5 Things to Know Before Becoming a Pescatarian

Whenever I tell someone I'm pescatarian, the first thing they warn me about is mercury poisoning — and it's a valid concern. When mercury dissolves into water it creates methylmercury; sea creatures can absorb this methylmercury just by swimming, and their mercury quantities increase as they eat smaller sea critters who've also been exposed.

If you ingest too much mercury, it can cause debilitating mercury poisoning. Symptoms include nervousness, irritability, numbness and physical tremors; left untreated, it can cause muscle weakness, difficulty breathing and long-term complications like neurological damage and coronary heart disease.

But fear of mercury poisoning is no reason to forego a pescatarian diet. "Some studies have shown that the benefits of eating fish outweigh the risks related to mercury," Sharon Palmer, RDN, told Today's Dietitian. These benefits to eating fish include lower blood pressure and cholesterol, decreased risk of diabetes and reduced risk of cardiovascular disease.

The best thing to do is just avoid — or limit — your intake of predatory fish like swordfish or King mackerel, as these fish often consume other fish that might also been exposed to mercury.

Just like meat, not all seafood is sourced sustainably. Commercial fishing can decimate oceans, but organizations like Seafood Watch have sustainable fish-buying guidelines and resources to keep in mind. These include the best types of fish to eat — such as certain prawns, shrimp, scallops, bass and arctic char — as well as what to look for with each of these fish, like locations where the fish were sourced and how they were caught. Seafood Watch also highlights fish to avoid due to overfishing or lack of oversight, including specific octopus, lobster, Mahi Mahi and shark.

While shopping, look for sustainability labels. The Marine Stewardship Council certifies almost 200 fisheries that demonstrate effective management and maintain healthy populations and ecosystems. Their label (it's blue with a fish and check mark) is recognized around the world for eco-conscious wild-caught seafood.

Going beyond fish staples like tuna, shrimp and salmon is not only eco-friendly, it will also help you optimize seafood nutrition. According to the Cleveland Clinic, the three healthiest fish choices include sardines, herring and mackerel.

Sardines are a great source of vitamin D, and pack 2 grams of omega-3s into each 3-ounce (85-gram) serving. They have one of the lowest mercury levels of any seafood. Herring, a fatty fish with 1.5 grams of omega-3s per 3-ounce (85-gram) serving, also has less mercury than omega-3-dense fish like tuna and swordfish. Mackerel are chock-full of omega-3s as well, although consumption should be limited since it can contain mercury.

Which fish should you avoid? The Cleveland Clinic recommends limiting the omega-3-lacking tilapia, mercury-dense tuna and imported catfish, which often contains dangerous chemicals.

Fresh seafood from the local fishmonger may be the most appealing, but it's wise to mix in canned or frozen seafood, too. And you should also include a variety of whole grains and grain products; dairy (cheeses and yogurts); legumes — think beans, lentils, tofu or hummus; nuts, berries and seeds; and fresh fruits and vegetables into your diet, along with the fish and seafood. Eggs are also a great source of vitamin D, calcium and protein, which are important for a healthy diet.

Meat alternatives are also filling grocery store shelves these days, and plant-based fish will soon follow. Impossible Foods and Nestle are among the brands working on plant-based fish options, while TUNO, a fishless tuna alternative from Atlantic Natural Foods, is already on the market, so keep an eye out for them.

While there are a lot of benefits to becoming a pescatarian, health has to be top of the list. Studies have shown that those who eat vegetarian-based diets (including a pescatarian diet) typically have a lower body mass index (BMI) than those who don't. Other research has proven that flexitarian diets are very beneficial to healthy body weight and blood pressure, and a reduced risk of Type 2 diabetes.

Seafood is expensive, though, so a pescatarian diet can hit your wallet hard. But as we mentioned, you don't have to always buy fresh. Stock up on canned and frozen to save a little cash when you can.

There also are benefits to the environment for going pescatarian. Factory farming and meat processing requires massive amounts of land — and contributes to high levels of carbon emissions. Eating less meat — and choosing sustainable fish and seafood instead — could help make for a healthier planet. Not to mention save more pigs.