmutter’s comment:
This interesting report again confirms the importance of DHA in terms of protecting the brain. DHA is also widely available as a vegetarian product, derived from marine algae.

From ScienceDaily.com:

Dr. Nicolas Bazan, Director of the Neuroscience Center of Excellence, Boyd Professor, and Ernest C. and Yvette C. Villere Chair of Retinal Degenerative Diseases Research at LSU Health Sciences Center New Orleans, will present new research findings showing that an omega three fatty acid in the diet protects brain cells by preventing the misfolding of a protein resulting from a gene mutation in neurodegenerative diseases like Parkinson’s and Huntington’s.
Dr. Nicolas Bazan, Director of the Neuroscience Center of Excellence, Boyd Professor, and Ernest C. and Yvette C. Villere Chair of Retinal Degenerative Diseases Research at LSU Health Sciences Center New Orleans, will present new research findings showing that an omega three fatty acid in the diet protects brain cells by preventing the misfolding of a protein resulting from a gene mutation in neurodegenerative diseases like Parkinson’s and Huntington’s.