Given how confusing and contradictory health advice from the “experts” can frequently be, it’s refreshing to find a principle upon which absolutely everyone agrees. One such principle is to eat more vegetables and fruit. Another is that seafood is one of the healthiest foods on the planet.

Fish in general is a high-protein, low-calorie food that provides a range of health benefits, but some fish are real superstars. Fish high in omega-3s that are caught or farmed in an ecologically sound manner and are low in contaminants include wild salmon from Alaska (fresh, frozen, and canned), Atlantic mackerel and herring, sardines, sablefish, anchovies, and farmed oysters.

White-fleshed fish, on the other hand, is loaded with vitamins and minerals, and it is incredibly low in calories. In addition, most fish are naturally low in the proinflammatory omega-6 fats (a possible exception being farmed salmon—see here). As of this writing (2017), the FDA recommends avoiding king mackerel, marlin, orange roughy, shark, swordfish, tilefish from the Gulf of Mexico, and bigeye tuna because they are the fish with the highest mercury levels.

In fact, in 2016 a study in the Journal of the American Medical Association found that eating fish—and other seafood—even once a week may help lower the risk of Alzheimer’s disease. This is despite higher levels of mercury in the brain from the fish. “This study provides evidence that the increased mercury exposure is not correlated with increased brain pathologies associated with dementia,” lead researcher Martha Clare Morris, M.D., told Life Extension magazine.

By the way, I hope you know that when I’m waxing on and on about the virtues of fish, I’m not talking about “mystery fish nuggets deep fried in recycled vegetable oil” or some similar Frankenfood from the local fast-food emporium or food court. I’m talking the real deal. Research shows that more nutrients are retained in fish that is baked or broiled, rather than processed and/or fried. But you knew that, didn’t you? And to protect against viral and germ contamination, handle uncooked seafood with care and properly cook fish or shellfish, as you would any meat or poultry.

Back in the 1980s, William Castelli, M.D., director of the famous Framingham Heart Study, said this: “I have no qualms about the American public eating three or even four meals of fish a week.”

Today, that statement sounds remarkably conservative, but understandably so. We really don’t know quite as much about nutrition and health as we think we do, and a lot of the time we’re just making our best guesses. Consider what Dariush Mozaffarian, M.D., dean of Tufts University’s Friedman School of Nutrition Science and Policy, told the New York Times on July 5, 2016, regarding nutrition: “Twenty years ago… we knew about 10 percent of what we need to know. And now we know about 40 or 50 percent.”

Maybe in twenty years we’ll find out that fish is really bad for you. Or maybe we’ll find out that the recommendation to eat it twice a week should be doubled. No one knows, but if I were a betting man, I’d bet on the latter.

Crustacea

(crayfish, prawns, shrimp, lobster)

Crustaceans are one of two main classifications of shellfish (the other being mollusks). They’re a class of arthropods which characteristically have segmented bodies. And they’re very, very tasty. Enjoy.

Crayfish (also called crawfish) are freshwater cousins of the lobster, found in most parts of the world. According to the Natural History Museum of Los Angeles County, more than 70,000 different species of these crustaceans have been identified. The most biologically diverse concentration of crayfish species in the world is found in the southeast United States. You can prepare them in the same style as lobster—steamed, boiled, fried, blackened, or baked. They’re a big favorite in Louisiana.

Prawns are basically really large shrimp, though there are regional differences of opinion about the distinctions. (In Europe and some Asian countries, prawns are considered large decapods with long antennae and toothed beaks, some varieties of which have slender bodies, with tails that don’t curve under as much as typical shrimp tails; but in the United States they’re just big shrimp.) One particularly desirable type is called the Black Tiger, a huge prawn that can grow to over a foot in length. Its name comes from the distinctive coloration of its shell: black with alternating bands of yellow. They’re usually sold frozen, with most commercial supplies coming from Asian shrimp farms.

Shrimp are one of about 740,000 known species of crustacea, the only group of arthropods that is primarily marine. They’re the most popular shellfish in the world, and they are probably one of the most popular varieties of seafood, period. And no wonder—they’re lean, high in protein, rich in nutrients, and delicious; some might say an ideal food.

First things first: Shrimp are a great source of protein, and a low-calorie one at that. One small 3-ounce (85 g) serving has 17 g of protein and only 90 calories. Shrimp have all nine essential amino acids, plus small to moderate amounts of nine important minerals. They’re relatively high in the important trace mineral selenium, with one 3-ounce serving providing 46 percent of the Daily Value for this cancer-fighting nutrient.

Then there’s astaxanthin. You probably never heard of astaxanthin, but it’s the main carotenoid pigment found in aquatic animals and it is responsible for giving salmon their pink color. The thing of it is, salmon get most of their astaxanthin from dining on crustaceans like shrimp—particularly krill. Why should you care? Because this red-orange pigment, closely related to other well-known carotenoids like beta-carotene and lutein, has stronger antioxidant activity than either of them (ten times higher than beta-carotene, in fact). Studies suggest that astaxanthin can be more than 100 times more effective as an antioxidant than vitamin E. And shrimp are loaded with it. In many of the aquatic animals in which it is found, astaxanthin has several essential biological functions, including protection against oxidation of essential polyunsaturated fatty acids, protection against UV light effects, pro–vitamin A activity, immune response, pigmentation, communication, and improved reproduction. In species such as salmon and shrimp, astaxanthin is considered essential to normal growth and survival and has been attributed vitaminlike properties. We’re just beginning to understand its potential in human health, but there’s every reason to believe it’s really good for you.

Lobsters are large crustaceans. They have hard shells and ten legs, two of which have developed into pincers. Although considered a gourmet food today, lobsters were so plentiful in the nineteenth century that they were used as fish bait or even fertilizer. Lobsters have firm, rich meat in their bodies, tails, and legs. You can also eat the lobster’s liver (known as green tomalley) or its roe (known as coral).

Fun fact: Lobsters migrate in autumn to calmer waters, and they do it by marching in single file on the ocean floor for a couple of days and nights! Each individual member of the convey touches the tips of its antennae to the animal in front of them.

Ounce for ounce, lobsters are somewhat similar to shrimp in nutritional value, with a few differences. Three ounces (85 g) of lobster meat has about 95 calories and delivers almost 19 g of high-quality protein, with all nine essential amino acids. It’s even higher in the cancer-fighting trace mineral selenium than shrimp is (3 ounces provides 56 percent of the Daily Value for this valuable nutrient), and in addition provides 32 percent of the Daily Value for zinc, plus small amounts of other minerals. Lobster is one of the best nonanimal sources of vitamin B₁₂, with 3 ounces (85 g) providing 50 percent of the Daily Value for that important B vitamin.

Mackerel

Mackerel has long been one of the most underappreciated fish. For example, in 2006 the New York Times published a story by food columnist Marian Burros, placed prominently on the cover of its “Dining In” section. The headline? “Holy Mackerel And Other Guilt-Free Fish.” The story—a paean to the health benefits and environmental friendliness of this terrific fish—began like this: “Like the shy kid at the dance whose charms are not readily apparent, unpopularity has kept some species (of fish) in circulation, waiting to be discovered. Atlantic mackerel wears its reputation like a pocket protector and horn-rimmed glasses, but a little attention reveals its sweet side.”

Mackerel live in both the Atlantic and the Pacific. The Atlantic mackerel (also known as Boston mackerel) is preferred, and it is the variety I recommend (more on that in a moment). A relative of the tuna, the Atlantic mackerel is found in the Atlantic’s cold waters, where it forms large schools and can live up to an astonishing seventeen years. Before 1870, all mackerel caught in New England waters was salted on board and sold that way in Boston. Fresh mackerel is very perishable, and it must be kept on ice or it develops a really fishy flavor.

Mackerel is a sleek, oily fish with a forked tail. It contains two kinds of meat: the red outer meat and the light inner meat. You can get it canned, whole, as fillets, and as steaks. Atlantic mackerel is often used in sashimi. Pacific jack mackerel (also called horse mackerel) is often canned. Spanish mackerel has only a small percentage of red meat and a milder taste than other kinds of mackerel. King mackerel (also called kingfish or cavalla) has a firm texture and distinct taste. Wahoo (also known as ono) is a very close relative of the king mackerel; it is a subtropical fish with a delicate flavor that is often used in sashimi. Cero mackerel (also called cerro or painted mackerel) is caught in waters along the coast of Florida; it has leaner flesh and a more delicate flavor than most varieties. Pacific mackerel (also called American, blue, or chub) is an oily fish with a strong flavor.

Mackerel is high in omega-3 fatty acids, and it’s also low in environmental contaminants. Atlantic mackerel come from marine fisheries, not fish farms, are primarily caught with purse seines and trawls, and have relatively low “by-catch.” They can safely be eaten more than once a week. All good news.

Three ounces (85 g) of mackerel has roughly 20 g of protein and plenty of good healthy fat, though there are some slight differences. Three ounces of Pacific mackerel has 6 g of monounsaturated fat and about 11/2 g of omega-3, while 3 ounces (85 g) of Atlantic mackerel contains 3 g of monounsaturated and a little more than 1 g of omega-3. But both are very good sources of the cancer-fighting trace mineral selenium, providing more than 50 percent of the Daily Value. And while Pacific mackerel has a respectable amount of vitamin B₁₂ (60 percent of the Daily Value), the Atlantic variety is a B₁₂ heavyweight, providing more than five times that amount.

Mollusks

(clams, mussels, scallops, oysters)

Mollusks include all the shelled creatures of the sea (except for barnacles). They form one of the largest groups in the animal kingdom, with more than 80,000 known species.

Mollusks have always been a readily available food source for humans. Mussel and oyster beds, clam flats, and other abundant shellfish reserves have traditionally provided an easy, accessible source of food, as evidenced by many of the archaeological digs that have uncovered huge middens heavy with shells. Mollusks are almost pure protein, naturally low in fat, and rich in a host of minerals, including zinc and copper.

And oysters really are a brain food, helping to boost your mental energy and acting as a mood elevator. The protein in oysters is rich in the amino acid tyrosine, which your brain converts to the feel-good, energizing neurotransmitter dopamine.

Some oysters produce nacre (a combination of calcium and protein), with which they coat any irritating sand or grit that gets trapped within their shell. This substance hardens into a smooth ball… we know it as a pearl.

Sardines

Sardines are a health food in a can.

I first discovered this way of thinking about sardines in Florida. My friend, the great New York celebrity nutritionist and author Oz Garcia, Ph.D., and I were jointly leading a seminar on nutrition for personal trainers in Miami Beach. We were driving around near the hotel looking for something remotely healthy to eat and couldn’t find anything promising. Garcia, who is a Miami native, stopped the car at a local bodega and came out with two cans of sardines and a couple of plastic forks. They were delicious and filling and ever since have been on my top ten list of the healthiest and most convenient foods on the planet.

Omega-3s help with mood, thinking, circulation, and glucose and insulin metabolism; they lower blood pressure; and they protect against heart disease. They’ve been referred to by more than one health writer (including myself!) as “wellness molecules.” Books have been written on their health benefits. By some estimates, sardines are as high in omega-3 fats as salmon; by other estimates, they are a close second. Either way, you can get all you need of this amazing fat from one little can of sardines.

And that’s not all you’ll get from one can of these innocuous fish. They are absolutely loaded with calcium—depending on the type of sardines, one can gives you 25 to 38 percent of the Daily Value. They also contain iron, magnesium, phosphorus, potassium, zinc, copper, and manganese, not to mention a full complement of B vitamins. And they are notable for being a superb nonmeat source of vitamin B₁₂: One little can provides a whopping 150 percent of the Daily Value!

Sardines are also a good source of selenium. Higher levels of this important cancer-fighting trace mineral have been found to be associated with lower rates of cancer in numerous studies. A can of sardines provides 58 to 75 percent of the Daily Value of this critical mineral.

Randy Hartnell, a descendent of three generations of Alaskan fishermen and president of Vital Choice, Inc., points out that sardines are highly sustainable “They grow without the need for arable land, fresh water, fertilizers, pesticides, veterinary drugs, artificial colors, flavors, [or] preservatives,” he says. “They’re among the last truly wild naturally organic foods available to us.”

As far as mercury is concerned, you have a lot less to worry about with sardines than with bigger fish. Sardines are small, relatively short-lived, and feed at the bottom of the marine food web, so they don’t bioaccumulate hazardous levels of contaminants such as the mercury and PCBs that are found in larger, longer-lived predatory fish.

There are three things to be aware of when buying and consuming sardines:

1. Sardine quality varies widely depending on when it was harvested, whether it was packed from fresh or previously frozen fish, and on the quality of the oil added. Few companies pack in certified extra-virgin olive oil, but some do—look for them. “You get what you pay for” generally applies.

2. Many people think they don’t like sardines because they’ve experienced cheap, lower quality versions that taste bad and misrepresent what a delicious, incredibly healthy food they can be.

3. To minimize cost, some manufacturers will freeze sardines and ship them to low-wage countries for canning (Vietnam, Thailand, etc.), lowering the quality and increasing the “food miles” factor.

Tuna

Canned tuna is the second most popular seafood product in the United States after shrimp. If other healthy foods were that popular, we’d be in good shape.

All of the good stuff about seafood applies, of course, to tuna. Although it doesn’t have as many omega-3 fats as salmon or sardines do, it’s still considered a fatty fish, and a serving of tuna does provide some healthy omega-3s. Here again, the source of the food is everything. The big companies with the household names cook their fish twice, first baking them on a rack, which results in a loss of a lot of the beneficial oils. Then they debone it, can it, stick in flavorings and additives, and cook it again.

Canned tuna from big commercial companies typically has fewer than 1/2 g of omega-3s. It’s better than nothing, but you wouldn’t write home about it.

Then there’s the issue of water packed versus oil packed. Many people avoid the oil packed because of a fear of fat, but the oil-packed version is more likely to retain its omega-3s. That is, unless you drain it, which is what most people do. Then the omega-3s are likely to leak out with the oil and go down the drain. That’s less likely to happen with water packed, but on the other hand there might be less omega-3s there to begin with. So, either buy the kind in oil and don’t drain it, or buy the kind in water. Better yet, in my opinion, seek out the small specialty companies that produce a better-quality product (such as gourmet or premium canned Pacific tuna) in the first place.

And tuna is a superb source of the vitally important cancer-protective trace mineral selenium. That water-packed can of light tuna provides almost 200 percent of the Daily Value. Even if you use one can for two portions, you’re still getting almost 100 percent of the Daily Value for this vital nutrient.

Tuna steak is likely to be higher in omega-3s but may be higher in mercury as well. (For a fuller discussion of the mercury issue, see here.) A 3-ounce (85 g) portion of yellowfin or bluefin tuna is still a nutritional bargain at less than 150 calories and around 25 g of high-quality protein. There are slight differences, though: The yellowfin has almost no B₁₂, while the bluefin contains more than 150 percent of the Daily Value.

All that said, whatever kind is used, tuna is still my favorite fish at a sushi restaurant.

White-fleshed Fish

(cod, flounder, halibut, orange roughy, pollack, rockfish)

White-fleshed fish are a perfect way to get all the benefits of seafood that the experts keep telling us about. They may not be quite as good as fatty fish, because they’re not a source of those powerful omega-3 fatty acids found in salmon, sardines, and the like, but they have plenty of other good things to recommend them. And although fatty fish have more omega-3s than lean fish, even lean fish contain some—and these healthful fatty acids are found in very few other foods.

Even white-fleshed fish are extremely rich in high-quality protein while being low in calories. One 3-ounce (85 g) portion of cod, for example, provides about 20 g of extremely high-quality protein, all for less than 100 calories. (A whole fillet is still a nutritional bargain, delivering a whopping 41 g of protein for under 200 calories.) Cod is also rich in B vitamins and minerals, especially the all-important, cancer-fighting trace mineral selenium. One 3-ounce portion of cod provides about half of the Daily Value of this vital nutrient.

Orange roughy is similar to cod in protein and calories, but delivers more selenium—one 3-ounce (85 g) portion has more than 100 percent of the Daily Value for this nutrient, which has been linked to lower rates of cancer. Note that, as of 2017, orange roughy is one of twelve fish that the nonprofit Food and Water Watch website recommends you avoid. (See the sidebar for the complete list).

Flounder and sole fall somewhere between the cod and orange roughy in the selenium sweepstakes, but are otherwise competitive on vitamins, minerals, protein, and calories. All are great foods.

Lean fish typically have a mild flavor, making them adaptable to every sort of cuisine. And most of them are similar enough in taste and texture that you can easily substitute one variety for another—cod for sole, grouper for flounder, and so on.

flavor like flounder.

Wild Alaskan Salmon

Before we get to salmon, I want to take a minute and talk about definitions. One of the biggest problems we have when we talk about food is that we all use the same basic descriptive words for foods—(i.e. salmon, or meat, or chocolate). But we are not necessarily talking about the same things, even though we think we are. Remember, the category “dogs” includes both golden retrievers and Chihuahuas but good luck getting the Chihuahua to play Frisbee with you.

If you and I discuss the health benefits of salmon, and I’m thinking wild salmon and you’re thinking farmed salmon, we may think we’re talking about the same food, but we’re not. Wild and farmed salmon are two very different animals.

Confused? Read on.

When this book was first published, many people weren’t aware of the difference between wild and farmed salmon. People were beginning to realize that salmon was a healthy food, demand for it was increasing, and no one gave a lot of thought to where it came from. At that time, I made a strong case for choosing wild salmon over farmed whenever possible. But the debate continues to this day. (Search “farmed vs wild salmon: which is better?” and you’ll see what I mean.)

Demand for salmon has increased exponentially, and to keep up with it, so has salmon farming. In 2015, the Wall Street Journal reported that the privately owned agriculture giant Cargill plunked down $1.5 billion for the Norwegian salmon feed producer, EWOS AS. According to the Journal, farmed fish production has already surpassed global beef output and leading the pack is… you guessed it, salmon. As of 2017, more than half the salmon sold worldwide comes from fish farms. Meanwhile, global stocks of wild salmon are half what they were just a few decades ago.

It’s easy to understand why everybody wants salmon. It’s one of the healthiest foods you can eat, because it’s chock-full of a particular kind of fat that has more health benefits than almost any other single food on the planet. The type of fat in salmon belongs to a family called the omega-3s, which is the general, family name for a group of three fatty acids. (It’s just a coincidence that there happen to be three of them.) Books have been written detailing the benefits of omega-3 fats to human health. (For a more detailed discussion of omega-3s and what they can do for you, see here). Omega-3s are helpful for heart health and brain health as well as for inflammation, circulation, memory, thought, and blood sugar control. And we know that salmon is one of the best sources of these omega-3s on the planet.

Not only that, salmon’s also a great source of high-quality protein. One 3-ounce (85 g) serving of wild salmon gives you more than 18 g of first-rate protein, not to mention 360 mg of potassium and almost half of the Daily Value of the important cancer-fighting trace mineral selenium. It also contains more than half of the Daily Value for vitamin B₁₂ and 30 percent of the Daily Value for niacin.

But it does.

It gets worse.

Wild salmon get their gorgeous pink color from eating krill and shrimp, which are high in a natural pigment called astaxanthin. Astaxanthin is a member of the carotenoid family and it has ten times the antioxidant activity of beta-carotene. (Stephen Sinatra, M.D., mentioned astaxanthin as one of his reasons for including wild salmon on his top ten list. See here.) But farmed salmon don’t get to eat krill and shrimp. They get their color a completely different way. Farmers can pick out the color of their salmon from a color wheel that looks exactly like the ones you see in the paint section of Home Depot. I’m not making this up—I’ve seen it. It’s called the SalmoFan, and it’s an actual farmed salmon color wheel where you can choose the shade of red or pink you’d like your “product” to be.

To reduce costs and contaminant levels, farmed salmon are being fed less rendered fish meal and more grain-derived feed than ever before. Unlike their wild cousins, farmed salmon have almost no vitamin D₃, and continue to be fed synthetic astaxanthan to color their flesh, pesticides to keep sea lice at bay, and large amounts of antibiotics to combat their extreme vulnerability to disease… too often unsuccessfully.

A 2004 study published in Science entitled, “Global Assessment of Organic Contaminants in Farmed Salmon,” looked at 700 salmon samples from around the globe. It found that on average, PCB concentrations were eight times higher in farmed salmon than in wild salmon. David Carpenter, M.D., a researcher on the study and the director of the Institute for Health and the Environment at the University of Albany, told Prevention magazine that the farmed stuff is “higher in contaminants and even flame retardants.” (For more information, go to www.prevention.com/content/which-healthier-wild-salmon-vs-farmed-salmon.)

And if you’re concerned about the global impact of farmed salmon, consider this. In British Colombia, hundreds of farmed salmon pens continue to obstruct the migration routes of five different wild salmon species, exposing them to potentially lethal parasites, predation, and diseases that have wiped out wild salmon runs in Norway, Scotland, Iceland, and other areas previously inhabited by healthy wild salmon runs. And it’s only likely to get worse—not better.

At the end of the day, both wild salmon and farmed salmon contain plenty of protein, and both have omega-3s. But there the similarity ends. Wild salmon has less calories than farmed, and a lot less proinflammatory omega-6s. Wild salmon eat their natural diet of krill; farmed salmon eat grain and fish pellets, and are a major source of PCBs. Still, there’s a serious argument to be made for the fact that salmon is such a great food that even less-than-perfect salmon (i.e., farmed fish) is better than no salmon at all, and that in today’s world, not everyone has access to wild salmon, and not everyone can afford it. I’d have to agree with that—if farmed salmon was absolutely the only salmon I could get, I’d probably eat it, and even if you do eat wild most of the time, the occasional farmed salmon fillet certainly won’t kill you.

But given a choice between farmed and wild, there’s little argument that wild is the clear winner.

THE EXPERTS’ TOP TEN LISTS

David Perlmutter, M.D., F.A.C.N., A.B.I.H.M.

David Perlmutter, M.D., F.A.C.N., A.B.I.H.M., is a board-certified neurologist and the author of several bestselling books, including Brain Maker and The Grain Brain Whole Life Plan.

In 2002, he was the recipient of the Linus Pauling Award for his innovative approaches to neurological disorders and was awarded the Denham Harmon Award for his pioneering work in the application of free radical science to clinical medicine. He is the recipient of the 2006 National Nutritional Foods Association Clinician of the Year Award and serves as medical advisor for The Dr. Oz Show. He has contributed extensively to the world medical literature with publications appearing in The Journal of Neurosurgery, The Southern Medical Journal, Journal of Applied Nutrition, and Archives of Neurology. Here is his top ten list:

1. Eggs (organic, and pasture-raised). Egg yolks are a great source of choline, an important nutrient for brain health.

2. Coconut oil. Coconut oil is one of the fundamental recommendations of the Grain Brain program. Research shows its consumption is associated with improved cardiovascular parameters and a slimmer belly!

3. Olive oil. Olive oil is one of the foods that has the greatest potential to keep us healthy. Consider that it’s a staple of both the Grain Brain and highly-praised Mediterranean diet.

4. Avocado. The avocado is part of my “anti-Alzheimer’s trio,” and is an incredible source of healthful fats.

5. Dandelion greens. Loaded with antioxidants, including vitamin C and vitamin A (betacarotene), the health benefits of this plant have been documented as far back as the tenth and eleventh centuries. Most important, they are a rich source of prebiotic fiber.

6. Blueberries. These are a healthy, low-sugar fruit, and a way to fight off Alzheimer’s.

7. High-cacao chocolate. There’s nothing wrong with indulging in a few pieces of dark chocolate (greater than 70 percent cacao) every now and then!

8. Kale. It’s jam-packed with vitamins, antioxidants, carotenoids, good fat, and fiber.

9. Wild salmon. This is an excellent source of the omega-3 fatty acid DHA, which turns on the growth of new brain cells while offering protection for existing ones. It’s also anti-inflammatory.

10. Brussels sprouts. Like kale, Brussels sprouts are in the Brassica family and are a relative of cabbage. They’re high in fiber, low in calories, and loaded with important antioxidants and plant chemicals such as indoles.