There's no shortage of information on the benefits of omega-3 fatty acids, aka those heart-healthy polyunsaturated fats found in fish. So is it really that bad to never eat fish?
Below, health experts explain the potential risks of a fish-free diet, plus how to ensure you're getting the nutrients you need if you're skipping seafood altogether.
What Are the Health Benefits of Fish?
Fatty fish like salmon, mackerel, sardines and rainbow trout are among the best sources of omega-3s, the anti-inflammatory fats that come with countless health benefits.
The two types of omega-3s found in fish are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).
"Omega-3s are known to be anti-inflammatory and are, therefore, [potentially] beneficial for staving off a variety of conditions caused by inflammation in the body, like Alzheimer's, heart disease and diabetes," says Anna Brown, RD, a Brooklyn-based dietitian and founder of the private practice Nutrition Squeezed.
"Additionally, omega-3s like EPA and DHA are beneficial for brain, eye and nervous system health. An increased intake is therefore associated with a lower risk of depression, anxiety, ADHD and dementia."
In fact, eating two 3-ounce servings of fish weekly is linked to a lower risk of heart disease, per the Mayo Clinic.
What Are the Key Nutrients in Fish?
Clearly, the polyunsaturated fatty acids in fish are important for our health. But EPA and DHA are particularly critical because the body can't make enough amounts of these fats on its own. That's why we need to get the essential fatty acids from foods like fish.
There are vegetarian omega-3 fatty acids, such as alpha-linolenic acid (ALA) found in some nuts and seeds.
"Fortunately, the human body is very talented, so we can convert ALA into EPA and DHA," explains Kris Sollid, RD, dietitian and senior director of nutrition communications at the International Food Information Council.
"But our bodies do this inefficiently, meaning we have to get a lot of ALA to generate enough EPA and DHA."
Estimates vary, but it's possible that only up to 4 percent of ALA may actually get converted to DHA in the body, according to Oregon State University.
"This is why it's recommended that we eat foods that provide DHA and EPA directly, in addition to eating foods that contain ALA," Sollid says.
Getting enough vitamin D is kind of a big deal. Proper immune function, bone health and blood sugar regulation all rely on the fat-soluble vitamin, per the National Institutes of Health (NIH).
But: "Very few foods naturally contain vitamin D," Sollid says. "The highest food sources of naturally occurring vitamin D include cod liver oil, farmed rainbow trout and sockeye salmon." Noticing a pattern here?
Like all animal-based foods, fish is a stellar source of protein, one of the three macronutrients that contributes to lean muscle mass, skin health and wound healing, as well as immune function.
A 3-ounce piece of salmon (less than the size of your palm) serves up nearly 21 grams of protein, per the USDA.
By skipping fish, you may miss out on a nourishing source of protein, because seafood has a higher proportion of heart-healthy fats compared to other animal proteins like red meat.
"Many types of canned fish are also a great source of calcium because they are canned with their bones," Brown tells LIVESTRONG.com.
"Calcium is important for bone, teeth, nerve and muscle health, so without adequate calcium, you may be at risk of developing osteoporosis and muscle cramps." Just 3 ounces of sardines can provide an impressive 25 percent of your daily value for calcium, per the NIH.
What Happens If I Don’t Get Enough of These Nutrients?
You probably won't present with a protein deficiency if you never eat seafood. After all, there are plenty of other protein options in the sea (or on land).
But missing out on vitamin D and marine-derived omega-3s could pose problems over time. "Insufficient vitamin D reduces calcium absorption and can contribute to osteoporosis, which results in brittle bones that are prone to breaking," Sollid says.
Low levels of vitamin D have also been linked to an increased risk of acute respiratory infections, according to an October 2018 review in the Annals of the New York Academy of Sciences.
"With the amount of sunscreen and sun protection we're using these days [a good thing!], most people in the northern hemisphere are vitamin D deficient for a majority of the year," Brown says. Nixing fish from the diet removes one of the only natural sources of vitamin D from our plates.
And while a true essential fatty acid deficiency is rare among U.S. adults, even a low intake of EPA and DHA isn't ideal.
"Given that fish are one of the main sources of EPA and DHA, a low intake could result in a higher ratio of omega-6s to omega-3s," Brown adds. "The ideal ratio is 1:4 of omega-3s to omega-6s. Unfortunately, the standard American diet provides a ratio closer to 1:16."
That higher ratio is sometimes linked to systemic inflammation, as well as the chronic diseases it's associated with, like type 2 diabetes, heart disease and autoimmune conditions, Brown says.
Most experts agree that eating some fish, even if it's farmed, is better than eating no fish at all. But if you eat farmed fish very regularly (think: more than three times a week), taking a break from seafood could actually be a good idea.
Research shows that farmed varieties tend to be higher in potentially inflammatory omega-6 fatty acids as well as pollutants like PCBs.
Can’t I Get These Nutrients From Other Foods?
For the most part, yes. We don't need to tell you that protein is abundant in the diet. So even if you skip seafood, there are plenty of other high-protein foods.
EPA and DHA are a tougher bunch. The fatty acids are found in fish and fish only. As we already learned, ALA (which is found in plant foods like walnuts, flax and chia seeds) can be converted to the essential fatty acids, but the amount we reap from the plant-based form is often minimal.
"For those who are vegetarian, vegan or do not eat seafood for other reasons, I would either recommend a non-fish omega-3 supplement made from seaweed and/or algae, or I would work with the client to ensure they are regularly eating chia seeds, flax seeds and walnuts," Brown says.
Vitamin D is another component of fatty fish that's hard to find elsewhere in the diet. Fortunately, regularly eating egg yolks and getting safe exposure to sunlight are two natural ways to up your serum vitamin D levels. Foods and drinks like milk, breakfast cereals and even some orange juices are often fortified with vitamin D, too.
Eating calcium-rich foods is doable even if seafood is taken off the table. Dairy products like cow's milk and yogurt, leafy greens like collard greens and bok choy and heart-healthy nuts like almonds are all good sources of the important mineral.
So, Is It Bad to Never Eat Fish?
Not so bad. While the Dietary Guidelines for Americans recommend eating fish twice weekly, skipping seafood doesn't mean your health is doomed.
"A fish oil supplement may help if you cannot meet that recommendation," Sollid says. "Seeking the nutrients that our bodies need from food first is usually the best route, but if that's not possible, talk with your doctor to see if a fish oil supplement is right for you."
Brown agrees: "It's absolutely fine to not eat seafood, but it's important to supplement or eat alternative sources of omega-3s, calcium and vitamin D."
Whenever you cut entire food groups out of your diet, it's a good idea to work with a registered dietitian to ensure you are getting the nutrients your body needs.
- National Institutes of Health: “Vitamin D Fact Sheet for Health Professionals”
- USDA FoodData Central: “Fish, Salmon, Coho, Farmed, Cooked, Dry Heat”
- Harvard T.H. Chan School of Public Health: “Fish: Friend or Foe?”
- Oregon State University: “Essential Fatty Acids”
- Annals of the New York Academy of Sciences: “Global Prevalence and Disease Burden of Vitamin D Deficiency: A Roadmap for Action in Low- and Middle-Income Countries”
- National Institutes of Health: “Calcium Health Professionals Fact Sheet”
- United States Department of Agriculture: “Dietary Guidelines for Americans, 2020-2025”