Fish is a great source of heart-healthy lean protein. Dining on one or two servings of fish as your protein every week can lower risk of heart attack by almost one-third. That’s because it contains heart-healthy omega-3 fatty acids, which lower triglyceride levels as well as help reduce inflammation throughout the body and support brain health.
The omega-3 you get from fish – also known as long-chain omega-3s, EPA and DHA — are extremely beneficial. But that doesn’t mean including fish in your diet doesn’t have a downside. Many fish species carry high levels of the metal mercury — a dangerous contaminant that can affect the nervous system. Pollution has only raised mercury levels in our oceans, lakes and streams, and this mercury is consumed by fish and converted to a toxin known as methylmercury. Fish that are high on the food chain consume other contaminated fish, thus compounding their mercury levels, which is why it’s best to choose smaller fish, lower on the food chain, to eat. Farmed fish, which you think would be safer, are also fed the same diet of growth hormones, antibiotics and other foods that are not found in their natural habitat and therefore should be avoided.
The primary concern with fish and mercury is in infants and young children, as their developing nervous systems are particularly vulnerable to mercury’s effects. That’s why pregnant women and those nursing are advised to be extremely careful about choosing the types of fish to eat. Experts recommend pregnant women avoid sea-water fishes like swordfish (myli meen), tuna and shark and choose fish that are found in local ponds like rohu, hilsa, surmai (kingfish) etc instead.
Adults who have high exposure levels (which is an unlikely outcome of eating a few servings of fish) can experience significant central nervous system damage as well.
Methylmercury poisoning is just one concern; fish can also contain a toxicant called polychlorinated biphenyls (PCBs), a manmade chemical disposed in water bodies.
Several organizations keep track of which fish are low in mercury and other toxicants, aren’t endangered and still manage to benefit your heart and brain health. Bangada (mackarel), hilsa, tilapia and pomfret (butterfish) are your best picks. Here’s a list:
Fish low in mercury
- Anchovies (Nethili in Malayalam)
- Butterfish (Pomfret)
- Catfish (Singhara)
- Herring (Hilsa)
- Mackerel (bangada)
- Salmon (Indian salmon is rawas)
Moderate mercury (Eat six servings or fewer per month; pregnant women and small children should avoid these)
- Carp (Rohu)
- Cod (Gobro)
- Tuna (Canned Chunk light)
High mercury (Eat three servings or less per month; pregnant women and small children should avoid)
- Grouper (Kalava in Malayali)
- Sea Bass (Asian seabass is bhekti)
- Tuna (Canned Albacore, Yellowfin)
Highest mercury (avoid eating)
- Tuna (Ahi)