Proportion of seafood in nutritious diet

In the daily nutritious diet of ordinary people, the proportion of seafood (including fish, shrimps, crabs, shells, algae and other aquatic ingredients) in the total daily animal food intake is recommended to be controlled at 20% to 30%, which translates into a weekly intake of 200~500g, and the average daily intake is about 30~70g. Groups with different physical conditions, dietary preferences, and living areas can fluctuate up or down according to their own conditions, and there is no absolute unified standard.

Speaking of which, my perception of this number really didn't come from textbooks. I was impressed by it when I helped my mother sort out the physical examination report last month. In the past two years, she used a health account to say that she should eat more deep-sea fish to prevent Alzheimer's disease. Steamed fish, hairtail fish, and saury were all on the table at every meal. Seafood accounted for more than half of all the meat and eggs she ate. However, her last physical examination showed that uric acid had soared to 480 μmol/L, which scared her and rushed to the nutrition department to register. The doctor said that her purine metabolism is weaker than that of young people. If the proportion exceeds double, there will be no problem. He adjusted her purine metabolism to about 20%. After a review in the past two months, the index has dropped back to the normal range.

But this ratio is not an untouchable warning line. I know friends who are doing low-carbon diet science popularization, and they have directly increased the proportion of seafood in animal foods to 60%, and almost all red meats such as pork, beef and sheep have been replaced by aquatic products such as cod, shrimp, and slippery shrimp. His logic is also very tenable: the absorption rate of high-quality protein in seafood is about 10% higher than that of red meat, and the saturated fat content is very low. It can also supplement n-3 polyunsaturated fatty acids that are difficult to obtain from other foods. After eating this for two years, his body fat rate has remained stable at 15% all year round, and his blood lipids and blood pressure indicators are much better than when he ate red meat every now and then. The only trouble is that he has to test his uric acid once a week, deliberately avoiding high-purine varieties such as crab roe and fresh squid, and always eats more than 300g of green leafy vegetables to promote metabolism.

Of course, there are many scholars who oppose this high-proportion eating method, and they especially do not recommend that inland residents blindly follow the trend. After all, many people in coastal areas have been eating seafood for generations, and their purine metabolism has developed adaptability. Inland residents do not have this dietary foundation. If the proportion of seafood has increased to more than 40% for a long time, the risk of gout and kidney stones will increase by more than 30%. Coupled with the problem of marine pollution, aquatic products caught offshore have the hidden danger of being enriched with heavy metals and microplastics. Eating too much will put a burden on the body.

Oh, by the way, special groups of people can completely skip this general proportion adjustment. For example, for pregnant women, many nutritionists will actively recommend increasing the proportion of seafood to 30% to 40%. Just choose low-mercury cod, prawns, and farmed salmon. Avoid species with high methylmercury content such as swordfish and wild large tuna. The absorption rate of DHA supplements is more than a little higher than that of supplements. When my best friend was pregnant, she ate steamed cod three times a week. After the baby was born, his gross motor and cognitive development were much better than those of children of the same age. On the other hand, if you are allergic to seafood, or are in an acute attack of gout, it is perfectly fine to directly reduce the proportion of seafood to 0. You don't have to listen to others saying "seafood is nutritious" and force yourself to eat it, which will be more than worth the gain.

There is also a very common misunderstanding. Many people think that seafood only includes fish, shrimps and crabs, and algae are always forgotten when calculating the proportion. In fact, wakame, seaweed, and kelp are also considered seafood. You usually add a small handful when cooking noodles or soup. They are low in calories and can supplement iodine. In inland areas, fresh aquatic products are not usually available. You can easily meet the minimum intake with this amount of algae, and you don’t have to worry about excessive purine levels.

To be honest, there is no need to dwell on the figure of 20% to 30%. My friend in Zhoushan has shrimp and crab on every meal at home, and seafood accounts for more than 60% all year round. There are no problems in his family's physical examination, and his metabolism has long been adapted to this kind of diet. There is no standard answer when it comes to diet. As long as you feel comfortable after eating and the physical examination indicators are normal, eat more or less, it all depends on your own preferences.