Fish oil, long recommended by doctors as a supplement to support, among other things, heart function and health – causes severe colitis and colon cancer in mice, according to a study by Michigan State University (MSU), the journal Science reports.
Jenifer Fenton, a nutritionist and nutritional researcher at MSU, conducted research to help determine the dose limit of docosahexanoic acid (DHA), one of the omega-3 unsaturated fatty acids present in fish oil, especially for people suffering from chronic diseases such as enteritis . They found that mice develop deadly late-stage bowel cancer when given a high dose of fish oil. As inflammation develops, it takes only four weeks for a tumor to develop, Science Fenton said.
In detail, the research team found that the cancer becomes more severe and its aggressiveness increases not only if the mice receive the highest doses of DHA, but also if they receive lower doses. The mice used in the studies were susceptible to enteritis. Inflammation is an important risk factor for many types of cancer, including intestinal cancer.
Our discovery supports literature that suggests harmful effects of consuming high doses of fish oil in relation to various diseases. Currently, researchers and the fish industry need to draw up dietary guides on omega-3 consumption, he adds.
The discovery comes as a surprise, since DHA was actually anti-inflammatory and, according to Fenton, the team assumed that feeding mice with DHA-enriched fish oil would reduce the risk of cancer, and we have now found the opposite. Mice are less suited to showing a good immune response to bacteria, and tumors grow faster.
Fenton notes that people don’t need to ditch fish oil, what studies have shown is the need to develop a dosing regimen. As with other nutrients, there is a Gaussian curve effect. On the left side there is too little nutrient, on the right – excess. It states that normally eating people get enough omega-3s and don’t need additional supplementation.
When it comes to fish oil, we don’t know how much is enough yet. We have many examples of taking supplements, nutrients, and chemicals that overstimulate cancer (for example, beta-carotene supplementation in smokers). Supplementation is only useful if it is used by a person who has deficiencies in specific nutrients, he notes.
Fenton’s next step is to measure omega-3 levels in people with bowel inflammation. (PAP)