“Spend your money on something more beneficial,” is the conclusion of a British researcher who studied data on omega-3 fats and type 2 diabetes.
The increase in omega-3 fats in your diet “has little or no effect” on the prevention or treatment of type 2 diabetes, according to a key review by a team from the Norwegian School of Medicine, University of East Anglia (UEA).
Researchers intend to analyze how omega-3, omega-6, and polyunsaturated fatty acids (PUFAs) affect glucose metabolism and diabetes diagnosis.
This study, considered the most extensive to date, has been commissioned by the World Health Organization, and its results are published online today. Bmj ,
Does fish oil fight diabetes?
Previous studies have been mixed for omega-3 and type 2 diabetes, and the data showed both positive and harmful effects.
Many countries recommend increasing the intake of polyunsaturated and omega-3 fats as part of a healthy balanced diet. In the UK, this means recommendations for eating two servings of fish per week, one of which is oily. There are no specific recommendations for omega-3 supplements in the UK. Despite this, fish oil supplements are some of the best selling supplements in the UK.
The UEA team evaluated data from 83 randomized controlled trials lasting at least 24 weeks in which 121,070 people with type 2 diabetes and without it participated. Some previously unpublished data has been included.
Good evidence of quality has been found for long chain omega-3 fats (LCn3) from fish oil. An increase of 2 g LCn3 per day over an average duration of 33 months did not significantly affect the diagnosis of diabetes or glucose metabolism. The review also showed that there were no changes during longer trials.
They believe that evidence that a dose of more than 4.4 g per day may have a negative impact on the risk of diabetes and glucose metabolism should be interpreted with caution.
There was less reliable data on the effects of alpha-linolenic acid (ALA, still omega-3), omega-6, and total PUFAs in the diagnosis of diabetes.
However, a meta-analysis again suggested that there is virtually no effect of glucose metabolism on the body. They found that an increase in ALA can increase fasting insulin levels by about 7%.
Researchers found that in some studies, data was missing, and in others, the risk of bias.
Relief, not surprise
Were the researchers surprised by their results? “In fact, we were very pleased because before we started the review, there were suspicions that omega-3s could have negative consequences for diabetes – both the risk of diabetes and the control of diabetes,” said Lee Hooper, a study reader. synthesis, nutrition and hydration. said Medscape News UK.
“But we did not find any negative consequences,” she said. – We were very happy about this. We also did not find any benefit. We have a ton of evidence here. It seems that the effects are completely neutral, they do not go positive, they do not go negative – a very insignificant effect.
“The exception is that when we get fairly high doses of long-chain omega-3s over 4.4 ha per day, it seems that glucose metabolism may be slightly worse at this point. Therefore, although very high doses can be negative, most of them do not take doses anywhere near this maximum, so this is probably not a problem for many people. ”
No convincing evidence
The researchers concluded: “There is no convincing evidence that changing our intake of LCn3, ALA, omega-6, or total PUFA changes glucose metabolism or the risk of diabetes.”
They also said supplements "should not be encouraged to prevent or treat diabetes."
They said that future data from longer, high-quality trials lasting at least 12 months would be useful.
Responding to the study in a statement, Douglas Twenefour, deputy director of diabetes care in the UK, said: “Although omega-3 fatty acids are critical to our overall health, people with type 2 diabetes are generally better off getting them with food. . at least two servings of oily fish per week than with supplements. "
Doctor, should I take omega 3 supplements?
This was one of a series of reviews conducted by the UEA team. “The World Health Organization asked us about the health effects of omega-3s, as well as omega-6s and total polyunsaturated fats for the full range of health effects,” Lee Hooper told us.
“We have already published our work on the effects of cardiovascular diseases, both cardiovascular diseases and stroke, as well as body weight. And again, it seems that omega-3s are very neutral regarding these results. ”
“Adding diabetes to it, and it’s not a problem, it’s great.”
So what should doctors say if patients ask about omega-3 supplements?
“We should say the following:“ Spend your money on something more useful. Spend them on the wonderful kind of physical activity that you really like. Or spend it on some food that you really love. Some great healthy fruits or great fish. ” ,
She continued: “Don't waste this on supplements. Go for things that will truly benefit you and you will enjoy. ”
BMJ 2019; 366: l4697 http://dx.doi.org/10.1136/bmj.l4697