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.

Vitamin D made it to the top in 2007 after the Canada Food Guide began recommending a daily supplement of 400 international units for people over age 50. Vitamin D deficiency has also been linked to high blood pressure, certain cancers, chronic pain, and multiple sclerosis. The best source of vitamin D is the sun. 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. Sources of omega-3s are vegetable oils, nuts and seeds, particularly walnuts and hemp and flax seeds.

Folic acid is a vital nutrient for pregnant women. Also known as folate, it helps the body to produce red blood cells and prevent anemia. It is critical for helping the fetus to develop a healthy spinal cord. Folic acid sources include dark leafy green vegetables, asparagus lentils, beans, oranges and orange juice. It is also added to many breads and cereals.

Iron is important for helping oxygen move through the body. A classic sign of iron deficiency is anemia, which can result in weakness and fatigue. Too much iron can also cause problems, including an upset stomach and difficulty with bowel production. The most readily absorbed source of iron comes from animal products — red meat, the dark meat of chicken, and fish. Non-animal sources include whole grains, spinach, and enriched cereals. To aid iron absorption, it's important to eat foods rich in Vitamin C, such as oranges, brightly coloured peppers, and strawberries.

The best way to take in your daily requirements of vitamins and minerals is by eating a balanced diet. For busy families, especially those with children for whom healthy foods are about as appealing as a trip to the dentist, that's an ongoing challenge.