Tuesday, August 31, 2010
To Eat...or Not to Eat...Seafood
Five weeks in, the sleepless nights are now starting to add up and my little bundle of joy is robbing my brain of valuable thinking time. Well, at least I tell myself that my thinking time is valuable...So my "baby brain" has to thank my friend Steve for all of the good blog post ideas he has been providing me of late.
Surprisingly (or not, for any other health professionals out there), very few of my friends or family actually ask me for nutrition advice. What is even more humorous is the discussions that occur regarding health or nutrition in my presence without anyone even so much as glancing my way. I have gotten used to just shutting my trap when this occurs because I have learned that unsolicited advice is rarely accepted with a smile. Maybe that is why I started this blog in the first place...to spew out all the information held hostage in my brain.
My friend Steve, however, is one of the few exceptions to this rule and a few days ago he asked me about what kind of seafood he should be eating, other than salmon (which is all most nutrition literature talks about). At the bottom of the email, he casually mentioned that the topic would make a good blog post and since I was stumped on what to write about next...voila!
Seafood is an interesting discussion, both from a nutrition perspective and an environmental perspective; one topic which I can claim to have a decent background in...the other, not. Here in BC, we are pretty fortunate to have the king's ransom of seafood at our doorsteps but few of us venture outside of a handful of comfortable favourites: canned tuna, fish and chips, salmon and prawns. When it comes to seafood, there are really two categories to choose from - the "superfoods" and the "healthy options". Read on, Steve...read on...
You guessed it, these are the cold water, fatty fish such as herring, mackerel, sardines and salmon. If you were only to eat one serving of seafood a week, make one of these stars your choice. Why are these so good for you? It isn't just the omega 3 fats...but that's a start.
Omega 3s Cold water oily fish such as salmon are rich in anti-inflammatory omega 3 fats and what makes them really special is the kind of omega 3 fats they contain. We get ALA from vegetable omega 3s like pumpkin seeds and hemp seeds but fish give us what are called the "long chain" or "preformed" omega 3 fats, EPA and DHA. EPA and DHA are not technically essential fats because in theory, our body can make EPA and DHA from ALA - but we suck at it. The most efficient of us turn about 20% of the ALA we eat into EPA and DHA, which are the potent omega 3s in the body; some of us can only convert 5%. So getting your EPA and DHA directly from fish makes a lot of sense, because we know that these two fats can help us soothe chronic inflammation, help us prevent chronic disease and even boost our brain function. In fact, EPA and DHA are so good for you that they are one of only two supplements I recommend everyone take, unless they eat 3 good sized servings of fatty fish a week. Wild fish is your best source; it used to be that it had far greater amounts of omega 3 fats than farmed but of course the farmers just started adding omega 3 to the feed to boost the level in the farmed fish. Nothing like "design your own" salmon...come on, people...eat wild! If your seafood does not specifically say "wild", it isn't.....so look for the label.
Vitamin D The next reason that these fish are so good for you is vitamin D, the other of the two supplements I recommend every man, woman and child consume. You can see my post on vitamin D here. There are very few natural food sources of vitamin D, which is critical for our immune function and likely helps us to prevent cancer. Salmon is the star here, with the most vitamin D: a wild Sockeye Salmon steak can have as much as 900 IU of vitamin D (which is 90% of the 1000IU that many experts are now recommending as a daily dose). Nothing else in nature comes close to this level.
Antioxidants Again, gorgeous wild salmon is the star here (remember, colour equals antioxidant pigments) and in salmon, it is the pigment astaxanthin that is responsible for the lovely colour. Same old story with farmed salmon...that pink colour is added via feed manipulation. A unique member of the carotenoid (like beta carotene) family, astaxanthin does not convert to vitamin A in our bodies but the significance of this is not really known. Astaxanthin is being studied for its potential role in reducing inflammation, protecting our skin from sun damage and preventing cancer.
The Healthy Choices
This is the category I will lump most other seafood into. Fish and seafood stand out for being beautifully lean sources of protein, making them a great addition to the diet. White fish and shellfish are low in fat and calories and nutritious: scallops are rich in heart healthy magnesium and anti-oxidant selenium; oysters excel for blood building iron and skin loving zinc and sablefish boasts the electrolyte potassium for healthy blood pressure. I generally recommend that (non-vegetarian) folks divide their daily protein choices between vegetarian sources, poultry and fish throughout the week for better health and choose red meats only occasionally.
There is one health caveat with shellfish and that is the cholesterol in foods like shrimp and lobster. However, these foods contribute very little cholesterol to our diets in comparison with red meats and cheese. In addition, unless you have a significant cholesterol problem, it is the saturated fat in our diet that we worry about with regards to our blood cholesterol levels than our dietary cholesterol intake so feel free to enjoy shrimp every once in a while, guilt free!
Mercury and other Contaminants
The biggest health risk that seafood poses is that of the neurotoxic contaminants, mercury and PCB. When it comes to seafood and contaminants, think to yourself: "Good things come in small packages." Women who are or can become pregnant and children are most vulnerable to dietary exposure to mercury and should take care to avoid highly contaminated species of fish.
Since contaminants like PCBs and Mercury are not excreted, they accumulate as you move up the food chain - yes, that goes for us too! All the fish we eat (if we are eating highly contaminated species) deposit these nasty toxins into our own system where they stay put and wreak havoc with our health. The superfood fish are all low in contaminants because they are small fish. Stay away from the "big game" fish like swordfish, marlin, shark and fresh tuna. When buying canned tuna, choose light tuna over white tuna, which comes from smaller tuna species.
Which fish are best for you when it comes to contaminant levels? Rather than have me reinvent the wheel, read this Health Canada article which lays it all out on the line...pun intended.
Now for the larger question...is it sustainable to eat seafood at all? This is a far more complex issue. With the best Sockeye Salmon run we have seen in BC in years, this little voice might get pushed to the back of our minds as we clammer down the dock to buy this delicacy by the bushel load. As news of the health benefits of eating fish grew, our appetite (and therefore demand) for seafood, salmon in particular, grew alongside. And what the affluent Western world wants, it gets - to the detriment of less affluent nations that used to rely on seafood as the main source of protein in their diets.
As our love for seafood grew, we learned to choose wild over farmed, line caught over trawled and local over exotic. These changes went a long way towards "greening" our seafood choices. However, some experts argue that we should refrain from eating seafood at all as even stocks of typically "sustainable" sardines and mackerel in South America and Scandinavia are at risk of overfishing (some say that we are already there) to supply us with fish meal used to fatten up farmed salmon. Others, like the pioneering chef Frank Pabst at Blue Water Cafe believe in introducing us to less favoured items like sea urchin and jellyfish.
I will stop there or risk exposing my lack of depth when it comes to exploring this topic. Where you stand on this issue is a personal choice but there are some great resources to help you make your decisions. Home grown Ocean Wise is an education program from the Vancouver Aquarium which guides you towards local businesses providing sustainable seafood options, designated by the Ocean Wise logo. The website also provides a list of more sustainable species. The Monterrey Bay Aquarium has its own program called Seafood Watch, where you can print off a handy little pocket guide that I like because it organizes itself with a stoplight system to categorize sustainable choices and also alerts you to high mercury choices so you can avoid them. If you have an iPhone, you can even download an app to keep at your side as you shop and dine.
In good health,