My wife has a PhD in nutrition and is also a registered dietitian. She's not on Hacker News, but she would agree with that statement. The vast majority of Amer

My wife has a PhD in nutrition and is also a registered dietitian. She's not on Hacker News, but she would agree with that statement. The vast majority of Americans are chronically deficient in vitamin D, for example. And many "Walmart-quality" supplements are so badly made that you gain no measurable benefit by taking them.