Comment by yorwba

NIST says "in general NIST’s measurements are accurate to within 2% to 5% for nutrient elements (such as sodium, calcium and potassium), macronutrients (fats, proteins and carbohydrates), amino acids and fatty acids. Its measurements are accurate to within 5% to 10% for water-soluble vitamins (such as vitamin C) and 10% to 15% for fat-soluble vitamins (such as vitamin D)." https://www.nist.gov/how-do-you-measure-it/how-do-you-know-y...

Maybe there's something where they're off by 30%, but how many people even track how much vitamin D they get from food?