Seafood for Thought: Part 1 (How to find sustainable seafood)

Overfishing is the greatest threat to our oceans today. About 130 million tons of seafood is harvested every year- that's double of what it was in the 1970s! 90% of all large, predatory fish (like tuna and cod) are already gone from the world's oceans, and
nearly 75% of the world's fisheries are fished to capacity, or overfished... a situation that’s only getting worse, putting at risk the over 120 million people worldwide who depend on fish for their incomes....

The fishing gear used to catch seafood is also destroying ocean ecosystems and catches non-target, often endangered, species like sea turtles, seabirds and marine mammals.

There’s also the issue of illegal fishing that puts further pressure on stocks, and on the food security of coastal communities.

According to Greenpeace, we’re taking 2.5 times more out of the sea than what is sustainable, and we need to ease up on the volume we consume. That said, lots of people like seafood and it’s recommended as a great source of that beneficial omega 3 fatty acid –DHA...

So what’s an environmentally-conscious fish lover to do?

Our seafood choices have the power to make this situation worse, or improve it. And to improve it, we need to start consuming seafood in a sustainable manner.

Sustainable seafood can be defined as species that are caught or farmed in a way that ensures the long-term health and stability of that species, as well as the greater marine ecosystem.

There are a few great programs out there that can help us get sustainable seafood on our plates.

Greenpeace’s Redlist
The Redlist is a list of seafood that are the most damaging and in need of immediate attention – a list of "what not to eat" and "what not to sell".
For example, in Canada, Atlantic Salmon (farmed), Atlantic Cod, Atlantic Haddock, and Atlantic sea scallops are on the Redlist.
Seafood markets and consumer preferences for seafood differ from country to country, so there are different Greenpeace Seafood Red Lists for different countries- make sure to look at your national Greenpeace website- click here.

SeaChoice (Canada)
SeaChoice is a Canadian sustainable seafood program, formed by five Canadian environmental groups including the David Suzuki Foundation. Their goal is to help Canadians take an active role in supporting sustainable fisheries and aquaculture.
They provide great seafood (and sushi) guides for your wallet with traffic-light scorecards- "Best Choices", "Some Concerns", and seafood you should "Avoid".
Click here to print out your own copy of the guides!

Seafood Watch (Monterey Bay Aquarium)
The Seafood Watch program helps American consumers and businesses make choices for healthy oceans. They offer handy pocket guides with a list of recommendation using the traffic-light system- seafood items that are "Best Choices," "Good Alternatives," and that should be "Avoided."
Their pocket guides are available for six regions of the U.S.: West Coast, Southwest, Central U.S., Southeast, Northeast and Hawaii and they also also have national and sushi versions of the pocket guides. All of their guides are updated every six months. Click here to print your own guide.

Ocean Wise (Vancouver Aquarium, Canada)
The Vancouver Aquarium is a non-profit association dedicated to effecting the conservation of aquatic life. Its Ocean Wise program works directly with restaurants, markets, food services and suppliers ensuring that they have the most current scientific information regarding seafood, and helping them make ocean-friendly buying decisions.
The Ocean Wise logo can be found in participating restaurants, markets and food-service outlets throughout Canada- currently there are over 300 participating members- all committed to providing ocean friendly alternatives to their customers. Click here to find out what restaurants are Ocean Wise in your area.

Not from Canada or the US?
Seafood Watch includes a list of organizations by country offering their own localized recommendations- click here.

Farmed versus Wild Salmon

Easy. Wild salmon's better.
But why?

First- a brief history:

Because wild salmon is only catchable from late May to late September (and even during the season, can be quite pricey), in the 1960s Norway invented a system of farming salmon in pens along the coastline. Today four countries produce about 98% of the world’s farmed salmon: Norway, Chile, the UK (mainly Scotland) and Canada. Most of the US’ farmed salmon comes from Canada and Chile.

Choosing wild salmon is better for the environment

• Farmed salmon are grown in floating netcages and fed processed anchovies, sardines, herring- all fish humans eat, thus reducing the amount of fish available for human consumption. Wild salmon eat deep-ocean small fish that are generally not eaten by humans. It takes a lot of fish- 3-5 lbs- to provide enough fish meal and fish oil to add 1 lbs of weight to a farmed salmon. Moreover, the small fish fed to the farmed salmon are caught closer to shore and are therefore more contaminated with PCBs, pesticides and dioxins.

• According to a 2003 study, a salmon farm of 200 000 fish releases as much fecal matter as 65 000 humans, killing marine animals and plants and causing harmful algae to grow.
  

• Over 1 million Atlantic salmon have escaped from their netcages into British Columbia waters. Farmed salmon have more diseases and can carry sea lice that eat fish flesh. The concern is not only that they spread their diseases but that they breed with the wild salmon and weaken their genetic makeup- farmed salmon have smaller fins and larger bodies- thus affecting their ability to survive.

Choosing wild salmon is better for your health

• A study that analyzed 700 wild and farmed salmon from 8 different countries found that farmed salmon contained 7 times higher levels of pesticides, PCBs and dioxins than wild salmon and eating it can increase your risk of getting cancer (see “putting it into perspective” below). As a result of this study, the US Environmental Protection Agency recommends you eat no more than 1 meal a month of farmed salmon from Washington state and Chile- the places with the least-contaminated farmed salmon. Farmed salmon from Canada, Maine and Norway were found to be twice as contaminated as the salmon from Washington and Chile, therefore the recommendation is to eat no more than 1 meal every 2 months of fish from those places. Lastly, farmed salmon from Scotland and the Faroe Islands were so contaminated that it's recommended you not eat it more than once a year!

• Salmon farmers often use antibiotics to help control the spread of disease. In fact, farmed salmon receives more antibiotics by weight than any other livestock. Many of the antibiotics used are the same ones used to treat human infections and traces of these substances are passed on to consumers and can contribute to the dangerous increase of antibiotic-resistant disease worldwide.

• Farmed salmon contains higher levels of unhealthy saturated fats and lower levels of beneficial omega-3 fatty acids because of the makeup of their feed—fish meal, fish oil and various by-products and filler.

Putting it into perspective

Your risk of cancer does increase if you eat pesticide-contaminated farmed salmon regularly. If you eat 6oz of farmed salmon from Washington or Chile once a month, your risk of getting cancer rises by 1 in 100 000.

Another way of looking at it

According to current stats, 33 000 of every 100 000 people will be diagnosed with cancer if they live to the age of 80.
If all 100 000 ate farmed salmon once a month, the number would rise to 33 001. If all 100 000 ate farmed salmon once a week, the number would rise to 33 004. If the farmed salmon was from Canada, the number would be 33 008.

Now, about 5000 of every 100 000 Americans will die of a heart attack, according to some estimates. If these 100 000 ate salmon- farmed or wild- once a week, the research estimates that there would be 1500 less deaths.

We know that cold-water fatty fish are great sources of the heart healthy DHA form of omega 3 that has a huge impact in lowering your risk of getting a heart attack or stroke. This is why it’s recommended you eat these fattier fish 2-3 times a week.

However, if you don’t want to eat fish- you can now purchase algae-oil supplements that provide the same type of beneficial DHA omega 3.
Fish oil supplements have been found to have very little, if any, contaminants.
You want to aim for 1 g of omega 3 from these sources but always talk to your doctor before taking any of these supplements!

Other tips and facts

Grilling your salmon and letting the juices drip away, cooking it until it reaches an internal temperature of 175 degrees Fahrenheit and removing the skin before eating it will reduce the amount of contaminants by at least half.

Farmed organic salmon means that the pens are less crowded and the fish are exposed to less pesticides.

All salmon from Alaska is wild. Chinook is the most contaminated, Chum is the least contaminated

Most salmon sushi is from farmed fish.

Most canned salmon is from Alaska therefore wild. It will have more sodium so buy salmon canned in water and rinse under water for at least a minute to reduce the sodium by about 40%.

Smoked salmon is usually farmed. Although the heating kills some of the contaminants, smoking creates others.

Farmed trout is high in omega 3 and less contaminated than salmon.

Sources:

Schardt D. Farmed salmon under fire. CSPI: Nutrition Action Healthletter. June 2004.
http://www.davidsuzuki.org/files/PSF_Salmon_Brochure.pdf

DHA makes smarter babies

I’ve been talking a lot about omega 3 and I’m sorry if this is of no interest to you! There was a comment (thanks Naznin!) re: DHA in breastmilk recently so I think this is an important topic to talk about.

During pregnancy, Omega 3 fats are incorporated in the fetal brain and lipids in the retina (eye). We know that the DHA form of omega 3 in particular plays an important role in optimal development of the central nervous system (ie. brain) and visual sharpness of babies. Developing infants can't efficiently make their own DHA and need to get it through their mother’s placenta during pregnancy and from breastmilk after birth.
The amount of DHA in a mother’s diet determines the amount of DHA in her breastmilk. This is why it’s important that moms and moms-to-be understand the need for them to get enough DHA in their diet. We know that Alpha-linolenic acid (ALA) (ie. flaxseeds, walnuts) form of omega 3 isn’t well converted to DHA so the moms’ best bet is to get a direct source of DHA.

According to the International Society for the Study of Fatty Acids and Lipids working group, maternal intake of DHA should be greater or equal to 300mg. Studies have shown that the average Canadian pregnant woman’s DHA intake is only about 80mg/day. Breastmilk is a source of DHA only if the mother’s DHA intake is adequate, which, as we’re seeing, it’s not. Nutritional education of pregnant women is necessary to fix this problem.

A reasonable explanation for why DHA intake in pregnant women is low is because DHA is found predominantly in fish/seafood, a food that is often avoided/limited by pregnant women. They’ve found that women eat fish once or so every 10 days during pregnancy because of concerns with respect to contaminants (eg, methyl-mercury in a few fish which can increase the risk of impaired brain development in the infant).

The Food and Drug Administration (U.S.) has recommended that women who are pregnant eliminate shark, swordfish, king mackerel, and golden snapper from their diets while limiting their consumption of other fish to 3 servings/week to minimize exposure to methyl mercury.

From Health Canada’s website: Predatory fish such as shark, swordfish, fresh and frozen tuna (not canned), have higher levels of mercury and should be consumed only occasionally. The health benefits of eating fish outweigh the risk of exposure to mercury if Health Canada consumption guidelines are followed. If you are an adult, limit your intake of these fish to no more than one meal per week. Pregnant women, women of child-bearing age and young children should be especially careful and limit their intake of these fish to no more than one meal a month.

A recent Canadian study found that the consumption of 2-3 servings weekly of salmon or rainbow trout, which would provide a daily averaged DHA intake of at least 300 mg/day during pregnancy, would not approach the tolerance levels for mercury, polychlorinated biphenyls, or dioxins and furans as set by Health Canada, the NRC (U.S.), or the World Health Organization.

However, if you don’t want to eat fish, algal oil (now available in capsules and just oil form) is a great source of DHA and, as I’ve blogged about previously, foods are being enriched with DHA now.

There is evidence from published clinical trials that women with higher DHA intakes (up to 1100 mg DHA daily), gave birth to infants with higher cognitive development scores and young children with higher IQ scores and mental processing scores up to 4 years of age.

A 2004 study published in Child Development found that babies whose mothers had high blood levels of DHA at delivery had advanced attention spans into their second year of life. During the first six months of life these infants were two months ahead of babies whose mothers had lower DHA levels.

Other current research suggests adequate levels of DHA may help reduce the risk of pre-term labor and decrease the risk of postpartum depression, improve babies’ sleep patterns and immunity (better allergy protection) and reduce to risk of allergic disease. Wow!

Once born, babies still need DHA and their only source of nutrition (incl. DHA) for growth and development is their mother's milk. Health Canada has reported that DHA represents an average of only 0.14% of the total fat in breast milk (due to current low DHA intakes) and it should be at least 0.35% - an amount that has been shown to result in better brain and visual functioning of infants. The direct consumption of DHA, at relatively low levels, provides a fairly rapid and marked improvement in the DHA level found in breast milk. An intake of 300 mg DHA/day during lactation has been found to elevate breast milk levels to 0.39% DHA.

Higher intakes of DHA (>200mg/day and up to 1183mg/day) during breastfeeding have resulted in babies scoring higher on cognitive tests after 30 months, greater visual development and acuity in term infants as well as optimized arousal in newborn infants.

Should moms choose DHA-fortified formula? I’ll blog about this another day but of course, breastfeeding is the best source of nutrition for your baby and also offers a plethora of other benefits! So, simple answer is: No. Increase your intake of DHA.

Sources:

http://dhaomega3.org ; http://www.ajcn.org/cgi/content/abstract/82/1/125?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=fish+oil&andorexactfulltext=and&searchid=1&FIRSTINDEX=0&sortspec=relevance&resourcetype=HWCIT http://jn.nutrition.org/cgi/content/abstract/135/2/206 ; http://nutrition.about.com/b/2005/09/27/dha-for-smarter-babies.htm ;
http://www.drlaura.com/sah/sahm.html?mode=view&tile=1&id=10576 ;;
http://www.hc-sc.gc.ca/iyh-vsv/environ/merc_e.html

What's Salba?

I first heard about Salba® through an email my mom received from a colleague of hers about a month ago. A few weeks later, a colleague of mine asked me if I had heard about Salba®. And since then, I've been hearing, and seeing, Salba® everywhere. A few weeks ago, while I was in Loblaws, I saw a cereal called Omega 3 granola, from President's Choice. It caught my eye and I looked at the ingredient list to find out what the omega-3 source was and lo and behold, it was Salba®!

What is Salba®?

Salba® is a trademark name for a very old seed called Chia (the white seed, not the black seed). Yup, chia as in the seeds used in Chia Pets!

Chia is a very ancient grain that was once a staple in the Aztec diet and is derived from the plant called Salvia hispanica L.

On the Salba® website, they compare Salba®, gram for gram, to normal foods. Below are their claims but it makes more sense to compare real measures. Chances are you wouldn’t consume much more than 2 Tbsp Salba® per day (12g), so let’s compare 12 g Salba® to real portions of other foods.

Salba® health claims on Salba® website. Salba® has....	Salba® (12g) nutrients	Nutrients of real portions of foods
1.5 x more magnesium than broccoli	46mg	18mg for ½ cup broccoli
1.1 times more fibre than All Bran	4g	12g for ½ cup
2.5 times more protein than kidney beans	3g	7g for ½ cup kidney beans
8 times more omega 3 than Salmon	2.5g	2.58 g for 4oz salmon
3 times more iron than spinach	0.95mg	1.6 mg 1cup raw spinach
2 times more potassium than a banana.	80mg	454mg for 1 banana
7 times more vitamin C than an orange	0.65mg	70mg for 1 orange
6 times more calcium than milk	92mg	319 mg for 1 cup milk

As you can see, the nutrition claims aren’t as dramatic when compared this way!

It’s also important to remember that the omega 3 is in the alpha-linolenic acid (ALA) form and not the more beneficial DHA form that’s found in fish or algae.

The website further claims that Salba® is the only type of Salvia hispanica L. that has undergone intensive clinical examination. To my knowledge though, there has been only one study done on Salba® (see below) and only 20 people participated in it!

They also claim that: “In acute and long-term clinical studies conducted on individuals with Type 2 Diabetes, Salba® reduced after-meal blood glucose and plasma insulin levels, thereby improving insulin sensitivity, reduced blood pressure, and was effective in reducing risk factors of heart disease, such as body inflammation (C-reactive protein (CRP) and coagulation factors (aspirin-like effect)”. Let’s look at this study:

For some reason ($?), a Toronto doctor, Vladimir Vuksan, and his team at St. Michaels decided to uncover the magic behind this seed and have published their results in Diabetes Care last year. Their research is the only one done on Salba® and, interestingly, Dr. Vuksan holds the patent on Salba®. Wouldn’t you say there’s a bit of conflict of interest involved? I would!

Their study was meant to determine if people with Type 2 diabetes that took Salba® along with conventional treatments had improvements in the cardiovascular risk factors.

27 eligible subjects were enrolled in the study but only 20 people with Type 2 diabetes were included in the final analysis.

The participants were randomly given either 15g/1000 calories of Salba® or the same amount of wheat bran (which, supposedly, has little effect in glucose tolerance). They were also instructed on following a diet recommended by the Canadian Diabetes Association that focuses on low glycemic foods, a 55% carb, 15% protein and 30% fat diet and 25-35g fibre diet. They were also told to maintain their normal medication therapies (which varied between participants). They stayed on the ‘treatment’ for 12 weeks. Then there was a ‘washout phase’ of 6-8 weeks and then the participants switched treatments (the Salba® people now took wheat bran and vice versa).

Interestingly, despite the claim that Salba® reduced after-meal blood glucose and plasma insulin levels and therefore improved insulin sensitivity, fasting blood glucose, AIC and fasting insulin were not significantly different at the end of the treatment phase OR when compared to the control (wheat bran) group!

Blood lipids were also not different between the Salba® group and the control group. As for the claim that Salba® is effective in reducing risk factors of heart disease, such as body inflammation (C-reactive protein (CRP)); the control wheat bran phase compared with the end of the Salba® phase. However, omega 3- both DHA found in fish and ALA found in ground flaxseeds have been shown to decrease inflammation.

The claim that Salba® has an aspirin-like effect is a bit deceiving because although the Salba® group did experience thinning of the blood, so did the wheat bran group- so there was no significant differences between the 2 groups.

A couple of other problems with the study:

Very small study group and relatively short study period. Physical activity during the study was not quantified, which might bias the results.

So, all in all, there is very little research to back up the health claims behind Salba® and any result is marred by the fact that the main researcher owns the patent on Salba®!

Not worth the cost, in my opinion. But if you want to try it, click here to order a sample: http://www.sourcesalba.com/contact-us-sample.php

According to the website, Salba® does not have to be ground up to get the benefits. It should be stored in a dry cool place, like flaxseeds. Because of its thinning effect on the blood, talk to your doctor before trying it.

Sources: http://www.sourcesalba.com/ ; http://www.salba.info/patent.html ; http://www.ctv.ca/servlet/ArticleNews/story/CTVNews/20071115/salba_071115/20071115/ ; http://care.diabetesjournals.org/cgi/content/full/30/11/2804

DHA + EPA in some foods

From my Fish vs Flax blog, we learned that all omega 3s aren’t created equally. It’s the DHA and EPA that are linked to a lower risk of heart disease, cancer, Alzheimer’s disease, eye disorders and other health problems. ALA (alpha-linolenic acid), although high in fibre, isn’t as beneficial. The conversion from ALA to EPA is low but is better than the conversion of ALA to DHA.

Generally, you should be aiming for 500mg (0.5g) DHA and EPA a day. Remember that intakes of 650-700mg DHA and EPA a day has been correlated with a reduced risk of coronary heart disease. If you have heart disease, you should be aiming for 900mg/day. If you’re pregnant or breastfeeding, aim for a minimum of 300mg a day.

Included below is the amount of DHA and EPA in different fish and other products if you don’t eat fish. I’ll talk about some of the Brand-name products below. Note that considerable differences may exist with respect to the reported levels of DHA and EPA, even for a given fish source, due to various factors (ie. geographical origin).

FOOD (170g for fish unless noted)	DHA+EPA (mg)	FOOD (170g for fish unless noted)	DHA+EPA (mg)
Atlantic salmon, farmed	3650	Scallops	620
Atlantic salmon, wild	3130	Skipjack tuna, fresh	560
Gold Seal Pacific Sockeye Salmon (100g)	2900	Pacific cod or yellowfin tuna, fresh	470
Compliments Sliced Smoked Atlantic Salmon (55g)	2450	Blue crab (85g) or haddock	400
Gold Seal Pacific Pink Salmon (100g)	2400	Catfish, wild	400
Coho salmon, farmed	2180	V-Pure algae supplements (3)**	270 mg DHA/89 mg EPA
Rainbow trout, farmed	1960	Shrimp (85g) or Atlantic cod	270
Coho Salmon, wild	1800	Naturegg Break-Free Omega 3 Liquid Eggs (50mL, 1 egg)	250
Rainbow trout, wild	1670	Clams (85g)	240
Swordfish	1390	Naturegg Omega Pro Large Eggs (1)	130*
Sardines (in tomato sauce) (85g)	1190	Naturegg Omega 3 Large Eggs (1)	80
Pacific oysters (85g)	1170	Lobster (85g)	70
Mackerel, canned (85g)	1050	Becel Omega 3plus margarine 2tsp	50
Compliments Smoked Wild Sockeye Salmon (55g)	900	President’s Choice Blue Menu Oh Mega j Orange Juice (1cup)	50
Pollock or whiting	900	Danone Danino Yogourt with DHA (100g)	40*
Flounder or sole	850	Silk Plus Omega 3 DHA Fortified Soy beverage (1cup)	30*
Sardines in vegetable oil, drained (85g)	840	Egg (1 large)	20
Halibut	790	Minute Maid Fruit Solutions Omega-3 Orange juice	20*
Rockfish	750	Tropicana Essentials Omega-3 Orange juice (1 cup)	20*
Fish sticks (6)	680	Neilson Dairy Oh! 1% milk with DHA	10*

* DHA only.
** V-Pure supplement is the first vegan source of DHA and EPA, is made from algae and is recommended by Vesanto Melina, RD specializing in vegetarian and vegan nutrition.

Many brand name products are jumping onto the omega-3 bandwagon and claiming their products are great sources of omega 3. Maybe... but remember to read the ingredient list and NOT the nutrition facts table to find out the omega 3 source. This will tell you if the product has any DHA.

If you see fish oil or algal oil, the product has DHA. We'll look at 2 products today:

Silk Plus Omega-3 DHA Fortified soy milk: The ingredient list show the product has both flaxseed oil and algal oil. So the product contains some DHA. The nutrition facts table says that 1 cup provides 400mg of omega 3- but the small print indicates that only 300mg of that is DHA. Many other ‘Omega-3’ soymilks have no DHA so be aware.

Omega 3 eggs. Many eggs now have omega 3- the chickens are fed flaxseeds and they actually convert some of that ALA to DHA. Some packages tell you how much DHA is present in one egg, some don’t. On average, omega 3 eggs have about 75mg of DHA. However, this DHA doesn’t compensate for the high cholesterol found in the egg yolks (average of 210mg/yolk). Omega 3 eggs have pretty much the same amount of fat and cholesterol than regular eggs and cost 3 times as much. Although recent research has found that total fat and saturated fat have a greater impact on our cholesterol than cholesterol, the Heart and Stroke Foundation of Canada still recommends 2 egg yolks/week. These omega-3 eggs are not worth it, in my opinion.

Sources: http://dhaomega3.org/ ; Liebman, B. Omega Medicine: is fish oil good for what ails you? Nutrition Action Health Letter. Vol 34: 8, Oct 2007 ; http://www.nutrispeak.com/omega_3s__epa___dha.htm ; http://www.lesliebeck.com/ingredient_index.php?featured_food=21

Does cooking fish destroy the omega 3?

The research has generally shown that cooking fish results in very little or no significant reduction in the percentages of omega-3 fatty acids as DHA and EPA when following “normal cooking procedure”.

A recent study (Jan 2007) looked at the effects of different cooking processes of grilling, baking, frying and microwaving on fatty acid composition of cultured sea bass.They found that the fatty acid composition of the fillets was not significantly changed by grilling, baking and microwave cooking. The sea bass did lose a small amount of polyunsaturated fatty acids (omega 3) when fried (amount unknown). An other source indicated that high cooking temperatures can destroy almost half the Omega-3 in fish.

However, it has been pointed out that the amount of DHA and EPA per 100 grams of fish typically goes up after cooking since the cooking process eliminates some of the water associated with the raw fish.

Bottom line: Baking and grilling are healthier cooking methods and won't destroy most of the essential omega 3 fatty acids found in your fish- use these cooking methods more frequently than frying.

http://dhaomega3.org/index.php?category=faq&title=1190400259 ;

YASEMEN YANAR, AYGÜL KÜÇÜKGÜLMEZ, BEYZA ERSOY, MEHMET ÇELIK (2007) COOKING EFFECTS ON FATTY ACID COMPOSITION OF CULTURED SEA BASS (DICENTRARCHUS LABRAX) FILLETS Journal of Muscle Foods 18 (1) , 88–94

Fish vs. Flax

Omega 3 is definitely a hot topic these days and we're now hearing that plant sources of omega 3 (ie flax seeds) are not as good a source as marine sources. This will be the first of many blogs on omega 3s cause there's so much to talk about!

Let's start with a bit of an explanation of omega 3s.

Alpha-linolenic acid (ALA) is a plant source omega-3 essential fatty acid (EFA). It is “essential” because our bodies can’t make it. Two other omega-3 fats are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).

ALA is found mainly in flax seeds and walnuts, and in flax, canola and soybean oils. EPA and DHA are found mainly in fatty fish such as herring, salmon, mackerel and bluefin tuna, and the fish oil supplements made from them. Marine algae, the base of the oceanic food chain, are rich sources of DHA but contain little EPA.

EPA is not technically “essential” because our bodies make it from ALA, although conversion is not efficient and rates vary, based on many factors. DHA conversion from ALA is so poor that some authorities think it should be classified as “conditionally essential.”

Conversion of ALA to DHA and EPA

The overall conversion efficiency from ALA to EPA plus DHA combined is estimated to be only 12%. However, the conversion of ALA to DHA has been found to be highly variable between people and was found to be as low as less than 0.1% (and a conversion to EPA plus DHA combined of less than 0.4%) in one study. Yet another study, this one from the U.K., has compared the apparent conversion efficiency of ALA to DHA in young adult men and women. Interestingly, no detectable formation of DHA was found in the men whereas an approximate conversion efficiency from ALA to DHA of 9% was found in women.

In summary, the conversion efficiency from ALA to DHA is very limited in healthy individuals.

Do we need DHA? Yes!

30 years ago, work done at the Department of Nutrition at the University of Guelph showed that the feeding of omega-3 enriched diets to female rats prior to mating and throughout pregnancy and lactation along with the feeding of similar diets to their babies resulted in the pups showing superior learning capacity compared to the group that had diets with negligible levels of omega-3. These authors correlated the superior learning ability in the omega-3 fed animals to higher levels of DHA in the brain tissue. Subsequent studies from numerous labs have supported these early findings and have led to the conclusion that DHA is a physiologically-essential fatty acid required at high levels in brain tissue for optimal neurological performance and functioning.

DHA is known to significantly alter many basic properties of cell membranes. These various properties and mechanisms of action of DHA in the nervous system are thought to underlie its role in brain functioning such as learning ability, memory, etc.
The high levels of DHA in the brain and nervous system are actively deposited particularly during the last trimester of pregnancy and during the first two months of infancy and very early years of a child's life.
A study of 815 elderly people living in Chicago found that those with the highest DHA intake had the most protection against Alzheimer’s disease. Several neurological/behavioral disorders have been suggested to be associated with depressed levels of DHA or DHA plus EPA combined. These not only include Alzheimer's, but depression (including post-partum depression), behavioral disorders such as Attention Deficit Hyperactivity Disorder (ADHD) and hyperactivity, as well as developmental coordination disorder.

EPA and DHA keep cell membranes flexible/elastic and block the actions of some compounds that cause inflammation and clotting. Chronic conditions like heart disease, diabetes, cancer, arthritis, certain skin disorders, gastrointestinal disorders (ie. Crohn's, inflammatory bowel disorders) are marked by inflammation. DHA and EPA have been shown to help reduce the risk of these chronic diseases by blocking inflammation and have also been found to improve many of these conditions.

Lots of studies have also shown an inverse relationship between the consumption of fish containing EPA + DHA and the risk of cardiovascular disease (CVD) and cardiac death. Higher intakes of DHA and EPA can lead to reductions in fasting triglyceride levels, lowering of the triglyceride:HDL-cholesterol ratio, thinning of the blood, reduction in blood clots, lowered resting heart rate, reduced carbohydrate-induced blood fat surges after a meal and reduced atherosclerotic plaques.

Population studies have also revealed apparent benefits of consuming fish containing DHA plus EPA in a wide variety of conditions including chronic eye conditions (cataracts, dry eye), epilepsy, allergic sensitivity in very young children, pneumonia, lung/breathing capacity and chronic pulmonary disorders, plus other conditions recently reported including bone and joint health and fibromyalagia.

Where do we get DHA and how much do we need?

DHA plus EPA are completely absent from plant food sources rich in ALA (such as flax, canola oil, and walnuts). Since the metabolic conversion of ALA to DHA/EPA (combined) by metabolism is very limited in humans, the most direct way of providing DHA plus EPA for the body is via their direct consumption.

The American Heart Association and the Canadian Heart & Stroke Foundation has recommended two fatty fish servings per week for people who are healthy individuals without cardiovascular disease. The DHA plus EPA (combined) equivalency of such fish consumption is approximately 250-300 mg/day.

The American Heart Association in its official Dietary Guidelines (2000) recommended that the daily intake of DHA plus EPA in individuals with coronary heart disease should target 900 mg/day since this amount has shown to be beneficial in affecting coronary heart disease mortality rates in patients with coronary disease. Consumption of one fatty acid meal per day (or alternatively, a fish oil supplement) could result in an omega-3 fatty acid intake (i.e. EPA and DHA) of ~900mg per day

Increasing intakes of DHA/EPA (combined) up to approximately 650-700 mg/day (4-5 fatty fish dishes/week) are associated with overall reductions in all-cause as well as coronary disease-related mortality.

A study showed that those consuming 5 or more servings fatty fish per week had a 31% overall reduction relative to those eating fish less than once per month. It is possible that other components in fish other than DHA/EPA may offer benefits independent of or synergistic to DHA + EPA.

What if you don't want to eat fish?

For many reasons- over-fishing, the buildup of toxic minerals and other toxic substances in fish flesh, environmental problems, and cruelty to fish and sea mammals- fish are becoming less and less of a desirable source of DHA and EPA for many people.

Vegetarians who consume an average of 4-5 regular eggs per week would have a daily intake of DHA of approximately 33 mg with 3 mgs present as EPA. The ovo (egg-eating) vegetarian could increase their daily intake of DHA considerably by consuming omega-3 eggs such as are becoming commonplace in the North American marketplace.

The absence or low-levels of DHA in the diet of vegetarians is reflected in their physiological levels of DHA such as that present in expressed breast milk. The levels of DHA in breast milk (total fat) from vegan women have been found to be approximately one-third the levels found in the breast milk from omnivorous women.

For vegan vegetarians who consume no fish or animal food sources whatsoever, increasing their intake of dietary ALA (omega-3) as well as reducing their intake of omega-6 and lowering their omega-6:omega-3 ratio can provide a moderately better metabolic conversion of ALA to EPA and DHA. That's because high levels of omega 6 is a contributor to the decrease conversion levels of ALA to EPA and DHA.

Algae is the only vegetarian source that provides a meaningful DHA amount. Algal sources of DHA have recently become available which, when taken as supplements or via fortified foods such as DHA-enhanced soymilk, can provide a non-animal source of DHA. Such supplementation with DHA in vegetarian women is known to dramatically elevate DHA levels in breast milk within a short period of time.

Should we still eat flax seeds? Yes

Flax seeds provide much more than the richest source of ALA. Flaxseed is approximately 38% oil, which is comprised mainly of ALA, 28 % fiber (approximately two-thirds insoluble), 20% protein with an amino acid profile similar to soybeans; 7 % carbohydrates (simple sugars, lignans, phenolic acids and hemicellulose), 4% ash, 2% minerals (magnesium, potassium, calcium, iron, phosphorous, sodium, copper, zinc, manganese, selenium), 0.32% vitamins A, B₁, B₂, D, E, and niacin, 0.15% lecithin, 0.1 % flavonoids and 0.1% phytic acid.

Besides the omega-3 content, flax’s most beneficial compounds are likely its lignans and fiber. Lignans are phyto-estrogens – plant compounds that can have estrogen-like actions.

Through the actions of the lignans and ALA, flax blocks tumor growth in animals and may help reduce cancer risk in humans.

The major lignan in flax is is a powerful phytoestrogen chemically similar to the breast cancer drug tamoxifen. Postmenopausal women consuming 5 or 10 grams of milled flax over seven weeks showed significant reductions in blood concentrations of the most potent estrogen, estradiol, and its less potent sister, estrone. This may be desirable for postmenopausal women who have a high risk of breast cancer. This lignan is also a potent antioxidant – 500% more powerful than vitamin E!
These lignans have shown such extraordinary potential that they have been studied by the National Cancer Institute for their cancer-preventative properties. Studies have shown a substantial reduction in breast cancer and prosate cancer in people with high inakes of this lignan.

Flax has been shown to lower blood cholesterol levels and help reduce the risk of heart attacks and stroke, likely related to fiber content, but partly through the actions of ALA, which may be especially important to vegetarians and people with low intakes of fatty fish.

In a cohort of more than 45,000 U.S. men followed for 14 years, each 1g/day increase in dietary ALA intake was associated with a 16% reduction in the risk of heart disease. In a cohort of more than 76,000 U.S. women followed for 10 years, those with the highest ALA intakes (approx. 1.4 g/day) had a 45% lower risk of fatal heart disease than women with the lowest intakes (~0.7 g/day). Findings from the Health Professionals Follow-up Study of 45,722 men indicated that each gram of ALA in the daily diet was associated with a 47% lower risk of heart disease among men with low intakes of EPA and DHA (<100mg/d)

Flax’s soluble fibers also promote intestinal health and glycemic control.

So much for trying not to make this long! That's it for now but stay tuned for DHA content of specific foods and the safety of fish oil supplements!

Sources: http://dhaomega3.org/ , http://www.chiroweb.com/columnist/maher/