The study looked at how well the body absorbs iron, zinc, protein, and vitamin A from different diets in France. They found that the amount of these nutrients absorbed can vary a lot between individual diets, and this isn't just based on how much animal or plant foods are eaten. By considering the specific bioavailability of nutrients in each person's diet, the researchers found that some people may not be getting enough of these important nutrients, even if they are eating a balanced diet. This means that just looking at the types of foods eaten may not be enough to know if someone is getting all the nutrients they need.