Fish for Compliments

By Dietitian, Juliette Kellow BSc RD

It’s well established that eating more oily fish helps to keep our hearts healthy thanks to it containing omega-3 fats. But what effect does it actually have on risk factors for heart disease and other conditions when used in conjunction with a weight loss program?

To find out, scientists from Cambridge took 116 overweight, insulin resistant women and allocated them to one of three groups. The 116 women were aged between 21 and 69 and had an average weight of 92.7kg, an average BMI of 35 and an average waist circumference of 99.4cm. The first group of 39 followed a weight loss program with the addition of omega-3 fats in the form of 1g capsules five times a day. The second group of 38 women followed the same weight loss program with the addition of a placebo oil – an oil that has no effect. The third group of 39 simply received the placebo oil.

Unsurprisingly, both groups of women who followed the weight loss program lost significantly more weight than the group who simply took the placebo oil, losing on average across the two groups 10.7kg. This weight loss helped to improve insulin sensitivity and reduce blood triglycerides and inflammation – all risk factors for heart disease.

Although they lost around the same amount of weight, the weight loss group who took the omega-3 fats lowered their triglycerides and improved levels of the hormone adiponectin, far more than those who followed the weight loss program with the placebo oil. Low amounts of adiponectin have been linked to type 2 diabetes, obesity and atherosclerosis.

The study took 24 weeks in total, and the weight loss program was broken down into a 12-week weight loss phase and a 12-week maintenance phase. The weight loss program was designed to achieve 10% weight loss in the first phase. The women participating were asked to attend fortnightly sessions where they received diet advice and were told to follow an energy-restricted diet of around 800 – 900 calories per day. In the second phase they were advised to stick to maintenance calories. The group taking the placebo oil only was not given any dietary advice.

The authors conclude that more attention should be given to omega-3 fats in the diet to help treat obesity and the risk factors for other diseases that can go hand in hand with obesity. Although they do state that these effects were obtained with a dose higher than can be realistically achieved through diet alone.

WLR says:

This is a small study and more research is needed to assess dose levels and if similar effects can be seen with a food based program. Nevertheless, as omega-3 fats have many health benefits – including keeping our hearts healthy and helping the reduce inflammation – it’s certainly not going to do any harm to include more of them in our diets.

Just last month, a large review of all the research revealed that eating one to two servings of fish a week, especially oily fish, helps to reduce the risk of dying from a heart attack by a massive 36 percent. This is supported by the Food Standards Agency, who recommend we eat two servings of fish a week, one of which should be oily fish such as salmon, mackerel, sardines, pilchards, trout or fresh tuna.