Women are naturally more prone to constipation than men because of differences in pelvic structure and hormones. Once in the menstrual period, it is more likely that intestinal flora imbalance will occur due to endocrine imbalance, which will not only make you fat, but also reduce your immunity. However, there are also female gospels. A study from Science Report shows that women can improve the diversity of intestinal flora by ingesting omega-3 fatty acids contained in fish oil, which can not only improve their immunity, but also effectively lose weight. The study, led by King's College London, collected 876 middle-aged and elderly women from all over Europe. In addition to their daily intake of omega-3 fatty acids and blood concentration, they also collected fecal samples to investigate the number of probiotics in the intestine. The results show that women with high concentration of omega-3 fatty acids in blood have more kinds of intestinal flora, especially lachnospira, which can secrete short-chain fatty acid SCFA, so they can not only lose weight, but also regulate blood pressure, prevent intestinal inflammation and avoid chronic diseases such as diabetes or heart disease. In addition, the diversity of intestinal beneficial bacteria can prevent many opportunistic infections. For example, the above Chaetomium family can prevent pseudomembranous colitis caused by Clostridium difficile in colon. The results of fecal sample survey also showed that the intestinal flora of women with high DHA concentration in blood was similar to that of women who were not easily inflamed in the past, and the feces also contained a lot of N- carbamoyl glutamic acid (NCG). NCG is an index to judge intestinal oxidative stress in modern animal experiments. The higher the NCG content, the lower the intestinal oxidative pressure. Therefore, the research team also believes that this study proves that omega-3 fatty acids are beneficial to the body, and some of them should come from providing intestinal bacterial nutrition and promoting the synthesis of NCG. Professor Shoukouche, a Japanese DHA research expert, also pointed out that compared with the high-priced oil products developed in recent years, such as linseed oil and perilla seed oil, blueback fish is cheap and easy to obtain, and it is the best omega-3 intake pipeline. If we refer to the food standard ingredient list revised by the Japanese Ministry of Education, Culture, Sports, Science and Technology in 20 15, we can find that tuna, especially tuna, has the highest DHA content in oil. However, in recent years, due to the serious problem of overfishing, tuna resources are facing depletion, and international environmental groups are also advocating the protection of this valuable marine resource. Therefore, people are advised to choose the common fish after the second place in the list.