Which of these can influence riboflavin absorption in the body?

Elevated fiber intake can influence riboflavin absorption in the body because high levels of dietary fiber can bind to certain nutrients and impair their absorption. In the case of riboflavin, a water-soluble vitamin, if fiber consumption is at high levels, it may potentially reduce the bioavailability of riboflavin in the intestinal tract. This is particularly relevant for individuals who consume large amounts of fiber-rich foods without adequate riboflavin intake, as the interaction may lead to decreased efficiency in nutrient absorption.

While the other options might impact overall nutrition and health, they do not have the same direct relationship with riboflavin absorption as elevated fiber intake does. For instance, a low-fat diet does not necessarily impair riboflavin absorption and may actually contribute positively to health with the right balance of nutrients. Increased caffeine consumption, on the other hand, could have various effects on nutrient metabolism but does not directly inhibit riboflavin absorption. Lastly, a high protein diet may not affect riboflavin absorption adversely and, in some circumstances, could even facilitate better absorption of certain water-soluble vitamins as part of a balanced diet.