A balance of nutrients essential to physical and mental health

It's not that any one nutrient is more important than another, says Wendy Reingold, a registered dietitian from Thornhill, Ont. It's that with approximately 50 vitamins and minerals needed every day to stay healthy, experts are reluctant to single any one nutrient out.

All of them are so super-duper important. People should be getting a variety of vitamins and minerals each day, and eating foods that are representative of the four food groups to get that variety.

But some nutrients consistently get more attention than others, and no more so these days than vitamin D and omega-3 fatty acids.

The best source of vitamin D is the sun. However, because people in northern climates have limited sun exposure, more consistently accessible sources are milk and margarine, both of which are vitamin-D fortified. Fish oils are a natural source (one tablespoon of cod liver oil provides 1360 international units). So are eggs and beef liver, but they contain much less vitamin D.

Fish oils are also an abundant source of omega-3 fatty acids, which have been studied for their effects on cancer, the immune system, arthritis, heart function, depression, and blood pressure. People use omega-3s to control cholesterol and to decrease joint stiffness associated with arthritis. Other sources of omega-3s are vegetable oils, nuts and seeds, particularly walnuts and hemp and flax seeds. You can also find omega-3s in an growing number of enriched products.