How Much Is Enough?

Vitamins are vital to our health. Here’s what you need every day and why.

- Lisa Bendall

IN 2013, Sandra McDowell had been having memory problems and dizzy spells for weeks. But it wasn’t until she noticed her heart pounding one night that she became concerned enough to see her doctor. “What went through my mind was: heart condition,” recalls Sandra, who lives in British Columbia, Canada. Her physician, however, suspected a different problem that was confirmed by a blood test. “I was low in iron,” McDowell says, who is in her mid-40s.

The previous year, McDowell had gone from eating meat twice a week to a complete plant-based diet. But she’d failed to replace the iron contained in meats that was now missing from her diet. “I had no idea that my health was deteriorating,” she says.

IT MIGHT SEEM surprising that people who have access to an abundant food supply can lack essential nutrients in their diets. However, it does happen more often than we think, and there are a variety of reasons. “As people age, for example, diets aren’t always balanced, or people eliminate food groups because they can’t tolerate them,” says Dr. Shanthi Johnson, a registered dietitian and a professor of kinesiology at the University of Regina, Saskatchewan, Canada.

In younger people, trendy diets or convenience foods can take the place of healthy eating. “The more we compromise on food groups, the higher the chances of becoming deficient in certain nutrients.” Johnson says. Individuals with malabsorption conditions, like Crohn’s disease and cystic fibrosis, may also have trouble getting enough nutrients.