 Don't count on a daily multivitamin to guarantee you a long life. A new NIH study finds that if you're over the age of 20 and healthy, they probably won't extend your time here. Medical contributor Dr. Celine Gounder says for others, they're important. People with chronic kidney disease, people who might not absorb vitamins because they've had bariatric surgery or because they have GI issues. Pregnant women should be taking a multivitamin with folate to prevent neural tube defects. Looking for a quality car?