Eating cold-water, oily fish is flat-out good for you. Good for your heart. Good for your brain. Good for your eyes.

Even the U.S. Food and Drug Administration—not always a nutritional cheerleader—says the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are good for cardio health, in particular by lowering triglycerides, making blood platelets less sticky so they don’t form plaque and preventing sudden heart attacks. The agency says people can consume 2 out of 3 daily grams of omega-3s from supplements.

Which is a good idea, because eating uber quantities of fish every day would deliver more than enough polychlorinated biphenyl (PCB) contamination. The larger fish we rely so heavily on, such as tuna and farmed salmon from the Atlantic Ocean or China, accumulate heavy metals, like mercury, that can cause a whole host of health problems. And, apart from Eskimos, who can eat fish every single day?

But which type of supplement to stock? The choice is expanding all the time, to the point where some stores have entire shelves dedicated to omega-3s. Here, we break the choices down to three areas: the fish oil standard, the up-and-coming krill source and vegetarian options.

Fish
At Natural Products Expo West in Anaheim, Calif., this year, an exhibitor had a ticker tracking the number of fish-oil servings consumed worldwide. At 10:30 a.m. on March 12, the count was up to 77,451,966,961, with an additional 536 servings tallied every second afterward.

Fish oil is the benchmark from which all other omega-3 oils are measured. That’s because of the healthy quantity of EPA and DHA, traditionally in a 180-to-120 mg ratio, which mimics the ratio naturally found in wild fish.

But studies demonstrate different health benefits for each omega-3. “EPA … fights inflammation, such as arthritis and low-grade chronic inflammation, which is harmful in the long term,” says Baldur Hjaltason, who oversees strategic business development for Norway-based fish-oil supplier EPAX. “DHA is a building unit and very important for healthy brain and eye development in infants. Poor memory has been associated with low concentration of DHA, so regular intake of DHA might be important to reduce the risk of memory loss in the elderly.”

While many fish-oil suppliers are angling to get into the food world (and technologies are allowing that to happen without compromising purity standards or taste and odor), EPAX has taken a different route: high-dose concentrates with different ratios of EPA and DHA to address specific health conditions. So its eye-health formula has a greater than 7-to-1 ratio of DHA, while its joint health formula has a nearly 6-to-1 ratio, advantage EPA.

Krill
This tiny shrimp-like crustacean from the Antarctic Ocean is taking the omega-3 market by storm. Krill-oil sales doubled in 2009, and are looking to double again this year, to $50 million, according to Mickey Schuett, director of sales and marketing at Boulder, Colo.-based krill-oil supplier Azantis. This is maybe 2 percent of the fish-oil market—numbers not unlike the ratio of organic to conventional foods.

While it’s easy to group krill oil in with fish oil because they both come from the ocean and both contain EPA and DHA, krill is an entirely different beast. It contains about 25 percent omega-3s (versus 30 percent to 85 percent in fish oil, depending on the concentrate in the specific product), but the real differentiator is 40 percent phospholipids and a bit of astaxanthin, vitamin E and protein. Phospholipids are the bricks and mortar of cell walls, seen as having a trifecta of benefits: enabling efficient cellular communication, enhancing transport of omega-3s into cells and, as vital fats, making the brain tick. Astaxanthin is a carotenoid antioxidant that has been found to protect against retinal damage, and is also what gives krill—and species that feed on krill like salmon and lobsters—their distinctive red-orange color.

Only a very limited number of human studies have been conducted on krill. One found that giving 90 people 1 gram a day of krill oil reduced inflammation, as measured by C-reactive protein levels, and also helped arthritis symptoms.

Another study hypothesized that since the omega-3s EPA, DHA and alpha-linolenic acid (ALA) have been shown to ameliorate insulin resistance, a hallmark of diabetes, that maybe krill oil could also be effective. Turns out it was even more effective for reducing blood-sugar levels and all blood-lipid parameters like cholesterol and triglycerides than either fish oil or placebo.

Clearly more research is needed on the tiny but mighty Euphausia superba. There’s also some concern about sustainability, since krill are the foundation of the marine food chain. (What would Willie say?) But more than 90 percent of all krill is harvested for the aquaculture industry, say krill suppliers, so shoppers should not be concerned that their personal supplement regime affects the krill population to any discernible degree at this point.

Also, aboard every krill-harvesting ship is a representative from the independent Commission for the Conservation of Antarctic Marine Living Resources who monitors the catch and conducts research.

Vegetarian sources
There are no shortage of ways in which you can get your fish-oil benefits without actually consuming an aquatic animal. The option with the best bona fides is fermented algae that provides pre-formed DHA, meaning it doesn’t need to be converted from ALA to DHA like some vegetarian omega-3 sources. This is the kind mostly found in infant formula. The catch: no EPA. However, Martek, the Columbia, Md.-based company that produces life’sDHA brand fermented DHA, announced at Expo West 2010 that it will begin producing EPA by the same fermentation technology.

Flax has been the preferred vegetarian alternative to fish oil, but its omega-3s come solely from ALA. Like DHA and EPA, ALA is polyunsaturated, but it’s a short-chain, 18-carbon fatty acid, versus the longer-chain 20-carbon EPA and 22-carbon DHA. The body has a challenge with ALA: It must work hard to convert it to the more beneficial EPA and DHA. Typically, ALA suffers from a poor conversion rate—along the lines of only 3 percent to 7 percent. Even so, flax oil and flaxseeds have been found to lower blood pressure, prevent heart conditions because of their lignan content and even manage hot flashes.

One new vegetarian source is echium oil. A relative of borage oil, it has been sold in Canada for some time but is just now hitting the American market in earnest. “It’s the coolest new oil because it has stearidonic acid, which converts to EPA at a 1-to-1 level, which gives you similar conversion rates to fish without the fish oils,” says Cameron Kupper, vice president of operations at Canadian oil supplier Bioriginal. Apparently, echium oil does not convert to DHA.

Finally, omega-3s have not gone unnoticed by purveyors of genetically modified organisms. Biotech companies like Monsanto and DuPont are researching and developing seed crops that produce high levels of omega-3s. DuPont’s New Harvest softgels, which contain vegetarian EPA derived from yeast, are already available at GNC stores.

Your customer’s call
Whichever omega-3 supplement source your customers choose, it’s important not to lose the forest for the trees, says Adam Ismail, executive director of GOED, the Global Organization for EPA and DHA Omega-3.

“Short-chain omega-3s like ALA typically come from plant sources and are considered essential for nutrition, while long-chain omega-3s typically come from sources like fish and algae and have been shown to reduce incidences of many chronic diseases,” he says. “The deficiency of omega-3s in the diet is so critical to solve for public health in the U.S. that consumers need to be seeking out more of each—it is not about a choice between the sources.” Thanks to the many options now available, consumers can now get their omega-3s from sources to suit their every whim.