People around the world enjoy seafood and fish. In addition to their appealing flavors, they are also rich in nutrients.

Which fish offers the highest nutritional value? Huang Yiling, a nutritionist at Taiwan’s Keyi Nutrition Consulting Center, discussed how to avoid contaminants in fish and highlighted which fish are most beneficial for health during an Epoch Times Health 1+1 program.

Small, Wild Fish More Nutritious, Safer to Eat

A study published in the March edition of Nature Food found that six species of wild fish used as aquafeed for farmed salmon were richer in nutrients than the farmed salmon itself. Small wild fish include Peruvian anchoveta, Pacific anchoveta, European sprat, Atlantic herring, Atlantic mackerel, and blue whiting.

Research results show that the calcium content of the above six kinds of wild small fish is five times higher than that of farmed salmon. In addition, the iodine content is four times higher, and the iron, Omega-3, and vitamins B12 and A contents are more than 1.5 times higher. As for vitamin D, the amount in wild small fish is similar to that of farmed salmon. However, farmed salmon contain more selenium and zinc than wild small fish, which is possibly a result of other aquafeeds.

In addition to their differences in nutritional value, Huang said that due to environmental pollution, heavy metal contamination and other toxins tend to accumulate in successive aquatic food chain stages. In this chain, where the big prey on the small, the result is that the larger species accumulate more of the heavy metals in their bodies. Therefore, she recommends eating fewer medium to large fish, such as salmon, tuna, and sailfish, and more smaller fish about the size of your palm, such as mackerel, sardines, and herring.

Huang suggested that we eat a variety of fish species for a broad range of nutritional benefits.

2 Types of People Should Eat Fewer Big Fish

Huang does not recommend pregnant women and children eat large fish. If they do, she said, it is recommended to eat only the lean portion because the skin and fatty meat of a fish contain most of the oil, which is where heavy metals are most likely found.

According to the advice from the U.S. Food and Drug Administration, some large predatory fish accumulate higher concentrations of methylmercury, which may cause harm to the neurological development of fetuses and young children. Therefore, it is recommended that pregnant women, women of childbearing age, and children between 1 and 6 years old avoid eating shark, swordfish, king mackerel, or tilefish. For fish with lower levels of mercury, up to 12 ounces can be eaten within a week if incorporating albacore tuna (which has more mercury than “light” tuna) eat only 6 ounces per week.

Research shows that embryos and fetuses are most susceptible to the effects of methylmercury, and children of women with higher mercury exposure are more likely to develop difficulties in attention, memory, and speech.

Canned Fish Supplements Calcium and Lowers Blood Pressure

In addition to buying fresh or frozen fish, there are many canned options to choose from. Huang said that the canning process helps retain the protein, minerals, oil, and other nutrients of the fish. At the same time, the fish bones are softer and can be ingested directly to obtain more calcium.

A comprehensive study suggested that long-term consumption of canned mackerel significantly reduced systolic and diastolic blood pressure in patients with mild essential hypertension. Huang said that if the canned fish is not too salty, it will have little negative impact on blood pressure, while the Omega-3 fatty acids in canned fish are very helpful in regulating blood pressure and lowering blood lipids. For people living in inland locations where fresh seafood do not come handy, canned fish is a relatively good alternative.

However, Huang said that some canned food may contain additives for seasoning purposes. Therefore, when purchasing canned fish, read the product labels to choose products with fewer additives and lower sodium.

Fish Supplies 9 Nutrients

Huang introduced the nine nutrients our body needs that can be obtained from fish:

1. Iodine

Iodine is a key component of thyroid hormone. Thyroid hormone regulates many important biochemical reactions in the body, including protein synthesis and enzyme activity. For pregnant women, iodine deficiency may lead to fetal neurodevelopmental defects, growth retardation, or miscarriage. In children, iodine deficiency can have adverse effects on growth and development, such as a below-average IQ.

2. Calcium

Calcium makes up much of the structure of bones and teeth and helps maintain normal body movement. It affects muscle function, blood coagulation, neurotransmission, and hormone secretion. Calcium deficiency can reduce bone strength and lead to osteoporosis, increasing the risk of falls and fractures.

3. Iron

Iron is a key component of hemoglobin, responsible for transporting oxygen to all parts of the body. The synthesis of some hormones in the human body also requires the presence of iron. Anemia occurs when there is insufficient iron, and symptoms may include gastrointestinal discomfort, weakness, fatigue, low energy, or problems with concentration and memory.

4. Vitamin A

Vitamin A helps maintain normal vision, reproduction, growth, and development, as well as the normal functioning of the immune system. A lack of vitamin A can cause dry eye syndrome and increased risk of respiratory diseases, measles, and diarrhea.

5. Vitamin B12

Vitamin B12 helps maintain the health of the body’s blood and nerve cells and helps make DNA. Lack of it can cause megaloblastic anemia, with symptoms including fatigue, weakness, pale skin, heart palpitations, loss of appetite, weight loss, and infertility.

6. Vitamin D

Vitamin D promotes calcium absorption in the intestines and prevents bones from becoming thin, brittle, or deformed. It can reduce inflammation and regulate immune function, cell growth, and glucose metabolism.

7. Omega-3

Omega-3 fatty acids help build cell membranes, and a deficiency can cause skin to become rough and inflamed. Research shows that Omega-3 in marine fish can reduce the risk of cardiovascular diseases such as myocardial infarction and coronary heart disease in the general population.

8. Zinc

Zinc helps maintain immune function, protein and DNA synthesis, wound healing, and cell signaling. Deficiency may affect the skin, bones, digestive system, reproductive system, central nervous system, and more.

9. Selenium

Selenium is important for maintaining the reproductive system, thyroid function, helping with DNA production, and protecting the body from free radical damage. Selenium deficiency may increase the risk of cancer, cardiovascular disease, thyroid disease, and cognitive decline.