How the Lack of Fish Affects the Body: Doctors Tell What it Means to Eat Little Fish

Fatty fish such as salmon, mackerel, sardines, and rainbow trout are among the best sources of omega-3s. There is no shortage of information about the benefits of omega-3 fatty acids, or the heart-healthy polyunsaturated fats found in fish. The grade

Below, health experts explain the potential risks associated with a fish-free diet, as well as how to ensure you get the nutrients you need if you’re cutting out seafood altogether.

What are the health benefits of fish?

Fatty fish, such as salmon, mackerel, sardines, and rainbow trout, are among the best sources of omega-3, an anti-inflammatory fat that has countless health benefits.

“Omega-3s are known to have anti-inflammatory effects and are therefore potentially beneficial in preventing various conditions caused by inflammation in the body, such as Alzheimer’s disease, heart disease, and diabetes,” says Anna Brown, RD, a Brooklyn-based dietitian and founder of Nutrition Squeezed, a private practice.

“In addition, omega-3s such as EPA and DHA are beneficial for brain, eye, and nervous system health. Thus, increased consumption is associated with a lower risk of depression, anxiety, ADHD, and dementia.”

In fact, according to the Mayo Clinic, eating two 3-ounce servings of fish per week reduces the risk of heart disease.

What are the main nutrients found in fish?


Obviously, polyunsaturated fatty acids in fish are important for our health. But EPA and DHA are especially important because the body cannot produce enough of these fats on its own. That’s why we need to get essential fatty acids from foods like fish.

Some nuts and seeds contain vegetarian omega-3 fatty acids, such as alpha-linolenic acid (ALA).

“Luckily, the human body is very talented, so we can convert ALA to EPA and DHA,” explains Chris Sollid, RD, a nutritionist and senior director of nutrition communications at the International Food Information Council.

“But our bodies don’t do this efficiently, which means we need to get plenty of ALA to produce enough EPA and DHA.”

According to Oregon State University, estimates vary, but it is possible that only up to 4 percent of ALA can actually be converted to DHA in the body.

“That’s why we recommend consuming foods containing DHA and EPA in addition to foods containing ALA,” says Sollid.

Vitamin D

Getting enough vitamin D is a big deal. According to the National Institutes of Health (NIH), proper immune function, bone health, and blood sugar regulation all depend on the fat-soluble vitamin.

But: “very few foods naturally contain vitamin D,” says Sollid. “The richest natural sources of vitamin D are cod liver oil, farm-raised rainbow trout, and sockeye salmon.”


Like all animal products, fish is an excellent source of protein, one of the three macronutrients that contribute to muscle mass, skin health and wound healing, and immune function.

According to the U.S. Department of Agriculture, a piece of salmon smaller than the palm of your hand contains almost 21 grams of protein.

By giving up fish, you may be missing out on a nutritious source of protein because seafood contains a higher proportion of heart-healthy fats than other animal proteins such as red meat.


“Many types of canned fish are also an excellent source of calcium because they are canned with bones,” says Brown.

“Calcium is important for healthy bones, teeth, nerves, and muscles, so without enough calcium, you can be at risk of developing osteoporosis and muscle cramps.” Just 100 grams of sardines can provide an impressive 25 percent of your daily calcium intake, according to the NIH.

What happens if I don’t get enough of these nutrients?

You probably won’t have a protein deficiency if you never eat seafood. After all, there are plenty of other protein options in the sea (or on land).

But a lack of vitamin D and omega-3s from the sea can cause problems over time. “A lack of vitamin D reduces calcium absorption and can contribute to osteoporosis, which leads to brittle bones that are prone to fracture,” says Sollid.

According to a review published in the October 2018 Annals of the New York Academy of Sciences, low vitamin D levels are also associated with an increased risk of acute respiratory infections.

“Considering the amount of sunscreen and sun protection we use these days [it’s a good thing!” Most people in the northern hemisphere are deficient in vitamin D for most of the year,” Brown says. Eliminating fish from the diet removes one of the only natural sources of vitamin D from our plates.

And while true deficiencies of essential fatty acids are rare among U.S. adults, even low intakes of EPA and DHA are not ideal.

“Given that fish is one of the main sources of EPA and DHA, low intake can lead to a higher ratio of omega-6 to omega-3,” adds Brown.

This higher ratio is sometimes associated with systemic inflammation, as well as the chronic diseases it is linked to, such as type 2 diabetes, heart disease, and autoimmune conditions, Brown says.

Can I get these nutrients from other foods?

For the most part, yes. Your diet is high in protein. So even if you cut out seafood, there are many other foods that are high in protein.

Fatty acids are found only in fish. As we have already learned, ALA (which is found in plant foods such as walnuts, flaxseeds, and chia) can be converted into essential fatty acids, but the amount we get from the plant form is often minimal.

“For those who are vegetarian, vegan, or don’t 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 make sure they are eating chia seeds, flax seeds, and walnuts on a regular basis,” says Brown.

Vitamin D is another component of oily fish that is hard to find anywhere else in the diet. Fortunately, eating egg yolks regularly and staying safe in the sun are two natural ways to increase your serum vitamin D levels. Foods and drinks such as milk, breakfast cereals, and even some orange juices are also often fortified with vitamin D.

There are foods rich in calcium. Dairy products like cow’s milk and yogurt, leafy greens like kale and bok choy, and heart-healthy nuts like almonds are good sources of this important mineral.

So, is it bad to never eat fish?

Not so bad. Although the Dietary Guidelines for Americans recommend eating fish twice a week, giving up seafood doesn’t mean your health is doomed.

“A fish oil supplement can help if you can’t meet this recommendation,” says Sollid. “Finding the nutrients our bodies need from food in the first place is usually the best way, but if that’s not possible, talk to your doctor to see if a fish oil supplement is right for you.”

Brown agrees: “It’s perfectly fine not to eat seafood, but it’s important to take supplements or have alternative sources of omega-3, calcium, and vitamin D.”

Whenever you eliminate entire food groups from your diet, it is recommended that you consult a nutritionist to make sure you are getting the nutrients your body needs.

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Written by Emma Miller

I am a registered dietitian nutritionist and own a private nutrition practice, where I provide one-on-one nutritional counseling to patients. I specialize in chronic disease prevention/ management, vegan/ vegetarian nutrition, pre-natal/ postpartum nutrition, wellness coaching, medical nutrition therapy, and weight management.

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