Doctors and nutritionists have a saying, “it doesn’t really matter if you take vitamins, but it matters if you live your life like someone who takes vitamins”. Basically, people who take vitamins also tend to eat better, exercise more and think about their health on a daily basis- and this is what leads to better health. The research on the efficacy of vitamins is inconclusive at best, but the evidence for these other healthy practices is rock solid.
Similarly, there’s lots of advice and research from psychologists, especially those who study adolescent well-being, asserting that families who eat dinner together gain a wide variety of benefits from doing so. From an excellent Time Magazine article by Nancy Gibbs: