Fish oils contain omega-3 fatty acids that play an important role in numerous metabolic functions. They are considered ‘essential’ because your body can’t make them; they can only be taken in through diet. Because of their double bonds, fish oils might help combat the oxidative stress that can occur during intense training. A study published in the International Journal of Sport Nutrition and Exercise Metabolism tested this theory on 20 male subjects.

For a 6-week period leading up to a workout consisting of 200 eccentric knee contractions, subjects received either fish oils or a placebo. Although there were no differences in markers of muscle damage or soreness between groups, DNA damage was lower in fish oil supplementing subjects immediately following exercise. 

True Strength Moment: Whether or not this protective effect helped these subjects realize greater gains than the placebo group isn’t known, but a previous study conducted on female volunteers suggested fish oils may have helped them achieve greater improvements in strength and functional capacity through weight training.