Weekly health quiz: Pollution, exercise and smartphones

1 For optimal health benefits, the following omega-3 source is the best:

• Omega-3-rich plant foods such as flaxseed, flaxseed oil, chia seeds, walnuts and leafy greens
• Small, fatty fish such as sardines, anchovies and herring

  In fish, the DHA and EPA are in the form of triglycerides, which are the most bioavailable. In most fish oil supplements, the DHA and EPA are delivered in the form of ethyl esters — a synthetic substrate with low bioavailability. To reap maximum health benefits, you want a majority of your omega-3 to come from your diet. That means eating small fatty fish such as sardines, anchovies, mackerel and herring. Wild-caught Alaskan salmon is another good source. Learn more.

• Fish oil supplements
• Krill oil supplements